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If your gearbox works properly when the engine is not hot and then it is hard to find neutral after a prolong ride, it usually means that the fluid in your clutch hydraulic system is contaminated with water.
DOT 3 and DOT 4 brake fluids are Hygroscopic (not Hydroscopic) which means they absorb moisture from atmosphere readily. As brake fluid gets old, more moisture is absorbed from atmosphere. The added moisture, will reduce the boiling point of the brake fluid significantly. As the fluid gets hot and the added moisture boils, it turns into air. Unlike fluid, air is compressible. When water turns to air, the same amount of lever throw will not cause the same amount of throw in the slave cylinder as before. In turn that will cause the clutch plates to not fully disengage when the lever is pulled.
When the rear wheel is not moving or is moving very slowly, the added drag will make it more difficult to find neutral and in some cases going into first gear.
I recommend you replace the fluid in the clutch hydraulic system with a brand new one and --FULLY-- bleed the system.
When replacing the fluid, it is best to remove as much fluid as you can from the reservoir using a paper-towel first. Just leave enough to cover the hole on the bottom of the reservoir. Then add fluid and bleed the slave and watch the fluid coming out the slave bleeder. When it starts changing color it means the new fluid is coming out.
When I replace the fluid in my bike, I take the clutch slave cylinder off the case and push the slave piston --ALL the WAY IN -- using a small wooden dowel before I start adding fluid to the reservoir. This forces all the old fluid out of the slave cylinder. I use a C-clamp or duct tape to keep the dowel in, I then add the fluid until all the old fluid is out. I then remove dowel before I start bleeding the system.
In some cases, depending on the angle of your clip-ons, you may also get some trapped air in the first elbow right after the clutch master cylinder. Getting that air out is kind of difficult when bleeding the system. After the slave is bled, you can pull in the lever and simply crack open the master cylinder banjo bolt while holding the level. Once the fluid starts coming out, tighten the banjo bolt before releasing the lever. Repeat this three to four times to get all of the air out. It is important to wrap the banjo bolt with some throw-away rag or towel, to make sure the fluid does not get on the fairing pieces or any other pieces on the dash. Brake fluid will eat paint and will also dull the clear plexiglass on the tach or speedo. Have a spray bottle filled with soap and water handy, in case you get brake fluid on those parts. Clean immediately with soap if you get fluid on any parts and later rinse thoroughly.
Also note if the throw-out bearing in the pressure plate is not working properly or if it is seized, it can cause all sorts of unexplainable problems with your clutch. It is a great idea to remove the pressure plate off the bike and inspect the throw-out bearing for smooth operation. If it is binding or seized do not ride the bike until that bearing is replaced.
Try the above and see if that solves your problem. If it does not, report back here and we go from there.
Regards,
-Fariborz
DOT 3 and DOT 4 brake fluids are Hygroscopic (not Hydroscopic) which means they absorb moisture from atmosphere readily. As brake fluid gets old, more moisture is absorbed from atmosphere. The added moisture, will reduce the boiling point of the brake fluid significantly. As the fluid gets hot and the added moisture boils, it turns into air. Unlike fluid, air is compressible. When water turns to air, the same amount of lever throw will not cause the same amount of throw in the slave cylinder as before. In turn that will cause the clutch plates to not fully disengage when the lever is pulled.
When the rear wheel is not moving or is moving very slowly, the added drag will make it more difficult to find neutral and in some cases going into first gear.
I recommend you replace the fluid in the clutch hydraulic system with a brand new one and --FULLY-- bleed the system.
When replacing the fluid, it is best to remove as much fluid as you can from the reservoir using a paper-towel first. Just leave enough to cover the hole on the bottom of the reservoir. Then add fluid and bleed the slave and watch the fluid coming out the slave bleeder. When it starts changing color it means the new fluid is coming out.
When I replace the fluid in my bike, I take the clutch slave cylinder off the case and push the slave piston --ALL the WAY IN -- using a small wooden dowel before I start adding fluid to the reservoir. This forces all the old fluid out of the slave cylinder. I use a C-clamp or duct tape to keep the dowel in, I then add the fluid until all the old fluid is out. I then remove dowel before I start bleeding the system.
In some cases, depending on the angle of your clip-ons, you may also get some trapped air in the first elbow right after the clutch master cylinder. Getting that air out is kind of difficult when bleeding the system. After the slave is bled, you can pull in the lever and simply crack open the master cylinder banjo bolt while holding the level. Once the fluid starts coming out, tighten the banjo bolt before releasing the lever. Repeat this three to four times to get all of the air out. It is important to wrap the banjo bolt with some throw-away rag or towel, to make sure the fluid does not get on the fairing pieces or any other pieces on the dash. Brake fluid will eat paint and will also dull the clear plexiglass on the tach or speedo. Have a spray bottle filled with soap and water handy, in case you get brake fluid on those parts. Clean immediately with soap if you get fluid on any parts and later rinse thoroughly.
Also note if the throw-out bearing in the pressure plate is not working properly or if it is seized, it can cause all sorts of unexplainable problems with your clutch. It is a great idea to remove the pressure plate off the bike and inspect the throw-out bearing for smooth operation. If it is binding or seized do not ride the bike until that bearing is replaced.
Try the above and see if that solves your problem. If it does not, report back here and we go from there.
Regards,
-Fariborz
