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Not really sure where to place this so Im putting it in general. I have a 2004 American Ironhorse with a hydraulic clutch. The clutch master cylinder has been replaced with a fairly stock vtwinpower unit ( at a shop ) and I have already rebuilt the master cylinder.
Problem is that periodically the clutch continues to loose pressure and then is an enormous pain to bleed, especially on the side of the road. What Im wondering is if my handlebars are contributing to my issue. My bars have a fair amount of turn down and when the wheel is positioned straight ahead this master cylinder is sitting at quite an angle. This results in the small fuild hole inside the master cylinder being almost uncovered when the wheel is straight ahead. To add fluid I usually turn the wheel all the way to the right and then put a board under the kickstand to get the reservoir almost level, fill it and then put the cap on tight. Has any had issues with the handle bar angle contributing to hydraulic clutch bleed issues? At this point I want to make sure Im chasing the right problem rather than changing bars and \ or master cylinder and whatever else.
This is not an issue with the brake master cylinder which sits at the same angle, although the brake master cylinder reservoir is taller in in height between the piston bore and the cap.
Im attaching a picture for reference,on the install angle. If you look closely you can see a 2x4 keeping the bike even more level.
The master cylinders are sensitive to bar angle. Yours looks pretty steep, and unfortunately I think there's a hole at the end that’s uppermost with yours. A buddy did a bar swap and found he couldn’t disengage - went halfway thru a intersection trying to stop.. He just needed more fluid, but his bars weren’t like yours.
I believe that you’re absolutely on the right track.
It's probably happening when you set the bike down on the kickstand and that's why your brakes aren't doing the exact same thing. I'd try new bars or I imagine your issue will continue.
If it didn't do it before the bar change you found your issue. You are sucking air into the system. A buddy of mine had the issue. I took the cylinder off, held it flat, filled it, bled it, (PIA) and put it back on. never another issue.
Oh, I have a portable vice on a stand. I wheeled it next to the bike, used an old set of bars to mount the system to, fill and bleed it. Still a PIA.
Last edited by Bass Player; Mar 1, 2021 at 10:57 AM.
This could be a long shot but your post brought back a tough learning experience.
My work had a customers Cadillac that was forever getting air in the brakes. We would bleed it get a good pedal, even kept the car ( over weekend) and it never lost a drop that we could see. It would take 2 weeks of 15-20 mi daily driving for the brakes to go soft again. A proportioning valve in the system would have brake fluid dampness but nothing would be really wet.
Finally proved things to a GM rep by locking the brake pedal down for 3 days and showed him the dampness.
Got ok to replace valve and was told latter it's fixed. Ended up talking with another rep and an engineer to close a tech case.
Ok let me shorten this. Have seen like symptoms on 3 bikes with Hyd. clutches. All three boiled down to seepage at a fitting or a bleeder valve.
It might only let a tiny tiny amount of fluid out when applied and only a tiny tiny amount of air back in when released. The air back in is the culprit.
If I hadn't experienced this myself I'll admit it sounds a bit over the top even to me.
Stuck at the house this morning and nothing to do. LOL
If it didn't do it before the bar change you found your issue. You are sucking air into the system. A buddy of mine had the issue. I took the cylinder off, held it flat, filled it, bled it, (PIA) and put it back on. never another issue.
Oh, I have a portable vice on a stand. I wheeled it next to the bike, used an old set of bars to mount the system to, fill and bleed it. Still a PIA.
Yeah I have thought about where I can mount the master cylinder to just bleed it, even sitting on the bike and holding it leaning to the right the bango is still slightly higher than the tiny hole that lets the fluid into the system.
The master cylinders are sensitive to bar angle. Yours looks pretty steep, and unfortunately I think there's a hole at the end thats uppermost with yours. A buddy did a bar swap and found he couldnt disengage - went halfway thru a intersection trying to stop.. He just needed more fluid, but his bars werent like yours.
I believe that youre absolutely on the right track.
You are correct. The system feeder hole is at the end which is closest to the banjo bolt which is why its barely covered when the bars are straight.
If it didn't do it before the bar change you found your issue. You are sucking air into the system. A buddy of mine had the issue. I took the cylinder off, held it flat, filled it, bled it, (PIA) and put it back on. never another issue.
Oh, I have a portable vice on a stand. I wheeled it next to the bike, used an old set of bars to mount the system to, fill and bleed it. Still a PIA.
well unfortunately I cant apply that logic as the bars and controls were changed at the same time
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Hydralic clutch issues
