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valves in 850 commando's

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valves in 850 commando's

Posted by ady_strowger at April 10. 2017

Hello

       I keep coming across references to valves needing attention in commando's every 40,000ish miles and as my bike has now clocked over 46,000 miles and I have noticed my exhaust clearances need adjusting more frequently over the last couple of thousand miles because they close up a bit but not that frequently that I want to take the head off yet.  Inlets are always ok I had a big valve job done by Mick Hemmings at about 23,000 so I've either got some valve seat recession going on with the exhausts or the valves are wearing thin or a bit of both, I run the bike on Castrol 40 and when the oil is nice and warm the throttle is turned to maximum grin factor so things are going to wear out and oh I mostly use shell v power or esso/ BP high (sic) octane stuff  as my fuel of choice so I would like to know of other commando owners experience with these matters.

Cheers......Ady

Re: valves in 850 commando's

Posted by dave_taylor at April 13. 2017

Previously ady_strowger wrote:

Hello

I keep coming across references to valves needing attention in commando's every 40,000ish miles and as my bike has now clocked over 46,000 miles and I have noticed my exhaust clearances need adjusting more frequently over the last couple of thousand miles because they close up a bit but not that frequently that I want to take the head off yet.  Inlets are always ok I had a big valve job done by Mick Hemmings at about 23,000 so I've either got some valve seat recession going on with the exhausts or the valves are wearing thin or a bit of both, I run the bike on Castrol 40 and when the oil is nice and warm the throttle is turned to maximum grin factor so things are going to wear out and oh I mostly use shell v power or esso/ BP high (sic) octane stuff  as my fuel of choice so I would like to know of other commando owners experience with these matters.

Cheers......Ady

Hello Ady,

I would reckon you do have valve recession as any other wear would open up the valve clearances. As far as I know all commandos have hardened valve seats, not as hard as modern seats but good enough. What seats are in yours'? Have they been changed and to what?

If your bike is performing okay and you don't mind the extra maintenance don't fix it until it tells you.

Dave.

Re: valves in 850 commando's

Posted by ady_strowger at April 15. 2017

Previously dave_taylor wrote:

Previously ady_strowger wrote:

Hello

I keep coming across references to valves needing attention in commando's every 40,000ish miles and as my bike has now clocked over 46,000 miles and I have noticed my exhaust clearances need adjusting more frequently over the last couple of thousand miles because they close up a bit but not that frequently that I want to take the head off yet.  Inlets are always ok I had a big valve job done by Mick Hemmings at about 23,000 so I've either got some valve seat recession going on with the exhausts or the valves are wearing thin or a bit of both, I run the bike on Castrol 40 and when the oil is nice and warm the throttle is turned to maximum grin factor so things are going to wear out and oh I mostly use shell v power or esso/ BP high (sic) octane stuff  as my fuel of choice so I would like to know of other commando owners experience with these matters.

Cheers......Ady

Hello Ady,

I would reckon you do have valve recession as any other wear would open up the valve clearances. As far as I know all commandos have hardened valve seats, not as hard as modern seats but good enough. What seats are in yours'? Have they been changed and to what?

If your bike is performing okay and you don't mind the extra maintenance don't fix it until it tells you.

Dave.

Hi Dave

Yes my thoughts to about the valve seats although Mick Hemings only touched the inlets for his big valve surgery he did on the head back about 1999 when I got the bike it had about 22000 miles on it and had come back from the USA with about 15000 nothing in the paperwork about new valve seats anywhere I was wondering if other commando owners had this problem or if it's poor quality valves wearing in use

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