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horrid yamaha


tobyd

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Could be, The clean oil i could see in the oil hole is now black. Presumably mixed with all the grim old skank left in the engine. At least i can now see the oil level.

 

The exhaust was fairly oily before this though. I'll take it apart and clean it out tomorrow. The motad system is quite cleverly designed to come apart in bits so you don't have to be an octopus to keep all 4 pipes in.

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Had it running yesterday burning off oil (which is going well) and thought I'd see if it would creep forward under its own power. Not trusting it yet I kept the brake hard on (hur hur) which was good because clumping it into first it tried to leap, like a salmon, despite the clutch pulled in... The clutch has something of a rattle and gets worse with the clutch disengaged anyway but this all seems to point to a glued together clutch. Since I would need to take it apart to free it all up (other tricks I understand involving locking the back well up at low speed, but doing skids on an untested or tax bike in the road doesn't shout 'clever' particularly loudly) I thought I may as well swap the whole thing for the spare from the original engine and fix the rattle at the same time.

 

Suggestion from Hooli re: carb sync noted but these things are somewhat famed for clutch rattle owing to a bit of a design fail. The oil pump is driven from a gear on the back of the Y clutch assembly. The pump drive-gear is located by a little pin. Seen here as the silver bit at about 3 o'clock.

 

post-18007-0-76029900-1540737441_thumb.jpg

 

The problem seems to be that the pin was slightly undersized so over the years the slight miss-size gets worse and the play on the driven gear gets worse and worse. The result is much clutch chatter at low engine speeds.

 

The solution is to make a new pin. There are a few posted solutions, one is a split pin hammered over an allan key. The other is a cut down drill bit. The original pin is 5mm, I just so happened to have a pack of 5.2mm drill bits that I got on sale.

 

Breaking out mobile pro machine shop...

 

post-18007-0-82658400-1540737654_thumb.jpg

 

Cut off the drill bit approximately right, holding the stub in the drill chuck (safety first) I ground it down until it was the right size then with the drill spinning slowly chamfered the edge.

 

post-18007-0-44265000-1540737666_thumb.jpg

 

Fits snugly into the clutch and minimal play on the gear end.

 

post-18007-0-24213300-1540737672_thumb.jpg

 

Its cold and on/off raining so I'm not going out to change it over today but this and a slight tank leak is the only thing holding up the MOT now.

 

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  • 3 weeks later...

Has it got a centre stand? Running it in gear on the stand, holding the clutch in & stamping on the back brake can free the clutch off too.

I assume you'll be stripping it down to do that pin though.

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Front wheel against wall, brakes on, revs, clutch in, stamp into first.

 

Usually unbinds them.

F'kin 'ell what's wrong with riding round with the clutch pulled in in 3rd and alternating rear brake and throttle?

With yours If it doesn't instantly free you've got major problems unless it lights the back tyre up plus you are putting loads of stress on the box dropping into gear with a decent amount of revs on.

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With yours If it doesn't instantly free you've got major problems unless it lights the back tyre up plus you are putting loads of stress on the box dropping into gear with a decent amount of revs on.

Or it just stalls. Which is the more likely result than engine Armageddon.

 

And if that doesn’t unbind it the clutch basket has to come out anyway.

 

I stick by my advice.

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Thanks folks!

 

Excellent resurrection.

Are you going to ride it then paint or strip and paint it now?

 

I think i'll strip it and have it blasted and painted over the winter, the swing arm is equally crusted so i'll see about having it and some of the other hardware done in default gunmetal and match the red as best I can from the frame. I'm not sure about the plastics, they are very tired paint-wise but in reasonable shape scar-wise. I'll ask around and see what the going rate for the fairing, side panels and back panel is, I dont much mind about the livery just a reasonable red match would do.

 

Yeah!! Back from the dead. Great work! Did you deal with the leaky tank?

 

I wobbed up the edges of the patch with JB weld and ran it there and back with about 2 litres of petrol in the tank, i'm faintly confident its petrol tight. I saw a clever idea about using a length of chain inside a much-holed plastic tube as the anode in a derusting tank. Fill the petrol tank with soda and water, put the chain in and run 12v from a battery charger over it and the chain sacrifices itself through the holes in the hose cleaning the tank up in the process. Then I'll slop in a can of POR15 for good measure.

 

The other one is due its insurance in Feb so i'll probably get it insured on a joint policy then and tax them both. So its back to cluttering up duty for a while.

 

It ran quite well, very gently on the old tyres and equally so on the new ones (something about needing to run them in for a hundred miles to wear off some residue or other? they didn't say that about the avons on my other bike). The gears shift fairly well, the adjustment is well out so i'll try and sort that. The back brake is either very weak or there is some air still in there so i'll bleed it down at some point too. Front brake is really good, for the extra pound or something for goodridge hoses over stock there is masses of feel not that i gave them much of a workout. Suspension is quite firm but otherwise fairly comfortable. Engine pulled fairly well from 2000rpm, speedo is a little sluggish but might just need some use. I think it'll be a reasonable commuter once painted and run in a bit. I'll investigate the state of the RR too. they are thankfully cheap on ebay.

 

Clutch seemed fine, it put it all back together with lashings of fresh oil and mixed the plates up. The old one doesn't seem very worn so I oiled it and wrapped in a plastic bag to fester. The clutch/oil pump still rattles with my pro fix pin so might try the dowel pin + allan key approach.

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