Author Topic: 400 valve guide trauma: blank stare, drooling. (Read 1803 times)

Killer Canary · « **on:** March 26, 2021, 05:13:29 PM »

Just when I thought I had it made.
I have new Yamiya exhaust guides (with stem seal grooves) installed and now my 5.5mm reamer has arrived.
Using what I hope is logic, I didn't expect it to insert into the new guides (it does not) but I DID expect it to fit through the old guides that I've removed (also does not).
The reamer measures out at 5.52mm(.2170") and the valve stem is 5.47mm(.2156") so .05mm(.0014") clearance but I imagine the reamer will bore slightly larger than it's OD.
For my own edification I'm going to chuck an old guide in the lathe and ream it and then test fit the valve but I'm expecting it to be sloppy.
Or no?
Should the reamer not fit an old guide that's already been reamed and used?
I am ignorant and eager to learn.

caluser2000 · « **Reply #1 on:** March 26, 2021, 06:14:28 PM »

Why Yamaha valve guides?

https://4into1.com/genuine-honda-intake-valve-guide-12021-149-405-cm200-cb350f-cb400f/

https://4into1.com/genuine-honda-valve-guide-12203-333-405-xr100-cb350f-cb400f/

Lots and lots of other goodies on that site for Honda SOHC M/Cs.

Killer Canary · « **Reply #2 on:** March 26, 2021, 06:29:13 PM »

You a funny guy.

caluser2000 · « **Reply #3 on:** March 26, 2021, 06:38:32 PM »

Just know where to get stuff from that's all. I've had my CB550F since 1986. My little bro had a 400/4.

We both had SOHC CB650s at one point.

Don R · « **Reply #4 on:** March 26, 2021, 10:00:18 PM »

I dunnow but had to re-sell a reamer once when I got one that wasn't right.

bryanj · « **Reply #5 on:** March 27, 2021, 12:33:28 AM »

That reamer is wrong and would give too big a clearance wrecking the new guides

Killer Canary · « **Reply #6 on:** March 27, 2021, 07:08:15 AM »

What exactly is wrong with the reamer?

bryanj · « **Reply #7 on:** March 27, 2021, 07:25:18 AM »

Fronm the sizes you gave it will give too big a clearance

Killer Canary · « **Reply #8 on:** March 27, 2021, 07:34:41 AM »

Thanks.
I"ll redo the calculations until I come up with the right size.
I thought I'd read Mike post that a 5.5mm reamer was correct.

Killer Canary · « **Reply #9 on:** March 27, 2021, 07:40:06 AM »

Hondaman's clearance spec in Jag's thread is exactly in line with the specs that I came up with for a 5.5mm reamer.
Okay, someone please just tell me what size reamer they use on steel 400f guides.

69cb750 · « **Reply #10 on:** March 27, 2021, 09:42:41 AM »

Quote

Hondaman's clearance spec in Jag's thread is exactly in line with the specs that I came up with for a 5.5mm reamer.
Okay, someone please just tell me what size reamer they use on steel 400f guides.

Ideal clearance is .001" for intake and .002" for exhaust.
You can use .002" for both, still in limit, just a bit looser then new.

bryanj · « **Reply #11 on:** March 27, 2021, 10:18:06 AM »

Appologies i missread your post as 5 thou, i think you still may be too big as a remer will frequently cut a small fraction oversize so you will be at nearly max before starting, also measure all the valve stems even if new as a lotof parts coming through have undersize stems, even new guides have been found undersize on the od

Killer Canary · « **Reply #12 on:** March 27, 2021, 10:22:22 AM »

Will do!
I bought spare guides but I want to get it right the first time.

MRieck · « **Reply #13 on:** March 27, 2021, 10:27:33 AM »

Quote from: Killer Canary on March 27, 2021, 07:34:41 AM

Thanks.
I"ll redo the calculations until I come up with the right size.
I thought I'd read Mike post that a 5.5mm reamer was correct.

I have the guides honed.....not reamed.

Killer Canary · « **Reply #14 on:** March 27, 2021, 01:09:44 PM »

I give up.
I'll take the damned thing in.

Bodi · « **Reply #15 on:** March 28, 2021, 12:04:02 PM »

I don't know if honing is better than reaming. Never tried honing. I understand that it's supposed to be better for Oilite bronze as it shouldn't seal the oil pores like maybe a reamer will, but the stock guides are steel or iron.
I actually bought a set of official Honda valveguide reamers (07984-2000000 I & 07984-3770000 E) for the 400F. Intake and exhaust used different reamers for unknow reasons. I may even still have them somewhere, last time I used them was at least 25 years ago.

Killer Canary · « **Reply #16 on:** March 28, 2021, 12:13:39 PM »

Thanks for the input , Bodi.
I was waiting to hear from you!
I measured all four exhaust valve stems; all four were .2155 so I ordered a .2159 reamer,
.0004 being the minimum stem to guide clearance specified in the Honda manual.
I aimed for the tightest spec assuming that the reamer will bore slightly larger than it's max OD.
This WILL happen!

caluser2000 · « **Reply #17 on:** March 28, 2021, 02:53:02 PM »

That's the one.

When I did my CB550 ones I just did "pop!" test. One stem was very very iffy. Tossed everything back together. The bike is still running fine 30 or so years later so I must have done something right

At 164.000kms up now oil usage is marginal.

754 · « **Reply #18 on:** March 28, 2021, 11:14:40 PM »

I thimk honing has its advantages.. and i am thimking same hone works for both, and you can set clearance to suit your needs
But....
Expensive, and you need good measuring equipment to check your work. More expense than its worth for occasional work.
Yes , different clearance between intake and exhaust.. one runs much hotter..

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Author Topic: 400 valve guide trauma: blank stare, drooling. (Read 1803 times)