dyno run video
 

http://www.youtube.com/watch?v=grLj9V8JPas

Congrats man, great result.

As I said earlier, I also dyno tested an Xt700cc. I tested it again a few weeks back but this time with a +3 Throttle body.

The bike lost HP and torque.

I have no idea why this happened. The TB was made correctly, but something was not right. Not sure if the loss in HP is coming from the TB or something else, but I only mapped it again and did not spend any time doing other tests to see I could find the cause of the power loss.

Not trying to put you off the bigger TB, but would be interested to see what is the outcome on your bike.

Sorry, forgot to ask, can you ask these guys to send you a copy if the A/F ratio printout and also, can they show you the dyno report corrected to SAE instead of DIN?

Might pick up or loose a bit of HP, but it is purely for comparisons I exclusively use SAE correction and it would be nice to see what it looks like in that format.

Maybe a bad hose on the airbox side or intake? Or bad injector?

will soon try a +2mm TB. I hope not to loose gain, but let's wait for the results.

I'will ask my dealer for this.

As far as Kennys +2MM throttle body, it has been tried & tested hundreds of times on the Raptor forums with no negitive feed back that I have found.

I have personally seen gains with the +3 TB on the raptors. About 1 to 2 HP at the peak RPM, so not sure why the Xt lost power.

The differance is that the raptors have a much longer intake compared to the XT, so not sure of that would make a differance.

Kev, did you test the +2 TB's power gains before and after on your xt?

One thing that has been in the back of my mind for a while is to try the modified pod filter from the Raptor as I am sure it will deliver more air volume the the stage 1 & 2 filters & in a more uniformed way, I would need to make a new intake pipe to suite the XT.

In the motors that I have worked with, the biggest change comes from changing the lenght between the throttle body butter fly & the inlet valve, the longer the inlet track the more torque the motor produces & the shorter the inlet track is the HP the motor can produce.

I have not been on the Dyno for some time now & will be doing some runs sometime, just been to busy at work to get some time off.

does anyone know the ouside diameter of the XT660 barrel?
cilinder and piston of my xt660 are in bad conditions. i need to insert a nicasil or a crome tube into the cilinder

thanks

I am at work at the moment & have all the measurements at home, I will post the sizes tonight for you.

How many KMS has the motor done? I am well a ware of the Raptor OEM nicasil not lasting in race conditions, but this is a first for a XT. You can bore the standard XT cylinder to 103mm with replating or buy a cast sleeve & resleeve the XT cylinder 102mm. My casings have been machined so I can take a 105mm piston for my next conversion.

http://cgi.ebay.com/ebaymotors/LA-SL...Q5fAccessories

http://cgi.ebay.com/ebaymotors/YAMAH...Q5fAccessories

Was the nicasil damaged by poor filtering with dirt entry in the motor, at what kms did you change your oil? Was your bike ridden in the dirt a lot?