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Posted

I was looking at a Cub with I think its a 72mm bore and a 4mm stroke increase - I wanted to go in the 600cc range but I can't justify the costs. Anyway I stumbled across RDZ site, and was wondering if this company is any good?

Posted

You're opening a can of worms...

For the money, you're better off with a 68mm bore and 4 mil stroke.

The 72's very possibly have the potential, but....are more money than the 68, and most builders at this moment are pretty much seeing the same numbers after a lot of porting on them that a standard cub puts out from the box.

 

72's are considered super cub, 68's are just big bore cub...and you'll have to buy a new head for the 72's, you can have your stocker cut to work on the 68...

 

majicmike as done some work on them...see what he says. I won't get one, personally....

Posted
RDZ is the original maker of the shearer pipes before the fallout .... they make some VERY nice motors but you can 100% garranty your ass your going to pay some dollars!

 

Correction...Matt Shearer IS the creator of the Shearer pipe, when he worked WITH RDZ....

 

RDZ builds fast bikes, but I personally feel they are little pricey, that's all

Posted
Correction...Matt Shearer IS the creator of the Shearer pipe, when he worked WITH RDZ....

i said they where the origanal makers of the pipes..meaning as in the fabed them under their name and sold them stamped with thier RDZ logo on it...

Posted

What you are looking at on RDZ site is the super cub. Yes they are alot more in price then the 68 bore for not alot more in "PEAK" numbers. But when you over ley the numbers 68 vs 72 the 72 makes 4-6 hp more though the entire curve and tops out at the same number.It makes about 6-8ftlbs of tq though out and peak as well.It depends on what you are doing with it. If you are a dunner and like to play around go with the 68 bore. If you are a bigger guy and dune drag race and test and tune on the track then the super is the way to go. But if you go to the track for an event right now the super is not the way to go becuase it will put you in a different cc class. Also the 4mm that ran a 3.59 was a super cub. I am starting to do some testing with the twister mini right now and its starting to look like I may be changing cylinders but weight is a problem with the twister cylinders.

Posted

Thanks for the replies, I have other questions as well. I know you have to clearance the case (4mm) for the stroker crank/rods, I assume I can do this at home with a die grinder? Are there templates available?

Posted

No NO and NO You do not have to trench the case for the 4mm crank and no you can not do it with a die grinder and no there are no templates. Trenching the cases is done with a mill. You maybe talking about boring the cases for the super and there again NO and NO no die grinder and no templates

Posted

Does the cylinder not mate to the cases? It's no big deal to have it machined, I'm just curious to what needs to be done. Seems to be a lot of knowledge here.

Posted

A 4 mil 68mm bore cub is a drop in, no machining required.

I don't know if the cases have to be bored for the 72 cub.

 

Mike...

Are those HP and torque numbers for the super out of the box (in other words, a casting/clean up port) or with more extensive porting done? I thought they were only 2HP better out of the box....I could be wrong...

Posted
A 4 mil 68mm bore cub is a drop in, no machining required.

I don't know if the cases have to be bored for the 72 cub.

 

Mike...

Are those HP and torque numbers for the super out of the box (in other words, a casting/clean up port) or with more extensive porting done? I thought they were only 2HP better out of the box....I could be wrong...

 

 

No right out of the box the 68 will make better hp. When you put a 72mm bore in a cylinder made for a 65mm bore things get messed up quick. The transfers and the exuast are bad and need big work. But those numbers are ported super vs ported 68. RDZ and someone else :whistling: only sell them (super cubs) ported becuase they loose HP. Also you do have to bore the case to fit the larger sleeve. Pretty much the super is only good for the dune racer because unless you look really close and know what you are looking for you could not tell the differance between the super and the 68. But my 10mm super is 520cc that to the avrage person looks the same as a 421 cub. :ninja:

Posted

When I get home I will post a dyno run and ALL I want people to look at is the curve NOT the numbers because I dont need a pissin match. As I have said before a dyno is a tool and thats it. When a dyno passes me Ill race a dyno.

Posted
When I get home I will post a dyno run and ALL I want people to look at is the curve NOT the numbers because I dont need a pissin match. As I have said before a dyno is a tool and thats it. When a dyno passes me Ill race a dyno.

 

I agree...Mike. I think in time the super's might be a great idea...time being, though...dollar per dollar, non-super would be my way out!

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