Head job

[dqnjuan]

Just seeing what shops you guys are using if any for valve jobs. Looking to get my head done lapped, new seals, and maybe some light port & polishing.

Ive heard about Thomas racing their website is expired and I'm in Maryland and their in Indiana anything closer would be swell.

 

[Jack]

http://www.hoosracing.com/

 

[gentlemanjim]

When I read the title I got all excited for all the wrong reasons.

 

[dwyatt]

Gotta take what you can get........

 

[dqnjuan]

Hahahaha

 

[XSLeo]

You might find that your best mechanic is looking back at you from the bathroom mirror.
That guy cares more about you and your bike than anyone.
Lapping vavles, replacing seals is an easy task. A mild polish job is an easy task too. Porting is best kept too a minimum. The ports are almost too large any way.
Cleaning up the casting marks is all you really need to do.

 

[dqnjuan]

Xsleo, I hear ya. And I would prefer to do it myself just can't afford to screw it up. I already own lapping sticks, and valve spring tool, so maybe if I get that dremel for xmas ill get brave enough to do it myself. Ill make sure I take step by step pics if I do so you guys can tell me if I screwed up.

 

[xjwmx]

Lapping is nothing, just very time consuming. The reason it's easy is it's time consuming - no zippppp...oops possible.

 

[pa23driver]

lapping isn't too bad... i use a cordless drill. chuck a length of tube nice and tight then slip the valve in the other end of the tube (dont put the valve stem in the chuck itself) add some lapping compound and spin the valve up at a decent rpm. you'll be done in no time.

as far as removing the casting marks just get a cheap set of diamond riffler files, i couldn't get my dremel into the ports

 

[xjwmx]

It's usually recommended to use the suction stick and a back and forth motion to avoid scoring grooves in the seat.

 

[XSLeo]

I took a rat tail file, using a torch I heated and bent the end to a anout a 45 degree angle. I used this for the rough work. Then use course sand paper around your finger to smooth out the rough spots. Working with finer and finer paper till it looks good.
Just smooth up the rough spots, try not to enlarge the ports.

 

[angus67]

i had always heard that a smooth port would lead to pooling of the fuel/air mix, and that a semi rough texture is more desireable because the rough texture keeps the mix tumbling and remixing. I have nothing to back this up, its just what I gathered over the years.
but i do agree to eliminate casting seams, and defects.

 

[dwyatt]

That seems to be right. I had my head ported by 650 Performance with the copy of the factory racing port jobs and it has a rough textured surface. I questioned Craig about this and it was done on purpose, no doubt to aid mixing/flow.

 

[Jack]

That seems to be right. I had my head ported by 650 Performance with the copy of the factory racing port jobs and it has a rough textured surface. I questioned Craig about this and it was done on purpose, no doubt to aid mixing/flow.

The rough barrier finish you're referring to aids in creating a high pressure point behind the low pressure front to provide just enough turbulence to lift and keep the fuel mixture suspended for complete vaporization,doesn't hurt flow.