Lifter exhaust - Vincent Comet Serie C

[Michel]

Hello,
Today, I notice that the lifter exhaust is out of order. The lift cable is well tight but the adjustment doesn't change anything. I can start the engine and I can ride without any problem. I read in the "Richardson" that the problem must in the exhaust lifter mechanism behind in the left cover. Before I strip down and I repair, do you think there are a risk to ride in this condition (I'm in holidays with the bike but without my tools) ? Thank you for your help.

 

[ClassicBiker]

I would be cautious of using the bike until I knew what had occurred in the timing chest. E15 has a habit of going astray and you wouldn't getting jammed between any gears.
Steven

 

[nkt267]

Could the cable be siezed?..John

 

[Michel]

Steven, I follow your advice and open the timing cover. Everything is OK without any jamming parts.
As John suggest, I carefully oil the cable and adjust it. Now everything is in order and the bike is back on Provence roads.
Thank you for your help.

 

[Michel]

The mystery grows: the ajustment is right when the engine is cold . The lifter exhaust doesn't work when the engine is warm.
Does anyone has an idea ?

 

[ClassicBiker]

Michel,
Glad nothing went walkabout in your timing chest. For the exhaust lifter to work on a cold engine and not lift the exhaust valve on a warm engine something must either be expanding or moving with the heat of the engine and introducing slack into the system. That or there is a loss of rigidity with some component once warm. Myself, I think I might be inclined to warm the engine to the point the exhaust lifter didn't work, remove the cable, the cable abutment (ET172), the spacer (ET168), and hook the cable anchor (E218) with something such as a screw driver to determine if the problem is within the timing chest or perhaps the cable is getting a bit spongy with heat. If it wasn't the cable at fault I would look to see what was happening to ET172, ET168, E217, and E218 once warm. My reasoning being ET168, ET172, and E217 all transfer the pressure of the outer cable to the crankcase, if they are not rigid and maintaining their position relative to the outer crankcase when warm then they are introducing slack and lost motion to the system. I suspect E217 of being loose in the case when warm and when you squeeze the lever of it moving into the case and E223 the return spring pushing it out again. When cold the case has sufficient grip for all to work. Keep me posted please, I'm interested to know what the actual cause of your problem is once you find it.
Steven

 

[ClassicBiker]

Posted this so you could see ET172 and ET168
Steven

 

[Martyn Goodwin]

This image, being part of the Alternative Spares List, may help. The ASL is a great resource and I recommend it to anyone with a Vincent. ET69 has a cam profile that lifts the exhaust valve as it rotates

Martyn

 

[brian gains]

look to the rear of the teeth on ET50, you may find that some/all the teeth have been chewed by ET218 where it has fouled on it. This happened to me but the symptoms are more temporary than permanent.

 

[karl johnson]

michel, i hope you are on the way to getting it sorted , i had exactly the same problem with my comet on hot starting the lifter not releasing untill a further adjustment being made. ,being new to vinnies, i discoverd the lifter lever was off a bsa it was wrong, i replaced the cable and lever with new correct parts. thinking cosmetic i suppose and behold it was cured. (correct lever is longer more leverige)
i personally would have lost money on a bet that, that a correct lever would sort it.
asuming yours is the correct long one sorry i cant help , if it is short ie off a goldie try it.