FB#74

Member
Feb 2, 2004
14
0
Hi, which are EricGorr's modifications to increase the power of cr500 for supermotard races?
It's possible to obtain 70-75Hp(or more :eek: ) at rear wheel?
 

MikeT

~SPONSOR~
Jan 17, 2001
4,112
11
Are you really using all that a CR500 has now?
 

FB#74

Member
Feb 2, 2004
14
0
Hi, do you want to know if i use all the power of my cr500?
(sorry for my "english")
No, but as I read that Eric Gorr tuned a Cr500 for road races,obtaining 70-75Hp,i'd like to know which are the modifications.
Probalbly in a future I'll do this mods even if i'm not able to use all standard power. :laugh:
 

MikeT

~SPONSOR~
Jan 17, 2001
4,112
11
I've heard a good tuner can make the power that is there more useable. Not necessasarily more, but easier to use.
 

cujet

Member
Aug 13, 2000
826
5
The exhaust time area is low for the stock CR500 engine, in other words, the stock exhaust port is too small for big HP numbers. By increasing the exhaust time area and using a pipe tuned accordingly the power can easily be increased to the 75RWHP range. Generally tuners can raise and widen the exhaust port. How much depends on which cylinder year you have, but as a general rule going up 2mm and about 7mm wider in total.

The transfer port timing is very close, so a general cleanup in this area is all that is done for 75RWHP. Using a small radius on the piston crown where it intersects the transfer port will increase flow slightly.

V-force reeds seem to work well when you actually can get them to fit the CR5 engine.

Also, good results have been reported with the 44mm carb, however I have not tried this.

There are some very good aftermarket cylinder heads that increase power somewhat.

Chris
 

john3_16

Member
May 17, 2004
808
0
That would be cool to see a modded to the max CR500...I know most people modify them to tame them...But to get more, is kind of insane but cool at the same time...

I wonder if anyone has bored out a 2 stroke 500 to like a 530, then ported it.....What a monster!
 

Studboy

Thinks he can ride
Dec 2, 2001
1,818
0
I had a 535cc Trinity Ported motor with the Mid/Top pipe and 44mm carb in my dads quad, and it was pretty impressive. I'll bet that it wasn't 75 horsepower though, more like 65, but it wasn't ported/tuned to the max. (Pump fuel, still good low end power, etc.)
 

mbw479

Member
Jul 28, 2004
1
0
i have a mate with a cr500 that is bombed for the beach drags that we have here each year which is a series of barrel races on the beach, it gets 80hp at the rear wheel, it has been tested on a dyno and has a top speed of 220kmph (about 130mph)
 

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