Road Toad Modifications

[BrianZ]

According to the Hodaka book, the Road Toad had problems with piston seizures when it was first introduced. The solution consisted of three parts:

1- Relieve the exhaust port bridge.
2- Change the carb jetting.
3- Modify the cylinder head.

I am aware of the details of the exhaust port modification, but what was done to the cylinder head?

What were the jetting changes?

Regards,

Brian

[taber hodaka]

Just good to see you on the chart. Clarence

[Bullfrog]

Danged if I can remember the details. Seems like tweaking the pilot jet a bit richer was the main thing on carb. And maybe remachining the head for a bit "thicker" squish band - with compression lowered a teensy little bit. Possibly maybe.
Ed

[BrianZ]

Looking at the parts diagrams for the 99 and 02 Toads shows the 02 Toad with leaner pilot and main jets. The cylinder head on the 02 Toad has a revised number with an “A” suffix added.

Maybe (just a guess on my part), part of the fix for the 99 seizures was to richen it up, but when the real culprit was found to be the exhaust port bridge, the jetting was leaned (back to the original specs) for the 02 Toad.

Brian

[olddogs]

I believe the A suffix denotes natural finish. The 99 was painted black and the 02 was bare. Pretty sure the same head. One trick we used was a couple tiny holes in the piston skirt where it traveled up and down the bridge. This allowed a little cool air and oil to contact bridge on every stroke. Chamfering bridge edges and piston skirt holes were critical. As per my aging memory.

[BrianZ]

Good point, I had forgotten about the change in finish for the 02 Toad.

Relieving the exhaust bridge is critical. I found this out the hard way when I forgot to do this on one of the Toad engines I built for hare scrambles. It seized in short order.

The Toad makes a great woods bike, but has a weakness with third gear. I ruined 2 transmissions when third gear failed.

Brian

[olddogs]

Watch for hardened or stiff rear sprocket hub cushions. Rough choppy hard pack can send shock waves right into the transmission through the chain and primary gear. A rear brake rod that's too tight can also lock the rear wheel when the shocks bottom. Rear wheel to fender clearance can also stop the tire for a split second sending a jolt straight into the transmission gears. Light and short wheelbase bikes are a blast in the tight woods. I raced Hodakas on MX tracks for many years but never got the chance to do any serious tight woods riding.

[BrianZ]

I got a set of the Strictly Hodaka improved rear hub cushions (the last set according to Paul), and didn’t have another failure subsequently. At the same time I was more careful when shifting into third, so that may have helped as well.

Since I am no longer racing the bike, I am considering making it road legal. It should be fun on gravel roads.

Brian

[viclioce]

I remember drilling 2 holes in the front of the piston, to add an oil passage which would lube the exhaust bridge. It was a 1/16” drill bit. I don’t remember the distances. If you need them I can ask Danny Cooke for the measurements.

According to the Road Toad specs, your supposed to relieve the exhaust bridge an additional .003 after each bore and chamfer the port edges. Victor