Valve Lapping

[suzukizone]

RE: lapping of the existing valves on the 81 GS850G, I'm told OK to lap the intake valves only but have also heard OK to also do the exhaust valves. Some thing about stellite material????? Valves & seats in pretty good state but wanted to get them seated perfectly as long as head is open.

Thank you!

DH

 

[Nessism]

Lapping is not to repair worn or damaged seats, it's only to clean them a little and check the seating pattern. Go easy and you will be fine.

 

[koolaid_kid]

You'll want to do both intake and exhaust.

 

[Big T]

Lapping both sets of valves should result in a line about 2 mm wide.

Much wider than that and you're needing new seats cut


You're replacing the valve stem seals while you're in there, right?

 

[Russ' GS1000E]

Valve lapping compound choices ??

 

[Nessism]

Lapping both sets of valves should result in a line about 2 mm wide.

Much wider than that and you're needing new seats cut


You're replacing the valve stem seals while you're in there, right?

I agree that 2mm is common for 8V engines (factory service limit is 1.4mm), yet most of these engines seem to seal up well anyway.

 

[rapidray]

Valve lapping compound choices ??

I like CLOVER brand in the green cans. It will come with 2 small cans, a can of coarse, & 1 of fine. Ray.

 

[suzukizone]

Forgot to say thanks. In the end my boss did them as I'm not smart enough (his view, fine by me) He had to cut all 4 ex seats in the end & lapped all 8 valves. Finished installing them last night & no leakage from any. I'm sure I would have messed up so glad for the help.

Thanks again,
DH

 

[goggleboy]

I agree that 2mm is common for 8V engines (factory service limit is 1.4mm), yet most of these engines seem to seal up well anyway.

I felt a slight rut around the valve when I lapped mine, and it was right at 2mm or a little more....

 

[Nessism]

I felt a slight rut around the valve when I lapped mine, and it was right at 2mm or a little more....

A rut like that is bad. You should get the valves faced.