Hi from South Korea.

sorry for my poor English but please read my topic and help me.

Recently I started my very first Engine overhaul.


My bike is 2006 Iron cast bullet 500. 5 speed.

Last year, I bought Hitchcocks`s brand new Cylinder head assy and I install it.

Now, I recognize that while doing overhaul, there is no Valve guide seals!

Of course I never think about seals because it was 'assy' and description told me 'supplied ready assembled.'.

However I tried set my new seals and there a another problem with Valve guide.

The Valve guide has no chamfer. so my two new valve guide seals are broke when I tried install it.

Because the valve guide`s edge is too sharp.





and Hitchcocks Valve guides are has chamfer!


like this.



like this.

I borrow garage temporary and after 2 weeks the contract is end.

what should I do for now? cut the Valve guide with chamfer cutter?

is there a any reward program by Hitchcocks? Please help me. :cry:

Thanks to read.
Oh I got E-mail from Hitchcocks and they said tuned cylinder head has no valve guide seal because of lubrication.

They want some pictures for help me.

and I sent this picture.


lot of carbon gets stuck on backside of valve and carbon keep stuck between valve and seat. (I guess. because engine pressure has lost sometime.)

I don`t want blame someone. I just want talk about this problem and find solution.
Thanks for read.
Valve guide seals are a relatively new idea, me managed very well without them for years.
You do get better lubrication without them but perhaps a bit more smoke.
I wonder if they are now fitted as an emissions control.
Anyway, they are not essential.
There is a good chance the carbon is a result of oil blowing past the piston rings.

500 bullet pistons are known for suffering from the crown collapsing. In the early stages, this traps the oil control ring, preventing it from moving and functioning properly. In the later stages, the piston can seize and the crown can seperate altogether!

Another thing to check is the crankcase breather setup. The late cast iron bullets had a breather modification which has them breathing through a tiny hole in the crankcase into the oil tank then out through a hose into a catch-can with a non-return valve in it. This hose and catch-can can become blocked with creamy white emulsified oil leading to positive crankcase pressure and oil finding its way up past the piston rings.

It also has a "return" hose from the catch can into the timing side with another non-return valve which I suspect prevents this breathing properly too, again tending to force oil past the valve guides.
stinkwheel wrote:
Sun Feb 23, 2020 9:43 pm
Austin mini valve stem oil seals fit the hitchcocks valve guides.
The mini van that I had back in the 80s used to smoke on the overrun (sure sign of worn valve guides)
When I pulled the head to check there was quite a bit of slop in the guides also the seals were shot what I did was pull the valves quick grind and replace the inlet valve seals with o-rings
It didn't totally cure the smoke but it reduced it to a level that I could live with
You may be able to use the same trick
Cheers Dai
Read up about “K-line” valve guide inserts which I’ve used in the past. If fitted properly (they need to be reamed) they fit the individual valve stem very precisely and stop oil loss.
Royal Enfield models were NEVER fitted with valve stem seals until 2005 with the Electra X - and in my humble opinion - if an engine was designed without stem seals - then they should NEVER be retro fitted. If you have to fit them then you have a problem which should be addressed - not disguised.

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