What is involved in replacing valve guides?

[Guest]

Well, I managed to bend the valves in my GPz (don't ask, please ).
My source for used valves gave me junk this time so I guess I am going to install new ones and get this marathon over with. I am thinking about putting in new valve guides while I am there, just in case the bent valves damaged one or more. What is involved in replacing them? Sounds like a machine shop job to me, but IDK. The sole machine shop around here sux, unfortunately. I'd even be willing to drive out of state (any adjoining state) to get them done correctly in a timely fashion.
Helpful suggestions very welcome. Thanks in advance.

[Suzuki_Don]

The most difficult part is removing the old guides. Usually the head has to be heated to around 220degC to 240degC and the guides are then driven out. It can help to drill (using a special cutter) a large portion of the guide out first and then drive out the remaining porton (thin wall).

BTW don't forget that each time a guide is fitted the valve seat has to be recut. I would not replace the valve guides unless they are broken, cracked or worn excessively. A lot of work/effort for little gain.

[rapidray]

The guides are EASILY removed with a driver made specifically for doing it. You will also need to have a valve job done if you change the guides. If there is no excessive wear on the guides & the engine is low mileage, unless the valve is SEVERELY bent, chances are the guides are fine & you would only need to replace & lap the valves. In a motorcycle head, or any other head with removable guides, you DON'T cut or drill them out. Ray.

[blowerbike]

Well, I managed to bend the valves in my GPz (don't ask, please ).
My source for used valves gave me junk this time so I guess I am going to install new ones and get this marathon over with. I am thinking about putting in new valve guides while I am there, just in case the bent valves damaged one or more. What is involved in replacing them? Sounds like a machine shop job to me, but IDK. The sole machine shop around here sux, unfortunately. I'd even be willing to drive out of state (any adjoining state) to get them done correctly in a timely fashion.
Helpful suggestions very welcome. Thanks in advance.

you are in indy.
john pearson is outside of eaton ohio.
not to far.
john has boxes of GPZ valves for you.
john can do your guides and a valve job/shim your valves also.
john has forgotten more than MOST people knows about your bike.
CALL HIM!
937-839-9723

[Nessism]

you are in indy.
john pearson is outside of eaton ohio.
not to far.
john has boxes of GPZ valves for you.
john can do your guides and a valve job/shim your valves also.
john has forgotten more than MOST people knows about your bike.
CALL HIM!
937-839-9723

Good info here. The guides are unlikely to have been damaged by the valve bending episode. Before replacing the guides though I'd measure the valve to guide clearance and then make a decision.

[koolaid_kid]

I agree, Ed, but that takes a machine shop, which Indy is sorely lacking. I'll give Mr. Pearson a call tomorrow and see what we can arrange. All appendages crossed.

[koolaid_kid]

Dropped it off at John's after a protracted discussion. He's going to make me 4 stainless steel exhaust valves and I am getting 4 stock valves from Z1. Very knowledgeable person, lots of Kaw experience. I don't think he has ever seen a GPz750 head before; he kept calling it a KZ. And he told me he mostly does 1100 work for drag racers. He's gonna do a valve job, check the valve guides, verify spring tension, check the pistons for clearance, check the cylinder block for chamfering, and even flow bench it.

Thanks for the reference blowerbike.

[blowerbike]

Dropped it off at John's after a protracted discussion. He's going to make me 4 stainless steel exhaust valves and I am getting 4 stock valves from Z1. Very knowledgeable person, lots of Kaw experience. I don't think he has ever seen a GPz750 head before; he kept calling it a KZ. And he told me he mostly does 1100 work for drag racers. He's gonna do a valve job, check the valve guides, verify spring tension, check the pistons for clearance, check the cylinder block for chamfering, and even flow bench it.

Thanks for the reference blowerbike.

OOOOOOOOOOOOPS!!
i thought you had an 1100 GPZ.
well...
john amazes me and what i know about kawi's came from working for him for a year.
i'm glad it worked out and anyone here should keep john in mind as to support the "little" guy.
he can do anything besides insert bearing crank work with out every leaving his shop.
you want a naturally aspirated KZ engine that will run 8'0's in the 1/4...he can do it 100% from his shop and farm nothing out.
FYI
john builds cranks/back cut-repairs tranny's/ports-flows cyl. heads/machines cases/installs HD basket kits/bores cylinders/he can also weld most types of material VERY WELL.
keep him in mind folks.
i'm glad it worked out for you!

[koolaid_kid]

No, I have the much more nimble 750 with a Wiseco 810 kit.
To someone with his experience, a hole is a hole and a valve is a valve, displacement doesn't matter. I think it's pretty cool that he is making custom stainless steel valves for me for less that the cost of OEM. Nice shop, too.

[bwringer]

Daggum, I just love a happy ending!


Truly, the saga of George's %$#@! GPz would fill a thick book and bring strong men to tears. At one point, George and I were discussing cam timing while sitting in a Mexican restaurant with a GPz cylinder head and a dial indicator on the table between plates of burritos. (The cylinder head was sitting on a towel... I mean, we're not heathens.)

The finish line is sooooooo close...

[wkmpt]

Dropped it off at John's after a protracted discussion. He's going to make me 4 stainless steel exhaust valves and I am getting 4 stock valves from Z1. Very knowledgeable person, lots of Kaw experience. I don't think he has ever seen a GPz750 head before; he kept calling it a KZ. And he told me he mostly does 1100 work for drag racers. He's gonna do a valve job, check the valve guides, verify spring tension, check the pistons for clearance, check the cylinder block for chamfering, and even flow bench it.

Thanks for the reference blowerbike.

I had an '82 GPz750, I really liked the looks (looked like the KZ1000 lawson bike), but my GS750 is a better bike. The manual I had for my gpz, though, routinely referred to the bike as a "KZ750R1 (GPz)", so FWIW I seriously doubt that there was any misinformation happening.

Unless, of course, there were major engine changes between '82 and '83. I know the bikes sure look different, so ya never know--well, I don't, anyway...