Ossa Mar

[stevev]

I'm looking for a sump guard for my Ossa. I think its a 71/72, it seems to have had rear passenger foot rest stays welded on the swing arm, I can't imagine these would be standard. I will try and attach some pictures, any feedback would be welcome. Cheers

[feetupfun]

Those footpeg brackets have been added by a previous owner.

Same for the bizarre sidestand mount

It looks like a Mk1 MAR to me

[feetupfun]

the routing of what looks like the ignition wiring up past the rear of the clutch cover is odd, with the magneto being on the other side. The standard wiring route on these is vulnerable to impact because it emerges from the bottom of the magneto case. A common mod is to reroute the wiring through the front of the magneto cavity in the engine casing to avoid problems. Maybe your wiring has been rerouted a different way to avoid problems.

A skidplate from any of the MAR models should fit your bike. The first model MAR had a skidplate made from a composite material that was easily smashed to pieces with use. Later MARs had a nice aluminium skidplate, so there are less aluminium bashplates in existance than there are OSSA MARs

Edited May 24, 2015 by feetupfun

[stevev]

Cheers for the info. I'll be getting the frame powder coated next week and then start a rebuild. I've been gathering as much info as possible to help, and when I'm finished I'll post a picture.

[goudrons]

Someone certainly has had a bit of fun with that swinging arm, as mentioned the side stand bracket looks like Stevie Wonder has had a go at welding.

 

If you're replacing it for an original resto, match up the replacement carefully as Ossa fitted different arms to different marks, methinks mk2, 3's and Verde's had the shock mounts over the spindle rather than in front like yours, which I believe is from a Mk1.

 

The top mounts on the frame also moved around over the years, shocks went from almost up right (mk1), to canted forward slightly (mk2), canted over almost flat (mk3) back to canted slightly like the Mk2 for the Verde.

 

If you're doing it for a decent ride, grind all that bollocks off, trees are perfect props, you also might want to drop the foot rests back and down and fit some wider ones, rather than those standard "blades".

Back around an inch to an inch and a half, down level with the back of the sump guard (when you get one) is about right.

 

In regards to the sump guard, Mk1's had a chocolate/fibre guard, like this

http://ossacels.com/ventas/index.php?id_product=67&controller=product&id_lang=1

Mk2 & 3's alloy ones.

 

Mk1 barrels had a flange and 2 stud fitting for the carb on 250's with a fibre spacer.

Mk2 & 3's had a stub on the barrel and rubber coupling to fit the carb with just a couple of jubilee clips.

All 350's I think all had flange and stud fittings like the Mk1 250s.

Verde's had a stub like mk2 & 3's, but also had cut outs to the barrel fins, so by the looks of yours, it's probably from a later "Verde" model, they made the Verde's from 1978.

 

If you're in the UK, Steve Sell is the man for all your parts.

Steve's e-mail is steve@marlimar-uk.wanadoo.co.uk mobile 07800 778048

You might need to leave a message, but he does get back to you.

Edited May 26, 2015 by goudrons

[old trials fanatic]

I wouldnt powder coat the frame. Only done it once NEVER AGAIN 

[trialsrfun]

Having a frame powder coated should not create any problems at all, are you sure you have had it powder coated as there are other finishes available which might be less suitable for a trials frame ?

[woody]

 

 

If you're replacing it for an original resto, match up the replacement carefully as Ossa fitted different arms to different marks, methinks mk2, 3's and Verde's had the shock mounts over the spindle rather than in front like yours, which I believe is from a Mk1.

 

The top mounts on the frame also moved around over the years, shocks went from almost up right (mk1), to canted forward slightly (mk2), canted over almost flat (mk3) back to canted slightly like the Mk2 for the Verde.

 

 

Frame is a MK1 as is the swingarm  -  MK1 swingarm has the shock mount just over the blob of weld that acts as a stop for the snail cam. MK2 had an extra 1" added to it behind the shock so the shock mount is forward of the snail cam stop. MK1 and MK2 shock position is the same, only difference is the extra 1" arm length behind the shock

 

MK3 swingarm was the MK2 but with shock mounts over the spindle and top shock mounts by bottom screw on sidepanel so they were laid down more than on the later green bikes. Green bikes have the top shock mount lifted to the top screw of the sidepanel, reducing their angle, swingarm shock mounts still over spindle but may have been slightly shorter than MK3.

 

If the engine is a 250, then as mentioned, the barrel is from a later green bike. Head is MK2 or 3.  All 350 engines had barrels with cut-outs in the fins so could also be a 350 engine fitted - engine number will confirm. 350 top end won't fit on a 250.  All 350 had stub fitting push on carbs, not bolt on.  Carb is MK2 Amal which was standard fit to green 250 bikes.

 

The picture is very grained, does it have a reed valve?

 

Rear mudguard loop has been shortened

[stevev]

Cheers Woody really appreciate your input, no reed valve. I bought a £35 chain guard from in motion, I have to say I'm pretty disappointed with it. It is clearly home made which is fine but the finish is very poor, but it'll do for now.