907 Front Sprocket

[black907]

Hi Guys

Quick question. Which of these front sprockets is correct.
The old one is more offset outwards with the sprocket face to the outside.
The new one has the sprocket more central with a boss either side.
The reason I ask is that the old sprocket has signs of wear on the outer face implying that the chain is "wanting" to run more centrally so I'm wondering if it was the wrong one.
Someone must know.
See pic, Old sprocket on the right, new on the left.

photo.JPG (113.37 KiB) Viewed 14714 times

[englishstiv]

The old sprocket looks like it may be a 900ie Monster item. Last two on my 907 looked as your new one does.

[black907]

[du907]

black907,

Here are pictures of the correct sprocket. Notice it has the same size "boss" on both sides. The retaining clip that is held on with the two screws into the sprocket fits in a groove on the spline shaft. This will set the sprocket on the shaft in the proper location.









I say go with the "new" one on the left.
du907

[black907]

Thanks for that. I went with the new one in the end so its all good.

[ducinthebay]

Check the alignment to the rear sprocket to give you the best answer.
- Square the rear axle to the swing arm pivot
- Use a laser or string to show the where the front sprocket should be.
- Pick the one that fits best.
(easiest if the chain is not installed)

Cheers, Phil

[Janky59]

Just to throw this in the mix, while doing some cleaning and replacing the frame wear block I am checking out the front sprocket situation.
I had bought the proper JTF737-15 front sprocket & a rear 42T ahead of time to have on hand when the current set is due for replacement so I’m doing some early reconnaissance work.
My 907ie came to me with this sprocket:

A147CAEC-BCC4-493B-BD21-F2392563FE99.jpeg (287.44 KiB) Viewed 9682 times

I don’t know what brand it is as there isn’t a single logo, name or number stamped on it anywhere. It shows some wear on the engine side face, not real severe, true that I don’t know if it has been on 1,000 miles or 10,000. The bike odo shows 16.7K miles currently.
Anyway, when I fit up the proper sprocket with the boss on both sides and lay on the chain, the chain doesn’t line up with the slider too well. It’s too far outboard as expected. I’ve made up a spacer to move the “even sided boss” sprocket inward to nearly the same position as what’s on the bike now and chain to slider alignment is pretty good.

3C385353-3FCA-40B0-BB7F-8C83F387C2F2.jpeg (247.07 KiB) Viewed 9682 times

37EA8B93-F884-4881-BDDB-4E2EB10BDB38.jpeg (209.8 KiB) Viewed 9682 times

So I have a bit of a mystery right now but I have some time before I need to sort it. I’ll run the currently installed chain & sprocket set this summer, maybe 2 seasons depending on how much seat time I get before it all needs replacement.I’ll post back what I end up with, cheers.