VFR400 NC30 Rings and Valve Stem Seals

[Mat400]

Good Day All.

So I have had my bike for around 6000 Kms and she started using oil and i noticed white smoke coming from the Exhaust.
Both on accel and overrun.
I am currently in the process of getting my piston rings as well as they Valve stem seals replaced as a leak down test/compression test showed signs of worn rings.

I would just like to get some advise as to the wear in process when replacing rings, if there is any.

All comments are welcome.

[Malc]

Warm it up fully, then work the engine hard from 3 to 14k in third gear for about 20 minutes.

[Mat400]

Thanks a lot, I also have a few sets of Rings from a rebuilt engine, how does one check the condition of the rings, either looking at it visually or measuring it? I would like to find out if the rings I have from the spare motor are in good condition or not.

[Malc]

Personally, if I was going to the trouble of replacing rings on an NC30/35 motor again, I would put new in irrespective of the apparent good condition of a 2nd hand set. It is just too much work to risk otherwise (IMHO).

That said, if you are going to use 2nd hand, put each ring in the cylinder it is intended for, about 15-20mm from the top of the bore and squared off, and check the ring end gap. If it is within spec, then you're probably good to go. HOWEVER, any used ring will invariably be polished and will not act against the freshly honed cylinder anywhere near as effectively as a new one, and you'll never create a perfect seal between the two, which the whole breaking-in process is all about after all.

[magg]

13011-MV4-305 ring set, $20 US each + postage from Partzilla.com