UPDATE: There was a O Ring stuck in the jet which caused the master cylinder not to function properly. Now i have the issue that my clutch wont build pressure when im bleeding my bike, tried gravity method and fluid comes out bleed nipple fine but for some reason the pressure stays same, tried pumping lever and releasing nipple wich wont build pressure either. Please help
(KTM SX 85) Formula Clutch Master wont pump fluid
I have a KTM SX 85 2006 with a formula clutch master and oberon clu-0085 clutch slave.
I have issues bleeding because my clutch master wont pump fluid from the resivour down the hydraulic pipe.
I have tested the hydraulic line by blowing through it and having the bleed nipple open on the clutch slave and this works perfectly as i can hear the air releasing, and when its tight nothing releases so i know that this cannot be the problem.
I disconnected the hydraulic line from the Formula Clutch master and tried pressing the lever to see whether the fluid is coming out where it connects to the hydraulic hose but no there is only air being pumped out when i press in the lever, i am confused because how can only air come out when the master is full of fluid and theres clearly pressure because when i hold my finger over the hole where the hydraulic cable goes into the clutch master and press the lever in and out i can feel the air going out and in putting suction on my finger.
I have spent alot on this bike already and hoping someone has a fix for this? I think when the lever is being pulled and the piston is engaging its not sucking the fluid from the resivour to pump out the hydraulic line? Is it clogged up? Can i take apart and clean to fix it?
I have issues bleeding because my clutch master wont pump fluid from the resivour down the hydraulic pipe.
I have tested the hydraulic line by blowing through it and having the bleed nipple open on the clutch slave and this works perfectly as i can hear the air releasing, and when its tight nothing releases so i know that this cannot be the problem.
I disconnected the hydraulic line from the Formula Clutch master and tried pressing the lever to see whether the fluid is coming out where it connects to the hydraulic hose but no there is only air being pumped out when i press in the lever, i am confused because how can only air come out when the master is full of fluid and theres clearly pressure because when i hold my finger over the hole where the hydraulic cable goes into the clutch master and press the lever in and out i can feel the air going out and in putting suction on my finger.
I have spent alot on this bike already and hoping someone has a fix for this? I think when the lever is being pulled and the piston is engaging its not sucking the fluid from the resivour to pump out the hydraulic line? Is it clogged up? Can i take apart and clean to fix it?
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I suspect the o ring found in your master is the reason it will not develop pressure. Rebuilding or replacing master should be the next step. Bleeding clutch can be a chore because the master delivers very small amount of fluid when lever is pulled back. Vacuum bleeding or gravity bleeding will usually help. Removing slave and reverse bleeding can help if piston has any travel. You can manually compress piston and force trapped air back to the master cylinder. There is a syringe tool available for stubborn clutches. You fill syringe with brake fluid and connect to slave bleeder to force fluid up to master.
Welcome to the forum. We have had good success with hanging the slave up high so that the hose is almost straight up, and pumping the master until the fluid squirts out from slave. I have never heard of the make of your master or slave. The KTM ones uses brake fluid, the Magura one uses hydraulic oil. The Magura was only used on KTM bikes for a few years between 2000 to 2010. Today KTM use brake fluid (DOT 4 or DOT 5.1, do NOT use DOT 5 as it will destroy the rubber seals). Is your system designed for brake fluid or hydraulic oil?
My system is designed for DOT 4. This issue is causing me alot of stress as ive just brought a oberon clutch upgrade for £120 and now the master cylinder is broken. They are around £175 new and I cant find anywhere what has the Formula master cylinder rebuild kits, KTM Dealer doesnt have that. Im looking to sell my bike as it will cost me more to replace the whole hydraulic system because if i buy a different master cylinder it most likely wont fit onto my hose or anything will it.
We have been riding MX with 2 atroke KTM bikes over 15 years starting at 50sx and now running a 150sx in MX3 or MX2. We have made a few upgrades to our bikes through the years, but never done anything to the clutch setup as it has always worked fine. Hope you have the original clutch master/slave set-up still so you can re-fit it!
I have my original clutch slave but I brought the oberon clu-0085 upgrade slave cylinder which is fully compatible with my bike, my hydraulic line is completely fine. upon inspection of my formula master cylinder, some of the O rings were broken and torn so thats why the pressure wont build, i am also missing O rings in between the line and the master cylinder. I just brought this bike and its missing alot to be fair.We have been riding MX with 2 atroke KTM bikes over 15 years starting at 50sx and now running a 150sx in MX3 or MX2. We have made a few upgrades to our bikes through the years, but never done anything to the clutch setup as it has always worked fine. Hope you have the original clutch master/slave set-up still so you can re-fit it!
Hi guys, I did a full master cylinder rebuild, new line, new clutch slave and still nothing.
The fluid runs out the bleed nipple on the slave when i hold clutch and undo the nipple, if i leave it to sit for 10 mins and then press lever it will have pressure for one press then instantly looses it.
HELP PLEASE.
The fluid runs out the bleed nipple on the slave when i hold clutch and undo the nipple, if i leave it to sit for 10 mins and then press lever it will have pressure for one press then instantly looses it.
HELP PLEASE.
You may have air in your hydraulics or your master still has a problem. Not likely to be a mechanical problem but still possible to have damage inside clutch. Your description indicates hydraulic actuator problem. Perhaps you can clamp or restrict slave cylinder piston travel and test again. If lever is soft when piston travel is prevented you can expect that your problem is trapped air in system or your master cylinder is defective.
Ive had no luck whatsoever, like i say, I done a full master cylinder rebuild and installed a brand new clutch slave and they wont bleed up.You may have air in your hydraulics or your master still has a problem. Not likely to be a mechanical problem but still possible to have damage inside clutch. Your description indicates hydraulic actuator problem. Perhaps you can clamp or restrict slave cylinder piston travel and test again. If lever is soft when piston travel is prevented you can expect that your problem is trapped air in system or your master cylinder is defective.
I followed the manual on KTM SX 85 to correctly install the piston set on the master and im sure that hasnt gone wrong.
There is a screw inside the master cylinder resivour that im not sure of its purpose. I cannot provide photos but does anyone have any idea?
How do i clamp or restrict clutch slave travel. I dont know these methods.You may have air in your hydraulics or your master still has a problem. Not likely to be a mechanical problem but still possible to have damage inside clutch. Your description indicates hydraulic actuator problem. Perhaps you can clamp or restrict slave cylinder piston travel and test again. If lever is soft when piston travel is prevented you can expect that your problem is trapped air in system or your master cylinder is defective.
I use a clamp or pliers to compress and restrict slave piston travel. Reckon careful use of vise grip locking pliers would work also. Careful not to damage slave.
I dont really know what im doing unfortunately, ive spent a month everyday fixing this bike and nothing working. it starts and kicks first time. its really gettin on my ti**I use a clamp or pliers to compress and restrict slave piston travel. Reckon careful use of vise grip locking pliers would work also. Careful not to damage slave.
I suspect you could use some help. I'm too old and too far away to help hands on. Perhaps you can find a local person whose kid races or rides and coax them to assist. Most mini riders dad's are helpful and have experience with bikes like yours. This is where a lot of the forum information is derived from. Folks who have troubles like yours. Perhaps a post in local neighborhood or racing forum or Facebook could find a local mini dad able to help you in person. Good luck to you
Ive had 3 mechanics out and theyre all baffled, had so much help off numerous people and everyone is like why is it not working? everything has been replaced so its really confusing. No worries though.I suspect you could use some help. I'm too old and too far away to help hands on. Perhaps you can find a local person whose kid races or rides and coax them to assist. Most mini riders dad's are helpful and have experience with bikes like yours. This is where a lot of the forum information is derived from. Folks who have troubles like yours. Perhaps a post in local neighborhood or racing forum or Facebook could find a local mini dad able to help you in person. Good luck to you
Do you still have the KTM master and slave? If so I would re-fit them to the bike. Then you can at least get the bike working.Ive had 3 mechanics out and theyre all baffled, had so much help off numerous people and everyone is like why is it not working? everything has been replaced so its really confusing. No worries though.
The bike was brought with 2013 clutch master and slave, although the bike is a 2006 these parts still are compatible.Do you still have the KTM master and slave? If so I would re-fit them to the bike. Then you can at least get the bike working.
I managed to bleed the slave and master and regain pressure so this is now fixed.
Onto the next problem, the clutch plates are sticking together when in the bike and also the basket has grooves in the fingers so thats causing the plates to lock in place even when the pressure plate moves.
Think im going to try file down the grooves carefully, re soak the plates in oil as they still have plenty of friction and see whether this works.
If not then ill have to replace whole basket and all the other stuff
Good thinking. By filing down the basket fingers the plates will work. Try to file the same amount off each of them, if not, one of the fingers might have to carry all the weight and possibly break off if you are unlucky. The only thing that should happen is the clutch will rattle more.The bike was brought with 2013 clutch master and slave, although the bike is a 2006 these parts still are compatible.
I managed to bleed the slave and master and regain pressure so this is now fixed.
Onto the next problem, the clutch plates are sticking together when in the bike and also the basket has grooves in the fingers so thats causing the plates to lock in place even when the pressure plate moves.
Think im going to try file down the grooves carefully, re soak the plates in oil as they still have plenty of friction and see whether this works.
If not then ill have to replace whole basket and all the other stuff
@augiedoggie is a big believer in washing out the motor with ATF. As a 2stroke does not have the gear oil getting in to the combustion chamber (the 2stroke oil mixed in to the fuel is what keeps the crank and piston alive) ATF is a good choice to wash the gearbox and clutch without having to tear down the engine. You drain the old oil from the motor, add ATF until it is at the right level, and then run the motor as per normal. Empty out the ATF after hour or two and your motor will have a nicely cleaned gearbox and clutch!
Ive got some new plates on order before i put back together just for ease of mind, ive filed the basket abit but not tried it yet, when i put my old plates in now they dont get stuck and come out freely so thats a good sign. Good idea with the ATF, will give that a go aswell as my oil keeps running through black as owt, eventhough ive ran 2 litres of Motorex 10w-50 through it over the last week without even riding it, just letting it sit and idle for 10 to fifteen mins at a time. Going to slap a new spark onit also and do front, rear cogs n chain also.Good thinking. By filing down the basket fingers the plates will work. Try to file the same amount off each of them, if not, one of the fingers might have to carry all the weight and possibly break off if you are unlucky. The only thing that should happen is the clutch will rattle more.
@augiedoggie is a big believer in washing out the motor with ATF. As a 2stroke does not have the gear oil getting in to the combustion chamber (the 2stroke oil mixed in to the fuel is what keeps the crank and piston alive) ATF is a good choice to wash the gearbox and clutch without having to tear down the engine. You drain the old oil from the motor, add ATF until it is at the right level, and then run the motor as per normal. Empty out the ATF after hour or two and your motor will have a nicely cleaned gearbox and clutch!
Should basically be a new bike by time im done with it. Ill let u know how to progress goes and ill be back to the forums if theres any more issues.
Much appreciated.
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