RK Tek head

[fyingdg]

Has anyone ever had RK Tek cut a new combustion chamber in their rd350 head? I a Beta 300rr head from them and it works great.
https://www.2strokeheads.com/index.php

[teazer]

Not an RD head, but I had them machine a TZ250 head out to fit on a TZ350 and they raised the compression, changed the combustion chamber shape and added their ripples.  Worked fine.

I can't really comment on before-after performance because I sold that bike after it was rebuilt and it now sits in someone else's collection with all the new seals going hard....
 

[fyingdg]

I'm going to send some rd350 heads to them and see what they come up with.

[Frank B]

Please give us an update once you install them   ;D

[bitzz]

Not an RD head, but I had them machine a TZ250 head out to fit on a TZ350 .....

Sorry i don't understand
The early (steel framed) TZ250 and 350 used the same heads.
The "later" ones, F or G, had a 'bath tub" head with the plugs at an angle (and they also got 6 transfers) ... which you can get the same effect by redirecting the transfers for a more modern swirl pattern, even on an aircooled RD.

Other than CC'ing the head and setting the squish there isn't much you can do to an air cooled Yamaha 2T head. Heat is the problem and until you address that....
If you go to all the work of CC'ing and setting the squish, get the head Oringed and pinned.
One solution was to install copper inserts into the combustion chamber (the copper conducts heat better) which eliminates hot spots, improving the swirl.
Here's a lousy pic of a RD400 Daytona head that I did
https://imgur.com/uhvfSO9

[teazer]

I didn't mean to be obtuse.

TZ250 is 54mm bore.  Same casting as the 64mm bore TZ350 but different diameter and volume.  I had surplus 250 heads and no 350 heads, so I had them machine a 250 head to fit on a 350.

I do have a set of 3G3 6 port barrels and a head converted by Motrac years ago to take inserts, but that's a whole other story.

If I was going to keep and race that TZ350E, I would have had my local machine shop machine the OEM head to accept appropriate Banshee domes, but it was for sale, so I wanted it as stock/original as possible.