Converting back to cable operated clutch.

[Tony saccParticipant @tonysacc93877]

The master cylinder I bought for the hydraulic clutch came from China, the only one I could find of the right size that didn’t cost a bomb.

The ad said it was for mineral oil, so, that’s what I used.  Unfortunately, the ad was wrong and the mineral oil swelled the seals inside the master locking it up.  I managed to free it up, but the seals were ripped and swollen to twice their original size.

I searched and searched but couldn’t find any replacement seals, not even from the manufacturer, so the master went in the bin and I converted it back to cable operation.  The only other option was a Brembo unit, but I’m not prepared to spend that sort of money on a master cylinder.  One day i may buy another cheap Chinese master and fit that.  For now, all that was left was to convert it back to cable.

The reason I converted to hydraulic was to make the clutch pull easier on my arthritic hands.  But there’s more than one way to do that.

So, in converting back to cable and make it easier on my hands, I cut the lever off the original screw acuator and fabricated a slightly longer one.  I also turned up a seal retainer and welded that and the extended lever back onto the screw.  The lever is around 8mm longer that the original from memory.

Next I had to modify the cover to return it back to it’s original configeration.  To do that, I turned up two stainless M5 threaded T nuts with an outside measurement of 6.06mm, then pressed them into the side cover.  With the screw actuator refitted, I was left with a slight gap between the actuator body and the hole in the side cover, a simple Delrin bush I turned up on the lathe fixed that.

So it’s back to the original cable operated clutch.  If I come across another master, that I can get seals for, the slave can be refitted quite easily. 

[OldironParticipant @oldiron]

Please give us an idea of the make & model of the bike or whatever when posting stand alone posts.  If this a continuation of a previous post please attach it to that. Its very difficult unless in the know to align this post with an item. BUT it looks like you did a great job on the clutch parts.  Instructions on some foreign items are abysmal.  ATB

[noel shelleyParticipant @noelshelley55608]

IF they still exist Allseals at Norwich may be able to help with seals but it is vital that you tell them it is for DOT 3 or 4 brake fluid. Noel.

[Phil PParticipant @philp]

Can we see a photo or two of the whole bike please, I guess you have done a few other mods to it that some may find interesting.

Phil P

[MacolmParticipant @macolm]

Try cleaning both parts of the four start thread, then lubricate with molygrease. If you are lucky, you will find a considerable reduction in operating force.

[David JuppParticipant @davidjupp51506]

Not sure how expensive, but I know some seals companies will custom machine seals to your drawing.  Often used to produce seals to suit slightly worn parts, but also useful for replacing obsolete or otherwise difficult to source seals.

[cedric 1Participant @cedric]

Honda CB350?

[bernard towersParticipant @bernardtowers37738]

Dot 5 (not 5.1) would be better for seal life and does not absorb H2O.

[Tony saccParticipant @tonysacc93877]

The bike is a 1974 Yamaha TX/XS650.  Highly modified.  Bought as a wreck, missing parts, rusted out, not going, damaged crankcase.

I do all work myself in my workshop: mechanical, electrical, machining, fabricating, metal polishing, anodising, blasting, welding, painting, upholstery (normally, but not on this one), wheel building, etc.  Only the rebore and chrome plating on rocker nuts, points cover and oil pipe were farmed out.

Engine is stock configeration, Crank split and reset with original bearings, bored .50 over, new pistons, ring, gudgeons, valves and seats reground.  stainless allens/bolts throughout.  Plus a few other bits and pieces.

Mods:  Permanent magnet alternator, single points cam, VM34 Mikunis, reed valve breather/catch can, spin on oil filter, cooler.

I’ve fabricated most of the parts you see in the pictures:  Aluminium tail light, side covers, chainguard, battery box, catch can, engine mounts, cooler base, headlight brackets, exhaust pipes, mufflers, exhaust bracketry, speedo mount, bum stop seat, stainless, brake rod and clevis.  Very little yamaha left.

Machining: PMA mount, chain adjusters, pancake filters, reed valve housing, manifolds, spin on oil filter base, front brake hose junction, risers.

I converted the twin points system to a single points system, making a new points backing plate and a twin lobe cam.  the twin lobe cam gobbling up quite a bit of time, getting timing to 15 degrees BTDC with a 93 degree dwell was lots of fun.

For the electrical system I designed and built a simplified system using three seperate harnesses.

Hubs were mounted on the lathe, casting bridges removed, flanges trued.  Rims were ground to remove damaged areas, rims and hubs polished and laced together using stainless spokes.

Painted in two pack midnight black.

There’s a million other things I’ve made for it, but that would make this post boringly long.

I can’t ride anymore due to age and chronic RA/PsA, fused fingers, no elbow joints, enthesitis, that sort of thing.  A few mods in my workshop allow me to continue.  I’ve been building bikes for close on 60 years, this one was simply something to engage my brain, design different items and keep me busy.  I prefer Brit twins, but they are simply too expensive now, so I picked this poor Japanese copy up for $2k.

[Tony saccParticipant @tonysacc93877]

Doubled up.

[cedric 1Participant @cedric]

Nice job!

[Grindstone CowboyParticipant @grindstonecowboy]

Impressive!

Rob

[Grizzly bearParticipant @grizzlybear]

Fantastic!

Good luck.

[Howard LewisParticipant @howardlewis46836]

Looks very nice, after a LOT of work!

Howard

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