New run Pistons for 72-76 175's

[john durrill]

Folks was talking to Al B this week and found out that Wiesco has an order from him for a new run of 175 pistons (Thats the tall piston). They ( the pistons) should be finished some time in July.
 Also he has one of the new MZb ignitions on his Jackpiner and is working out the lighting. Daine has the new Ignitions now with lighting coils.
 We were talking about what was the most needed part for Pentons that as of now are unobtanium or in very short supply. Steering head races came up. I think we ( my son and I) have found something that can be made to work and would like input from the group on it.
 Stock races are ID 26 mm x OD 43 mm x width 11 mm.
You folks correct me if i have mismeasured.
The only races close to that we have found are used on some Yamaha bikes.
 The latest model with the bearings in question is the Yamaha TW200
(1987-01)
 The bearings closest to our Penton races are 25x43x11. There should be a way to bore, ream or other wise open up the ID from 25 to 26 mm with out weaking the races ( thats only .020 off the ID of the inner race) and give the group a source of replacement parts at a reasonable cost. any ideas on how to do this effectively and inexpensively? We ( my son and i) have been toying with this idea for a year now. We could use a brake cylinder hone and how ever many hours and stones it took with our mill , lathe to make one set up, but that would not help the group as a whole.
 The same bearings can be had from Sudco and Pro Flow in tapered rollers.
Ideas and advice needed !!!!! * Grin*
John & Peter D.
Ps, We just got Peter back home. He had back surgery yesterday and i will be short my rideing partner for about 3 months.
So i have time to make up some more protective caps and work with the bearing idea.

[firstturn]

John,
  I didn't know your riding Pardner was in for repair.  He will be in my prayers and please tell him.
  On to the races (the metal type[)]).  I am not at my shop area so I am asking a question.  What is the clearance  between the ID (26mm)of the races and the steering head assy (pipe)?  I can't remember.  You may not have to remove anything.  Of course I dream a lot too[:0].


Ron Carbaugh

[Cappy]

John,
Great news on the pistons, I know I'll be standing in line for one of them in July.  I hope Peter has a speedy recovery.  I had mine fused 2 months ago and hope to be back in the saddle within a year.
Regards,


John Cappel

[john durrill]

Ron.
 checked a steering stem and the od is 1.017 inches. thats close to 26 mm ( 1.0236 ). the yamaha bearings are 25 mm (.9842 inches) ID.
 checked the stock Penton race and its 1.694 inches OD.
 thats very close to the Yamaha bearing OD which is 43 mm (1.6929 inches) could just be my vernier calipers dial gage is not accurate enough.
If we can find a good way to remove .0338 we have replacement bearings for all the cmf pentons made. That would be only .0169 off the thickness of the bearings ID wall. That should not weaken the bearing enough to be a problem.
 Has any one Ideas? is this something bearing makers do for special app's?
John D.

[firstturn]

John,
  I have not done any machine work since being in the hospital, but I know the first and easiest thing I would have done would be to chuck up a carbide ginder tool and just run it into the inner diameteter of the race.  In other words the grinder tool will have a taper and it won't take much to cut the dismeter to the specified measurement.
  If this doesn't make sense just email me and I will call you.  
  Say Hi to Peter and he is in my Prayers.


Ron Carbaugh

[Rain Man]

Jackpiner pistons huh, wa soon   ohboyohboyohboy.