Rod choices for open 2 stroke more questions than answers ??

oldkart

Premium User
Over the years I built a lots of dirt bike and quads crankshafts. I used aftermarket rods supplied by different sources,with no problems. Over the last 30 years I had information of rods lengths ,upper and lower bearings including thrust , pins and clearance information. Buttttt I have lost those old catalogs with an endless supply of accurate information. Here is the question is why not use these rods from mx ect. In our kart engines??? We all had those old 80 up to 250 2 strokes we beat on growing up . We didn't. Have the best oils or information about them but they were tuff as nails.
 

sundog

Member
Most of your high end modern kart engines have bulletproof rods so, unless you need one for a specific purpose I don't see the need. That being said, if you find a better rod that fits the Yamaha KT100 let me know.
 

oldkart

Premium User
I agree with quality but the jap mx rods and others took lots of punishment. Hodaka Husqvarna Bridgestone Sacs Honda Yamaha Kawasaki Suzuki on and on I recall a hodaka air cooled thinking 100cc , man it was tough it rode me harder than I rode it lol.
 

flattop1

Dawg 89
The open class has transitioned too the mx engines in part .
You can use the whole engine no need to swap the rod .
The old free air stuff did get thrashed hard . The rpm range was it lower then the current kart specific engines ?
 

oldkart

Premium User
Back in the day of found and cheap dirt bikes the rpm was determined by how much your. But vibrated lol. I would think the hodaka and maybe others turned 10,000 plus. Not really sure some of those rods look very similar to the air-cooled kart. engines. Without a doubt someone here has tried it.
 

flattop1

Dawg 89
Pistons were the problem I had with my Bridgestone rotary port .
Never a rod . Too much advance and too lean .
 

Pete_Muller

Moderator
oldkart,

I have not seen anything Hodaka that would work in the kart engines I've worked on. Just so happens that I know a guy that probably has one of (if not THE) largest collection of Hodaka stuff in the country. Tons of original parts, many still new. I've had the chance to dig through a good amount of the stuff in his shop, and nothing had the right combo of diameters/widths/lengths. Even he is struggling to find certain size/length rods to rebuild some of the more obscure Hodaka engines (like the 175cc they built).

That said, I think you are correct in that probably most of those original Japanese engine con-rods were probably forged by one or two outside companies for all the manufacturers. They have that certain..... look.... this is fairly unique.

As far as longevity... I had no problem wadding up the b/e rod bearing on my modified 125cc Yamaha flat track bike back in the early 70's, LOL. That was on Klotz, and I haven't touched the stuff since! Went to Green Label Bendzall back then, and never had another issue. The revs we see in kart engine surpass anything I've seen in a comparable displacement bike engine though... and I'm guessing the abuse the rod takes probably goes up by the square of the rpm, or something like that. :oops:

PM
 
I agree with quality but the jap mx rods and others took lots of punishment. Hodaka Husqvarna Bridgestone Sacs Honda Yamaha Kawasaki Suzuki on and on I recall a hodaka air cooled thinking 100cc , man it was tough it rode me harder than I rode it lol.
I'll tell whats tough is gettin whipped by a HODAKA in front of all your buddies while on your Elsinore.... My Super combat could hang with the RM's and YZ's of the day it's just that you had to ride a little harder.
 

oldkart

Premium User
Off subject but what were the hodaka models . I was thinking 3 but after 50 years I forget. But I do recall a jump I made on one and racked myself on the tank !! I did land and then laid the bike down curled into a fetial position for 10 minutes. Yeap good old days lol
 

Don K

Member

Terry & Bev Larson are terrific to work with. If he has it, it is for sale.

I completed two Hodakas last year, a 75' Road Toad my girlfriend uses and a 75 250 SL enduro I ride. Both are really fun to ride around town. Lily livers in Prius' are appalled by the smoke!

I know this doesn't have anything to do with the original thread but it's fun.

DK
 
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