Sod it ! Lets do it !

What I'll never know is how long into the 12000 miles on the old piston nipped up and was it caused by over revving the bike on a hot day OR did the obvious incorrect fitting of the oil expander ring contribute ??



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Going back to that question Andy, I once accidentally overlapped the oil ring expander on an auto engine i was putting together. The ring compressor would not tighten enough to let me start the rings in the bore. in that instance. looking at the situation, i saw that. with the expander overlapped, i could not press that section of the oil control rings all the way into the ring groove on the piston. I was afraid that if I had mashed the thing together, that I would have damaged the ring groove on the piston and possibly bent or turned one or both oil control rings, possibly damaging the bore but certainly losing any semblance of oil control in that bore.

Your experience was much less serious, everything went together with no damage and you had a good semblance of oil control. My opinion is that having the section of overlapped expander in one area would create a tendency for that ring to push out harder on that section of the oil control rings, which MAY have the effect of moving the piston slightly off-center. uncertain if friction would increase.  Likely the pressure pushing out on the remaining portions of the oil control rings would be less than projected, having effectively lost some of the circumference of the expander. This might give the effect of well worn oil control rings which may have been a source of oil loss while running, blowing out the exhaust possibly.

Heres the post I've been itching to put up

In the last couple of hours I've been on my maiden shakedown ride after just a brief fire-up in the garage with a few minutes ticking over and bleeding the lube system both at the top of the filter housing and the double rocker oil feed banjo,big releif when seeing oil coming out.

Good start-up after a few kicks and deliberately left it a couple of minutes to warm up before moving off. 3000-3500 revs maximum and not letting the motor 'lug'. It feels sweet and sounds fine after an initial 10 mile ride. Didn't want to stray too far from home..just incase anything turned to ratshit.

Early days and I'm chuffed,I'll venture a bit further next oppurtunity. Want to get to around 400-500 miles but will go with the 'feel' of the motor as well.

Couple of lessons learned :- 1. Make sure the mind set is up to the job, I deliberately took a long time to do the job and yes on the odd occasion rushed certain operations that I re-did after not being happy/confident.

2. We've all got a budget for these projects but after pondering....can I get away with new rings and a piston clean-up ? NO NO NO ! put the hands a bit deeper in the pocket and stump up for a new piston and rings,you've got one cylinder and one piston....and one chance...don't skimp on it.

Heres to happy riding days ! Thanks for all the input lads.

Rock On Andy!

Thanks lux,I'm running stock comp 9:1.No doubt things get a bit hotter at 11:1. Having access to quality measuring kit I'm happy the clearances are okay and also I don't rev the nuts off the bike,I've also got an oil temp gauge to keep an eye on,especially during hot days [not that we get that many here ]