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1972 Ossa Mar Top End And Clutch Suggestions For Competition?

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Hi all

I currently compete on my mar and this winter will be taking a close look at the cylinder, piston, rings etc and clutch to freshen up. What do you suggest i use for the clutch, surflex?, barnetts?, what springs etc, any suggestions for lightening the pull. Any porting alterations or better alternatives over the tarabushi pistons / sleeves. Just looking for your experience and suggestions. I using the ossa works manual for specs.

just as a side note i've raked some rock shocks to the 1976 position, lightened the bike a bit, lowered the pegs and fitted a 28 mm oko, not interested in fitting a reed case.

cheers

bob

I fitted a Keith Lynas (www.ossaplanet) supplied-Wiseco piston and it turned my TR77 into a different bike (well sort of, you know what I mean!) Revs quicker and cleaner and sounds a whole lot better mechanically as well, not cheap but I reckon well worth it. I,d enquire for mods with Keith, if anybody would know he would, seems to live and breathe Ossas. Hope this helps!

just wondering....

Why no interest in fitting a reed valve/case?

  • Author
just wondering....

Why no interest in fitting a reed valve/case?

i have the case and reeds but i want to take it one step at time plus I'm pretty happy with how it's running right now, playing with the idea of lightening the flywheel also, maybe next winter

cheers

bob

I spoke with Mick andrews a while ago and in his opinion reeds are not necessary.

Although if you talk with Keith Horsman you get a different story.

I have a few ex-works engines and they came with about half a dozen flywheels of different weights so that may be one way to go.

Theres actually not much wrong with a well set-up standard engine in my opinion, it all depends what you are riding against. Here we have a pre 1978 class so youre not up against a Fantic for example.

rex caunt sells some lighter clutch springs which help greatly.

  • Author
I spoke with Mick andrews a while ago and in his opinion reeds are not necessary.

Although if you talk with Keith Horsman you get a different story.

I have a few ex-works engines and they came with about half a dozen flywheels of different weights so that may be one way to go.

Theres actually not much wrong with a well set-up standard engine in my opinion, it all depends what you are riding against. Here we have a pre 1978 class so you're not up against a Fantic for example.

rex caunt sells some lighter clutch springs which help greatly.

i tend to agree that a well set machine is good, i do like the 28mm oko change. i will go with the lighter clutch springs, do you have a contact for him?

much appreciated

http://www.rexcauntracing.com/

He never actually lists the Ossa springs in his products category for some reason, normally you can find them in his ebay shop but they aren't listed there either at the moment. He definitely sells them, may be out of stock at the moment. Contact details are on the website if you want to ask him

  • Author

thanks for the info everyone, sent rex an e-mail

looks like i'm needing to bore it out (.005 piston clearance now)

cheers

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