The Hodaka Club Forum

What are the modifications to convert the 03 engine to use the more common 125 pistons?

Mike Perrett

Use Road Toad crank throws with 125 piston rod and bearing, 94, 95 model. It has been a while since I did one of these, working from memory, road toad crank pin and thrust washers. I am pretty sure the late model, painted tank, dirt squirt crank throws are the same as the Road Toad so that should work also.

Danny Cooke

Danny, use the 02 crankshaft, not the 99, is that correct?
Mike Perrett

The crankshaft from model 99, 01 or 02 will work fine . . . unless I am forgetting some detail.

Ed

I need educated. Isn't the 02 toad primary kickstart, while the 99 is not? If that is true, won't the crankshaft be different.
This is bad. I rebuilt Rick Mott's 03 engine some years ago, and cannot remember what I did. Lack of meditation, no doubt.
Mike Perrett

Ok, did a little checking.

1. The 01 Dirt Squirt, 01 Road Toad and, surprisingly, the 82 Dirt Squirt all use the same two crank throws... part # 992701 and 992702A.

2. The 99 Road Toad uses the same 992701 left crank throw but the right crank throw is a different part number...992702.

The difference between the right 992702 crank throw and the 992702A has to do with the thickness of the thrust washer surface. The 992702 is designed to use the thin approximately .5mm crank pin thrust washer. The 992702A is designed to use the thick approximately 1mm crank pin washer.

So with that info we can come up with the needed parts to convert the 03 Wombat to use the early rod and piston.

1 - crank pin part # 992703
1 - set of crank throws from any of the above listed models
2 - crank pin thrust washers .5mm thick for the 99 mdl and 1mm thick for the other models
1- 942710 piston rod or one of Pauls new 125 rod kit
1 - early 125 piston. I have used the Super Combat piston with good results and it is already ported for the reed valve. Could also use other 125 model piston but ports on the intake side of the piston would have to be cut for the reed valve.
Note...if using one of Pauls rod kit you might not have to purchase additional thrust washers if the kit comes with the required thickness thrust washer.

Danny Cooke

Or, for those of us who are simple-minded ; just swap in a crank assy from a 99/01/02 & use an early 125 rod & piston. While I suspect Danny has the details right, most of us won't dis/reassemble crank parts, but will simply do a swap..

Also, don't forget the 01 DS - same as the RTs. Folks often forget it.

Mike - I suspect it might be medication, rather than meditation...

Bob

Athough a "swap" is appropriate the crank will still have to be dis-assembled, parts replaced, pressed back together and trued.

Danny

thanks everyone, I will copy this info so I will have it next time. I perfer the 94 piston with the two rings for better sealing. Another 03 will live again.
Mike Perrett

Mike,
You used all 03 parts when you built the motor for the WomAce. I had purchased 2 motors from Ebay and you were able to make 1 good motor from the parts. I got the 03 piston from California Hodaka. You also drilled the case so I could run premix.
All remaining parts were given to you last June at Toronto OH.

Rick Mott