Ct90 Not Shifting

zshulk56

New Member
Hi folks first time here. I have a 78 Ct90 . I got it running last summer and it ran fine randomly it started not starting. I wanted to rebuild the engine so I figured this was as good a time as ever to do it. So over the winter I have rebuilt the engine. I put in a dratv big bore kit, beyond that everything is stock. I put the engine back in the bike today and got it to start up finally. My joy was quickly dashed when i put the shifter on and tried to shift the engine. No movement in the shifter. So I took apart the right side of the engine and best I could tell was the gearshift arm wasn't properly engine with the drum. Almost as though there wasn't enough tension on the springs on the gear shift arm. Once I thought I got it to engage correctly, it would get hung up between gears. I thought this may have been because the engine was not running. so I reassembled got the bike started up and again no movement just like before I took it apart again. I don't think it is anything in the inner case as a can take a screwdriver on the bolt on the star shaped plate and turn through the gears without any issues. I also have that bolt nice a tight with loctite in place. I didn't take any pictures or videos while I had it open but can sometime this week. In the mean time are there any suggestions as to what I should look for.
 

zshulk56

New Member
I will try and pull it apart and post a video of sometime this week to see if that will help thoughts. I personally don't have a ton at this point.
 

joel1234567

Active Member
Will it shift with the side cover off? Theres a triangular plate with three balls in it that sits between the case and clutch. Not sure of the proper name at the moment. Its a pita to get it aligned properly when you remove and reinstall the right side case. Ive had it move a bit when putting on the side cover and the bike wont shift afterward.
 

zshulk56

New Member
I hadn't tried it until I had the clutch out it completely. Once I somewhat manually engaged it into the shift drum it would shift but not completely move between the detents in the star plate on the end of that drum. Ill see about that ball bearing plate when I open it back up. should have time this weekend to take it apart
 

dirtbkr188

Active Member
The best way to keep everything under the clutch cover in place is to lean the bike over on its left side, making sure the shift lever doesn't contact the ground, or it will make reinstalling the clutch cover almost impossible.
 

zshulk56

New Member
The shift fork looked fine to me. It also shifted no problem prior to the rebuild. And yes I tried to put it on once with the bike vertical and it was a hard pass.
 

zshulk56

New Member
Got in the tonight and think I got it all sorted out. The shift fork was definitely not engaging with the drum properly. I just kept fiddling with it trying to get it to snap into place properly unti it did. Then once everything was reassembled I thought I was having the issue with alignment that @dirtbkr188 had described. Turns out after I rebuilt the clutch and install dratv's springs which I didn't realize were much stiffer when I ordered them. Turns out with these springs and the new friction plates if the clutch is adjusted as per the factory the clutch is much to tight to shift so I loosened it till it just seemed to shift properly. I guess I will just continue to keep an eye on it and adjust it as it wears.

Still have to put it in the bike and put the rubber to the road and actually make sure it works in real life and not just on the bench. Once its in I might even put up a picture of the bike. Thank you guys for your help/suggestions.
 

OLD CT

Well-Known Member
The ST70 Dax stroker build has pictures of the worn shift forks that do wear out, for reference. Glad you did get it sorted.
 

GaryG

New Member
Got in the tonight and think I got it all sorted out. The shift fork was definitely not engaging with the drum properly. I just kept fiddling with it trying to get it to snap into place properly unti it did. Then once everything was reassembled I thought I was having the issue with alignment that @dirtbkr188 had described. Turns out after I rebuilt the clutch and install dratv's springs which I didn't realize were much stiffer when I ordered them. Turns out with these springs and the new friction plates if the clutch is adjusted as per the factory the clutch is much to tight to shift so I loosened it till it just seemed to shift properly. I guess I will just continue to keep an eye on it and adjust it as it wears.

Still have to put it in the bike and put the rubber to the road and actually make sure it works in real life and not just on the bench. Once its in I might even put up a picture of the bike. Thank you guys for your help/suggestions.
I have read that you need to assemble the parts that go onto the face of the clutch basket with thick grease and have bike on it's side to get cover installed with everything in place. The part with the three ball bearings has to be right side up, and you have to have the small spring and tube in place so you can adjust clutch when cover is back on. There are You Tube videos that show these parts and how they work together to disengage and engage the clutch. Good luck!
 
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