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Let us know, how much chain hits to side of rear tire, or do it so at all... Are you planning to change chain line offset?

it touches by a hair. See below.
From retaining ring to outer edge of the drive shaft there`re 3,55mm (on my bike) so the most simple thing would be to have a 3,5mm spacer made for the front sprocket and one for the rear that has minimum the same thickness. (for german TUV chain tire clearance would still be too small) A 2 or 3mm wider spacer in the rear would slightly misalign the chain but the additional sprocket and chain wear would probably be acceptable. (You`ll need to measure yourself on your bike, it could be different)
Offsetting the wheel is very hard in the original swingarm as this would involve removing material from the brake caliper bracket or the brake caliper bracket and the right excenter.
I don`t want to machine existing parts. I don`t want to weld a machined old sprocket to the existing sprocket to offset or don`t want to machine the inner section of the existing front sprocket so the retainer ring sits deeper allowing a thicker spacer in the front (well maybe that would still be acceptable depending how it`s done). I wouldn`t like to run into problems when I have to replace a sprocket with a new one which then required the same modifications.
There`re several other reasons like ie bike geometry, that made me decide to go for the 907ie swingarm although it makes me run into some new problem (P750 brake caliper bracket won`t go with the 907ie swingarm, 907ie brake caliper bracket not with the P750 rear brake disc)
Btw. I wonder how it was done to use a 8mm spacer on the rear. There`s only 10mm clearance between the rear sprocket bolts and the swingarm...

I hope she'll be ready for the celebration

... am meanwhile doubting it strongly

Instead of having the rear wheel chain adjuster at the 6 o' clock position, why not put it in the 12 o' clock position? This is what I did when I fitted an Avon Azaro AV-46 150/80ZR16, and the side and centre stands are now ok.

simple and smart. The easiest solution. But you`re changing steering angle. Both new front and rear wheel are higher than the old ones. The bike will lift ca. 15-17mm front and rear. With rotating the excenter you`re lowering the rear which should impact the agility of the bike (theoretically).
If you just used a higher rear tire and kept the old front you can also turn it upside down. That should bring it back to the height level it was with the old rear tire.

G.

PS: I know the chain is rusty. It`s an old, dry one I only use for testing.

.....after this.... 8 mm (cut and welded spare gears)









metzeler 16' 180/60 Marathon is already fitted.

2 questions; what will you do the next time you need to change the rear sprocket and how is the front sprocket mounted on the drive shaft ?!

how is the front sprocket mounted on the drive shaft ?!

+1.
A pic would be nice.

Hello G.
I have already read before your against opinion about this "welding" and I was thinking follow.
- Every how many kilometers will need replacement for gears?
- After how many years these kms will be covered?
All above calculated,but flat tire moment not calculated.
Also me I have stock new tires (2004 production) but this is not solution any more.
The cost is not worth for our baby to feel free from this cancer until.........
Merry Christmas to all.

I will be back with more detail photos.

Hello stylianos62.
Can you please post here a working drawings of rear and front crowns?

paso750 wrote:2 questions; what will you do the next time you need to change the rear sprocket and how is the front sprocket mounted on the drive shaft ?!

I'm wondering the same question. We need a photo of the other side. Is your sprocket like a cup? Or did you enlarge the axle?
I have used an old rear sprocket without teeth, I cut them, like an spacer but I didn,t weld it.

I figure I'll revive this old thread and see what everyone has done about their front sprocket. Has anyone been able to move their front sprocket out toward the end of the shaft to help with clearance for the 180/60-16, yet? If so, how did you do it?

I just finished off my front and rear tires on the Paso and am needing to replace them. I already picked up a 130/70-16 front tire (Dunlop D208) and was hesitant to purchase a rear tire, so I picked up a used Dunlop D250 from a local dealer for free to check clearances with.....and the chain hits the D250, too. I know how I want to shim the rear sprocket out (have a buddy make a spacer with his plasma cutter), but I cannot think of a good way to shim out the front sprocket. The front sprocket already has a built-in offset into it, and by testing out a spare from another bike, it appears that the front sprocket is heat treated completely, so I can't simply machine a deeper recession into it for the retainer.

So, has anyone successfully moved their front sprocket out further to compensate for shimming the rear sprocket?

Terry, there are 2 possibilities:





I`m currently going for the second, had the teeth removed from an old sprocket and the threadholes of a new sprocket drilled through (5mm). The sprocket teeth were cut off with an angle grinder, the lathe did the rest.
I just need a shim ring of ca. 1-1.5mm now to fill the gap between retainer ring and rear side of outer sprocket to eliminate clearance (green in the pic above) and then find out how to get to the offset I need.



G.

paso750 wrote:Terry, there are 2 possibilities:

I had thought about the first option, as it is a variation of what I was trying to do with my ST2 due to chewed up output shaft splines...

I like the idea of the second one. I believe that turning an old sprocket into an adaptor (or making a new one) would be the best option. If a sprocket adaptor was designed using the old retaining clip, we may be able to find a sprocket from another bike that may:

1) Be flat and bolt directly to the adaptor
2) Will be readily available in the future
3) Lower cost than OEM/designed for the Paso
4) Allow us to go to a 525 chain if desired

Does anyone know of any other bike with the same output shaft dimensions and number of splines as the Paso? I'd hate to think I would need to machine a new sprocket every time I need one, but it's not like I will go through a bunch of them any time soon.

I've got a few old front sprockets from the other Ducs and I'll have to give one to one of my buddy's to machine down and work from there. I already was wanting him to machine one of them for my ST2 (it destroyed another retaining ring in under 6000 miles).

Never know, someone come up with a neat system for shimming the sprockets out, and you can sell some kits to other Paso owners who do not have access to machining equipment or do not have machinist friends.

Well, I have mounted a used Dunlop D205 that I picked up for free and put it on the bike. The chain definitely hits the tire and the tire hits the chain guard...

Tire hitting the chain guard...



Chain hitting the tire...



So, I removed the chain and looked at the OEM sprocket on the shaft and there simply isn't much shaft available beyond the sprocket and appears to be about 3.5 mm. I removed the sprocket and looked at it as a mounting adapter for another sprocket as Gerhard suggested. It looks a bit positive. This is the overall height of the OEM Paso 750 sprocket (approximately 12 mm)...



I had two 520 sprockets that are different than the Paso's laying around, so I figured I'd check these out. I stacked the Paso sprocket with the retainer on top of it and then a sprocket from a 748 to get this...



The combination is 26 mm tall, so this would be the same as a 14 mm offset from the original Paso sprocket location (26 mm minus the stock 12 mm). Then, I placed a front sprocket from a 2001 Monster 900ie that has a shoulder on both sides of the sprocket and got this...



This results in a total height of 22 mm, or an offset of 10 mm. I liked this smaller offset and wanted to look at what it would be like on the Paso, so I placed the OEM sprocket on the shaft, put the retainer in place, and then slid the Monster's sprocket in place....



I don't like the idea of having that much of the sprocket unsupported as it may put too much strain on the sprocket bolts and if they stretch any, there is a risk of damaging the splines on the output shaft. I'm thinking of going with this arrangement, but will have a shaft extension machined so I can bolt it to the end of the shaft and give the sprocket more support. If I do not spline the extension, I will have it made with the OD just a little smaller than the smallest ID of the sprocket spline teeth. Ideally, I'd like to duplicate the splines and figure out a way to bolt and pin (to avoid rotation) the extension in place.

I was curious about the sprocket cover, and even without grinding any of the second sprocket, there is plenty of clearance to reinstall the sprocket cover without the chain or sprocket hitting it. I also looked at the swingarm protector, and it looks like if the two tabs on either side of the swingarm are cut off the sides that hold it in place, a spacer can be installed where it bolts to the swingarm with the chain guard to shift it over. This way, the swingarm protector can continue to be used correctly.

Here is a picture of the alignment without moving the swingarm protector over...




I'm hoping to get a few things machined over the next week or two and hope to have the Paso back up and on the road very soon...

man, what bs did I measure that time?! Option 2 is 11mm offset. That corresponds about with what you have measured.

paso750 wrote:man, what bs did I measure that time?! Option 2 is 11mm offset. That corresponds about with what you have measured.

I couldn't tell you the times I have to measure, re-measure, and then measure again because I start getting all the measurements confused. I thought the pictures of the sprockets stacked on top of each other would be an easy way to see the difference.

I wish I had a drill bit that will cut through hardened steel because if I could drill out the holes on the old Monster sprocket, I can do a test fit of the system quite quickly. It would be great if a system could be derived to modify the OEM front sprocket and then just buy 2000-01 M900ie front sprockets and not require any more machining after the original modification (other than drilling threads out of the new sprocket holes).

I still don't like the unsupported section of the second sprocket, though......that bothers me. I wish I could easily make a splined shaft extension.

I still don't like the unsupported section of the second sprocket, though......that bothers me. I wish I could easily make a splined shaft extension.

agree, but if you don`t have any official rules that say you have to have min 5mm clearance between tire and chain and if it`s enough that the chain just doesn`t touch the edge of the tire an offset of 5-6mm may be enough. In this case you may have 2mm max overhang which is still not perfect but nothing to really worry about.

paso750 wrote:agree, but if you don`t have any official rules that say you have to have min 5mm clearance between tire and chain and if it`s enough that the chain just doesn`t touch the edge of the tire an offset of 5-6mm may be enough. In this case you may have 2mm max overhang which is still not perfect but nothing to really worry about.

True....

I've been thinking of a shouldered end piece to bolt on the end of the shaft. This would prevent the outer sprocket from walking off the shaft if the two bolts happen to loosen or break. Basically a spacer to fill in the deficiency of the output shaft's length and then a flared section (or simply a washer) and bolt it into the end of the shaft. Just a little added protection from having the sprocket potentially slide off the end of the shaft.

I'd like to find a flat 520 sprocket with the same splines as the Paso. It would make everything a lot easier, plus, if it has holes in it like the one pictured on the left in this photo, maybe we could get lucky and a couple of bushings could be made for the retaining bolts (instead of having to drill the threads out of a new Duc sprocket)...