There has been talk recently about the supply of 100 CC pistons. Especially the Ace, early SR and Road Toads. Also the 03 Wombat 125.
If one needs a 2 ring piston for a Toad, what are the options? I have an Ace 100 B+ with a SR reed valve kit from 1974 that is .040 over. It has the dike D ring. What are my options if I burn a piston and need to go larger. I know these pistons are becoming scarce and the investment would be high to remanufacture them. Are we headed for a cliff?
Rick Mott
In order to be old and wise, you must survive young and stupid!
Your rat piston will workfine. You can have pistons made by wiseco with a 12 minimum just find some buddies to go in with you. I have had snow mobile pistons made for customers of mine to my specs a couple of times its pretty easy
Rich, When you say that Wiseco will make them with a minimum order of 12, is that all for the same oversize? What I am asking is can you order the 12 pistons, say reeded Super Rat pistons, and get them in a range of oversizes? Also, do you know what the approx. price would be?
One a second line, I talked with representatives of Wossner Pistons a couple of months ago at the AIMExpo. They said they could do the same thing (make up custom order pistons) with a minimum order of 8 pistons. At that amount of pistons, it would be approx. $200 per piston kit.
Yes. All 12 from the first order have to be the same size. But additional orders can be a different size an I believe you don't have to order 12 more. That's what I was told by a mechanic down in Roswell, the guy with the 1976 Model 03 I was trying to buy. ; D Victor
Soooo, this never really gave me any answers. Looks like the 100 cc reed valve pistons are hard to find. Would a model 93/94 piston work if you drilled it for the reeds? I don't really care if its a 1 or 2 ring piston. Would like to use it with a road toad. Are all the pin to top height all the same? Skirt length? Thanks for any help.
Richard, probably just a typo on your part, but the 93 piston is a 100cc piston, where the 94 piston is a 125cc piston.
As far as I know, all the 100cc pistons are the same as far as piston pin placement, skirt length, etc. The biggest difference with any was the dome shape (height). The Ace 100 style 2 ring pistons had a high dome and came only on the Ace 100's (all types) and the early (96) Dirt Squirt. The low dome pistons came on all the aluminum cylinder 100's and both of the Super Rat's. The early Super Rats pistons did not have the reed valve holes in them (but you can drill them in).
For a complete description (even has pictures) go to the Strictly Hodaka site and under FAQ go to the TECHNICAL TIPS & SERVICE HELP. Under that tab is a long explanation of the two types of pistons for the 100cc engines.
My bad on the 94, should have known Paul had a page on these. So could I use a drilled ace100 piston in a road toad cyl with a ace
100 head(due to piston dome) Thanks so much, Bud
If I remember correctly, the Road Toad has an aluminum cylinder. The cylinder studs on the aluminum cylinders were 8mm, where the Ace 100 head was designed for 7mm cylinder studs. I also believe the stud spacing was different. So, if it is an aluminum cylinder, I would so NO, you can't use an Ace 100 head on it (without modifications, and then I still don't know if it would work).
Back in the day before reed valves were commonly used I got one from Webco and installed it on my 90. I just marked the width of the intake size in the cylinder and drilled 4 1/2" holes in the piston. Worked really well as it would stay up with the 100's. I also went to a 20mm carb.
