Ace 100 gears in an Ace 90 case?

[jaybird]

My Ace 90 has started making a terrible clatter in the gearbox. It sometimes shifts with a crash, and the transmission now rattles in every gear at one throttle setting or another.

Therefore, it's time to split the cases and see what's going on in there.

As long as I'm going in there, I wonder if it would be possible to fit the 5-speed Ace 100 transmission into this Ace 90's case.

Can it be done, and has anyone done it?

Tom

[junker2k]

The 5 speed will not fit with out some work. But it can be made to fit.
Jack K

[jaybird]

Thanks Jack. I'm no machinist, so I'll probably end up sticking with the four-speed.

I'm still curious to know what has to be done to make a 5-speed fit.

Tom

[admin]

There also was the Ace 90 five speed transmissions. These were made for racing but they will fit without modifying the cases. Main shaft, five gears, new countershaft I think that was what all needed? They had a (91) part number.
Thanks
Paul

[junker2k]

I thought I remembered when Harry put the 5 speed in mine, the inside of the case had to be cut down. I guess I will have to find the hop up notes that I still have to be sure. My mind is not what it was back then and that was a few years ago.. This was the racing 5 speed as there were no 5 speed Hodakas yet.
Jack K

[admin]

Jack I have those notes here someplace and will try to find them. I know the width of the gears on the (91) set were thinner than the (90) gears.
I do know that putting an Ace 100 transmission into a 90 set of cases the cases do need to be machined to accept the Ace 100 set.
Thank you
Paul

[dirtsquirt74]

Jack - I have an ace 90 motor with a five speed in my Yamagouchi. I am not sure what dad did to accomplish it. I was led to believe the gears were thinner. I do know the combination turned it into a good trail bike. It is still running to this day.

Richard S.

[taber hodaka]

The five speed race gears for the ace 90 worked great just a little machining had to be done on one case. I am still riding mine. And I think I have the literature for installation. There was a close and wide ratio set and there was a c clip to hold on the sprocket not a nut. Clarence

[dirtsquirt74]

I must have the close ratio gear set. My motor loads up easily on a trail ride. I then need to stop and let it clean out.

Richard S

[junker2k]

Richard, I'm not sure the gear ratio has much to do with it loading up. I think a little stronger right hand and hang on, that will clear it out.
Jack K