OSSA

I have a Tr300 that I just replaced the shift drum for and now I am having problems getting the engine back together. I have tried literally everything but the clutch fingers keep binding against the inside of the clutch cover and the kickstart will not engage or at least due to the engine being locked up. I have taken it apart and put back together about 20 times now and the main gear of the clutch is always flush against the primary gear on the crankshaft so I know that is not the issue. The tranission is also seated tightly against the engine and the secondary gear is at the right distance. I assembled my transmission drum based on this video but also noticed that the …

Well I finally got around to making up a spare diagnostics cable. I have BTWICE one, but got the USB TTL interface a couple of years ago to make some more. I used another user here (darn if I can remember name right now) for the TX/RX and ground pins (already knew power from battery ones). Worked great! I tested my BTWICE first, then the one I made. I had to pick a different COM port that matched to the new cable I made, but the driver I had worked great. I see where you can download drivers for the USB interface I used also. I was running under Win7, reset the TPS and a few other tests. I did not try loading new maps with it though- but I expect it wil…

I am looking for a wiring diagram for a 2012 ossa explorer. I am all so looking for a picture of the back side of the key switch showing what color wire is installed on which terminal on the switch. At this time my bike will start in both key positions.

Hi What is the correct timing for the stator on a 250 MAR? The flyer manual I have (250 and 175 engines) mentions "Plonker, Pioneer and Stilleto" which of these should I reference for working on a MAR? regards Gordy

Hello again, Some more questions if you guys don’t mind.. I’ve got the manual and I’ve searched the forum but am still unsure about a couple of things. Firstly I’ve got an MK1 ( I think) with MK1 engine ( number M -342454) I’ve found the gasket and seal kit on the inmotion website but it only shows one set / option for a MAR 250 with no reference to production years. Are all 250 mar engines identical? I could be totally wrong but I seem to remember seeing reference to a smaller crank on the early MAR on a US website.Just wanted to double check before ordering . Im also a bit confused on the rear brake cable routing.. the ma…

I recently acquired a Pluma/Plonker that came from a high elevation. I live at about 1,000 ft. elevation above sea level and the bike runs too lean. The bike has a 24mm IRZ carb and I want to keep this carb on the bike. I know finding IRZ jets isn't very easy and I want to limit the number of jets I purchase. Does anyone know what jet sizes and needle clip position this carb came with or should have for a lower elevation? Currently, the carb has a 45 pilot and a 101 main jet. I could guess and get a 50 pilot and a 110 main, but like I said, would be nice to know more specifically without all the trial and error.

Hi there, First time using the forum and I’m looking for a bit of help with my Ossa. My dad and I acquired it many years ago and it was our intention to get it back to working order and maybe use it for the odd trial. My dad passed away before we got round to it so now I’m going to have a go myself. My dad was an engineer and knew the history of the bike. I’m ok with routine maintainance and minor repairs having owned modern MX bikes but have never done a restoration on a classic so it’s a bit beyond my experience/ skills. The bike is currently dismantled in boxes etc and has been like this for years im probably going to get the engine rebuilt profes…

Hi everyone. Is anybody have electric connection of OSSA Explorer? I have only TR280 workshop manual, but its not the same. Thank you!

My 250 almost always requires 2 kicks. If I stop and immediately restart, 1 kick will usually do. But if it's stopped long enough to walk a section, it will probably require 2 kicks to restart. One the other hand, if the bike has been sitting for months it may start on a single kick. My 280 is somewhat more recalcitrant. It probably takes an average of 2.5 kicks. I have some theories as to why this might be so, but I'm wondering if others have managed to make theirs a 1-kick starter. This really doesn't matter during practice or if ridden as a trail bike, but during a competition it saps my limited energy. Both bikes have Easy-Start kits. I'm a bit of a l…

I have found many discrepancies on various sites for these two models. I thought they were practically the same and that only the colors changed. Is anyone able to elucidate me? On the Ossa website he says that there are different cases in one 350g of oil and 450g in the other. The total weight of the bikes is 2 kg different They have different gearbox bearings. I thought they were the same ? Do you know anything about it? Thank you

Hi guys where can I get a new complete kick start for an ossa 1976 250 mar. There like rocking horse poo . Thanks

I have fitted a headlight to my OSSA MAR using the rubber straps, but it is very loose. I cannot see any way of tightening the straps. Am I missing something?

hi where could i get a year of manufacture for a ossa mar so i can get it road registered. many thanks

I went for a first ride on my restored Ossa MAR today and experienced a few issues I have put down to carb. The AMAl is the original from 1973 so I figure it has probably seen better days. All I know is that despite new jets and refurb kit the bike has no zip making climbing banks almost impossible. I'm thinking therefore of changing carbs to a Mikuni. I appreciate that this one has been done to death but...The general concensus seems to be a 150 main and 35 pilot on a VM26 Mikuni but this is only part of the story. The Needle and Jet needle are very important also. The standard VM26 comes with a O-0 needle Jet and a 4J13 Jet needle. For those who have fitted a VM26…

I have a 1974 Ossa MAR. If it sits for any period then the kick start lever will not kick freely to clear the clutch. I let it sit for days with the clutch lever clamped to disengage the clamp. It still doesn't kick free so I read on this board some time back that one way of dealing with this problem is to put the front wheel up against the wall and then start the bike. I did this and even though the clutch was not free, when I started the bike it ran as if the clutch was disengaged. What am I missing here? I need to take it somewhere to ride it and do any shifting so I haven't (I'm 73 yrs old so lots of trial and error is hard work). With it up against the wall with…

Ok guys, being a bit cheeky here. My Amal has had its day I feel so looking for an alternative carb. OKO seem to get a good review and I’m aware of all the copies and the preferred purchase site. What do people use 26 or 28 mm and most importantly what are the best jet sizes? It doesn’t say on the Ebay site what jets are in as standard when you purchase a carb.

Anyone know what other bikes use the same front brake pads as the 15 Factory 300? They do not have locating pins, but rather rounded areas that lock into the caliper.

Does anybody know if Mr Sell is still offering his services? I have tried contacting him via phone numbers listed online but no joy as of yet. Thanks in advance

Planning on replacing all the bushings of the linkage suspension of my 2013 Explorer. I can only find a 2012 Explorer parts manual. Are all the bushings the same between 2012 and 2013 Explorers? Or should I use the part numbers from the 2013 TR280i parts manual. I compared the p/ns between the 2013 TR and 2012 Explorer and couple of the bushings p/ns are different. Any input would be greatly appreciated. Thanks!

I have fitted sealed bearings in my OSSA MAR mk3 front wheel. Do I need to get felt washers for when I fit the wheel back into the forks? If so where can I get them from? Note: This is a restoration I'm doing and there were no felt washers when I took the wheel apart.