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 Post subject: Rocker Geometry
PostPosted: Tue Sep 27, 2011 11:32 pm 

Joined: Sun Nov 07, 2010 10:54 pm
Posts: 425
Location: Brisbane
I have a question regarding rocker geometry,
I used the front head from a 750, and the rear head from a 650.
Ported, etc,etc.
I used the 42mm and 35mm valves from the 750 and used two front cams from a 900ie.
When it came time to fit the rockers the opening rocker left no room for the closing shim.
So I had 3mm(approx) of stelite brased onto the end of all the valves, all then fitted using opening shims in the middle of the range and closers towards the thinner end of the range.
I did relieve the closing rockers to give better clearence to the guide seal, but not much.

It's shim time and the heads are off and there seems to be more wear in the guides than I would like after only 15k kms. The guides are still useable but as the rear head is hard to get off, now is the time to do any alterations.
The cam difference is Std 750 inlet 9.35mm exhaust 8.5mm lift.
900ie inlet 11.8mm exhaust 11.4mm lift

Have I got the geometry of the rockers wrong?
It would seem that the rocker is pushing the valve stem away as well as down. (and wearing the guide oval)

Should I have used 900ie valves that may be longer, are they?


 Post subject: Re: Rocker Geometry
PostPosted: Mon Nov 14, 2011 6:40 am 
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Joined: Sun Jan 09, 2011 1:26 am
Posts: 175
Images: 6
Location: Melbourne, Australia
Hi Graeme,
Steve here. It's been a while not logging on so much these days. You may recall the new house coming before all playthings????
The TT2 is packed up ready to return to the new home just before Christmas hopefully. Then I'll need to set up the garage....

Anyway, my only suggestion is to contact/email Bob Brown of the Desmo Centre here in Melbourne with your query, as he might be able to impart you with some ideas. This is the bloke who built the F1 for Kevin Magee to race. http://bobbrownducati.com/

Good luck.
Just, don't expect any fast turn around....


"...Honey, it's only a project bike...."

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