Piston Rings

Questions regarding the DR750

Piston Rings

Postby BigBob » Mon May 01, 2017 4:26 pm

Following a camchain tensioner spring failure a few weeks ago, which resulted in bent valves etc, I am rebuilding the engine.
So I`ve lashed out on a new camchain and tensioner (over £200!) and a new 1.00 oversize piston and rings (now unobtainable but was £340) plus gaskets (£100) so lots of ££££
The problem I have is with the top two piston rings. One is marked R and the other is RN.
So the question is, which one is the top ring?
It doesn`t say in the Holy Book and though I`ve done this before, I can`t remember the order as I did know back in the day.
I`m pretty sure it`s R on top and RN 2nd with letters facing up, but prefer confirmation.
Must be going senile :crazy:
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Re: Piston Rings

Postby O.R. » Mon May 01, 2017 5:14 pm

Sorry to read your engine has been damaged.
Contact DHC6 for the ultimate cam chain tensioner upgr@de. Even when your OEM/HRT spring fails, the chain will keep its tension.

Answer to your question, see chapter 3-55 and 3-56. R is top ring, RN is second ring. Now you are sure :tup:
R.jpg
RN.jpg
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Re: Piston Rings

Postby spendango » Mon May 01, 2017 6:37 pm

You may want to sell one of your MANY machines to fund your rebuild :wave: :wave: :wave: :wave:
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Re: Piston Rings

Postby BigBob » Mon May 01, 2017 6:43 pm

Thanks for that, I was looking on pages 3-31 and 3-32. Silly me.
I`ve seen the DHC6 modification and it looks quite brutal, though I`m sure it will work fine.
I`ve already bought another OE tensioner so that will have to do.
According to Stefan Hessler the early ones fail after about 100,000 km and the later modified ones are a bit better.
I have several Bigs so I guess this one will last me for a long time.
The last one lasted for nearly 175,000 miles and 28 years before it broke and I can`t see me riding bikes still in another 28 years. I`ll be 96!
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Re: Piston Rings

Postby BigBob » Mon May 01, 2017 6:44 pm

I`ll give you first shout if I do Spen. :tup:
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Re: Piston Rings

Postby spendango » Mon May 01, 2017 8:52 pm

No worries,
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