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-   -   Yamaha XT 600 single carb + KTM shock - How it was made (https://www.horizonsunlimited.com/hubb/yamaha-tech/yamaha-xt-600-single-carb-77386)

Svaneberg 21 Jul 2014 22:02

Yamaha XT 600 single carb + KTM shock - How it was made
 
Starting point: A Yamaha XT 600 3UW year 1993.
A picture says more than a 1000 words, so there will be more pictures than words in this thread (I’m terribly sorry about the quality of some of the pics. Apparently I chose to use an extremely crap camera).

Preparation:

http://s21.postimg.org/6ieiv4xav/image.jpg
http://s14.postimg.org/urkjfy0z5/image.jpg
http://s14.postimg.org/ibntm77n5/image.jpg



Welding of re-enforcement (A good part of the metal that sits between the 2 vertical frametubes where they meet the ”spine” had to be removed to facilitate the carb. Furthermore I had to move the upper shock mount approx. 5 cm back to make room for the air inlet tube):

http://s14.postimg.org/in59yyo35/05t.jpg
http://s14.postimg.org/n7rgdw7sh/image.jpg
http://s14.postimg.org/fwvy1rre9/image.jpg
http://s14.postimg.org/qxr36sjn5/image.jpg
http://s14.postimg.org/y140jive9/image.jpg
http://s14.postimg.org/t017vwdbl/image.jpg


My homemade manifold. I initially bought a 2-1 manifold from a Grizzly, but it was way too long and the carb would be located too long back. Furthermore the manifold bending made the carb hit the startermotor.

http://s14.postimg.org/klgzu2mwh/12t.jpg
http://s14.postimg.org/5um7w5isx/image.jpg
http://s14.postimg.org/519m3jcs1/image.jpg
http://s14.postimg.org/7jvb47yi9/image.jpg


Carb in place:

http://s14.postimg.org/6y6c843g1/18t.jpg
http://s14.postimg.org/53thqdgfl/image.jpg
http://s14.postimg.org/d0dyylrw1/image.jpg
http://s14.postimg.org/6nytorott/image.jpg


Mounting of the KTM LC4 rear shock:

http://s14.postimg.org/dfp8rmdtd/23t.jpg
http://s14.postimg.org/778ibs5m9/image.jpg
http://s14.postimg.org/rc22h8zg1/image.jpg
http://s14.postimg.org/po2x2llkh/image.jpg
http://s14.postimg.org/vdj5mwrqp/image.jpg
http://s14.postimg.org/8emg3zvqp/image.jpg


I had to fabricate a new inner fender as i’d removed the airfilter/batterybox :

http://s14.postimg.org/g0zesvskx/31t.jpg
http://s14.postimg.org/y8w8trvqp/image.jpg
http://s14.postimg.org/tqty1ofox/image.jpg


An airfilter is also needed:

http://s14.postimg.org/fpmjtv1ip/34t.jpg
http://s14.postimg.org/nskq56m41/image.jpg


A few pics where I show the original shock mount:

http://s14.postimg.org/otkyub33l/image.jpg
http://s14.postimg.org/vp57dexkh/image.jpg

rndef 21 Jul 2014 22:08

Would luv to see it but we can't see the pics!

Svaneberg 21 Jul 2014 22:25

Crap :censored: Will see if I can get them pics posted right tommorow. Too damn tired :(

Svaneberg 22 Jul 2014 07:54

Yamaha XT 600 single carb + KTM shock - How it was made
 
Hehe yearh you're right. Although it actually worked on the preview. The pics are uploaded to docs.google.com and retrieving the links was a nightmare. I'll try to upload them somewhere else

Svaneberg 22 Jul 2014 08:42

Now the pics should be showing :D

nickargas 22 Jul 2014 09:14

Quote:

Originally Posted by Svaneberg (Post 473843)
Now the pics should be showing :D

what kinda air filter did u use for the carb dude?
now we are expecting to see a vid or something man :P

Svaneberg 22 Jul 2014 09:24

Just a k&n clone from a car. What I had lying in the workshop

Svaneberg 22 Jul 2014 10:34

First start-up with the Carb. Bike has now done 3000km since and has been tuned in:


https://www.youtube.com/watch?v=Q_A7...ature=youtu.be

nickargas 22 Jul 2014 14:14

Sounds amazing... can't wait to put mine on!! Your Carb is a mechanical moving Carb right?

Svaneberg 23 Jul 2014 16:40

Yamaha XT 600 single carb + KTM shock - How it was made
 
Yepp. A Keihin fcr 39 flatslide with accelerator pump (which is not working on the vid. That's why it stalls when I give it fast full throttle. It,s now fixed)

nickargas 24 Jul 2014 12:35

If mine doesn't work properly u will hook me up with one too? :D:D:D

nickargas 24 Jul 2014 12:44

By the way do.u have detailed measurements? Did mine with a ruler so they're not accurate...

Svaneberg 25 Jul 2014 15:00

Actually I also just used a ruler and a Dial caliper. Use a piece of papir and draw up the intake mounts and holes on the paper. Then transfer the Drawing to a piece of metalplate approx. 5mm thick and build it up from there

nickargas 16 Aug 2014 06:27

http://youtu.be/3B8oBMBV7LY just converted mine... whole day yesterday I was trying to adjust the carb... I've got some un burnt gas and when I open the throttle really quick sometimes it lags... smaller fuel jet maybe? I've opened up the Carb and put the the omega safety on the top notch on the needle...

Svaneberg 16 Aug 2014 11:22

Yamaha XT 600 single carb + KTM shock - How it was made
 
Bravo. Good job :). I see you Got the manifold mocked together. What carb are you using? Remember to only tune one thing at the time :). How much did you have to alter the frame? It sounds on the vid That you have some piston or valve rattle. Jakob

nickargas 16 Aug 2014 11:42

Yeah man it's the valves... I've adjusted them as the manual said but here in Crete is too hot and they need to be readjusted... didn't alter the frame at all....I'm using a dellorto phm 38mm mechanical carb... the bike is completely different... its like riding a Duke 2

Svaneberg 16 Aug 2014 12:04

Nice :) the dell'orto is pretty tough to Dial in for idle and medium throttle. But it rocks at full throttle :). The bog you are experiencing is due to lack of acc pump. When you WOT the vaccuum isn't high enough to draw fuel fast enough. That's why most mechanical slide (round or flat) carbs use an acc pump :). Do you have Any pics of the mounting process? Jakob

nickargas 16 Aug 2014 13:04

Acc pump ? Which one did u use? Is that way I get so many un burnt fuel and some lags? My idle is ok I guess... in the middle revs is most of my problems .. wot? What's that?

nickargas 16 Aug 2014 13:05

Will take some photos for u yeah!

Svaneberg 16 Aug 2014 13:45

:)I use a Keihin FCR39 flatslide carb :) yes my guess is that's why you have the lags as the vaccuum drops when you twist the throttle (WOT=Wide Open Throttle) therefore not being able to draw fuel fast enough. That's why an accelerator pump is added so it pumps fuel in the manifold when you twist the throttle Quick. :)

nickargas 16 Aug 2014 14:07

Oh ok!! I know u have a fcr 39mm man! I was asking to know which acc pump are u using lol!!!

Svaneberg 16 Aug 2014 21:46

Arh ok. The acc pump is build into the carb :)

nickargas 17 Aug 2014 06:27

Didn't know fcrs' had acc pump! Maybe dellorto has one too? What does it look like?

Svaneberg 17 Aug 2014 08:59

Nope. Dell'ortos don't. Just try to Google "accelerator pump fcr 39" or similar :)


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nickargas 17 Aug 2014 09:14

I'm gonna keep it for a while and then trade it for a fcr and cover the difference

nickargas 17 Aug 2014 10:52

I forgot to ask... what pulse did u put on your vapor jakob? I think my rpm is a bit off...

Svaneberg 17 Aug 2014 12:12

Yamaha XT 600 single carb + KTM shock - How it was made
 
I spliced into the orange wire going from the TCI to the ignition coil. You need to use the wire with 1k resistance. Otherwise the rev counter will Go nuts. Jakob


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nickargas 17 Aug 2014 15:33

I just did what the manual said and wrapped it around the cable that leads to the spark plug but it does not work properly...

Svaneberg 17 Aug 2014 15:35

Yearh. That's what I experienced too. That's why I spliced into the orange wire :)


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nickargas 18 Aug 2014 07:14

How about the temp sensor? When I put it in the spark plug I can't fully bolt the spark plug because the cable is in the way...

Svaneberg 18 Aug 2014 07:15

I'm not using the temp sensor, but a suggestion would be to Mount it on the oil bolt on the right side Engine cover :)


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nickargas 18 Aug 2014 10:15

I.just put mine on the hangar below the bolt for the oil, on the frame... via heat transfer it shows me the engines temp... p.s. still can't believe this is an xt... it sure goes like a Duke 2 man!! Thank you for the inspiration jakob! Single Carb works wonders...will take some photos and I will upload them on dropbox or imageshack for you as promised man! Would be very happy if we ride together once!

xtrock 18 Aug 2014 10:43

so what you have on 0-100km/h?

nickargas 18 Aug 2014 11:30

Don't know xtrock... haven't timed it or dyno it... I will make a new video for u as promised wearing the head band so u can check the vapor tacho for the speed and the time... what mechanical mods have u done to yours xtrock?

xtrock 18 Aug 2014 11:40

Quote:

Originally Posted by nickargas (Post 476722)
Don't know xtrock... haven't timed it or dyno it... I will make a new video for u as promised wearing the head band so u can check the vapor tacho for the speed and the time... what mechanical mods have u done to yours xtrock?

So far i only have the KN filter, new exhaust all the way, dynojet kit stage 2. It runs perfect all the way, no missfire and pulls very good on all gears. Have standard 15/45 i have tried the 14 but didint like it, to short on 1gear.

nickargas 18 Aug 2014 19:22

Had the same on mine prior to the conversion.. plus my exhaust is custom made with a bigger fmf powerbomb... the.difference is staggering... I took a video for u but camera was tilted a bit high... will try again for u tomorrow man...

xtrock 18 Aug 2014 20:07

Quote:

Originally Posted by nickargas (Post 476771)
Had the same on mine prior to the conversion.. plus my exhaust is custom made with a bigger fmf powerbomb... the.difference is staggering... I took a video for u but camera was tilted a bit high... will try again for u tomorrow man...

Sounds great, i guess you now have the xtra power we all want.. What is the cheapest carb for this?

Svaneberg 18 Aug 2014 20:12

The easiest and cheapest Way is to use the carbs from a raptor (2 parallel carb setup). The Best single carb is IMHO a keihin FCR 39/41. Alt. A mikuni TM 40.


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xtrock 18 Aug 2014 20:48

Quote:

Originally Posted by Svaneberg (Post 476778)
The easiest and cheapest Way is to use the carbs from a raptor (2 parallel carb setup). The Best single carb is IMHO a keihin FCR 39/41. Alt. A mikuni TM 40.


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Ok thanks, the difference from stock is that you get two carbs and not the vacuum slide?

Svaneberg 18 Aug 2014 20:54

Well. If you Go for the raptor setup you'll actually get 2 parallel working cv carbs (vacuum slide) instead of the oem 1 mechanical/1 vacuum. The single option Can be both vacuum (bst 40) or mechanical (fcr/tm/PHM). The fcr and tm will incorporate a accelerator pump. Jakob


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xtrock 18 Aug 2014 21:02

Quote:

Originally Posted by Svaneberg (Post 476785)
Well. If you Go for the raptor setup you'll actually get 2 parallel working cv carbs (vacuum slide) instead of the oem 1 mechanical/1 vacuum. The single option Can be both vacuum (bst 40) or mechanical (fcr/tm/PHM). The fcr and tm will incorporate a accelerator pump. Jakob


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Yes i see now on pic that raptor have 2 slide, why will these give more power than original?

Svaneberg 18 Aug 2014 21:08

Well because the work parallel as oposed to the oem which only work the left carb up to approx. 1/3 to1/2 throttle thus only letting fuel mixture in through the left intake valve. With the parallel setup you get fuel mixture in through both valves from idle on.


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xtrock 18 Aug 2014 21:27

How about the handling of the bike with this new carb in like winter/ offroad where you need a gentle steady low rpm? iam thinking thats why they made the bike with this second carb when rpm is rising? http://www.tenere.co.uk/forum/viewtopic.php?f=14&t=1126

Svaneberg 18 Aug 2014 21:38

Mine is handling very Well due to the slide being only partly open under low rev. For an explanation of the oem vs single setup see Here:

The general issue is that the smaller carb areal, the better low end torgue. Thats why Yamaha designed the dual carb on the XT. Running to approx. 1/3 throttle only activates the 1st carb for better low end as the air vacuum in the manifold is low and therefore, it cannot draw from a, let's say 39mm carb as the vacuum is too low and the engine will bog. As the throttle is opened more and RPM and therefore vacuum increases, the second carb (vacuum controlled), is activated, thus giving more air/fuel mixture to the engine.
This setup has definately it's advantages, however also some disadvantages: When running up to 1/3 throttle (only 1st carb engaged) only the left intake valve is getting air/fuel mixture thus getting cooled by fuel. The right intake valve is running "dry" making it extremely hot. Furthermore you don't have the advantage of 2 valves at up to 1/3 throttle.
With the single carb (in my case FCR39) you have the slide acting as a variable sqare areal so you will get the same function as with the original dual setup. However when you do WOT or close from almost closed throttle/low engine rpm, the wacuum in the manifold isn't high enough to draw the extra air/ful mix needed and the engine will bog. That's why the carb needs an accelerator pump to give an extra squirt of fuel when WOT. The original dual carb doesn't need that as the 2nd carb is a vacuum controlled carb and therefore the slide won't lift until the vacuum is high enough. Conclusion - using a single AP carb will utilize both intake valves from engine start and also won't need to "wait" for vacuum to build up. Result is much quicker respons.

Br
Jakob


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xtrock 18 Aug 2014 21:59

Is the raptor 660 carb bolt on for the 3TB?

Svaneberg 19 Aug 2014 06:52

It should be more or less. Try a search in the threads. I'm sure I Read somewhere That somebody did it :)


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nickargas 19 Aug 2014 15:00

Do you know if fork springs out of a 3tb will work on an 2003 model xtrock?

xtrock 19 Aug 2014 15:59

Quote:

Originally Posted by nickargas (Post 476857)
Do you know if fork springs out of a 3tb will work on an 2003 model xtrock?

Dont know if they made changes on the fork, just measure and you will know. I have original springs if you need measurements.

nickargas 19 Aug 2014 16:28

Naah its ok... will replace them anyway because they were made with the technology of late 80s... thanks for the offer... tried to take a video yesterday for you but there was a lot of traffic and I couldn't open it up properly... all I can say is with 15/45 gears I reached 127 kmph in 4th...and with a digital tachometer none the less that its pretty accurate... don't have a fork stabilizer and I have a lot of vibrations man... kinda dangerous but I will get on the highway for you and try again...

xtrock 19 Aug 2014 16:53

Quote:

Originally Posted by nickargas (Post 476868)
Naah its ok... will replace them anyway because they were made with the technology of late 80s... thanks for the offer... tried to take a video yesterday for you but there was a lot of traffic and I couldn't open it up properly... all I can say is with 15/45 gears I reached 127 kmph in 4th...and with a digital tachometer none the less that its pretty accurate... don't have a fork stabilizer and I have a lot of vibrations man... kinda dangerous but I will get on the highway for you and try again...

Well its not like you have to ride suicide misssion to make video ;) If you make one 0-80 its ok, thats where the fun is in city riding.. I have the progressive springs in front and they are really good! http://www.ebay.de/itm/Wilbers-Gabel...item4adaa7d2dc

xtrock 19 Aug 2014 17:51

Have been checking out a little with the raptor carb and seem hard to find some in good condition, these raptor machines have been abused in desert/dirt all the time. I quess the ones that are up for sale are sold for a reason, buy a problem i think. And how many hours they have been running is impossible to find out. Price with shipping and taxes will end on 350dollars + kit for overhaul it.

nickargas 19 Aug 2014 19:09

Ok man... the video I took yesterday was up to 83 kmph so I will upload it asap and send u the link man...

xtrock 19 Aug 2014 21:12

Quote:

Originally Posted by nickargas (Post 476888)
Ok man... the video I took yesterday was up to 83 kmph so I will upload it asap and send u the link man...

Great thanks man! Is it possible to lift 2gear for wheelie?

nickargas 19 Aug 2014 21:13

With clutch yeah

nickargas 20 Aug 2014 06:10

http://www.ebay.com/itm/2x-Wirth-Gab...-/331295466088 thinking of buying those... wirth or promoto?

xtrock 20 Aug 2014 19:26

Did you post the video? How about if i use two orignal carbs, remove the vacuum and use two of the first carb? would it be better ?

nickargas 20 Aug 2014 20:01

Copying both vids now... one is my first ride after 5 years and second one is the one with 0-83 I took for u

nickargas 20 Aug 2014 21:03

Xt600 messing around: http://youtu.be/IVLpujh5tXI

xtrock 20 Aug 2014 22:35

Quote:

Originally Posted by nickargas (Post 477014)
Xt600 messing around: Xt600 messing around - YouTube

impossible for me to count sec from 0-80 on this video, better if you check time next time you ride.

Svaneberg 21 Aug 2014 08:25

Yamaha XT 600 single carb + KTM shock - How it was made
 
Quote:

Originally Posted by xtrock (Post 477004)
Did you post the video? How about if i use two orignal carbs, remove the vacuum and use two of the first carb? would it be better ?


If you set up 2x 1st carb(the mechanical one) to open simultaneously and get the jetting right it should work better than Stock. If you use the 2nd mechanical carb as the "kick in" like the oem vacuum carb, I don't Think you Will gain anything other than jetting issues as you still only Will be feeding the Engine through 1 valve at up to 1/2 throttle. Jakob


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xtrock 21 Aug 2014 11:29

How about the accelerator pump, i then have two and no place to fit the hoses? Fuel supply, is it ok to feed from bowl nr1 or do i have to get fuel diretly to both?

Svaneberg 21 Aug 2014 15:55

Both needs to be fed in the bowl, both needs to have same float height, jetting needs to be the same for both carbs and you won't have the advantage of an acc pump


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Svaneberg 21 Aug 2014 15:57

What i'm saying is: if you use cv carb you're good, if you use slide carb (mechanical) you need an acc pump :)


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nickargas 21 Aug 2014 20:40

Jakob progressive springs or just plain harder springs? I wanna convert it into supermoto later and I'm between promoto progressive spings or wp harder springs for the fork... whats your opinion?

Svaneberg 21 Aug 2014 21:29

Depends. Do you want hard damping from fully stretched forklegs or a more soft damping which hardens the more the legs compresses :) I you WP straights in my fork.


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xtrock 21 Aug 2014 21:41

Quote:

Originally Posted by Svaneberg (Post 477107)
What i'm saying is: if you use cv carb you're good, if you use slide carb (mechanical) you need an acc pump :)


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What iam thinking about is the vacuum hose from carb 1 that comes into opening to carb 2. Maybe this is not a acc pump?CV carbs here dont have fuel bowl.


If you look at this its inside part 24, from this the hose is going to carb 2 opening. 1993 Yamaha XT600EE Carburetor | Yamaha Sports Plaza

Svaneberg 21 Aug 2014 22:02

The oem setup does not have an acc pump. The item 24 you are referring to is a coasting enricher which prevent popping in the exhaust when you close the throttle due to air/fuel mixture being too weak. The cv uses carb 1's float Bowl as it only needs to draw fuel through one jet.


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xtrock 21 Aug 2014 22:18

Ok, but what to do with this hoses if i use only mechanical carbs?

nickargas 22 Aug 2014 05:00

Jakob I want good brakes and when I brake I want not to lose traction due to damping... but our roads here in Crete are full of puddles and very shitty... can I get somehow the best between those two? If u check the link of the wirth springs u can see that the springs are both fatter (hard damping ) and they are progressive too... that's why I'm asking...

Svaneberg 22 Aug 2014 07:04

Quote:

Originally Posted by xtrock (Post 477159)
Ok, but what to do with this hoses if i use only mechanical carbs?


If it's not vent hoses, I would just blank them off (Press a small bolt in the end of the hose) as you don't need Any vacuum to the 2nd carb (if you are using only mech carb) :)


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Svaneberg 22 Aug 2014 07:06

Definately Go with the Wirth :)


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Svaneberg 22 Aug 2014 07:12

Xtrock: you might want to consider using a carb setup from a kawasaki 250 ninja. Directly bolt on. Only needs to be re-jetted. I Know it's cv but unless you want 2x keihin fcr35 which is VERY expensive, this could be a solution. (Raptor is also cv) :)


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xtrock 22 Aug 2014 07:54

Ok what year is bolt on? I see they have two smililar intake, the cv carb is much bigger so i dont think the airhose will fit bolt on.

Svaneberg 22 Aug 2014 08:18

Yamaha XT 600 single carb + KTM shock - How it was made
 
Is has to be from the older models as the never has smaller carbs. I Think it is up to year 98 but i'm not sure. Try to do a Google search on the subject or send a PM to Jens Eskildsen on this forum. He did the conversion a while ago. :)


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nickargas 22 Aug 2014 15:05

Also a friend of mine has installed a double Carb out of the rgv.Gama

Jens Eskildsen 22 Aug 2014 16:29

I also tried the ninja carb. The carbs fit in both the intakerubbers, and the right carb fit the rubberhose coming from the airbox okay. The left hose is too small as I recall. I fitted a larger hose over the existing ones.

The ninja carbs is a bit shorter, but can fit.

I also experience more power, but the carb was old and worn, and I used a lot of time trying to dial it in. I basically changed a worn stock carb, for a worn nija carb....

In the end I bought a complete rebuildkit for my stock carb at ebay, and got the "lost" power back.

The stock carb works pretty okay, the problem seems to be old age any many kilometers on the secondhand ones still around.

THUMPTHUMPTHUMP 10 Nov 2014 13:29

I got a set of early ninja carbs 30mm ones. I also bought new carb to cylinder manifolds. I am starting with Jens jet sizes, 115 mains and 40 pilot. I will shim the needles with the two fiber spacers I have and bolt them on and see how they do compared to my jetted up stock carbs. If you have any advice Jens let me know. I am running air pods for filters. THUMPTHUMP

THUMPTHUMPTHUMP 15 Nov 2014 17:09

Jens, Getting ready to put the ninja carbs on. I live at the same altitude as you. I put in 115 mains , a 40 pilot . Do you remember what the air screws were set at? I am starting at 2 1/2. Did you raise the needles? The choke cable from my 86 xt will work fine. THUMPTHUMP.

Jens Eskildsen 16 Nov 2014 14:22

I think I raised the needles 1mm, and leaned it a bit out from there. I think youre about right regarding the idle screws.

Somewhere in the progress I also had an intakeboot-leak, so cant recall the exact jtting after that was fixed...

luketratts 20 Dec 2014 22:26

Hi Jens, I am a newbie to posting...until now I have just been reading the infinite knowledge you guys post..

Are you still using the tail riser on the shock, like the one that you measured up with great detail in 2013???

Ps, I am a massive xt fan, mine is identical to xtrocks bike just a tad bit lower which I am looking to rectify...

Jens Eskildsen 21 Dec 2014 17:58

Yeb, it's still mounted...


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