goreboy Posted October 29, 2009 Report Share Posted October 29, 2009 (edited) Hi all, i`ve just rebuilt my jt25 (bought as project) most bits are new or refreshed, i wanted to replace the old knackered silencer, any ideas guys? also mid box is very heavy, is this correct? struggling to get it to run nice, starts a dream, seems to run lean though, i`ve lifted needle as far as possible and mixture screw is 1 turn out, still seems to be pinking though. i read that stock ain jet is 95, with 36 pilot, needle clip 1 down from top, needle d36 and mixture 3.5 out but i`ve got 108 main jet,with 36 pilot, need clip at bottom, needle d36 and mixture 1 turn out how come it seem lean???? .... i`ve cleaned carb to ensure no fuel blockage on another note, the motor is very tough to kick over now, seems very high compression, i did fit all the barrel base gaskets (all 3) that were in the kit, as the piston came flush with top of head with just two. is this norm after rebuild? Cheers for all help Edited October 29, 2009 by Goreboy Quote Link to comment Share on other sites More sharing options...
traintracker Posted October 31, 2009 Report Share Posted October 31, 2009 I rebuilt a 95 JT35 and found that not a lot of people have been into those, at least that I could find in America. I was concern about running the recommended 80:1 Gas/Oil ratio so I went 50:1. This seemed to produce more pre-detination due to more oil and less fuel. I went back to the Gas Gas recommended and I have less of it. I need to see what jets are in it, as I misplaced the paper I wrote all that on. I have found a filling station that sells fuel without ethanol in it. This is harder to find in our area (Washington state,USA) I think this has made a difference also. Especially in the starting. The bike starts very good but has such a high kick-starter gearing ratio that it is a challenge for me. I also checked the carb intake boot after it ran a while on break-in and re-tightening it, this also helped. I bought this bike in a box and thought it would be a good way to get back into trials ( as I have been paralized in my feet from a street bike accident 7 years ago) Now that I have finished it I have about as much invested as I could have paid for a slightly newer bike but......I know the bearings, shift drum and forks, as well as, all seals are new. A local guy purchase a 2000 Sherco for $1,500 US out of Idaho, I have pretty close to that in this with all the rebuild. Steve Quote Link to comment Share on other sites More sharing options...
spenser Posted November 4, 2009 Report Share Posted November 4, 2009 (edited) For the older GasGas parts, try Mountain Motorcycles in Vancouver (actually Coquitlam) British Columbia, they have a ton of stock parts. You can find them through trialscanada.com (advertisement). There are a few riders from Washington (Bill Thompson) who regularly compete in Vancouver and could maybe bring what you need back with them. Spencer Fitschen Edited November 4, 2009 by Spenser Quote Link to comment Share on other sites More sharing options...
jse Posted November 4, 2009 Report Share Posted November 4, 2009 Hi all, i`ve just rebuilt my jt25 (bought as project) most bits are new or refreshed, i wanted to replace the old knackered silencer, any ideas guys? also mid box is very heavy, is this correct? struggling to get it to run nice, starts a dream, seems to run lean though, i`ve lifted needle as far as possible and mixture screw is 1 turn out, still seems to be pinking though. i read that stock ain jet is 95, with 36 pilot, needle clip 1 down from top, needle d36 and mixture 3.5 out but i`ve got 108 main jet,with 36 pilot, need clip at bottom, needle d36 and mixture 1 turn out how come it seem lean???? .... i`ve cleaned carb to ensure no fuel blockage on another note, the motor is very tough to kick over now, seems very high compression, i did fit all the barrel base gaskets (all 3) that were in the kit, as the piston came flush with top of head with just two. is this norm after rebuild? Cheers for all help The mid-90's engines were designed to run on a minimum of 95 octane fuel, which, if you live in the U.S., is not available at the pump anymore. In order to rule out fuel as a cause, try mixing at least a 50/50 mix of high-octane pump fuel and 110 race fuel to see if this aleviates the condition at all. Jon Quote Link to comment Share on other sites More sharing options...
goreboy Posted November 4, 2009 Author Report Share Posted November 4, 2009 Hi guys, i`ve found the lean problem, i`ve just rebuilt the motor, and like an idiot i forgot to fit crank seal behind timing plate when on bench, seal fitted, now running slightly rich on 108 main... that will do to run motor in on. will lean out later. anyone tell me how much oil should be in fork legs? ... and what weight. i seem to use all of travel, just in field pulling wheelies, i`m 76kg Cheers Quote Link to comment Share on other sites More sharing options...
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