Destroking a cbr600rr

[Mgiossi]

So i know about and have seen the amazing performance for the R5 on track. My question is has anyone tried other mw's? I have been toying with the idea of destroking a cbr600rr. Its a personal decision i know i can maybe find and buy a already built r5. So can anyone give me an idea where to start and who to talk to? Im assuming a new crank and rods will be a definite but anyone know what else ill need to find? Also have a built 600rr SB motor 2mm over with all the fancy stuff. I dont know if anything there will work or help with this?

[GixerJockey]

Just throw all of your money in the toilet now, and keep racing whatever your current bike is. It'll be cheaper that way.

[MUZ720]

I think most guys pick the R6 for this mod because the R6 the best handling middle weight . I know guys out west and down south use GSXR 600s . Have not seen an Honda with this Mod. Cranks are pricey and have not seen one make it a whole season without issues.. at least to my knowledge anyway. But they are fast. good luck

[scottieducati]

Guys out West are not running de-stroked GSXR's, they "kill" a cylinder and run 3/4ths of a 600, or a 450 which enables them to compete in the 450 class. Not sure about down south, but know for sure in CA it's for 450cc racing.

[MUZ720]

Charlie Mavros at Daytona and I believe a few guys in Wera have run them.. so out West is open to how far...

[Petorius]

Totally read this as "destroying a CBR600rr"

[isaac_]

Totally read this as "destroying a CBR600rr"

Is there a difference?

[Kurlon]

Two paths to explore:

A) Have your OEM crank destroked - Marine Crankshaft, APE Racing, etc can do the work. Add in the cost of four custom longer rods or get into the fun of determining if you can safely deck the cylinder block that far.

B) You big baller you, a billet crank you say? To shreds your wallet says? Doable, longer life span than a crank weakened by destroking, still gotta do rods/etc.

In the mean time there is an R5 for sale on Facebook.

[csmutty]

Two paths to explore:

A) Have your OEM crank destroked - Marine Crankshaft, APE Racing, etc can do the work. Add in the cost of four custom longer rods or get into the fun of determining if you can safely deck the cylinder block that far.

B) You big baller you, a billet crank you say? To shreds your wallet says? Doable, longer life span than a crank weakened by destroking, still gotta do rods/etc.

In the mean time there is an R5 for sale on Facebook.

How are most of the R5 guys doing it? Decking or longer connecting rods?

I would guess that decking would yield better results if possible because of the decrease in rotational mass?

[Kurlon]

I'm betting most are going rods. Decking brings up cam timing issues, potentially head gasket issues, etc. It also requires machining, vs getting a bunch of parts you can just bolt in. A good set of Carillos, even if longer should be able to hide the extra mass required for the additional length pretty well, and the longer rod ratio means even less side loading on the pistons so you get better skirt life?

[csmutty]

I'm betting most are going rods. Decking brings up cam timing issues, potentially head gasket issues, etc. It also requires machining, vs getting a bunch of parts you can just bolt in. A good set of Carillos, even if longer should be able to hide the extra mass required for the additional length pretty well, and the longer rod ratio means even less side loading on the pistons so you get better skirt life?

What about going with a custom piston with a longer connecting rod eye to dome length? Then you get skirt length and potentially less weight since they are aluminum?

[Kurlon]

Possible, but you end up with a much heavier piston, with the weight in the worst possible place, and the effort involved in getting a custom set is a PITA compared to asking for x.xx MM longer rods for an R6 from Carillo, etc.

[seacoastsport]

I'm betting most are going rods. Decking brings up cam timing issues, potentially head gasket issues, etc. It also requires machining, vs getting a bunch of parts you can just bolt in. A good set of Carillos, even if longer should be able to hide the extra mass required for the additional length pretty well, and the longer rod ratio means even less side loading on the pistons so you get better skirt life?

Secret to success;
Billet Crank
Custom Rods
Stock Pistons
Custom Head Gasket
Amazing Head Work
And a lifetime of cam timing

-ak

[Mgiossi]

If anyone wants to buy my daytona 675 race bike ill be happy to go buy that r5 lol

[BMMCBR]

If you show up to an AM LW race with one of these I'm kicking you in the dick.

[Mgiossi]

Hahahahahahaha miss you brendan

[sdog30]

I know 3 guys who have done the R5 and all of them have had trouble finding a reliable place to mill a crank. I think Grush might have a person. All three of them have had hack work from falicon, though. No expressed warranty on botched cranks either. Mark Rizoma had even told me you could visibly see how far off the crank was when it was sitting in the journals.

Both Grush and Randle have had issues with engine longevity, as well.

There was a rumor Ducette was converting a gixxer last year. Let's see if he shows up with one for 2018 after seeing what Sammy did with his R5 last year.

[Kurlon]

I thought Grush and the others went with billet cranks from Marine Crankshaft last season?

[Rada]

I still think this whole thing is stupid as fuck. I know. The rules allow for it but it's still stupid.
If I was going to do one I would certainly use a billet crank..

[sdog30]

I thought Grush and the others went with billet cranks from Marine Crankshaft last season?

Not sure what they used last season, but I know they both had falicon cranks in the beginning and they were not quality and also not very willing to refund the cost.

And Adam is right, it's a gun in a knife fight. No worse than allowing sv's in ultralight superbike. It's an all sv class for the most part now.

[backinthesaddle]

How about a throttle stop that makes the throttle only twist maybe 50%? :sarcasm

[Kurlon]

Not sure what they used last season, but I know they both had falicon cranks in the beginning and they were not quality and also not very willing to refund the cost.

And Adam is right, it's a gun in a knife fight. No worse than allowing sv's in ultralight superbike. It's an all sv class for the most part now.

The R5 is a pretender in a GP class, yeah it's better than the SS/SB bikes that people bring, but it's nothing compared to what is actually legal. If someone brings a full on 250 the R5 will get smoked.

[seacoastsport]

I know 3 guys who have done the R5 and all of them have had trouble finding a reliable place to mill a crank. I think Grush might have a person. All three of them have had hack work from falicon, though. No expressed warranty on botched cranks either. Mark Rizoma had even told me you could visibly see how far off the crank was when it was sitting in the journals.

Both Grush and Randle have had issues with engine longevity, as well.

There was a rumor Ducette was converting a gixxer last year. Let's see if he shows up with one for 2018 after seeing what Sammy did with his R5 last year.

Marine did the 3 cranks for R5 motors that we built last year. No issues, just bring your checkbook.

Also, no issues with longevity if assembled correctly with the proper parts as I stated above

-ak

[tls25rs]

There was a rumor Ducette was converting a gixxer last year. Let's see if he shows up with one for 2018 after seeing what Sammy did with his R5 last year.

Pretty sure Rick has an R5 that he raced the last weekend or two

Notice the fairing says R5 not R6 2017 LRRS Round 7 - Racing Is Life

Fairing on this one says R6 2017 LRRS Round 7 - Racing Is Life

[Tas]

Pretty sure Rick has an R5 that he raced the last weekend or two

Notice the fairing says R5 not R6 2017 LRRS Round 7 - Racing Is Life

Fairing on this one says R6 2017 LRRS Round 7 - Racing Is Life

He raced it the last 3 rounds. I quickly spoke with him about it. I think he needed it to stay with and/or ahead of Sam G.