HELP- XT600 cuts out at 65MPH
 

Hi All,
First time poster. I have a Yamaha 1986 XT600 that cuts out at freeway speeds. Heres the specifics.

The Bike: 1986 Yamaha XT600 - 4000 original miles, completely stock. Sat for a couple of years with fuel in it.

The problem: It cuts out and sputters and misses when cruising at 60+ MPH. Cruising in town below freeway speed is fine except for a barely noticeable hiccup between gears upon throttle decrease when you pull in the clutch to shift. Idles and starts fine. Strange thing is that it accelerates STRONG all the way to 100MPH as long as it is at FULL throttle. In fact, even while you are at 60+ MPH attempting to cruise and it is cutting out and sputtering, if you give it FULL THROTTLE, it accelarates FINE with no miss right up to top speed. In fact all full throttle acceleration, idling, etc is fine EXCEPT the cutting out at 60+ MPH cruise.

So Far: I have replaced the fuel and cleaned the carburetor including the jets and slides. I have had a Yamaha mechanic clean the carb as well as drill out a plug for a "non-adjustable" jet but the same symptoms occur. They have been re-jetting but they tell me it has little to no affect on the freeway speed cruise problem.

I had thought maybe ignition but discounted that idea completely because it runs up to high RPMs fine and accelerates fine as long as it is at full throttle. It is only the 60+MPH cruise where it stumbles. A little more throttle at 60MPH has little to no effect but nail the throttle and off we go with no miss!

HELP :helpsmilie:

Check
 

I've had something similar with a '86 Tenere, which has the same carburettor, but probably a different inlet system / air filter arrangement.

Checks:
1. Make sure your air filter is is very, very clean. Is it washable on your bike? If so, wash 3x times in petrol, let dry, and oil lightly with engine oil or air filter oil.
To test the difference, test it without air filter see if the problem goes away.
2. 'Synchronisation' of the second (RH) carb. As far as I know there has been an official modification from Yamaha. The valve in the mixture channel to cil head should not start opening at 5 mm lift of the primary slide, but @ 7 mm. Adjust by putting 7 mm drill under slide LH carb, and adjust screw till butterfly valve just opens.
3. Do not touch the jetting. Yamaha is king in this, no fiddling! Use stock jets, and make sure the needles are in the correct positions:
- LH carb: needle 5C37, clip in 4th notch from top
- RH carb: needle 4A71, clip in 4th notch from top
Use the original jets.
4. Check the vacuum operated slide of the seconf (RH) carb: does it move easily and smoothly, does it return to it's rest position aftr opening?

Your problem has probably to do with too rich a mixture at constant speeds. Rereading the above, I expect the most from 1 and 4, so try them first, provided your jets and needles are at factory settings.

Auke

Work methodically!!
 

My 83 tenere did exactly the same thing!!

After many complex technical consultation with the Yamaha mechanics one thing became frightfully clear!!

We are all very often so paranoid that we immediatly assume that the most technical problem is the issue. After much discussion we too my bike andstarted at the begining of the system,fuel, clean pipes, change filter,spray carb cleaner through the fuel inlet pipe into card.

Reassemble bike , test. Problem persisted. you now know the carb is clean, so start at the other end of the system 'air' check the filter and filter box clean the both well. I found washing my filter in prepsol engin degreaser and giving it a good rinse dry and re-oil yielded excelent results!! Personally i dond feel petrol removes enough of the old dirty oil.

Do this before ajusting jets, needle and seat, etc. You will be astonished at how much a clogged up air filter influences the mixture dyamics. When blocked up badly the bike runs very rich causing major overfueling esspeially when cruising at relativly high speed. Chech your spark plug if it is very black and 'dusty' bike is running rich.

I feel only once all these step have been taken and still no improvement, then start adjusting needles and jets as those are the only things left in the equation and they are the most tricky.

Well good luck

Hope its been of some help!!

Keep us posted!

check the diaphram isnt perished or holed, this might cause the 2nd carb to behave strangely at the transitional point from full throttle to cruise position

Before taking everything apart, check if the inletstubs are still ok. They sometimes fail when a prt of the rubber piece comes off the alloy piece (and then will more or less cause what you described.)

grts,
Joris

I used to have an 89 xt600, and it had similar sounding problems after I did some work on it (Supertrapp, K&N, opened air-box, up two sizes on main jet), it would cut out at certain higher speeds.

It was a hard diagnosis, and a simple fix:

The kickstand safety switch.

Somehow, certain vibrations or something were causing the switch to cut in and out, causing me all sorts of grief.

Disconnected the switch and problems went away.

Maybe this isn't the problem on your bike at all, but I wanted to throw it out there just in case, I never did figure it out, a Yamaha parts guy fixed it over the phone for me.

Missing yamaha
 

Any time you have a diaphram operated carb (constant velocity) You have something to check. Any small hole will give you the symtoms described and sometimes the diaphram will just be altered (by age or chemicals) as in stiffer than original and cause wierd problems. Sometimes you just have to replace with a Known good unit and see it that fixes the problem.

I seem to have exactly the same problem with my XT 600 -84, except that for me, sputtering starts when cruising at speeds over 70 kph (45 mph). I would really like to know if rdelta has solved his problems in this matter, and if so, what the solution was. (I wonder if anyone will notice this post, almost two years late)

Same problem here
 

I have the same problem. It sputters a few times when driving over 90kmh at motorway, then it cuts out, but starts easily when starting again. Also it may do that when coming off from a motorway (100kmh) to the ramp. When its almost time to stop I notice that the engine isnt running and the rew light is on. Hmm I guess it may be because I adjusted the 2nd carb to open earlier. Need to put it back where it was and check without airfilter also..

Hi Ilpoj, your problem seems to bee a bit different, I think. English is not my mother tongue (as for You, I would guess), so I'm not too sure what the term "cuts out" means, but in my case the engine doesn't stop completely, it just sputters and misfires and sometimes it stops for a few tenths of a second, then it comes back again. This happens when cruising at moderate speeds (70 kph and more). At low speed and idle, the engine runs almost fine, but there are occasional misfires even then (barely noticeable). The only time it runs perfectly is when accelerating at full throttle. I believe that this is the same problem as rdelta had , only in my case the condition has progressed a bit further, and therefore I get the sputtering at lower speed and also some (very little) misfiring even at idle. I am the only owner of this bike, I bought it in 1984 brand new, and I know that the carburettors have never been tampered with. The bike has now 45000 km on the meter, 44000 of those came the first ten years. Back in those days, when I was young and beautiful, the bike was used almost every day (even in wintertime), and it always ran perfectly, at all speeds and throttle positions. Nowadays, when all that's left of "young and beautiful" is the and, the bike is only used a few km each summer, and I must confess that I've been a bad boy when it comes to draining the carburettor, so like for rdelta, the bike has been sitting a lot with fuel in it. Therefore I had the carburettors cleaned with ultrasound, but it didn't help. I checked the synchronization of the carburettors, according to Clymer handbook the secondary carb should start opening when the primary's throttle is up 5 mm. In my case it opened at 3 mm, which I changed to 5 mm but it didn't make any difference. aukeboss wrote that it is now supposed to be 7 mm. I'll try that too, but I don't think the sputtering has to do with the second carb, since it (sputtering) happens att speeds and loads when the second carb is inactive. I have run my engine while standing still, bike on sidestand (there is no sidestand (kickstand?) safety switch on my bike, there never has been) and the rubber boots from the air filter removed. If I run the engine at 4000 rpm, it sputters and misfires heavily. The primary carb's throttle is only up 2-3 mm, so the secondary carb is not engaged. If I lift the throttle of the secondary carburettor with my finger, nothing happens since the butterfly air valve of the secondary carb is closed. If I instead with my finger affect the push lever of the secondary carb, causing the butterfly air valve to open slightly, the engine tends to die, probably because it's getting too much air(?). I believe that the engine is sputtering because the air/fuel mixture is too lean, not too rich. I have noticed that if i choke the engine (using the lever on the handlebars), I can get the engine to run much better. Not perfectly, but the sputtering is significantly reduced.

Yep
 

Running the engine without the airfilter will indeed make it run lean. Remember, the airfilter is like a cork in the intake system. For obvious reasons however we need it.
The setup without the airfilter and with are not comparable, and what we want is a bike that runs fine with all the necessary accessories on.

You will never see real action from the 2nd carb without loading the engine. On only a little opening of the first carb you already will reach the red zone, so this is not a good test.

Recommend to really clean the airfilter first. Three times in clean petrol, and then lightly oiling will do the trick. Test, and then come again.

Auke

Hi aukeboss (and everyone else of course). First of all, I should say that I indeed have cleaned the air filter. Not in petrol though, since the Clymer manual warns you that "gasoline will break down the seam glue used to hold the filter together", instead I washed it a couple of times in kerosene, and then a few times in soap and warm water, whereafter the filter elements were rinsed under running warm water and left to dry overnight. They were then sprayed with Castrol foam air filter oil as I put the filter back together again. The sputtering problem was the same both before and after cleaning the air filter (the filter wasn't very dirty). Since I have had this bike for rather a long time, the air filter has grown dirty and been cleaned many times before, and I have never had any sputtering/misfiring, or for that matter noticed any difference in the engines behaviour before and after cleaning the air filter. I see what You mean about the engine running lean without the air filter and that testing without load isn't ideal, but since the sputtering is the same when testing it like this as when you're riding the bike with the air filter connected, I still think it has some relevance. Besides, if the air filter was the problem, wouldn't there be a (large) difference between running the engine with or without air filter? The sputtering and the effect of choking the engine is the same whether the air filter is used or not. Or could it be that with the air filter, the engine gets too little air, and without the filter it gets too much, causing the same behaviour in both cases? Personally, I believe that the problem has something to do with either that the bike has been left unused for long periods (with fuel in it), some years it hasn't been started at all, or simply aging of some components (o-rings maybe, or the rubber on the intake manifolds or something like that). I don't think it has to do with wear, because the problem has turned up in the latest ten years, first very subtilely, then accelerating each year, and during these ten years the bike has hardly been used. All input is welcomed though, so don't hesitate to post.

If you had an airflow delivery issue to your carb (blocked air filter etc) you would be running too rich. Adding choke would make it worse. Since the engine runs better with choke on I would surmise that you are indeed too lean.

I think the clue here is that you let the bike stand for long periods with the fuel still in. This can create two possible problem areas that I would suggest you have a look at.

First off. Petrol when left standing can create a wax like residue that can collect around parts such as the jets and float chamber which will inhibit fuel flow----> lean

Secondly, modern petrol has a higher alcohol content than that which was used when the bike was designed. It may be well worth your while to check the state of your rubber components within the carb for perishing (diagphrams O-rings etc). Even if the fuel alcohol level is within the manufacturers tolerance level, alcohol is corrosive to these parts none the less.

Thirdly, and perhaps something you should check first...is your float level set correctly? If you think you are running lean that is always the first check before carb dissasembly.

My 94 XT600 had the exact same issue. It was a combination of ethanol in the fuel creating issues and float level problem. Once the fuel issue was resolved with an additive, the needle was replaced and all is running well now. Most fuel in the US has at least 10% ethanol in the mix.(at least in Northeast USA) Starting to be a big problem for some boats & bikes. Try replacing the needle and see if that helps. Worked for me.

My 89XT had similar problems. It would just die while riding, mostly when going "faster" rather than slower. I cleaned the carbs twice and no improvement. Air filter cleaned and no improvement. Finally opened up the petcock and there it was...GUNK around the petcock. Cleaned it and it's been running nicely since ... knock on wood!

86 XT600 sputters also
 

I have the exact same problem as the original Poster of this thread.
If I ride on trails, it is just fine. If I keep the speed under 50, it runs fine.
If I take it over 50, and try to maintain a steady speed, it starts sputtering. If I give it a little gas, the sputtering stops, and I accelerate. It only sputters when trying to cruise at any speed over 50 mph.

What I've done.
Rebuilt the carberator, and taken apart several times to clean.
Cleaned the air filter

The needle has no adjustment on it. So maybe a new needle might do the trick, as I think that should only cost about $10.

One more thing that I've really noticed, is the gas mileage is horrible. I think I only get about 35 mpg. I can fill up the tank completely, and I know when I get close to going 100 miles, I'm just about out of gas. It has the stock tank, and this is while driving in the city to my work. I'm thinking for a one cylinder, the gas mileage should be a lot better than my Honda Accord.

If anyone else has any solutions, or suggestions, please post.
Thanks,
Craig

sounds a bit like what i was having happen on my 03 xt cleaned carb new filter even had it on the dyno.still no improvement so did a compreshion test and it was well down .the top piston ring was worn .

I had a XT600 would run fine untill you tried to cruise at 60mph after about 10 minutes engine would stutter and surge like it was running out of fuel, sometimes it would accelarte past this but then start to surge again. If I stop and let engine cool it would run fine until you tried cruising at 60mph for more then 10 minutes.
It turned out to be the pick up coil breaking down when engine got hot.
The easy way to check is get a complete generator and pick up from a good friends bike just swap the complete side case.
I could not get a pattern pick up for my 3AJ same as 1VJ so had to use second hand one, Yamaha only sell the pickup with the generator about £400

1vj cutting out
 

hello on my bike i had great difficulty getting it to run at slow speeds so i cleaned out the carb and put the petrol pipe straight to the carb from the lh petrol tap to eliminate the pump and i noticed i had very fine fumes leaking from the rubber seal which seals the float bowl on carb i think it had gone hard after 20 years so i got a new one from yamaha fitted this and it run ok at low revs and through the range because before this if opened the throttle it would suck air in and cut out unless full throttle and it would rev ok once i sorted carb out i put petrol pipes back to how they should be and it now runs ok .

Last time that happened to my 1990 XT600E it was nothing more than and obstruction above the needle. That caused the bowl to run out of fuel in moments of high fuel consumption (above 60MPH).

When I took it apart, that little white screen above the needle valve was packed with crap up to the fuel inlet. So I took it out and threw it in the trashcan.

Now I always use an inline filter and no problems yet.

thanks for suggestions
 

I'm going to check my compression then. I'll post if this fixes the issue.

It does not sound like the coil, as the sputter happens right away when I hit 50mph. It is a California model, and I live in Colorado. The previous owner did have it jetted, but maybe not correctly.
I've cleaned and rebuilt the carberator, with no change.

This is very fustrating. I like everything about the bike except for this sputtering. Just about ready to sell it if no fixy.

1984 Yamaha XT 600 high rpm cutting out/sputtering
 

Hi All,

I'm new to this site, so bare with me!

I have a 1984 Yamaha XT 600 that I got free. Bike was sitting in a back yard in weeds for about 3 years. I massaged it back to running order. Pulled the carbs and rebuilt them, fluid changes, replaced plug, etc.... I'm very mechanical. The bike misses and sputters at 3/4 to full throttle accelleration. I can even pull in the clutch and it will continue to miss/sputter as if it has a rev limiter. I can't figure if it is starving for fuel or it is an electrical issue. The bike has a Super Trapp and I went up 2 main jet sizes on both carbs. Checked the vacuum diapham on the secondary - good shape. No fuel restrictions of any type..... fuel system is clean! The plug and Super Trapp are somewhat black, showing plenty of fuel.... maybe a little on the rich side. I've had this problem prior to enriching the fuel carberation. The kick stand switch has been disconnected and bypassed. Any Ideas are greatly appreciated.

Me Too!! Same as the 1st poster.
 

I purchased a 1986 xt600 with 15,000 on it. Although I haven't yet really cleaned the air filter, I did have my carbs professionally cleaned with no noticeable effect. Later, I ordered a second set of carbs from fleabay. I put them on and...vroom! Smooth sailing at high speeds! The second set was from an '86 TT, and aside from the choke setup, the carbs look like they are the same.

However: the butterfly on the 2nd carburetor on the replacement set was adjusted to open much later than what I had before. Also, there was a plug that had been drilled out, exposing an adjustment screw. Interesting note: When I had my 1st carbs cleaned, the mechanic was surprised that the plug had not been drilled out to expose the screw.

Today, I adjusted my original set's 2nd carb's butterfly to open like the replacement set, and went through the effort of switching them out again. It did not solve the problem. I don't know everything that has been done to the replacement carbs, but I am sure the answer lies in the carburetors.

Something extremely tedious that could be helpful to clue into the solution, is to run the bike at the cursing speed and let it sputter. Then, hold in the clutch and flip the kill button; don't let the bike back into gear until it comes to a complete stop. Then, remove the spark plug and inspect it. If it is white-white, that means it's too lean. If it is blackish, then it is running too rich.

If I learn the secret key to this problem, I will post. If anyone knows more about this, please, please post. :ninja:

Check the resistence readings on your ignition source coils as well as the pick ups.
i've seen several running issues disappear since getting mine rewound.

XT600 dies after 60 mph
 

I have read a couple threads regarding this issue. I would just like to make my case known and see if there are any similarities with my motorcycles problems and if there are any solutions.

I have a 1994 Yamaha xt600, I bought it just recently, I have no idea what any previous owners have done to it. However, upon buying it I proceeded on a whole slew of TLC for the bike. I cleaned the air filter, cleaned the carb (mostly, I couldn't get the float pin out), changed the spark plug, and changed the oil.

Ok, so now the issue. I take my bike up to 60+ mph either taking it easy getting it up there, or going full throttle. Both ways, once I am cruising in 5th gear it seems to do just fine for the first little bit. Then it will do one of two things, start to sputter and slowly lose speed as I am getting no horsepower. Or, it will go a little further but when I accelerate past 1/4 throttle it will start the sputtering thing. When either situation occurs it sputters and loses speed and sounds on the verge of dying all the way till either, it dies, or I have been able to downshift enough without it dying that it picks back up again. Both times I pull to the side of the freeway embarassed going slower and slower. If it dies I can always start it right back up right away. It feels almost like it is running rich, but I when I took out my spark plug it was mostly whiteish like it was running lean. I do have blackness on my exhaust (super trapp) which leads one to think it is running rich.

I was thinking maybe the side stand switch would be the next best bet, but this sure doesn't appear to be anything electrical related. Especially since my bike will stutter all the way down to 25 or 30 mph before it comes back. So after that my next option is a rebuild of the carb (with the diaphram included?) So I just need to find a good kit for this or get hosed by the Yamaha repair shops.

Any input on this is greatly appreciated!

Now this is a long running thread.
It would be great if those that have resolved their issues could post their resolutions!
Just to add my 2 cents worth.
I've had a few XT's over the years and a few other various motorcycles.
But XT's.
I recall once on a road trip on the XT550 would run fine but once I tried to sustain my revs over about 4000rpm for longer than 3-5 minutes it would begin to surge and lose power. Being on the road I didn't have too many tools at hand but I did have a phillips screw driver, I did the obvious things like drain the carby bowl etc.. and I disassembled the fuel cock. In it I found a nice piece of compacted fluff. It was probably the best fuel filter I could have had as it was full of those nasty bits you don't want in your carby. Anyway removed the fluff and all was good.
Another XT 600 I owned would occasionally missfire when HOT. Only when hot, really hot. This issue went from an occasional missfire to an occasional cut out to eventually I would have to push start it, at which time it would fun very poorly. It was an issue with the pickup. I never did solve this as a fellow bought it before I fitted the part.

Always wondered if he managed to get home on it. He was a German fellow who was going to ride it around Australia. (If your there I hope it went well)
Anyway I'll stop my ravings now and finish my beer..

Resolutions? I have a 1984 Xt600 with the same issues... Hope it wasn't formerly owned by one of the previous posters! :blink:

If anyone has had a chance to lock down the issue, please do share. I've replaced the air filter with a brand new UNI filter and upped to a 130 main jet which helped at idle but the sucker still doesn't like to run without a choke on then pops on decel when cruising at 50MPH and then dies. Easy to restart as stated above but embarrassing as all get-out. :blushing:

I'd like to say I could read the plug but I have a slight oil leak at a valve seal and that makes the plug always read "shiny, wet and black" (yeah I know Mom, I'll get around to fixing it soon.) :rolleyes2:

Any new developments? it would seem everyone is out riding and forgot about the forum or sold their scoots and don't care anymore...

Things wrong with my bike:
-I know previous owner tore out some of the stock muffler baffling
-I have a Uni filter installed. (stock one was AWOL)
-Kickstand switch bypassed.
-Slight oil leak from a valve seal

Things I have tried:
-Added a inline fuel filter and cleaned tank and carbs
-replaced ignition coil with universal unit thinking a cracked coil was acting up when warm
-replaced jets, air screw, carb o-rings & gasket, needle valve and the seat (with filter still on) all with new OEM parts.
-Replaced all fuel lines with new hose and clamps. (except long breather that goes up to the tank.)

Things I might try soon:
-Replace enrichening diaphragm
-Replace secondary carb diaphragm
-drink beer until the problem stops bothering me

:eek2: Ok, so I have been cheating and looking at other forums for other makes of thumpers and they mentioned the vent hose that attaches to the tank can get clogged and it could cause similar sounding symptoms. Also I know my muffler is more open than it should be so I will attempt 2 experiments to see if I can remedy the issue. :detective:

1: I will replace the vent hose with known good hose and inspect it for blockage (did I mention when I got the xt600 it had a rust problem in the tank?) I figure that could cause it to starve itself of gas theoretically when the throttle is released and the enricher diaphragm kicks in and leans the mixture, and the vacuum line being clogged doesnt allow the main jet to suck enough gas to keep her running... (just a guess since I'm new to the carb game, please correct me if I'm wrong.) I will post results by Monday.

2: I will also see if restricting the exhaust using my welder and tack welding some washers to the tailpipe makes a difference. I'll only do this if the first experiment proves unfruitful because I know my Xt600 needs some back pressure or a bigger jet due to fuel/air screw tests.

I know I'll actually post on this again because I'm a desk jockey and will be in front of the computer again Monday... and either be excited or pissed given the results of tomorrow's tinkering

Mainjet has little effect on the idle!

bike dieing on idle a popping sure sounds like either the PILOT jet is clogged or it isn't big enough!

good luck!


Vando

UPDATE!

First I want to clarify, When I said "main jet" I meant the one in the bowl, I was unaware the other jet on the secondary carb is also called a "main jet" on sites like bike bandit, I'm sitting at 130 in the bowl right now.

So the popping was due to a lean condition I went through the bike to look at every possible angle for leaks... and found one right at the snorkel that attaches to the top of the airbox. doh Wow, what an idiot I can be. That fixed I took it for a spin: no more lean issues. So I learned to be careful to seat that fully when I clean the airbox next time.


That took care of the lean condition and I was able to turn the air-fuel screw in to factory specs again (2-3 turns). But the bike still dies at highway cruise speeds. I replaced all of the fuel lines previously with clear lines. I noticed a crap-ton of bubbles in the fuel line after it died on the highway. If I unplugged the vent line that runs up to the tank, bubbles disappear and fuel flows as usual.

I don't know what its called specifically and its not shown on the parts diagram but the black screw in "tank vent valve?" on the bottom of the tank looked suspect. I replaced the line running up to it and the problem persisted. The valve deal was dirty looking and I noticed it has a check valve or something inside of it and rattles if shaken. I tried to blow it out with no luck. (valve apparently works) but when I tapped it on a paper towel there were black flecks that came out. I couldn't try it out again today as the weather turned shitty again.

Has anyone else had issues with tank venting etc or know of any fixes?

Found the name of the questionable part. It was apparently a California model and it is called the "roll over valve" and is part # 20 on the California tank diagram. WTF I hate California stuff. I;m off to research how people bypass this garbage.

OK, so California models suck. Literally, the clogged "roll over valve" that goes from the tank to the canister was causing a hardcore vacuum in the tank and making gas and air evacuate the carb bowl. This "roll over Valve is listed at #26 on this diagram:
1984 Yamaha XT600 (CA) XT600LC Parts, 1984 Yamaha XT600 (CA) XT600LC OEM Parts - BikeBandit.com
The previous owner just removed the canister and plugged a long piece of fuel line from the broken roll over valve to a nipple on the carb just above the Fuel line nipple. "Thar's yer problem..." I just removed the roll over valve entirely and it will just act like a vented tank now I'll eventually try to put a one way valve on there like they sell for MX bikes to let air in but no gas fumes out. in the winter when I store it I will WD40 an empty tank or fill it with gas and add stabil to prevent rust from condensation.

The scoot will run with that nipple on the carb plugged or unplugged. It just makes a sucking noise like "ffuff fuff ffuff" as you go down the road. This leads me to believe that dirt could get sucked into my carb bowl... so I'm going to cap it off. pretty sure thats a safe bet as the parts fiche doesn't even show the nipple on the carb.

So if you have stumbling issues at highway speeds make sure its not due to crappy California emissions gear that is faulty/improperly removed. I made sure this fix was repeatable and sound advice. I put the parts back on and the fuel line to connect them and it caused stumbling EVERY TIME. Take it off and it stopped EVERY TIME. Also make sure you're not lean due to your airbox snorkel coming off under your seat as I'm sure that was not helping the troubleshooting process. doh

fuel problem
 

Hi GUYS MY BIKE IS CUTTING OUT AT HIGH SPEED WHO CAN HELP

Decompresion
 

Hi guys what are the chance that it is the decompressing lever in the cam that can cause the bike to cut out at high speed

Clean out the filter in carb. Under the fuel cut off valve.

I have an 86 xt600s and when I first got it I had the same issue the cutting out at high speed and was also rough to start the previous owner had installed the wrong spark plug! The plug installed wasn't the recommended plug and had the wrong heat rating (not hot enough) not saying for sure that you guys have the same issue just wanted to throw it out there

Sent from my HTC6535LVW using Tapatalk

1990 XT 600 dying
 

Hello, I realize this is an old thread.

I have a 1990 XT600. I've had it for 3 years and it's never given me any problems. I am not sure if it's a California model. I think its just an EA.
Yesterday morning it started acting like it wanted to die while on the freeway connecting into town. I was going 55mph at the time but as I got into town the speed limit was only 35 and it continued acting as it wanted to die. I would pull the clutch in and it would die, I'd pop the clutch out and it would start but keep cutting in and out. I coasted into a parking lot and it died. It started right back up and I made it to work. On the way home it did the same thing. So where would I look for something that would cause the engine to die intermittently? Coil? Some sort of sensor? Kill switch making intermittent contact with handlebar? I've searched the Internet for other having this issue and this was the only information I've found so far.

I suspected the kick stand sensor so I kicked it a few times while riding and nothing happened.

Thanks for your help.

Yes you can check the switch on the sidestand first, but i think its time to do a clean of carb. Iam thinking the filter inside carb is clugging up from rust, check tank and see if filter inside is still there.

Thanks xtrock
 

I will check those things. Hope that's it. :-)

Hi if it depends on the throttle mosition its carborator. I had simular problems enging shuting down at 50 km/h caused by a broken regulator. At too high voltage the CDI switched of for emergancy: Engine of at 50 km/h.
Good luck!

Thanks TA-Rider
 

Thank you TA-Rider. That's good info.

Just injecting some new life into this thread....

I had this problem - bogging at 4500rpm - and limped home some 600km from Aachan to London a few weeks back, in the slow lane.

After cleaning everything else, switching inlet manifold rubbers etc I finally got to underneath the valve seat as above today and found a small nest of s**t under there.

Cleaned out, problem solved and celebratory fish and chips consumed.

Hat tip to Ted