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Post by tomster on Nov 9, 2011 22:26:58 GMT
Have ya tried firing it up in the dark, to see if it's arcing out anywhere?
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Post by Crusty on Nov 11, 2011 15:27:12 GMT
I think I know whats wrong with my bike.
It's a prick-tease. I'm not joking.
Went to start it this morning and it coughed and spluttered for about a second and then fired up.
Did a short "bag of nails" impression 3 miles up the road but appart from that was fine.Nigh on perfect on the way home.
It obviously decided that it needed a bit of loving. I'd decided to check through all the ancilary wiring for the ignition this weekend and obviously the problem is there and I was getting too close!
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Post by Crusty on Nov 20, 2011 12:29:24 GMT
Did some more investigating this morning.
I cannot find an electrical fault anywhere I isolated and bypassed everything and it still runs like a dog on startup.
So... I had another look at the spark plugs.
No. 1 looks like it hasn't been used (white electrode, no deposits at all but the other electrode has tan coloured deposits) so I think this one is alright. No. 2 Black sooty No. 3 Beautiful tan colour No. 4 A bit sooty, but with areas of tan colour.
It can't be an electrical problem with 2 and 3 having such different results so I'm back to the carbs.
Views?
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Post by Crusty on Nov 26, 2011 15:51:31 GMT
So I have good news and bad news. I've had the valve clearances measured and they are all too tight. So tight that you can't even get a feeler guage in. So it needs to go into a bike shop to be done as my mate doesn't have any spare thin shims so that he can measure what size is actually needed
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Post by Crusty on Dec 3, 2011 20:14:29 GMT
Eventually found the problem.
The valve clearances had all closed up so that the intake valves were sticking open when the engine was cold but as the engine warmed up the head expanded more than the valves, so then the bike ran properly.
It cost me £130 to have the shims done. Posted so that if you find this thread because you have the same symptoms as descriped...
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Post by tomster on Dec 3, 2011 22:18:38 GMT
You're a good man, Crusty, and I'm really pleased you've got it sorted. I've both of mine to do and I'm not looking forward to doing them.
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Post by Graham on Dec 4, 2011 0:09:18 GMT
Nice one crusty. It's not the nicest job so £130 sounds bloody good to me. Tom.. . good luck.
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Post by Crusty on Dec 4, 2011 9:16:49 GMT
Half the cost was labour, half shims (and coolant).
Good luck with doing them yourself, the shims are tiny! I doubt that I'd even be able to pick one up let along swap them around in an engine.
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Post by scobri on Dec 4, 2011 11:51:49 GMT
Quite an easy job, Would be around a couple of hours work, if they are closed up that much you may need to check clearances twice though to make sure every one is spot on. I have done quite a few of these,not a bad price at all,Shims are about £6 each from Yamaha. I do have quite a few now.
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Post by Crusty on Dec 4, 2011 12:19:26 GMT
I have 5 spare now. If anyone needs any, say what size you need and if I have one I'll stick it in the post.
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Post by tomster on Dec 4, 2011 15:09:47 GMT
That's good to know. Thanks very much.
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Post by Crusty on Dec 4, 2011 15:16:19 GMT
After all the help that Kenny gave me (spare parts, offers of replacement head and carbs etc.) it would be very poor of me if I didn't do the same...
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Post by Graham on Dec 4, 2011 17:31:14 GMT
I thought I had already but doesn't look like it so I will start a thread just for shims & make it stick at the top of whichever board I put it in. That way we can all post saying what shims we have available to swap or sell. I will do one for "Wanted" & another for "Available".. . after I've had my tea. ;D
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Post by Crusty on May 14, 2013 14:24:47 GMT
Oh no, not again....
It's started doing the same thing. I've got to have the shims done every 10 thou? Fucking hell. No more red-lining it...
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Post by flywithspence919 on Jan 19, 2022 1:43:11 GMT
Up until Sundy morning everything was fine, then.... the bike would barely reach tickover speed on startup, and thats with holding the throttle wide open. But... after about 5 minutes it suddenly bursts into life and will then run fine (and I mean just like normal, including a 170 mile journey home.) Then this morning, it burst into life as normal, but then when I stuck it in gear it died and then went back to the 'holding it on full throttle at barely tickover' routine again. Once again, after about 2-5 minutes it was fine again, suddenly leap into life. Same again this evening on my way home from work. I suspect fuel starvation caused by a dodgy pump/controller (do the carbs empty themselves out slowly over a few hours) but am open to suggestions as to what is causing this problem. N.B. Eventually found the problem. The valve clearances had all closed up so that the intake valves were sticking open when the engine was cold but as the engine warmed up the head expanded more than the valves, so then the bike ran properly. It cost me £130 to have the shims done. Posted so that if you find this thread and you have the same symptoms as described you don't have to read the whole thing to find the solution.... Where did you purchase the shims from?
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