Topic: help removing valve guides

[camelman]

I am rebuilding/porting a spare head and want to remove the valve guides.  Does anyone know how to do this without a press?  I can heat the head if required.  The head is for a CB350F.

Thanks,
Camelman

[bucky katt]

make sure, VERY sure that you beadblast the ports and top of the heads around the guide so you dont score up the guide holes while removing them. i THINK that heating them in the oven for a bit will work but someone with more experience should chime in. i use my 20 ton shop press.

[Terry in Australia]

That's a good tip Bucky, re: beadblasting them first, I'm about to replace the valve guides in a CB750 head so I'll be watching this thread too, I've never replaced any (all mine have been good) but a mate heated his head in an oven @ 500 deg F, sprayed WD40 on 'em and tapped them out with a drift, and did the reverse on installation, and it worked fine. Cheers, Terry.

[754]

Bucky, ever notice the Beemer twin manual method for removal? dont  need  to beadblast, and guide holes stay original size much longer

[77honda]

I just replaced my valve guides in a CB750 K7 head, made a drift that was about .001 -.002" smaller to slide into valve guide with a step about .002" smaller than guide OD, heated head in oven to about 150 deg and then just tapped them out. (Also bead blasted before removal).

Installed new APE guides, put guides in freezer for a couple of hours, heated head up again and used drift to put them in, just needed lite tap and they went in easy.

Mike

[Terry in Australia]

I just replaced my valve guides in a CB750 K7 head, made a drift that was about .001 -.002" smaller to slide into valve guide with a step about .002" smaller than guide OD, heated head in oven to about 150 deg and then just tapped them out. (Also bead blasted before removal).

Installed new APE guides, put guides in freezer for a couple of hours, heated head up again and used drift to put them in, just needed lite tap and they went in easy.

Mike

Thanks Mike, was that 150 deg F or C? Cheers, Terry.

[77honda]

deg C, just put it in the bosses oven (real boss) when she was out shopping.

[Terry in Australia]

Thanks mate, I bought a little electric oven on EBay for 2 bucks a couple of years ago, and it'll just fit a set of CB750 barrels or a head, but nothing bigger, sadly. It's still in "F", so I'll just crank it up to 400-500 Deg F, I guess. Cheers, Terry.

[bucky katt]

Bucky, ever notice the Beemer twin manual method for removal? dont  need  to beadblast, and guide holes stay original size much longer

actually, i've never gotten to see a factory for the airheads. and when i worked at a dealer, if there was a problem with a guide or valve, the head was replaced as it was cheaper because of the labor rate charged 95 an hour back in 2005.

[MRieck]

There should be no need to go over 300 Degrees F. You'll run the risk of the seats coming out and you start to kill the heat treatment. Branch Harley heads are notorious for being soft as they pour weld into the head ( to fill the chamber) and overheat the casting

[HondaMan]

There should be no need to go over 300 Degrees F. You'll run the risk of the seats coming out and you start to kill the heat treatment. Branch Harley heads are notorious for being soft as they pour weld into the head ( to fill the chamber) and overheat the casting

MRieck, you're the first guy I've heard mention that about the Branch heads since about 1995, great point! They frequently blow head gaskets, and that was one big reason why...

[MCRider]

There should be no need to go over 300 Degrees F. You'll run the risk of the seats coming out and you start to kill the heat treatment. Branch Harley heads are notorious for being soft as they pour weld into the head ( to fill the chamber) and overheat the casting

MRieck, you're the first guy I've heard mention that about the Branch heads since about 1995, great point! They frequently blow head gaskets, and that was one big reason why...

My understanding is that after they are drifted in they may need to be reamed to the valve stem size. Machine shops usually have these reams, so I've always had a shop do my guide removal and install.

[Jerry Rxman Griffin aka MuthaF'er]

Thanks mate, I bought a little electric oven on EBay for 2 bucks a couple of years ago, and it'll just fit a set of CB750 barrels or a head, but nothing bigger, sadly. It's still in "F", so I'll just crank it up to 400-500 Deg F, I guess. Cheers, Terry.

Hey hey there Kooler King! My daughter took offense to that remark. She said you should never put anything but a K head into your Easy Bake $2 EBay oven. Be careful and don't put too big a light bulb heat source in either  Stick to cupcakes 

[camelman]

So it sounds like I should heat the head up to 300F, then drift the guides out with an appropriate drift.  Is the comment about reaming the guides afterwards a hard and fast rule, or are there circumstances that make that a requirement?

Thanks,
Camelman

[754]

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.

[MRieck]

There should be no need to go over 300 Degrees F. You'll run the risk of the seats coming out and you start to kill the heat treatment. Branch Harley heads are notorious for being soft as they pour weld into the head ( to fill the chamber) and overheat the casting

MRieck, you're the first guy I've heard mention that about the Branch heads since about 1995, great point! They frequently blow head gaskets, and that was one big reason why...

All on the exhaust side too. 

[MRieck]

I'm going to have my son video tape me doing valve guides.......he'd kill me if he read the words "videotape". I'll have him post it on youtube also. Both in and out. I use a drift though the one to to put the guides is different.

[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

[MRieck]

There should be no need to go over 300 Degrees F. You'll run the risk of the seats coming out and you start to kill the heat treatment. Branch Harley heads are notorious for being soft as they pour weld into the head ( to fill the chamber) and overheat the casting

MRieck, you're the first guy I've heard mention that about the Branch heads since about 1995, great point! They frequently blow head gaskets, and that was one big reason why...

Thanks Mark....I've seen it.

[mick750F]

There should be no need to go over 300 Degrees F. You'll run the risk of the seats coming out and you start to kill the heat treatment. Branch Harley heads are notorious for being soft as they pour weld into the head ( to fill the chamber) and overheat the casting

MRieck, you're the first guy I've heard mention that about the Branch heads since about 1995, great point! They frequently blow head gaskets, and that was one big reason why...

Thanks Mark....I've seen it.

   Hey Mike and Mark...Reading this just gave me a thought...Wouldn't it be great if there was a closed thread were a couple of Gurus like you two could have a back and forth on ideas, techniques  and experiences without having to answer to questions...just kind of talk and let it go. Maybe open it up to questions when you were all talked out? Or have a separate thread for questions? Yeah, I know about the HondaMan thread in the FAQ section but this would be different, no? Just a late night thought...glad that you are both here contributing. Guys like you two and others are what make this place what it is.

Mike

[77honda]

Here is drawing for valve guide drift that I used and also photo.

Mike

[bryanj]

I assume you are fitting new guides, all honda replacement guides need reaming after fitting and the valve seats will need re-cutting.

reamers are an odd size and adjustables dont do the job right

[bucky katt]

i think that both Dynoman and Z-1 Enterprises sell guides ready to use, no reaming required. i may be wrong on that but i'm pretty sure that they do.

[UK Pete]

I bought mine from Dynoman and they are pre reamed and ready to fit , when i removed my old ones i blasted off the carbon, heated up the head and tapped them out, they came out real easy, when i get round to fitting my new ones i am going to re heat the head, freeze the guide then press them in using the old guide with a bolt through it as a drift, and a valve spring compressor as a press, just set it up and wind them in, does any have any thoghts on my method
Pete

[Yoshi823]

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