Topics

My RD350A is still on the original 64.00 bore, with original Dykes ring type pistons.
I just bought a pair of 250C heads, that I am in the process of converting for my 350.
My plan is to stay with the original pistons for now, and rebore when needed. The question is then how much these pistons vary in dome angle, before I fire up my lathe.
Anyone knows the dome angle on Mitaka/ Wøssner/ Wiseco, etc?

Hi!
I am away at work, but looking at various fiberglass front fender options for my RD350A. I have forgotten what the width between the fender mounting bosses on the fork is. Maybe someone with a 350 could take a quick measurement for me?

Today, I realized that my planned brake upgrade will not work out like I thought. My bike is a RD350A, and my plan was to use a TX650 disc hub with a custom made 298mm "TZ replica" rotor from ISR, an Economy Cycle reproduction alloy caliper, and a RD400C RH fork slider. And a caliper bracket to allow for the larger disc. It turns out that this relocation bracket will have to be much larger than I had expected, moving the caliper close to a 9'o clock position. So much for a stock appearing upgrade. I do have a set of TX650 fork lowers, but they will require a lot of machining in order to be same diameter and weight as RD lowers.

I also have complete FZR 400 or 600 fork legs, and just found out that the caliper lug spacing is the same as on RDs, 81.50mm c-c. So now I may look into FZR or R1/R6 calipers? What size discs did the FZR models have? Ideally, I would like to find the lightest fork/brake combo using the stock spoked  front wheel, and avoid caliper adapter plates if possible. The stock RD disc and caliper is pretty heavy, near 4 kg.......

Hi all! Great to be back in 2SW 
I found a pair of RD250C heads on ebay, that I plan to modify for my RD350A.
(I already posted on the UK ACRD forum  http://www.aircooledrdclub.com/smf/index.php?topic=58165.0 )

I just assume I could machine the combustion chamber to a somewhat thoroid shape when increasing the volume, since they use 3/4" reach plugs vs 1/2" for 350 heads. Any comments on this?

Then the issue of head gasket arrangement. I have 2 gasket options already on the shelf, O- rings and RD400 copper gaskets. As far as I can see, there is basically 3 options:
One is to machine off the gasket recess on the top of the cylinders, use the 400 gaskets, and use locating dowels to center the heads.
Second is to machine O-ring grooves in the top of the cylinders, and spigots on the heads, for centering the heads in the original gasket recess the cylinders.
Third is to machine spigots AND O-ring grooves in the heads, leaving the cylinders untouched. If the heads are strong enough, this seems to be the most attractive and easiest solution.
Any comments, recommendations or warnings?

Remember, I am talking about modding 250C heads for a 350A. And, yes I am aware that they are bigger, so will need cutting down somewhat. Also, if anyone have pics of cutaway 250,350, 400 heads, that would be most helpful!