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 Post subject: F1 replacement gearbox
PostPosted: Thu Aug 18, 2011 10:59 am 
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Joined: Thu Aug 18, 2011 4:35 am
Posts: 3
Hi guys,

Been following this forum for a while now and finally registered after having a breakdown earlier this week.
When out for a run heard a funny noise and then struggled with gera changes. When checking this out on the side of the road I could not find anything unusual and suspected the gear return spring to have failed. Carefully drove home (10 miles) and stopped twice to check, but found nothing untoward then. When I arrived home I noticed oil on the chain and rear tyre and the chain was a bit slack. When drainginthe oil I found parts of a bearing cage, suspect the output shaft bearing went. Clutch works fine and engine sounds good in neutral.
Can you guys suggest any replacement engines/bikes boxes for an F1B with dryclutch engine, my shortlist is as follows: F1, 650/750 Alazzurra/Indiana/Elefant, 750 Paso/Sport or 1991 750SS. But would a more modern or pantah wet clutch box fit straight in (750,600, 620)? Note I'm located in Scotland and if you've got a spare that you're willing to sell please let me know.

Thanks,

Jurgen


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 Post subject: Re: F1 replacement gearbox
PostPosted: Fri Aug 19, 2011 1:05 pm 
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Joined: Mon Oct 04, 2010 7:47 am
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Jurgen,

Welcome to the forum. Their are several gearboxes that will work in your F1B. Some of the gearboxes are a direct swap and some only parts can be swapped. The transmissions / gearboxes that would be a direct swap would be 750 Paso and 750 Sport. Most small case Ducatis up to and including 1998 the gears and transmission output shaft will interchange but the difference in the input shaft as wet clutch motor have a short input shaft for the clutch to mount. Also the new transmissions / gearboxes haver roller bearings and better metallurgy. Hope this helps.

Palmer


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 Post subject: Re: F1 replacement gearbox
PostPosted: Sat Aug 20, 2011 3:02 am 
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Joined: Sat Oct 16, 2010 8:57 am
Posts: 43
Location: Germany
There are different mainshafts installed in F1B engines.
Up to Motor-no. 1494 swap to new gearbox layout need
some modifications...

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Up go the revs, out go the lights


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 Post subject: Re: F1 replacement gearbox
PostPosted: Sat Aug 20, 2011 8:08 pm 
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Joined: Thu Oct 14, 2010 7:30 am
Posts: 130
If i remember correctly the difference in the mainshafts up to the 90's is an oil seal so the clutch doesn't get wet. But I've been wrong before.


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 Post subject: Re: F1 replacement gearbox
PostPosted: Sun Aug 21, 2011 8:12 am 
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Joined: Sat Oct 16, 2010 8:57 am
Posts: 43
Location: Germany
They changed the diameter of the mainshaft on the opposite side of the clutch,
from 20mm to 17mm. Maybe with different bearings one can fix the change.

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 Post subject: Re: F1 replacement gearbox
PostPosted: Sun Aug 21, 2011 1:57 pm 
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Joined: Mon Nov 22, 2010 10:54 am
Posts: 9
I had the exact same issue 2 years ago.
One of the layshaft bearing (on the clutch side) simply exploded.
As every gear moved inside and was quite scratched, I replaced the whole gearbox with a Paso 750's one. It is plug and play, apart from the shafts diameters. And I have been unable to find any suitable bearing to compensate the bigger diameter of the paso shaft.
Fortunately, shaft diameter is the same where gears are. So I re-used my original mainshaft and layshaft, placed the Paso's gears on them, and used the usual bearings.

Bad news is that I think it broked again 2 weeks ago. Did not had time to open it yet, but I have serious doubts. Strange noises are coming from below...
The repair was 2.500km old.
Probably not from the gears, rather a lubrication problem. Need to open to make sure.


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 Post subject: Re: F1 replacement gearbox
PostPosted: Thu Aug 25, 2011 12:46 pm 
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Joined: Tue Oct 05, 2010 9:21 am
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Upgrading the bearings in F1 (and Ally) cases is advisable for street bikes and very advisable for race. These are the bearings under the clutch basket and chain sprocket. Originally we were using heavy duty ball type but now use roller type. Straight cut primary gears have very little thrust load which allows for this. The bearings to be used are NJ205ECP and NUP205ECP (SKF #s). The two piece inner race type being used under the clutch. Got to tip the hat to Bruce for this one. –Cranky-


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 Post subject: Re: F1 replacement gearbox
PostPosted: Fri Mar 11, 2016 2:10 pm 
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Joined: Wed Nov 17, 2010 5:43 pm
Posts: 59
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So I got the fancy new roller bearings to install since I have my cases split. What's the correct orientation of these? Inner race flange toward the interior of the case, or toward the exterior?

Thanks,

Geoff


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 Post subject: Re: F1 replacement gearbox
PostPosted: Sat Mar 12, 2016 11:48 am 
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Joined: Thu Oct 14, 2010 7:30 am
Posts: 130
Geoff, The flange [inner race] should face the gear [inward] usually it is a snug fit on the shaft keeping the gear and shims[if any] in place when you are jiggling the things together fitting the stuff into the case. Be sure to check the end float on the shafts after assembly.


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