gasgas1 Posted September 23, 2008 Report Share Posted September 23, 2008 Hi folks i can't seem to bleed my clutch up on my jt 250 ive checked the clutch pipe & its clear(no blockages),ive put a new plunger in the master cylinder as the seal had split,i just cant seem to get fluid in to the pipe & down to the nipple to bleed it,the master cylinder is also clear,can anyone shine any light on this Quote Link to comment Share on other sites More sharing options...
280pro Posted September 23, 2008 Report Share Posted September 23, 2008 Hi folks i can't seem to bleed my clutch up on my jt 250 ive checked the clutch pipe & its clear(no blockages),ive put a new plunger in the master cylinder as the seal had split,i just cant seem to get fluid in to the pipe & down to the nipple to bleed it,the master cylinder is also clear,can anyone shine any light on this im having the same problem aswell Quote Link to comment Share on other sites More sharing options...
jse Posted September 23, 2008 Report Share Posted September 23, 2008 Hi folks i can't seem to bleed my clutch up on my jt 250 ive checked the clutch pipe & its clear(no blockages),ive put a new plunger in the master cylinder as the seal had split,i just cant seem to get fluid in to the pipe & down to the nipple to bleed it,the master cylinder is also clear,can anyone shine any light on this First, make sure that there is some clearance where the hand lever adjustment screw meets the plunger that goes through the rubber boot at the master cylinder (the M/C piston must come back completely to the circlip stop). If the piston does not retract back far enough, the hole between the reservoir and M/C bore wil not be open. You'll need to get some non-compressable fluid into the hose, otherwise the air will compress and expand when the lever is pulled in/out and no real vacuum will be created. Fill the master cylinder with fluid, loosen the bleed screw a little, pull the lever in, place a finger over the bleed nipple, release the lever, take finger off bleed nipple and repeat. This should start to draw fluid into the line. You may want to rotate the bars so that the M/C is up high and the loop in the line after it leaves the M/C faces down as an air bubble often gets trapped there. Jon Quote Link to comment Share on other sites More sharing options...
gasgas1 Posted September 23, 2008 Author Report Share Posted September 23, 2008 cheers m8 i think i might know wat it is now ,the spring in front of the plunger was broke so i replaced it but it was a tiny bit shorter than the original so it must be blocking the hole from the master cilinder Quote Link to comment Share on other sites More sharing options...
jse Posted September 24, 2008 Report Share Posted September 24, 2008 cheers m8 i think i might know wat it is now ,the spring in front of the plunger was broke so i replaced it but it was a tiny bit shorter than the original so it must be blocking the hole from the master cilinder Guys my age can remember the old master mechanics joke about sending a new apprentice to the parts store for a "piston return spring", but there really is such a thing. The return springs in the older clutch master cylinders were noted to sack out after a while, which caused the piston to not fully return back to the stop at the circlip and gradually cause the lever to have less and less effective throw (and make bleeding the system impossible). The new rebuild kits have a longer, stouter spring to avoid that problem. Jon Quote Link to comment Share on other sites More sharing options...
280pro Posted September 27, 2008 Report Share Posted September 27, 2008 First, make sure that there is some clearance where the hand lever adjustment screw meets the plunger that goes through the rubber boot at the master cylinder (the M/C piston must come back completely to the circlip stop). If the piston does not retract back far enough, the hole between the reservoir and M/C bore wil not be open.You'll need to get some non-compressable fluid into the hose, otherwise the air will compress and expand when the lever is pulled in/out and no real vacuum will be created. Fill the master cylinder with fluid, loosen the bleed screw a little, pull the lever in, place a finger over the bleed nipple, release the lever, take finger off bleed nipple and repeat. This should start to draw fluid into the line. You may want to rotate the bars so that the M/C is up high and the loop in the line after it leaves the M/C faces down as an air bubble often gets trapped there. Jon hi i tried this but i still cant get any pressure to build up any more tips? Quote Link to comment Share on other sites More sharing options...
jse Posted September 27, 2008 Report Share Posted September 27, 2008 hi i tried this but i still cant get any pressure to build upany more tips? I would think the next step is to get a syringe and force some brake fluid into the bleed screw up to the M/C. Once the line is filled, it's a lot easier to bleed the system. If that does not work, I'd go back (reverse engineer the processes) and carefully inspect each change you've done, starting from the most recent back to the first and don't assume that any were done correctly (the part you overlook will most likely be the cause of the problem and over confidence has blown up many a race engine). Take that particular piece apart (and keep track of how the parts were assembled by laying them out in order of disassembly), inspect each one carefully for improper installation/damage, make sure the re-assembly order is correct (use a diagram if at all possible) and carefully re-assemble them. Jon Quote Link to comment Share on other sites More sharing options...
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