New valve guides + valve size

BelgiqueBasterd · Apr 6, 2007

Just picked up my new valve guides, tried to get the valve in , but it doesn't fit? Could it be that the valve guides need to be pressed in the head first and then honed to the right size or did I just get the wrong guides? Part numbers match with the husa parts list.

Anyone happen to know what diameter the stock valve stems are? Als the in and outside diameter af a valve guide would be handy.

Thanks, Christof.

oyk · Apr 6, 2007

hi , long time ago had the same problem in my fe600 1994
turned out to be wrong part! somewhere in 97 they revised the valve guides along with many parts in the top end

BelgiqueBasterd · Apr 6, 2007

Sorry forgot to mention what bike, it's a 2002 650

Dr_C · Apr 6, 2007

Dear Mr Bastard,
check that the end of the valve stem has no "burr". If so, gently grind the edge.

nsman · Apr 6, 2007

As valve quides are a light press fit in the cylinder head and removing them requires thermal expansion and light force from a special tool the correct head to quide fit cannot be guaranteed as there is always the chance of metal stretching and transfer if an exact copy of the original guide is used as a replacement.As such it is normal for the guide to be slightly oversize to enable the correct interference fit.
As well the inner surface of the quide(where the valve slides)cannot be machined to fit the valve as the expansion of the quide inward from the press fit installation in the head makes this difficult calculate.
Also the installation of a new valve quide often results in the valve not being in the perfect original alignment with the valve seat..
As a result of these conditions it is normal for the valve bore to require reaming to the correct size to achive the correct valve stem to quide spec.
Also it is normal that the valve seat be cut to again maintain perfect alignment and resulting gas seal.

BelgiqueBasterd · Apr 6, 2007

Dr_C said:
Dear Mr toughie,
check that the end of the valve stem has no "burr". If so, gently grind the edge.

Mr. Toughie?? please explain?

Had that problem before and then followed Taffy's advice on grinding of the burr and they went straigth in, with the new guide it doesn't, so the burr is not the problem this time.

BelgiqueBasterd · Apr 6, 2007

nsman said:
As valve quides are a light press fit in the cylinder head and removing them requires thermal expansion and light force from a special tool the correct head to quide fit cannot be guaranteed as there is always the chance of metal stretching and transfer if an exact copy of the original guide is used as a replacement.As such it is normal for the guide to be slightly oversize to enable the correct interference fit.
As well the inner surface of the quide(where the valve slides)cannot be machined to fit the valve as the expansion of the quide inward from the press fit installation in the head makes this difficult calculate.
Also the installation of a new valve quide often results in the valve not being in the perfect original alignment with the valve seat..
As a result of these conditions it is normal for the valve bore to require reaming to the correct size to achive the correct valve stem to quide spec.
Also it is normal that the valve seat be cut to again maintain perfect alignment and resulting gas seal.

Thank you, that's what I needed to know, well it's off to the cylinder head specialist then I think.

Christof.

Dr_C · Apr 7, 2007

BelgiqueBasterd said:
Dr_C said:

Dear Mr toughie,
check that the end of the valve stem has no "burr". If so, gently grind the edge.

Click to expand...

Mr. Toughie?? please explain?

Had that problem before and then followed Taffy's advice on grinding of the burr and they went straigth in, with the new guide it doesn't, so the burr is not the problem this time.

I tried to call you by your nick, but the B-word (in my spelling) was apparently censored automatically.

The big brother watches you!

If no burr, then trust nsman. After fitting guides in the head, the hole usually gets somewhat smaller and needs reaming or honing.

Search

Search

New valve guides + valve size

BelgiqueBasterd

oyk

BelgiqueBasterd

Dr_C

nsman

BelgiqueBasterd

BelgiqueBasterd

Dr_C

Similar threads

Register CTA

Recent Discussions