The Hodaka Club Forum

I was thinking about having RK Tek design a new head for the bike I'm building and would like to run a radial head. I don't know if it would have better cooling than the stock head or not. So I would like to know what head does every one run that is switching over to radial head? I have some heads at my shop and one the bolt hole spacing is right on, I would only have to weld the combustion chamber then drill the holes bigger for the cylinder stud. The other is a odd looking head but kind of cool looking in it's odd way. What ever head I use I know RK Tek will make it work good. I have had them make heads for my maicos and Suzuki RM's that work great. http://www.2strokeheads.com/VintageMX.htm

This is the other head on a iron 125 cylinder.

For a Hodie, tests have shown that the stock head design cools as well as a radial head modified to fit. But there is no denying the racy good looks of the radial head.

Ed

Yes Ed I think the stock head would work good but after seeing the bike that you rode of Paul's last week I need to make one with a radial head. I watched the video of you on that bike and it seemed to pull from the bottom to the top good. How did it fill to you?

Here is three heads one is a 74 cr125 (black head) one is a sachs 125 (the biggest head) and the other is a head for a indian 125. The bolt holes for the indian and the CR line up with the hodaka and have a center plug hole. The indian head would have to have it welded up and then mill a gasket surface in it. The sachs would have to have the plug and the stud holes moved. The CR would be like almost bolt on to bad it's not a radial head but if you had a aftermarket head laying around it would worth a look. I can see it now a FMF porcupine on a super combat.

sachs head

Indian head

Top of Indian head

Top of sachs head

This thread sort of shines a light on two differing schools of thought. Flyingdg wants a really racy looking cylinder head (even if it doesn't really do anything for performance) . . . and I prefer to fly along underneath the radar with a completely stock looking head (especially since there is no performance loss by doing so).

Now, having said that . . . there are performance enhancements which can be achieved with either the stock or a radial head through the use of differing combustion chamber and squish band designs . . . and the head on the ISDT RR bike did not have a stock Hodaka combustion chamber shape. However it is completely impossible for me to attribute any particular performance improvement to that since there were quite a few other modifications in place in that particular engine. I can report that it ran purty dang well! Yes.

Ed

I just got off the phone with a guy that is talking about remaking the webco head for the hodaka and a FMF copy of the porcupine Honda head for the hodaka super combat. He said the webco head will be done in about two weeks. I don't know if he will be selling on Ebay or how he is getting them out on the market.

I thought Ed said there was no noticeable difference in performance why spend all that money on one of those heads when the originals work the same? just wondering Scott

'Cuz they look cool.
Not enough for me to spring for the $$, but no arguing that they do look trick!
Laurie

I think the stock head is a good head....but when I go to a bike show l like to see what people did to there bike to change it for better or worse. I don't now if my bike will have a radial head or not but it wouldn't be a hodaka head or a head that was made for a hodaka.

There is a vintage CR125 cylinder head comparison here:

http://www.vintagefactory.com/Vintage%20Tests.htm

Scroll down to find it. It isn't really conclusive but it gives some insight into what factors to take into consideration when shopping for an aftermarket head. They did rate the Webco head favourably, but it's not a radial head.

Brian

they do look cool I agree but if they don't improve anything then they better be cheap lol

I still don't know what head I'm going to run on my wombat. I have a radial head and this head off a carabella 125 welded up to have a new combustion camber cut in them. I kind of like this head the most and think it will have better cooling than the stock head. DG

For an iron cylinder wombat you could definatly improve cooling as its kinda small and compression can be upped also. The super Combat head would be difficult to improve on according to Harry Taylor since it is large and has that huge lower horizontal fin below the vertical fins , and it comes out dirrectly from the combustion chamber. Som radial head are actually inferior since the fins do not prutrude directly from the chamber.

Rich

Does anyone know the scoop on this top end set-up? Borrowed from an Aussie board.

very rare jensen head and cylinder. would love to have one of those! Scott

That's Lee Fabry's bike out of Southern California. It was recently on Ebay, but didn't make it's reserve.

Looks like it went to Australia.

Yep thats Lee Fabry's bike the cylinder and head was mad by Eric Jensen its a 100

Rich

I decided to use the Carabla head on my 125 wombat. So I welded the head up and sent the motor to RK Tek to see what they could do for the old wombat. Here is what I got back from them. They made a flat top piston out of the stock piston and cut a new combustion camber in the head to match the piston. Kelsey also said this would work good on pump premium gas. From the photos you can tell I'm not the best welder but it will work OK.
http://2strokeheads.com/

http://2strokeheads.com/