907 Front Sprocket

discussions specific to the 907IE
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black907
Posts: 17
Joined: Tue Oct 30, 2012 12:55 pm
model: 907 I.E.
year: 1992
Location: SW Scotland

907 Front Sprocket

Post by 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
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englishstiv
paso grand pooh-bah
Posts: 1111
Joined: Wed Apr 09, 2008 9:57 pm
model: 907 I.E.
year: 1992
Location: Manchester, England.

Re: 907 Front Sprocket

Post by englishstiv »

The old sprocket looks like it may be a 900ie Monster item. Last two on my 907 looked as your new one does.
DUCATI 907ie 1992
HARLEY DAVIDSON ELECTRA GLIDE CLASSIC 1991
black907
Posts: 17
Joined: Tue Oct 30, 2012 12:55 pm
model: 907 I.E.
year: 1992
Location: SW Scotland

Re: 907 Front Sprocket

Post by black907 »

:thumbup:
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du907
Posts: 346
Joined: Fri Jul 08, 2005 12:00 am
model: 907 I.E.
year: 1992
Location: Winston-Salem, N.C. USA

Re: 907 Front Sprocket

Post by 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.

Image

Image

Image

Image

I say go with the "new" one on the left.
du907
black907
Posts: 17
Joined: Tue Oct 30, 2012 12:55 pm
model: 907 I.E.
year: 1992
Location: SW Scotland

Re: 907 Front Sprocket

Post by black907 »

Thanks for that. I went with the new one in the end so its all good.
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ducinthebay
paso grand pooh-bah
Posts: 1323
Joined: Sat Sep 03, 2005 12:00 am
model: 750 Sport
year: 1990
Location: SF Bay Area

Re: 907 Front Sprocket

Post by 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
Duc in the Bay
1990 750 Sport x2-Rosso Blanko (900ss copy) & Nuovo Nudo (Scrambler project)
1991 907 -mostly stock
2002 ST4s - Lots of mods.
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Janky59
Posts: 49
Joined: Sun Aug 28, 2022 6:56 pm
model: 907 I.E.
year: 1992
Location: Salisbury, MD USA

Re: 907 Front Sprocket

Post by 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
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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
3C385353-3FCA-40B0-BB7F-8C83F387C2F2.jpeg (247.07 KiB) Viewed 6287 times
37EA8B93-F884-4881-BDDB-4E2EB10BDB38.jpeg
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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.
Current moto stable:
‘21 Beta 390RS
‘18 BMW R1200RT
‘11 Ducati Hypermotard 1100 EVO
‘92 Ducati 907ie
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