Author Topic: Ossa betor forks cap  (Read 7032 times)

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Offline 09.0

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Ossa betor forks cap
« on: June 07, 2012, 05:21:50 AM »
On my74  phantom there is a bleed hole of some kind in the top fork cap and I'm not really sure what the idea is behind it. It seems to be a one way valve set up to let air in but not oil out?
Mine pisses out oil when riding.
I cannot get it apart. In the workshop manual I have it's a simple ball and spring arrangement but mine is completely different and more complicated. Im trying to get it apart to stop the oil from coming out. Other than that should I just block up the holes?

« Last Edit: June 07, 2012, 05:54:04 AM by 090 »

Offline jerry

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Re: Ossa betor forks cap
« Reply #1 on: June 07, 2012, 08:37:03 AM »
My understanding is that it it to let the air oiu but not the oil but the problem is if you get a bit of dirt between the ball and the seat face it will leak oil and air but I reckon youve worked that out already. My mail is that their ineffectual any way and your better off to buy an unvalved set screw them in and presto problem goes away. Cheers Jerry

Offline jerry

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Re: Ossa betor forks cap
« Reply #2 on: June 07, 2012, 08:38:26 AM »
Spell check sorry make that "out" apologies for my mangled English!

Offline euro bikes

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Re: Ossa betor forks cap
« Reply #3 on: June 07, 2012, 08:49:01 AM »
It's to stop air build up in the forks,my MK4 Bully has them and they work fine. Do you have the right amount of oil in them about 200mls. The thing is to point the holes out away from the bike so any that comes out squirts away.

Offline matcho mick

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Re: Ossa betor forks cap
« Reply #4 on: June 07, 2012, 11:50:54 AM »
mine work ok too,just lets the air out,but no oil,think Jerry's on the money,orifice is enlarged too much by dirt probably!,same setup on early DT250 forks from memory, :P
work,the curse of the racing class!!
if a hammer dosn't fix it,you have a electrical problem!!

Offline Tahitian_Red

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Re: Ossa betor forks cap
« Reply #5 on: June 07, 2012, 12:13:51 PM »
Get the non-venting type.  My racing Phantom and 250 Pursang both have them, but when they start leaking I'm going with the standard type.

So, if the forks are leaking you must have that thing running.  What do you think so far?
 ;D
The "Factory Novice"
California, USA

'74 Suzuki TM100, '75 Bultaco 250 Pursang, '77 Honda XR75, '77 Suzuki RM125B, '77 Yamaha YZ400D, '79 Honda CR250RZ Moto-X Fox Replica, '83 Honda ME480RD Mugen

Offline 09.0

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Re: Ossa betor forks cap
« Reply #6 on: June 07, 2012, 12:40:24 PM »
Get the non-venting type.  My racing Phantom and 250 Pursang both have them, but when they start leaking I'm going with the standard type.

So, if the forks are leaking you must have that thing running.  What do you think so far?
 ;D
i love it! I have only kind of sorted it as I have entered it in the nationals this weekend and have t raced it. It's been a great bike to restore and everything seems to have fallen into place from start up. If it doesn't start second kick then it's starts on the first one!
Thanks for all the replies. It seems most think it's the type
With a ball and spring but it's a different system. Maybe it's because I am running more oil than standard though. I have decided to block them up with a small screw and some loctite which is doing the job.

Offline djr

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Re: Ossa betor forks cap
« Reply #7 on: June 07, 2012, 06:22:41 PM »
Hello, I have exact same fork caps on my 1976 Ossa MAR trials bike, they leaked all the time so I blocked them off .
Haven`t had any problems , but this is a trials bike , the forks would be working harder on a moto cross bike.
I tried to get some unvented caps to fit the forks but found they where differant {thread size or dimensions ? I cant remember}
I have found there can be differances between Ossa/Bultaco/Montessa   Betor forks  even when they are the same age, some
parts are unique to each manufacturer.

   -  dave

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Offline Mick D

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Re: Ossa betor forks cap
« Reply #9 on: June 24, 2012, 11:30:56 AM »
I know this link is for Metralla fork caps, But I am pretty certain he also manufactures the 35mm betor caps.
http://www.ebay.com.au/itm/BULTACO-METRALLA-FORK-CAPS-NEW-STAINLESS-2-OF-SECONDS-/370624899886?pt=AU_Motorcycle_Parts_Accessories&hash=item564af72b2e

I have bought a bit of stuff of him. And been very happy with it.
"light weight, and it works great"  :)

Offline firko

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Re: Ossa betor forks cap
« Reply #10 on: June 24, 2012, 11:45:09 AM »
There's a bloke who sometimes advertises on Marks Swapmeet and www.vft.org who makes nice alloy fork caps for both Ceriani and Betor forks. I've bought both Betor and Ceriani caps from him and they're superb. I've just searched back through my computer for his contact details but unfortunately couldn't find anything. Hopefully someone else may have bought something from him and have his details.
« Last Edit: June 24, 2012, 12:21:15 PM by firko »
'68 Yamaha DT1 enduro, '69 Yamaha 'DT1 from Hell' '69 DT1'Dunger from Hell, '69 Cheney Yamaha 360, 70 Maico 350 (2 off), '68 Hindall Ducati 250, Hindall RT2MX, Hindall YZ250a , Cycle Factory RT2MX flat tracker, Yamaha 1T250J, Maico 250 trials, '71, Boyd and Stellings TM400, Shell OW72,750 Yamaha

Offline matcho mick

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Re: Ossa betor forks cap
« Reply #11 on: June 24, 2012, 02:21:42 PM »
I know this link is for Metralla fork caps, But I am pretty certain he also manufactures the 35mm betor caps.
http://www.ebay.com.au/itm/BULTACO-METRALLA-FORK-CAPS-NEW-STAINLESS-2-OF-SECONDS-/370624899886?pt=AU_Motorcycle_Parts_Accessories&hash=item564af72b2e

I have bought a bit of stuff of him. And been very happy with it.
Jim's a bit of a bully freak too,does some nice machining for a variety of bike makes, :P
work,the curse of the racing class!!
if a hammer dosn't fix it,you have a electrical problem!!

Offline flower pot racing

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Re: Ossa betor forks cap
« Reply #12 on: June 24, 2012, 06:41:38 PM »
http://www.billetparts.co.uk/catalog/index.php  You need look no further than here.  BEAUTIFUL parts and very reasonably priced.  All made in England and supplied to ....  well I am sure you can work it out who is elling his stuff.  He (and others) sell on ebay, but why not buy direct as it is cheaper.

Firko.  You may be talking about Jastco?  His parts were so beautiful you would want to build a a bike around the fork nuts!  I am 99.9% certain thathe is no longer with us and was a very ill man towards the end.  I think his son runs the tooling business and may not share the love of bikes, so I am not sure if they are still available

Offline flower pot racing

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Re: Ossa betor forks cap
« Reply #13 on: June 24, 2012, 07:57:19 PM »

Offline firko

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Re: Ossa betor forks cap
« Reply #14 on: June 24, 2012, 10:16:16 PM »
Quote
If this what you meant Firko?
Damn it you're right Ben, it was John Astleford. Unfortunately he died and his unbelievable workmanship is no longer. Thankfully I bought enough fork caps and crown bolts for my stash before he dropped off the perch. ;)
'68 Yamaha DT1 enduro, '69 Yamaha 'DT1 from Hell' '69 DT1'Dunger from Hell, '69 Cheney Yamaha 360, 70 Maico 350 (2 off), '68 Hindall Ducati 250, Hindall RT2MX, Hindall YZ250a , Cycle Factory RT2MX flat tracker, Yamaha 1T250J, Maico 250 trials, '71, Boyd and Stellings TM400, Shell OW72,750 Yamaha