[jbranson]

I just got this in the mail today.

A "Neway" valve seat cutter set for the 175 Honda. After some research I put together the necessary part numbers to handle 175 seats and got Neway to put it together in a kit for me.

Now I can keep the seats fresh and help prevent any cupping of valve contact area as seen here: http://www.jrbranson.com/showandtell-3.htm
Don't want to be doing this to my pricey SS valves.
JohnnyB

Updated the link above showing what the tool can do with damaged seats.



Edited by - jbranson on Jan 26 2006 06:06:12 AM

 

[jbranson]

It will do valves up to about 35mm I think.
It's not really meant to do the horrible seat I did in a couple of the photos. Just meant to freshen things up with they get worn or pitted.
JohnnyB

 

[jbranson]

Scott,
Yep..it has pilots that insert into the guides (hehe..sounds gay). Very very accurately sized pilots with a very slight taper. You jam the pilot in the guide and slip the tool over the pilot, then use the T handle to turn the tool.

I don't think the question qualifies you as a fucktard, but I really like the word fucktard, so I want to my message to include the word fucktard a few times.

I'll be doing the heads on both our race bikes before next season. I'll let you know how the work...as if I could tell if they don't.
JohnnyB

 

[jbranson]

FR,
I've heard the multi angle seat work (3 angle used to be a big deal) can make more of a flow difference than you might think. A lot of flow is lost when the valve is at very low lifts. The multi angle seat work gives the air at these small valve lifts a much easier path pass the valve and seat...basically "rounding off" the path the gases take rather than having them go around corners.
But I rather think you are correct, on a two valve engine of vintage design, and in the state of tune we run them it probably doesn't make a difference worth worrying about.

I run Manley and Ferrea stainless valves. I've been peening a dip in the contact surface of the exhaust vavles due to the seat being worn and due to the initial softness of the stainless. I consulted with Pete Talabach about the issue. My previous solution has been to replace the valves every year or so. Pete informed me that typically the stainless work hardens so well that this dip in the contact surface can be ground off the valve...carefully...leaving a hardened layer behind it that will not peen nearly as bad in the future. A job he's capable of doing. Next time the need arises I'll take him up on the offer and have him grind a set for me.

At the compression and the rpm I run my engines at it's very very hard on the exhaust valve, some problems are to be expected. In a professional race engine they'd probably be replacing/servicing the valves every couple of races.
JohnnyB

 

[jbranson]

FR,
It gets easier every time you do it.
Nothing wrong with not pulling the head for two years. If a race bike is running good no reason to really.

A whole lot of the work I do is because the bikes are still in the development stage. I need to keep an eye on changes I make to ensure they aren't leading to a catastropic failure that will cost me a lot more money if I don't catch it in time. Also rarely a year goes by that I don't make a change to piston design, or valve train, or head gasket thickness.
I built the engine in my wife's bike with durability in mind, I'll be removing the head for the first time in two years this spring to put some new valve springs in and look things over. It's hasn't missed a beat in two years...but it makes less hp than the engine in my bike.

And...some bikes are just way easier to work on that others. Takes about 15 minutes to pull the engine out of my bikes and put them on the bench.
JohnnyB




Edited by - jbranson on Jan 27 2006 3:37:05 PM

 

[jbranson]

Rosko, only if it has the right heads...each cutter head is a specific angle. You have to know which angles your head uses (can be found in a good factory service manual) and then buy the proper heads. Typical for Honda is 30 degrees, 45 degrees and 60 degrees.

The heads also have to be in the right diameter range for the seats you are cutting. I can provide anyone that wants them with the proper part numbers to put together a kit for a vintage honda.

On a scale of 1-10 in the mechanics ability rating...I'd give this about a 7. It's not hard to do the job...but it would be pretty easy to totally screw up your head and have to have the seats replaced.
JohnnyB