Valve timing (again)

chris300hills · Post by **chris300hills** » Sat Oct 20, 2007 6:29 pm

Sorry to bring up this subject again which seems to have been covered in so many previous threads but I am trying to get my bike back on the road after a disastrous CCT episode (incl new valves) and am determined not to do any more damage.

The problem is that all of the advice I have seen here and elsewhere seems to start from the premise that one of the cylinders is timed OK and you do the other one from there onwards. I am trying to set the valve timing on both cylinders from scratch (don't ask!!) I have done the front first then the rear but how do I know if at the FT mark it was TDC on the compression stroke or exhaust?

I know there is a serious danger that I have overlooked something blindingly obvious but I think I have spent too long thinking about this now and can't see the wood for the trees.

Hope this makes sense and someone can help?

Chris

KarlosVTR · Post by **KarlosVTR** » Sat Oct 20, 2007 7:09 pm

im going by the assumption that there is a wasted spark on the exhaust stroke

so i reckon as long as 1 cylinder is timed from scrathc perfectly, the other one timed to the perfectly timed one should give you a timing triumph

Beamish · Post by **Beamish** » Sun Oct 21, 2007 9:21 am

I am sorry to sound negative but get a known good mechanic to have a look. I have recently had a disaster changing CCTs after following 'good solid advice' it was prob 100% my fault but I cannot see what I did wrong, join the RAC for next to nowt and get it taken to a good garage.

Post by **sirch345** » Sun Oct 21, 2007 9:57 am

I would also assume there's a wasted spark, so it will make no difference when setting the valve timing from scratch which revolution the crankshaft is on. The main thing (that you have done) is timing the first cylinder (in your case the front ) in conjunction with the second.

Even if there wasn't a wasted spark you'll not do any damage, it just won't start.

I've said it plenty of times before but I'll say it again, always turn the engine over by hand (using a socket on the end of the crankshaft) ANTI-CLOCKWISE four or five times before pressing the starter button! Just to double check the valves are clearing the pistons. Turn it slowly, then if a valve did hit one of the pistons you'll not damage it.

Chris.

chris300hills · Post by **chris300hills** » Sun Oct 21, 2007 10:08 pm

Guys,

Thanks for the replies - as helpful as ever. I hope I can now finally finish this job.

Sirch, don't worry I have turned it over by hand at least five times - won't make that mistake again!!

Chris

Pete.L · Post by **Pete.L** » Mon Oct 22, 2007 9:54 am

Hi Chris
in answer to your question.
As long as the cam lobes are properly aligned on the front and then after rotating the engine everything is aligned on the rear that's all you need to do.

Pete.l
and yes there is a wasted spark

chris300hills · Post by **chris300hills** » Sun Dec 02, 2007 10:29 pm

I think I originally started asking you guys for help after I messed up changing the CCTs six months ago.

With your assistance and two new exhaust valves later, bike back on the road last week.

Thanks for all your help - don't think i could have done it wothout your help.

Chris

Post by **sirch345** » Mon Dec 03, 2007 9:17 am

chris300hills,

I appreciate you getting back to us with the outcome

I'm glad too hear you got there in the end

Cheers,

Chris.