Author Topic: Timing  (Read 1026 times)

Online a101960

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« on: 13.04. 2009 16:42 »
Well, yesterday I set up my timing to 35 degrees (5/16) BTDC as advocated by SRM for alloy heads. The bike goes very well in fact it pulls better than ever it has done before. The reason for re-timing was because I had sent the cam ring off to Hawker Electrical to have it checked and re-ground if any discrepancy was found. For a long time I had been plagued by one cylinder burning richer than the other, and fitting anti bias gasket had made no difference. Not only was the cam ring miles out but the bearing was loose in the housing this was also rectified. On fitting the housing and cam ring it was apparent that there was a great improvement over how it was before the remedial work was done. A quick check revealed that I now had a 12 thou points gap on both cylinders, things were looking good. I found TDC by using an MCA tool that is like a spark plug fitted with a graduated stem. It worked very well you do not have to worry about the problem of the stem not being presented vertically to the piston crown because the piston will still push the stem up and give a very accurate indication of TDC. I mounted a timing wheel on to the crank and every thing worked just fine. The bike started first kick, and incidentally the petrol had been it the tank since last October, so such for tales about stale petrol! Anyway the acid test was how did it perform out on the road. Beautifully is the answer. It pulled like a train and was very responsive to the throttle. The bike is totally transformed, and what is more both plugs are now the same colour. So there we have it: mission accomplished. More torque, better acceleration, the occasional spit back that I had is now gone, and there is a nice even burn in both cylinders. It is always said that you should only change one thing at a time when attempting to diagnose a problem. Of course I do not know which of the three things that have been changed since I last used the bike have actually given me what I was looking for. I am inclined to think that it was a combination of the re-profiled cam ring and the work done to the bearing housing. Anyway a great result. I am a very happy bunny. Oh and I used a cigarette paper to set the timing. It did take three attempts though.

Offline snowbeard

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Re: Timing
« Reply #1 on: 14.04. 2009 23:45 »
this is good to hear!  so had you also had the new valve guides and seats in before running it again?  or had you gotten a shot after that work?

I'm wondering how much change I might see in just the redone head, then change the timing a bit. of course, with my manual timing I found that she liked running at what should have been retarded best, and I got no improvement with advance, but that just corresponds to the 35 degree suggestion!
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