Swapped out the cush drive on my '95 900.
Picked up a used cush drive (sprocket holder part) as mine was displaying movement between the pins and bushes. There was always some movement which I put down to wear, but I suspect that mismatched parts could be the reason.
I found the used "new" drive to be a nice tight fit into the bushes. I also noted that there was 5mm more clearance between my swingarm and the sprocket nuts which was quite welcome. The "new" cush drive sits into the hub more fully and is about 5mm narrower.
Did the factory change the sprocket carrier/cush drive for more clearance at any stage?
I am thinking that my bike came with a miss matched part off a bike with a steel swingarm, an earlier cush drive, or one from a 750 with a narrower wheel/hub? The "newer" part fits better with slightly thicker pins (about 1mm) and sits into the hub snugly and with better clearance. The factory did go to thicker pins sometime in the mid nineties IIRC.
The vendor is a "grey" importer so I would not be surprised at some swapping of parts to get the bikes prepped.
I was not aware of different cush drive inserts. I'm also not aware of any changes to the pins or carriers for 5" wheels.
Did you buy your bike new?
5 years ago with 4500 miles. Its always had bush/pin play.
Both cush drives with pins removed and flat on the bench, "old" one 5mm taller. Pins the same but for a mm in thickness at the bush end. I think they were beefed up due to some breaking.
Old cush gave only 2-3mm sprocket nut to swingarm clearance, new one has 7-8mm which is great. Hows the clearance on yours?
It's never been an issue...
I'll measure it for you a bit later when it warms up...22F right now.
I'm pretty sure there's 3 different carriers, and I may have one of each to measure.
Thanks. You might save Nate going out to the shed in the cold. [laugh]
I suspected there were 3 kinds, but I've only found 2.
M750 - 13mm offset
ST2, M900ie - 18.5mm offset
I suspected that the M900ie was going to be the '3rd' kind, as it's the one that has the oddball symmetrical front sprocket.
But it was the same as the ST2.
Standard Ducati front sprocket produces a 10mm offset when you flip it.
Why the carrier difference is 6.5mm vs. the 10mm at the sprocket?
Who knows....
Drive pin 82110091A diameter is 0.629" (15.98mm)
Cush drive 70090051A inner diameter is 0.642" (16.30mm)
Both of those are brand new in the bag.
Pic of how I measured:
(http://farm9.staticflickr.com/8339/8187979423_875f0a6e29_c.jpg) (https://www.flickr.com/photos/79721557@N02/8187979423/)
The one I removed was 18mm and the one that went on was 13mm. So that accounts for the 5mm. Maybe its got to do with tyre/wheel width and chain clearance. The pins were a mil bigger diameter on the 13mm offset carrier.
The one I removed was 18mm and the one that went on was 13mm. So that accounts for the 5mm. Maybe its got to do with tyre/wheel width and chain clearance. The pins were a mil bigger diameter on the 13mm offset carrier.
Edit:
According to LT Snyder, it was the threaded part of the cush drive pins that goes into the carrier that was increased in diameter. So I guess the pins were worn ( by 4500 miles).
So I thought about swapping the pins to the old carrier. (EDIT). Of course this will not work due to the pins having a shorter length on the sprocket side by at least 5mm. This means it is a 750 version as SD has measured. I'm guessing small case motor, steel swingarm and narrower rear wheel equals different offset. Strange about the 900ie though.
I will source new pins at the next tyre change. Where do you buy them?
I'm pretty sure the major control on the carrier is whether it's a 4.5" or 5.5" rim.
I got my pins from a dealer.
Those, the cush drives, wheel bearings, and shipping turned my bargain wheel into ~market value wheel. [laugh]
But it'll all be new, so that's nice.
Ive seen the TPO pins, beautiful, but $$ :o
I thought I was so smart getting the whole carrier and pins for $40. Who wants to buy a cush drive for a 750 for $40? [laugh].
Quote from: Speeddog on November 15, 2012, 10:54:55 AM
I suspected that the M900ie was going to be the '3rd' kind, as it's the one that has the oddball symmetrical front sprocket.
But it was the same as the ST2.
I don't know for certain, but I thought the odd ball front sprocket was due to the M900ie using the 748's transmission and output shaft, hence the different front sprocket to adapt to the dual swingarm instead of the single.
Also, I've wondered if the M900ie sprocket would be useful in other Ducati swingarm and engine swaps? I dunno, just a thought.
Perhaps it's due to the 748 transmission, but my Monster S4 has the same trans and uses the normal sprocket. ???
I had an M900ie in for a chain and sprockets a while back.
I carefully measured, and the alignment was better with a normal sprocket.
I've passed that info onto my brother. Very useful.
Quote from: koko64 on November 16, 2012, 05:21:14 PM
I've passed that info onto my brother. Very useful.
Yes he did. Thanks Speeddog. I'll save myself $20 next time I need a 14t front!
Cheers,
GK
i have a customer with a 10/96 m600 just like minnie and it has a carrier which places the sprocket too far out. it has been fitted with a 5.5 rear wheel, and i replaced sprockets the first time i saw it and have just done so again 15,000km later and the rear sprocket was quite worn on the outer adge of the teeth. when i replaced them i put the laser aligner on the outside of the front sprocket (flat side out) and it hit the middle of the rear sprocket ish when the rear (axle) had been aligned with the same tool. as the aligner line usually sits on the chain outer side plate this meant the chain was about 5 or 6mm out of line i thought. the front edge of the rear sprocket would have been turned in slightly by the aligning process, as you're just pointing it at the front one basically, but sitting the tool on the front sprocket gives you a nice parallel line as it can't move. when the sprocket is mounted on the cush drive carrier there is a mm or so carrier protruding at the center, just like minnie and the 851 and every other one i could see at the time.
i then noticed on a customer's 01 m750 that it had much more centre protruding, like the carrier was machined to allow the sprocket to sit further in toward the centre of the bike. i've seen a lot of these on ebay, mostly 25mm axle ones from little engined bikes (nominally 4.5 rear wheel). but some called m750 00.
i've also seen some of the (i think) 4.5 rear wheel bikes with a much thicker spacer fitted b/w carrier and swingarm. probably in the order of 5mm. possibly only st framed bikes, i don't recall the pattern.
anyway, i need the 13.mm offset carrier. i didn't think of checking that dimension.
the pins changed when they went to lh thread into the carrier. the early ones that had the nuts come off were rh thread in the carrier, then they went to lh. when you tighten the sprocet nuts on the lh ones it tightens it all up. on the rh ones it unwinds the pin if you don't have the pin and carrier fixed. so while the nut is tight against the sprocket the pin is not tight on the other side and it can wind in (towards the outside) and unload the nut.
Id be happy to swap with him Brad. It's a good one, nice and tight in the bushes and the bearings are good.
What you describe makes sense. He has the big wheel, but he needs the smaller wheel carrier to get alignment with the small case front sprocket/swingarm combo. You can try it and measure it up.
Quote from: Speeddog on November 16, 2012, 01:12:26 PM
Perhaps it's due to the 748 transmission, but my Monster S4 has the same trans and uses the normal sprocket. ???
I had an M900ie in for a chain and sprockets a while back.
I carefully measured, and the alignment was better with a normal sprocket.
Speeddog, I have my Monster in for the winter and would like to measure the alignment of the chain (among other details). Would you be willing to let me know how you checked the chain and sprockets? Thanks!
If you've still got the sprocket carrier I'm interested.
Yes I have it, but it suits the 750/600 narrower wheel.
Got the carrier today [thumbsup]
OR, I know you wanted the 750 cush drive/sprocket carrier. Yet you have a 900, so what's your plan with the part?
The cush drive I machined to get the sport wheels to fit was about .15mm - .2mm out on the sprocket mounting face. The 750 is a godsend as I only have to machine for a new circlip, reduce the boss accordingly and throw in some thinner bearings.
Plus if anyone else wants to follow the route I took it'll save having to machine down the cush drives pins and cut the thread. And no need to make a complete new sleeve\spacer just take about 3mm off the inside end and reduce the O\A length.
I know this doesn't make a lot of sense but once I continue in my spoke wheel howto it'll all become clearer.
Picked up cush drive pins from the local dealer for 55 bucks! Thats what the 750 carrier owed me and what I got back for it (thanks Rob).
I fitted them with a light coat of high pressure grease on the pins where they insert into the cush rubbers.
The carrier/cush drive play is gone.
Note that the pins have a left hand thread into the carrier.