Hi all Im new here.
I have a mix and match bike with the major parts being KHR and XR parts plus some other parts of known and unknown make. Am at present doing a very slow process of finding out what I got, with a long term plan of getting the bike on the track.
Hope I can share my findings here, and I can get som help identifying the various parts.
First question is regarding pistons.
In Gordon Jennings article from June 65 on Jerry Branch and KR tuning, there are pictures of what is said to be one original and one modified pistons.
Both the original and modified piston seem to have narrower diameter at the dome going half way down to the top ring. Jerry states in the interview he is using standard K pistons as they are lighter than the KR pistons. All K/KH pistons I have seen are only aftermarket stuff and they are all straight with no smaller diameter at the top.
Link below is to Beauty of Speed webpage where this picure can be seen
http://www.beautyofspeed.com/data/doc_cycle-world_jerry-branch/cycle-world_1965_jerry-branch_03.gif
I posted the question above at FHP teck talk, got some answers, but none had knowledge of such piston design (Im not talking about the chafered crown modified by Jerry Branch, but the narrower diametre crown on both pistons in the article). I recently pulled the cylinders off, and found a piston that look excactly like the one claimed to be a standard K piston. Interesting is there is not only a narrower crown, but there is an additional groove going round the dome. A groove similar to a ring groove, narrower only 1.15mm/0.045 inch wide. Studying the Gordons article once more, Im sure those pistons got that same groove.
Question is if any of you got knowledge of this piston? Is it a standard K piston or a racing piston? See image below.
The 1955-62 K model parts manual lists pistons with rings 22251-52 replaced by 22251-52A
The May 1954 Dealer net price list for Competition motorcycles lists
22101-48R solid skirt alum for WR, KR and KRTT,
22251-48R solid skirt Dow metal for WR, KR and KRTT
22101-54R solid skirt alum for KHRTT
GuS