dond Posted March 18, 2009 Report Share Posted March 18, 2009 I have an 82 Ossa TR80 350 and I need to know what the original jet sizes are for the Amal Mk2 carb. Does anyone have that info. I have spent a lot of time on the net looking and I am surprised that info is not out there somewhere. DonD Quote Link to comment Share on other sites More sharing options...
wayne_weedon Posted March 18, 2009 Report Share Posted March 18, 2009 If I can find the carb for one of my grippers which is still packed away since my last move I'll have a look for you. I was working on a MK2 Amal from my Cota330 today and that has 20 pilot and 140 main. I expect the Ossa to require something in that ballpark. Wayne.... Quote Link to comment Share on other sites More sharing options...
roberto Posted April 10, 2009 Report Share Posted April 10, 2009 Hi and good luck with the gripper. Here is the info you need for the carb Amal 2627-408 is the correct carb 130 Main jet 15 Low speed jet 105 Needle jet 2B1 needle in the 3rd position No.1 slide (gas valve) 2.5 Air jet (found on the filer side of the carb) With that the bike should run perfectly (maybe a little fat on the bottom). Take care and if you need any other gripper info let me know, I have rebuilt a number of them and am working on one now. 1 Quote Link to comment Share on other sites More sharing options...
buggyboy Posted May 8, 2009 Report Share Posted May 8, 2009 Hi, I'm in a really bad place at the moment with my gripper, it's an early yellow 250 though and uses the 2626 carb, at the moment I have it set up as below. Amal 2626-1 150 Main jet 20 Low speed jet 40 Choke jet in float bowl 106 Needle jet 2B1 needle in the 2rd position from bottom No.3.5 slide Not 100 % sure what the air jet is ? The issue I have is that I am only able to get it to run on tic over with the air screw out 3/4 to 1 turn otherwise it runs way too weak and you can stall it by blipping the throttle. As it is; it is useable but it is so flat at the bottom... Top end is great, pulls really well. I have tried numerous things, even swapping the 40 Choke jet into the slow run/ pilot jet, this just means that I can open up the air screw about another quater turn, I have replaced the needle jet, pilot/slow run jet, needle gaskets etc. The slide is very worn and I have a new one on it's way but I am at a bit of a stumblilng block, I am now starting to wonder about the mechanics or the engine and how worn rings/ crank seals and skirt clearances will affect the running/ mixture? Can either of you or any one else shine any light on the situation. Many thanks, Andy Quote Link to comment Share on other sites More sharing options...
roberto Posted May 9, 2009 Report Share Posted May 9, 2009 Andy, the carb specs were taken off a bike which I recently sold. The bike worked very well as the complete motor I rebuilt. So I really cant tell you much more. The slide data you give me is way off. The number one slide is a lot richer so maybe the bike isn Quote Link to comment Share on other sites More sharing options...
buggyboy Posted May 10, 2009 Report Share Posted May 10, 2009 Hi Roberto, thanks for your reply. I would feel fairly confident in saying that the settings on the 250 would be different from the 350 though not really that significant, I have borrowed a carb from a friends gripper which has the No.1 slide in it and is indeed the 408 spec, on the side of my carb it just hs 2626 and then underneath that it has the figure 1 overstamping a figure 2, don't know much more than that?, other than it runs almost exactly the same with my friends carb with the air screw in exactly the same position. My friend has just bought one of those OKO carbs from ebay for Quote Link to comment Share on other sites More sharing options...
woody Posted May 11, 2009 Report Share Posted May 11, 2009 For a fibreglass tank I think you should use only Caswells. It's a US product but they have a UK website/store. If you google it you'll find their website and contact details. Are you sure it hasn't just worn through for some reason, vibration/rubbing etc. rather than fuel eating it. It's nearly 30 years old and could have suffered all sorts of abuse. My old 325 slimline Sherpa has been used regularly for many years with no problem to the tank and I know of several other bikes with glass tanks that have suffered no problem with today's fuel. My Majesty glass tank is showing no sign of suffering from modern fuel either and it is never without fuel sitting in it. Quote Link to comment Share on other sites More sharing options...
buggyboy Posted October 5, 2009 Report Share Posted October 5, 2009 Well to bring the gripper situation up to speed!! I purchased some gas tank sealer from casewell net, but I also decided to strip the tank back first on the external to do a proper Job... When stipping it back I found a multitude of sins beneath multiple layers of paint and pogo dog turds plugging holes ( After a few weeks work I cut out all the damage and rebuilt the fibre glass tank, then got together with a friend to try and seal a couple of tanks with the compound from Casewell. It has to be said that reading and adhearing to the instructions is very important as you are far better to over do it and tip out any surplus! the ambient air temp is also quite important as too cold and the stuff just won't run very easily... Needless to say after sealing the tank a nice coat of paint has brought it back to looking like new and a set of stickers from Anglia Vynal art are set to top it off a real treat... The better half isn't amused but it has been sitting on the dining table for a couple of weeks now so thumbs up I am very pleased ) After the nice coat of paint on the tank I got a bit carried away and decided to go right through the rest of the bike, I now have the engine down, have ordered up all the bearings and now in search for what seems to be hens teeth!!!! Pistons and Rings for a 250 Gripper!!!! I am starting to wonder if they did ever actually make them???? or if mine have shrunk by about 2mm ) Can anyone out there help with Gripper piston supplies? Do they cross over with another Jap bike for example with modifications?? I know the RL uses a 70 mm piston as does the RM and the DT 250, I can get away with just a ring set but this is proving to be just as hard a search as the piston, it would seem that the smallest two stroke rings available a 1mm section but the gripper ones are of a .80mm section. I have mailed Tarabusi Directly as they were the makers of the original piston that has come out, I hope to get a reply soon but if anyone can shed some light in the meanwhile I would greatly appreciate it.. Quote Link to comment Share on other sites More sharing options...
woody Posted October 5, 2009 Report Share Posted October 5, 2009 Don't know if you know about this site already but if you don't there is a list of specialists at the bottom. You might get a Gripper piston from one of the US specialists. Mats Nyberg Ossa site If you can't get one you can use a 72mm MAR piston which takes it out to 244cc, Gripper was sleeved down to 238cc with its 70mm piston. You just need to cut the slot in the back of the MAR piston using your original as a pattern. Quote Link to comment Share on other sites More sharing options...
buggyboy Posted October 7, 2009 Report Share Posted October 7, 2009 Hi Woody, many thanks for your reply. I have come acrosss the Mats Nyberg site on several occasions, I find that searching anything with Ossa in the title brings up only a handfull of sites, this being one of them. I had a reply back from Vitale Manquinas, he has a whole selection of pistons in stock, believe it or not they are Wiseco, unfortunately though by the time the dreaded postage is applied they aren't cheap. To be honest I had found that the Tarabusi piston is available from Tarabusi website but this is again the 72mm diameter one for the MAR, I think that maybe I have gotten too carried away with trying to find another 70mm piston. If I take the bore out to fit the MAR piston, what sort of skirt clearence will I require and can you advise if there is enough meat as it were in the liner to take the bigger diameter? The next question would also be as to how much further I could go?? Just thinking of the future? Do you know also if the MAR piston uses a .8mm ring? Thanks again, Andy Quote Link to comment Share on other sites More sharing options...
woody Posted October 7, 2009 Report Share Posted October 7, 2009 Skirt clearance I don't know (haven't a clue about real technical stuff like that...) I'm guessing you mean for the rebore, in which case it would be the same as the MAR I would think. All that fitting the 72mm MAR piston involves is a rebore as the liner is plenty big enough. Maximum oversize piston is 72.60 for the Tarabusi although the Wiseco increments in .25 measurements I think so they may go to 73.00. On the 250 MAR that is about as far as you can go as the cylinder stud spacing prevents a bigger liner. On the 250 Gripper the studs are spaced further apart if I remember correctly, like the 350 motors, so once you've reached the 250 maximum oversize there is scope for overboring I would guess. If you're only on 70mm now though, it's unlikely you'll ever need it. The rings on the MAR and Gripper are the same type, the really thin wire rings. Not sure of the actual thickness but 0.8mm sounds as though it would be about right Quote Link to comment Share on other sites More sharing options...
feetupfun Posted October 7, 2009 Report Share Posted October 7, 2009 This is about your 2mm ring gap comment If the old piston has a ring end setup like the MAR piston, the standard ring end gap is huge as measured by putting the ring in the bore, because the locating pin separates the ends of the ring while most bikes the pin sits within a recess in the ends of the ring. Quote Link to comment Share on other sites More sharing options...
buggyboy Posted October 12, 2009 Report Share Posted October 12, 2009 Thanks for the feedback on this issue, I appreciate that the ring gap will include the peg spacing also but looking at them I still think the gap is a little excessive even still. After looking at the piston picture supplied by Andreas at Vitale Manquinas I have come to the conclusion that it to is a 72mm piston and not an original 70mm one. I am now thinking that I will have no option than to bore it to take the MAR piston.. Andy Quote Link to comment Share on other sites More sharing options...
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