Topic: help removing valve guides

[MRieck]

 Bronze guides should be honed, not reamed. Be careful with "pre reamed" guides....they quite often need to be opened up.

[Sam Green Racing]

Some of the Branch heads are heavily modified, complete change in Chamber shape, he used to have a little booklet in the 90s had a lot of usefull info on Evo heads. The Sporty my buddy had that would often go thru the first 3 gears with the tire in the air, it had Branch heads.

I would not go past 300deg F.

A long time ago I figured out that you can drill the top of the guide to nearly OD, then snap off the head, then drive it, into the port. This usually results in a guide bore that is scratch-free, round and not worn, in fact it looks more like a burnished hole, and no carbon gets dragged thru the bore.When glass beading around the guide in the port, it does not always get all the carbon out.. AND digging around it to get those last bits, can make an even better place for carbon to sit, that is even harder to remove, next time.

 Its not the easiest, nor the fastest, but it gives the best results. I had been doing that a lot to twin heads, then when I got my BMW, I noticed in the manual that they recommend that method on the airheads..

 Give at least 5 thou clearance on your drivers, and when installing, they can burr on ends or shrink up so they may need reaming, and a reamer wont last forever on bronze guides. Ampco 45 is not really soft material. You will know if you nead to ream, valve needs to move freeley in guide.

Boring the old guides to minimum thickness is a procedure a Buddy of mine used for years.....easy to do on the Serdi

What's a Serdi mister ?

Sam.

[MRieck]

Some of the Branch heads are heavily modified, complete change in Chamber shape, he used to have a little booklet in the 90s had a lot of usefull info on Evo heads. The Sporty my buddy had that would often go thru the first 3 gears with the tire in the air, it had Branch heads.

I would not go past 300deg F.

A long time ago I figured out that you can drill the top of the guide to nearly OD, then snap off the head, then drive it, into the port. This usually results in a guide bore that is scratch-free, round and not worn, in fact it looks more like a burnished hole, and no carbon gets dragged thru the bore.When glass beading around the guide in the port, it does not always get all the carbon out.. AND digging around it to get those last bits, can make an even better place for carbon to sit, that is even harder to remove, next time.

 Its not the easiest, nor the fastest, but it gives the best results. I had been doing that a lot to twin heads, then when I got my BMW, I noticed in the manual that they recommend that method on the airheads..

 Give at least 5 thou clearance on your drivers, and when installing, they can burr on ends or shrink up so they may need reaming, and a reamer wont last forever on bronze guides. Ampco 45 is not really soft material. You will know if you nead to ream, valve needs to move freeley in guide.

Boring the old guides to minimum thickness is a procedure a Buddy of mine used for years.....easy to do on the Serdi

What's a Serdi mister ?

Sam.

My spiritual advisor Sam.

[Sam Green Racing]

 

Sam.

[UK Pete]

Bronze guides should be honed, not reamed. Be careful with "pre reamed" guides....they quite often need to be opened up.

 Mike I checked the Dynoman site and the guides mi bought are pre honed, i take it that they can be fitted as is with no further work
Pete

[MRieck]

Bronze guides should be honed, not reamed. Be careful with "pre reamed" guides....they quite often need to be opened up.

 Mike I checked the Dynoman site and the guides mi bought are pre honed, i take it that they can be fitted as is with no further work
Pete

Pete...don't be surprised if some are too tight. It certainly happens

[UK Pete]

Don't forget Peter, I have a 6.6mm reamer for doing 750F2 valve guides.

Thats good to know tim Thanks
Pete

[dmcampbell77]

I'm currently rebuilding a CB650C (1981) and I have pulled the valves, springs, collars, etc. I was going to pull the valve guides until I realized that I was going to have to blast and bake them. So with that said, I have three questions.

1. Hypothetically (of course), if I had attempted to knock a guide out from the chamber side, using a flat punch, and barely tapped it to see if it would move (and obviously didn't) what are the odds of the guide still being straight, functional, etc.
2. How likely is it that oven cleaner (used sparingly to clean carbon) will seep under the guides and damage the o-rings?

3. Has anyone ever had any issues with oven cleaners and heads, valves, springs, etc.

Thanks for any useful info!