biffco

How much are they from Steve ? And what is a clutch lightening arm? And how much too ?

Which do people recommend ??

I have a contact email address for Steve of - steve@marlimar-uk.wanadoo.co.uk I have sent an email and it has been getting bounced back everyday since about Wednesday. Does anyone if it has changed ??

I have just found out that where I thought I had a 250 MAR, it is in fact a 350. Last year I brought a new Minuki carb for the bike but spec'ed for a 250. What jets and setting should I change too?? i have noticed the bike has a low down flat spot , so hopefully this is the reason why?!

Why a strong grip ??

The engine no, and frame no. Are the same.

This list also seems to confirm it. I guess my bike is one of the last '75 350's ??

The frame number starts B 2425## I have found the below chart that doesn't go this high, but on the marked column it is just below. If this is correct then it is a 350?? Has anyone else got a different list that has my frame no on it ? ( I don't see it on the link above)

Hi Stan, how do I check this ? Can I remove the right hand cover and pull the rod out ? Can I then retrieve the ball if it's still there ? Maybe with a magnet ? if it's behind the seal on the output shaft how do I check for this ? cheers james

During a trial this weekend I noticed a creaking from the clutch mechanism whilst pulling in the lever. It is also heavier and notchier than my mates OSSA clutch. The noise seems to come from the cable, but I worry it might be transmitting up the cable from the clutch arm ?? Will a cable be the answer to my problems, and is there any way to make it lighter than it is ?

Thanks for the replies. In responce to some of the questions/ comments. The tank isn't the original. When I got the bike, it had been imported from Italy, and came with the fibreglass tank. I have since fitted an ally one. I too have fitted a Minuki carb as the original Amal 626 was very much worn out. I have found out the hard way about the sump plug, as I caught the original and have cracked the sump What is the thread size for this so I can get a replacement plug ? I'll get the engine number net time I'm near the bike. I had noticed the rear axel slot had been lengthen too. This will of shortened the wheel base, is this a good thing ? I'll take a look at the spark plug , the middle hole currently has a decompressor gizmo in it. Does anyone else think this will make a difference as it is or should I put the spark plug back in the centre hole?

Has anyone had any luck with the cheaper levers on eBay? Or are they a waist of money ??

I have an OSSA that has come from Italy. It was sold as a 250 , which I beleve it to be, but today at a trial it was pointed out that as I have cutout on my fins, that it may be a 350?? The engine no. Matches the frame no. But the number doesn't show up on any of the lists I have seen. Any info in aging the bike etc would be appreciated. Or even recommended upgrades, mods etc...

C3 bearings have greater clearance between the balls and track. This allows for higher running temperatures. When the bearings expand due to the heat the running tolerances are up to specification.

Following the last trail I did, I now unfortunately have a crack between the sump plug hole and the case edge. I assume the only way to fix this will be to strip the engine and get it welded ?! With this in mind what parts at a bare minimum will I require ( seals, gaskets, bearing etc...) I don't know anything about the history of the engine, the power seems ok ( though I have never rode another MAR to compare it to), but whilst it's apart what else would you suggest I consider doing to it ? On the same trial that I cracked it, it started slipping out of first gear and going to neutral. I have re-ground a better point on to the detent pin which has improved it. Again whilst I have the thing in bits, is there anything else I should consider replacing to improve the gear selection ? These are photos of the cracked sump and of the piston and bore looking through the exhaust port.

Can anyone give me a list of bearings and seals needed to rebuild the OSSA mar engine ??

A little update - I've only just got back to looking at the bike , but it has been left with the front wheel up on the bike stand. I tilted the bike both ways, and no more came out. In total I got 700 ml out. I then filled the bike back up with 900ml of oil with the bike sat with its wheels on the ground. Following this I immediately drained it back out. To my surprise I only managed to get another 700ml out !!!!??? I can't understand where it could be unless it's passing the crank seals ? Am I fight in thinking that if the seals are gone then the bike would struggle to run too ?? I put the 700 ml back in and fired the bike up. If started up first kick as it alway has, and road around the garden fine. Your thoughts please ??!

I road the bike for 5 mins round a gravel car park. There was no excessive smoke, and the ground and bike were dry ??

Following the issues with my mar first having an oil leak, then jumping out of gear, I have removed the oil and refilled it a couple of times. The first time I drained the remainder of the oil that hadn't already leaked out, then filled it with 900cc / ml of oil. Following a 5 min ride I left it to drain again over night. After re fitting the detent plunger I went to put the drained oil back into the bike. To my surprise there was only 600 ml in the catch tank ?????!!!!!! Where are the other 300ml ??

I removed the detent plunger and found the end worn. I re machined the end to a point and put back together. The first couple of times I tried pulling away in 1st it again initially stayed in gear, then slipped in to the false neutral but after that it stayed in gear every time I tried. I'll take it for a ride in the woods soon to give it a proper test. Fingers crossed. ?

The last trial was at the Christmas trial for the GVCMCC at Cowcombe. Thank you for your replies. I'll remove the detent spring this week and report back

When I purchased the bike I spaced the bash plate away from the engine, is I will look at bending it back to clear the engine without spacers.

I tried measuring the plug, it appears to be tapered ? From about 14mm to 14.5mm and somewhere between 1.5mm pitch and 18tpi ? So I guess either M14 fine or 9/16 UNF ? The plug does look modified already,(badly) which allows it to protrude lower than it should.

I've not done anything yet, looking for suggestions, before I start. Is your suggestion something that can be done with the engine still in the bike ?

I purchased my bike last year from a company that deals in 2nd hand trials bike , and have done about 6 trials in it so far. Following returning from a trial I put the bike in the garage. When I next saw the bike I noticed a small pool of oil. I left a tank under it to catch the drops and drain the rest. In total I caught about 200ml of oil plus what ever went on the floor. So there was probably only 250ml Max in it after the trial. On investigation I found a crack in the sump from the oil plug hole to the mating face of the crank case. As a temporary measure I have covered the crack with 'plastic metal' to allow me to fill it up. Once I fires the bike up it initially ran ok, and went through all the gears. After about 5 mins of slowly looping round the garden in 2nd, I dropped it in to 1st. It would stay in 1st for about 5 seconds and then slip in to neutral. It seems to be a 'false' neutral as when selecting 1st again it doesn't clunk into gear, But again, as you pull away it it will go back into neutral after moving about 1 or 2 bike lengths. From experience, what damage do people think I have done, and what do I need to do to fixed it ??