Recently purchased 1989 MC18, everything wonderful but speedo doesn't
work. Former owner put new cable on with no luck. But when I look inside
on driving end of business(ie not the end where it goes onto speedo), the cable end is squarish and does not reach
far enough to touch a round hole being somehow driven off front sprocket.
I could not see well enough to tell if that round hole was threaded or not.

I look at Tyga website and it lists the same pattern speedo cable as
fitting 18/21/28. Is that truly correct? If that is, then I suspect I am
missing some piece inside that interfaces between the cable end and the
drive.

Any ideas?

Thanks in advance!
Maxine

The square end of of the cable should go into a square hole in the speedo drive. If you undo the cable from the speedo end, push the cable down into the drive and then try spinning the rear wheel. If the cable rotates then its just a matter of the cable being too short. If it doesnt rotate then take the drive off ( the 2 allen bolts) and make sure the plastic socket is still there (its white, well it was when it was new) that is driven by the gear box sprocket bolt. If it is, turn it by hand. If the cable still doesnt rotate then its the speedo drive. They are pretty common so you shouldnt have to much trouble getting one if its ducked.
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If I have to take the carbs off once more...

hang on!, i think the nsr only has a square at one end. The end that goes into the drive should have a little bar with a slot in it. The slot locates and thats what turns it. Are you sure the inner part of the cable isnt in backwards? that would do it (you can pull it out and turn it around see). The square end shoudl go into the speedo not the drive.
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If I have to take the carbs off once more...

thats what I was just going to say stephen after taking mine to bits for a look.Its in upside down.
Psycho

Square end is at speedo and the slotted end is at drive end. What is supposed to engage that slotted end? A special nut that holds on sprocket, some kind of adapter? When I look in hole after disconnecting drive from plastic cover all I see is some kind of nut holding on sprocket, nut has a round hole in it I see nothing that the slotted cable end fits inside, in fact when I bolt up drive it does not go in far enough to engage or slide into any other part associated with sprocket. I suspect there is something missing that the flat end fits into. Anyone have any pictures of theirs that I could compare mine to or vice versa? Thanks, Maxi

The cable goes into the top of the drive and there should be like a little flat screw driver end down inside. Thats what drives the cable.

On the other end of the drive there should be a plastic socket that is pressed onto the drive. This locates onto the bolt that hold the gear box sprocket on.

The sprocket turn the plastic socket. That then turns thought 90deg and drives the screw driver type blade which turn the cable. Hope that helps.
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If I have to take the carbs off once more...

That answers my question the plastic piece you mention is missing. Anyone have any idea where I can find one? This list rocks cant believe folks went through the trouble to pull drive off and look just to help a newbie, may I return the favor to someone someday. Thanks, Maxi

HHHM looking at this post it looks like my MC21 front end swop, on to my 16 is gonna have a speedo problem. the 16 cable runs off the front wheel can i retro fit the MC 18 speedo drive to my engine? any ideas!
wayne get the fairing off i,m comming round