Got new rings for the 1993 500cc Bullet. Oil scraper seems about OK (possibly) at about 10 thou, but the middle and top rings are more than 25 thou. How can this be?
Also, I ordered a new bottom valve collar as it didn't have one. The outside diameter is a tad under 32mm, but the o/d of the outer springs that I ordered are around 37mm. They just don't look right. They also, look as if they will become spring bound when I put the valves back in (can't at the moment as the head is at the engineers for some oversized guides to be fitted).
I had a similar problem with a set or rings for my M21. Oil scraper OK at zero gap and 1st and 2nd at 65 thou! The answer I got from the supplier was :
"The quoted end gap is only a minimum to prevent the ring gap from closing up when hot. A larger gap is not a problem."
I have not had the bore measured. It has no lip and honing marks are still visible (not that that can be relied upon). What I don't get is that one of the rings, the oil scraper seems ok, but the other two are not. I can understand if all rings had too large a gap.
Not if the ring set is just made up from individual inaccurately measured rings or mixed up packets. I would at least get the bore size confirmed and then query the rings with the supplier.
I've had personal experience with the Indian made bullet pistons as supplied by Hitchcock's. Two of my WD Enfield's have them (dome top pistons fitted to give a bit more compression). But it was obvious from a friend's experience that the rings were absolute crap/cheese/ licorice. Hitchcock's became aware of this pretty quickly and the pistons are now supplied with European made rings (Italian I believe) and the three Enfield's involved are now running many miles with no problem. Ron
PS Typing at the same time as Ian. Yes those are some strange sizes and tolerances?
