XT660Z reving like a loony
 

Hi guys. Not new to the forum but been away a while and forgot all my log in details so i had to re register.

Got a small problem. was riding back from work yesterday in the rain and my bike started reving up to 4k rpm on its own. managed to make it to the pub and thought i'd worry about it in the morning.

This morning same problem. i rode it for about 15k then pulled over and had a little look. The tick over screw is right out so its not touching. the carb sliders look and sound as if they are hitting the stops when closing. The previous owner has removed the air box and put 2 small filters on the inlets, but this has never been an issue before.

The bike has been sitting for 2 years while i've bee overseas working, i removed the carbs last week, cleaned them, drained the brown petrol from the tank and filled up with fresh. and have since done about 400k.
It also has a pro duro exhaust.

I have to ride back to wales today (about 200k) and although the over reving isn't an issue when going over 40kph it does get a bit annoying at roundabout or traficligt speeds.

Anyone got any ideas please??

Thanks
Paul

strip and clean the carbs thoroughly sounds like the floats and the shut off valve is letting fuel through

Hi wolfzero.

Gave the carbs a bloody good cleaning last week. But i've just managed to sneak out of the office for a closer look and it feels like the carb isn't closing fully unless i slam the throttle closed.
I guess the problem lies in either the cables sticking or the reurtn spring has lost some of its springyness (technical term that). I'll give it a liberal dose of WD40 and see how it gets on. Failing that i'll fabricate a new springing mechanism as a temp fix. and if all that fails i'll just have to ride round roundabouts a bit faster and time my approach to lights and junctions a bit better.

Thanks for the feed back

Paul

if the carbs are clean then def give the cables a good oiling with some engine oil wd40 is ok for cleaning and light oiling but i find engine oil is better for stuff like cables as it sticks around longer :thumbup1:

Thats the plan long term.
For now the only tools i have are a leatherman and a can of WD40. Got to get to wales tonight as i fly to asia for a couple of weeks tomorrow morning. will give it a major overhaul when i get back

Many thanks

Paul

Hi Guys,
well i made it to my folks house in one piece,the reving got worse so i stopped to take the carbs off for a look and found that the primary inlet rubber had perished. so i bodged it back with pritstick glue (office paper glue i'd bought for my son) and a bit of sticky tape, wedeged the carbs in place with a bit of rubber hose, couldnt fit the air filters so ran it home another 200k reving at 6500rpm with the clutch in. Motorways wern't too bad,it crused quite happily with no throttle at 100kph.
round abouts and trafic lights and the occasional traffic jam were a lesson in clutch and brake control, and my arse pinced the seat a couple of times on wet roundabouts.

anyway. the carb is now off and my mate is going to sonic clean it in work. not quite sure what this entails, but he did the same to his carb and i came out looking brand new inside and out.

What i do need now is a set of inlet rubbers, but the only ones i can find are for the XT600, does any one know if they are the same. or where i could go to get some?
I will be in malaysia for the next 2 weeks and will have to order them over the tinternet so they are ready for me to fit once i get back.

By the way, i remembered my old log in details and i was once known as chiopompom?? blame the wife for that one.

Thanks in advance and ride safe

Paul

The inlet rubbers in my '89 had separted from the alum. mounting flange. I cleaned it good, and glued it together with Gorilla Glue for plastics.
I put a small blob on the rubber in a clearly visible area (after reassembly). If I try to pry off the blob, it will tear the rubber, before the glue joint separates.It has been about 1.5 years and is still holding strong!
If this glue is available in Maylasia you might try it.
Good Luck Steve

yhprum,

That was the other option, the bike is in the UK at my folks place, i live in malaysia but don't get home (malaysia) too much due to work.
I will look for gorila glue on the net and get some sent to the house.
Cheers

Paul

Good day to All.

Bit of an update.

After a nice trip home to malaysia I again graced the shores of blighty on monday afternoon. my good friend had sonic cleaned my carb and it looks mint. I araldited the inlet rubber back onto the inlet manifold and proceeded to enjoy a couple of beers and one or two gin and tonics while the glue set and the sun came down.

Tuesday morning arrives, I have a 200 mile journey to undertake today, so its up with the larks and get cracking on puting the baby back together.

on first rebuild there was no change to the insane reving. so striped the carb and gave it a good blow out.
Second fitting brought the reving down to a steady 4500, but it sounded better.
Again i removed the carbs, made a coffee and had another look. I found the problem, should have seen it first time but there you go.
One of the small screws that fix the butterfly valve to its shaft was missing and i had a perfect flow of air through the secondry carb.

Tada! problem solved!! or is it??????

Where is the screw?

Had a good look around the inlet valves and no sign of it. Did it fall out on one of the many occasions i have removed the carbs?
I honestly didn't know
So, with no time to loose I'm kitted up and heading of to work in the midlands, a nice 3 hour ride. she's running like a dream, the sun is shining exhaust note burbleing in through my new nolan N103 (good deal of my old race mechanic in kuala lumpur) and all is well in biking heaven.

Cut too 5:30pm last night, i've just left the office and heading out to my digs about 30 miles away, get to a roundabout and the noise that came from the top end can only mean that the screw has been found.

engine spins over OK, but after a few turns a pleasant cloud of fuel/air mixture getly wafts from the lower casing around the drive sprocket.
Now i'm relativley confident that this realy shouldn't be happening and can only assume that i've done a bit of damage somewhere that will probably entail taking the engine apart (luckily this was done 2 years ago so all bolts free etc)

On the plus side, i happened to break down right next to a hotel, so after abandoning the bike in the disabled parking place, i got their last room, had a shower and got stuck into the strongbow at the bar.

Got talking to a friendly local who called his south african mate who has a bit of a bike workshop here, he's going to pick the bike up today and have a little look.

Hopefully it only a piston or a little top end damage, and it was due a rebore anyway.

Thats about it for now, I will keep this going until i'm either back on the road or selling spares:innocent:

Damn butterflies

Paul