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By mart
#94119
I have an issue with the rocker arm clearance on my '51 Model G. The rocker arm hits the spring retainer before it touches the valve stem cap. Ive just had the valve seats re cut which has made the valves sit deeper in the head.
My question is- do I grind the rocker arm to create clearance, therefore making it weaker, or is it practical to fit a spacer plate under the rocker set, to lift the whole mechanism ? ( the exhaust rocker is fine BTW ) any thoughts much appreciated- thanks
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By Wheaters
#94123
Haggis wrote:
Mon Nov 23, 2020 1:18 pm
Looks to be plenty meat on that rocker arm to allow you to slim it down a bit.
I agree. But it’s important to take the bare minimum off and probably more importantly, leave the newly exposed metal surface on the inside of the rocker arm nice and smooth. If there’s any grooves or scratches left across the arm they will possibly cause stress cracks and you’ll find the end breaking off.
By mart
#94124
I bought the bike as a runner but who knows whats been done to it over the years. I have bought a complete rocker set, which is virtually unworn, fitted new guides, valves ( which match the originals) , valve springs and had the re cut done. The rocker set matches the set that came off, though that set could be incorrect of course. the seats were badly pitted so had to be cut quite deep. all of this started because the valve lifter wouldnt engage with the pushrod!
thanks
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By Wheaters
#94135
In the long term it would be probably better to have new valve seats fitted, which would restore the valve gear geometry. A valve that sits well down in the seat doesn’t flow well. Also, because the combustion chamber volume is increased, the compression ratio will be reduced. A double blow to performance.

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