Valve adjustment gone bad...


18 replies to this topic
  • abigweasel

Posted November 29, 2006 - 06:00 PM

#1

I just finished a valve adjustment (one E valve out of spec), got the timing set and of course the bike won't start. I've checked the timing at least 3 times and even replaced the spark plug but nothing. The bike is an '02 426 that has never given me any trouble starting, hot or cold. Is there something I'm overlooking, or do I need professional help?

  • rexbond007

Posted November 29, 2006 - 06:19 PM

#2

do you have spark?
is it firing?
is the decomp valve stuck open?

  • 642MX

Posted November 29, 2006 - 06:27 PM

#3

Welcome to TT.

Has the bike been sitting for long? maybe it has a clogged pilot jet?

  • abigweasel

Posted November 29, 2006 - 08:02 PM

#4

Ya TT is a really good site.

Bike had been sitting, but with carb drained. I checked the decom lever, opens and shuts fine. As for spark...it seems weak, but the plug is new, so maybe that is normal? I'm still thinking I screwed up the timing. For TDC I'm using the small vertical line that is about 2 deg clockwise from the sideways "I" shape. Is this correct? I physically checked the piston by sticking a coathanger in the spark plug hole, but ya never know...

  • rexbond007

Posted November 29, 2006 - 08:21 PM

#5

check out this link; it will help you with pictures of tdc.

http://www.thumperta...ad.php?t=394342

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  • warrior86

Posted November 30, 2006 - 05:09 AM

#6

maybe spray a lil ether in there to see if you get anything out of that. It sounds like you have everything together right.

check the obvious: make sure air filter is clean, fuel is ON, and you should be good to go. Its not making any signs of starting? maybe you need to rejet for winter???

  • 642MX

Posted November 30, 2006 - 05:25 AM

#7

maybe spray a lil ether in there to see if you get anything out of that. It sounds like you have everything together right.

check the obvious: make sure air filter is clean, fuel is ON, and you should be good to go. Its not making any signs of starting? maybe you need to rejet for winter???


I would not recommend using ether. :D



It sounds like you probably have it timed right. Just for fun, why don't you pull the carb and give it a good ole fashion cleaning and then try to start it again. FCR's are extremely picky about dirt, gun and varnish; and just because you drained it doesn't mean the all the jets are clean. :worthy:

  • Goosedog

Posted November 30, 2006 - 06:11 AM

#8

The obvious question here to me is...was it running before you did the valve adjust? If so then you can rule out all the sparkplug and carburator suggestions. Go back over your proceedure for the adjustment and see what you might have put together wrong.

  • DPW

Posted November 30, 2006 - 06:17 AM

#9

The obvious question here to me is...was it running before you did the valve adjust?


That's funny...I was looking at some older threads on valve adjustments and there are a lot of thread like this. The end result is usually..." oh yeah the bike has been sitting for 1 year and was not running before"....clean the carb and "Shazam" the bike starts.

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  • Goosedog

Posted November 30, 2006 - 06:34 AM

#10

That's funny...I was looking at some older threads on valve adjustments and there are a lot of thread like this. The end result is usually..." oh yeah the bike has been sitting for 1 year and was not running before"....clean the carb and "Shazam" the bike starts.


Point taken, but it still seems to me one would crank up a bike that's been sitting (or at least attempt to) to evaluate what it needed before just going right to a valve adjust.

  • grayracer513

Posted November 30, 2006 - 09:07 AM

#11

...it still seems to me one would crank up a bike that's been sitting (or at least attempt to) to evaluate what it needed before just going right to a valve adjust.

It would be wise to do so, since if it sat for any length of time with the valves open, the possibility of a layer of light rust building up on the seats is there. Checking the valves under those circumstances, before they had run long enough to clear the seats, would throw the measurements off by quite a bit. Rust can occupy as much as ten times the space taken up by the metal that was oxidized.

Carbon can also dry and flake, and fall onto the valve faces. Far better to run it up first.

  • abigweasel

Posted November 30, 2006 - 04:16 PM

#12

Thanks all, now that work is over I can trying some of these suggestions. I'll check the carb....

  • warrior86

Posted November 30, 2006 - 09:20 PM

#13

I would not recommend using ether. :bonk:



It sounds like you probably have it timed right. Just for fun, why don't you pull the carb and give it a good ole fashion cleaning and then try to start it again. FCR's are extremely picky about dirt, gun and varnish; and just because you drained it doesn't mean the all the jets are clean. :worthy:



Is starting fluid really that bad to use? :D I know your supposed to use it sparingly but i figured a quick squirt to see if the thing will start at all would be a good way of diagnosing. Sorry if i gave bad info.:prof: :cry:

  • BEAN329

Posted December 03, 2006 - 07:28 PM

#14

Yes it's bad, in a high compression engine it's bad. In a lawn mower, ok.

  • abigweasel

Posted December 19, 2006 - 04:52 PM

#15

Just for some resolution....

My bike is running at last. Turns out my intake timing was off by 1 tooth. Looked normal with an unloaded camchain, but when I cranked on the tensioner it was obvious it was off. Also, my carb was pretty gross, desert sand having got the best of it. At least that's what it looked like. Anyway, I fixed both of those things simultaneously so I'm just gonna say both were the problem. Thanks everyone for steering me right. Of course now I have a new problem....

  • KJ790

Posted December 19, 2006 - 04:58 PM

#16

Ah, I got here too late. I was going to suggest putting tension on the cam chain, happened to me the first time I adjusted the valves on a bike.

  • grayracer513

Posted December 19, 2006 - 05:01 PM

#17

Turns out my intake timing was off by 1 tooth. Looked normal with an unloaded camchain, but when I cranked on the tensioner it was obvious it was off.

This is why it's important to double-check the timing by backing everything up slightly (just 5 degrees or so) and then roll the engine forward to TDC with the chain tight from the crank up to the exhaust cam, and from there back to the intake. :thumbsup:

  • abigweasel

Posted December 19, 2006 - 05:08 PM

#18

Yup, I had one of those "eureka!" moments. Doesn't happen very often for me, so it was pretty cool.

  • Florida_426

Posted December 20, 2006 - 09:00 AM

#19

I'm with the majority here. Double check the timing mark (the "H" mark) and do it with the tensioner on, then check the lash to be sure. And I second cleaning the carb carefully.

Bill





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