Author Topic: Exhaust valve lifter  (Read 431 times)

Offline Oggers

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Exhaust valve lifter
« on: April 22, 2021, 11:13:55 AM »
Folks

Nipple on the handlebar end of the exhaust valve lifter cable for the Velo MSS came away today. Not surprised - it looks original and there is quite a bit of force exerted on the cable to operate the lever at the other end. The operation works fine enough and I have ordered another cable, but would there be any fairly easy way I can reduce the force required on the handlebar lever to prevent possible re-occurrrence? 
« Last Edit: April 22, 2021, 01:26:25 PM by Oggers »

Offline iansoady

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Re: Exhaust valve lifter
« Reply #1 on: April 22, 2021, 04:23:19 PM »
The usual - make sure the cable has an easy sweep with no sharp bends and is kept away from hot bits as far as possible. I've started to use Venhill's nylon lined outers which do make a difference.

When I had my Venom I changed the layout so that the outer operated the lever rather than the inner. See attached. That avoided the cable getting burnt and melted on the exhaust. The original routing was daft IMO.
Ian
1952 Norton ES2
2008 Yamaha X-Max 250

Offline TGR90B

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Re: Exhaust valve lifter
« Reply #2 on: April 22, 2021, 06:36:43 PM »
If you reckon the broken cable was original that would make it at least 50 years old. How old are you now?
Getting grumpy, but not as grumpy as mini-me.

Offline Rex

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Re: Exhaust valve lifter
« Reply #3 on: April 22, 2021, 06:47:26 PM »
I recently replaced the valve lifter on the Panther. It was one of those relatively small pointed-end jobs as used on smaller bikes, and it took a lot of effort to lift the valve lifer on a running 600, plus the movement was minimal too.
I replaced it one of those much beefier ball-ended jobs (original British item 2nd hand off Ebay, and not a monkey-metal modern repro) and it works a treat.
Simple answer, bigger lever = less effort.

Offline Oggers

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Re: Exhaust valve lifter
« Reply #4 on: April 26, 2021, 02:30:35 PM »
Ian

I like it....I have oiled the inner and reduced the bends and yes, I agree the original rouring is daft - far too close to exhaust.

Rex

Force exterted by you on the handlebar lever will make no difference to the force exerted on the nipple. However, a larger lever at other end will.

Offline Rex

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Re: Exhaust valve lifter
« Reply #5 on: April 26, 2021, 04:09:50 PM »
Your nipple would've pulled off whatever size the lever on the handlebar was. I changed the lever on mine to get an easier and more effective decompress rather than to give the cable an easier time.