CR500 on a blaster

[BlueDiablo]

I know what would make it run like a raped ape... Running it on Alcohol. I heard it gives you 3 times the Horsepower from gas. Or just try with one type of oil im not sure what its called but Klotz make it and it contains alcohol and is for racing use only.

[Dier-Wolf]

I dont run ...... ahhh whats the use

[flotek]

Originally Posted by mowery701

I know what would make it run like a raped ape... Running it on Alcohol. I heard it gives you 3 times the Horsepower from gas. .

usually its more like + 15% over what it makes on gas

[Dier-Wolf]

Any comments on my calculations Eviltwin?

[500Sabertooth]

I know this thread is a little past...but I'd like to comment...

The specs of the Sabertooth setup has NEVER been a secret. We have crank options from 70mm to 72mm to 76mm. I personally, having the option to run anyone of them, choose the 70mm crank. Why you ask? Well I'm glad you asked...RPM is the answer my friend! If I wanted a stump puller I would build the 76mm stroker, but due to the limited RPM it would not make the HP that the 70mm will. Remember I'm drag racing and for that the best setup is the bore and stroke combination that maximizes the balance between rpm and power.

So lets talk about the old CR500 cylinder for a second as compared to the Sabertooth jug. The CR 500 does not have triple exhaust, nor does it have anything even close to the transfer and intake area that the Sabertooth does. But then again, why should it...it was a early 80’s cylinder design that was never meant to rev past 7500 rpm. If you look at the dyno pulls you posted the power signed off at only 7000 where it made a rapid decent. The 79 mm stroke is part of that reason. I’m sure it makes plenty of torque like a 4 stroke does, but don’t expect it to meet your HP expectations. There’s only so much you can do with porting on a cylinder design like that. Vibration is another issue, it eats HP...not to mention frames. I’m going to go out on a limb and say that on gas your CR500 is in the low 70’s. I can say this by experience as I have seen some fully drag ported CR’s on alky with a 15 shot of Nitrous on the dyno only sneak into the low to mid 80’s. On gas with a inframe pipe the Sabertooth hit’s 92hp. On alky were in the triple digits.



At 7000 rpm when your powerband is OVER, not only is mine making more power...but it's still climbing! You’re too hung up on displacement. Unfortunately it doesn’t mean jack if the cylinder is inefficient.

The Sabertooth was designed to be EXACTLY what it is today, a high hp high rpm single to compete with the larger Banshees. Like I said, I have a longer stroke option for the torque hungry guys, but in a drag race it will get eaten up by the high rpm 70 mm version.

By the way Dier-Wolf...I see you’ve run in the mid 4.5’s at the track with your CR500 conversion, not bad but I’ve seen plenty of 65 to 70 hp 350cc Pro-X motors do that. To answer your question I’m currently running at 4.05 and with the current changes by next season should get it into the 3’s . I must say your CR500 TRX is one of the cleanest conversions I’ve seen, I have to hand it too ya on that.

[Dier-Wolf]

7000 and my powerband is over??? i dont think so, believe i mentioned in other posts that it seems im alway in my power band after i get into it, it never lets back down or bogs for some reason, it was that way when i was running it with the 250 pipe and its sitll that way now with the FTZ drag pipe.

There are 2 other guys with same year CR500's here (still in bike form) and theirs dont act that way either, but then again they are stock with no modifications what so ever.

All i know is my engine pulls like i was tied to the back of a f16, hell i've bent 3 handle bars already just holding on when the power band kicks in....... I have ridden alot of 2 strokes and i must say, the engine has amazing power that just doesnt seem to want to stop.

As for cr500's ripping frames apart, i dont even wanna go there again, i heard enough ballony all over the internet about that, and all i can say is, do it right and it wount, i have mine now for 2 years and i have zero problems.

[500Sabertooth]

I'm going off of the dyno chart you posted...it's right in front of you. At 6800 RPM you're peaked out at 69 hp and your curve is heading south...way south, At 9000 rpm your down at 35hp while were still at 98hp, see what I'm saying? It's not magic...it's just physics, Put a tach on it and you tell me what RPM it pulls. When geared tall enough torque will feel like RPM cause it pulls a long time in each gear...but dont confuse it, it's NOT rpm, and will not rev nearly as quick as a shorter stroke motor.

[Dier-Wolf]

Dyno i posted is Stock CR500 engine of that year, and with stock pipe. has nothing do to with my setup..

In any case, right now im geared at 14 and 38 and even on pavement with slicks it fishtails out of control if i pop the clutch... All i know is it has Tons more power than anything i've ridden and that includes big bore 2-stroke kits for the banshee and im not talking the crappy 370 kit either.... I ride those things without even the slightest bit of fear and throw them around, on this im must more in respect of the bike.

[500Sabertooth]

That's cool, like I said I'm sure it runs decent. For comparison sakes...I run 15/33 gearing leaving in second hard enough to slam the wheelie bar off the line. If I were to put a 14/38 on it would just sit there and spin.

[flotek]

Originally Posted by Dier-Wolf

Any comments on my calculations Eviltwin?

not really... other than things on paper dont always translate to faster track times or more usuable power .

below is a quote from a wel lknown engine builder who works on these types of conversions :

Most of the cr500 "ported" motors we seen on the dyno made around 60hp at the rear wheels,with the common setups that are often found
with cr500s. We have also seen around 80hp, ported cylinder,
cut head, intake, carb, v-force reed, our "secret" pipe. And that is possible with a super broad powerband.
They are tuff motors too.