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Hard To Start - Valve Timing Out A Tooth?

timing starting backfire 850 mk1

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#1 mh1848

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Posted 02 May 2015 - 08:34 am

well I did my shims a while ago - and also overhauled the carbs (new tubes and seals) but then had a period of ill health - and also had some other bits and pieces to do (new front disc, tyre and wheel bearings) - so its only been the last couple of weekends i have been trying to get it up and running

 

it is very reluctant to start (spark fine, plenty fuel getting through) tries to fire up and catches a couple of times but just wnot pick up - got it running eventually last week and after a while did even out and sounded not too bad. -  but this week - pops and bangs and flames up carb inlets - catches bu would not pick up

 

but i have a nagging suspicion that the timing may be one tooth out - i used to have a XS250 that would not start when warm and it was a valve timing issue - so if one tooth out one way makes it hard to start when warm, ....................

 

any thoughts before i take cam cover off again?

 

cheers


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#2 Studley Ramrod

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Posted 02 May 2015 - 08:48 am

Difficult to say for sure, new toobs could mean you need to adjust the pilots and do a carby balance. Also, being stood for a while doesn't always help. I guess the only way to eliminate the timing slip is to check.

 

Mine was a poppin an fartin on start up, had a leak in the vacuum pipe which was letting air into the intake and also caused the fuel pump to struggle.


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#3 dapleb

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Posted 02 May 2015 - 09:54 am

Heya mh, sorry to hear you have been poorly.

As SR. I would.be chicken.the carbs again.too. though the tooth ooot thing shouldn't be too hard to.check.
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Doin valve clearances? Use dappers valve shim exchange program and the job will be carroty - Free (other than you postin me yer shims) for sporting members.

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#4 mh1848

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Posted 07 May 2015 - 01:25 pm

thanks for advice guys and as you say will try checkin the carbs agin - as i said new emulsion tubes, new seals, new needles and circlip on correct notch, mixture screws 2 1/2 tunrs out, fuel levels set correctly

 

if it still does not catch then will bite bullet and check valve timing

 

my ill health was a ruptured appendix - followed up by a secondary infection resulting in a week on drips and loss of about a stone in weight and five weeks off work


TDM 1991 - two into one micron mated with a A16 Road and Race Supplies Stainless short can - Conti Road Attacks - Kagazume Wavy Rear Disc - Bagster tank cover - homemade sheepskin seat cover on top of custom seat cover - NonFango topbox on homemade mount - custom fusebox - very loud airhorn and cyclone alarm


#5 Kelpie

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Posted 08 May 2015 - 06:38 am

 
my ill health was a ruptured appendix - followed up by a secondary infection resulting in a week on drips and loss of about a stone in weight and five weeks off work


Ugh! Been there and done that. Well done for surviving a horrendous time! I hope you're getting over it and feeling much better!
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#6 dapleb

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Posted 08 May 2015 - 09:51 am

Ughhh glad you made it through mh!!!!

Lettuce snow how ya get on with the boike.
"Whats up", "Piston Broke", "Yeah me too...hic"

If you want to mark your location on the Carpe map: http://www.carpe-tdm...opic.php?t=5117

Doin valve clearances? Use dappers valve shim exchange program and the job will be carroty - Free (other than you postin me yer shims) for sporting members.

Active member of TPLQHCSRSFC and TSRMCMAS (even though a year off) and avid fan of PM not sent.



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