[smo0oth1]

This is a stock 09 CRF450 throttle body. The inlet is 53mm and tapers down to 44.5. Monday I'll bring it to the machine and bore the taper to 50mm. I'll keep this thread updated to show the bore and wiring steps for the install.

 

[crisco]

Does that tb measure 50mm at the butterfly or will you have to make a new plate?

 

[smo0oth1]

Does that tb measure 50mm at the butterfly or will you have to make a new plate?

Yes, The butterfly is 50mm. Its just the last inch r so in the rear of the TB that chokes down.

 

[VelociRaptor]

This TB is also used by the LTR drag guys.

 

[crisco]

Nice. Odd they taper it so much. Now how do i get one to fit on my Raptor? Its gotta be cheaper than a WK tb...

 

[smo0oth1]

Nice. Odd they taper it so much. Now how do i get one to fit on my Raptor? Its gotta be cheaper than a WK tb...

The taper is more than likely the same size as the CRF head port. I've ported my XR head to match the 50mm the TB will be.
I'm 100% sure you could get this on your Raptor cheaper than the WK TB lol!

 

[DL700]

the intake design and inlet going into the throttle body have a great deal of effect on its performance, , even though the tb would work on other models(such as a Rap 700) it wouldnt make near the power

they are tapered for air speed

 

[smo0oth1]

Got my piston back today(105mm & 12:1), Increased the valve sizes to 40mm and 33mm, pockets cut .040 deeper and to 23 degrees to match my XR head. Also had antifriction applied and deburred. Tomorrow I'll be sending it out with the crank to be stretched and balanced.

 

[tbird88]

whats the yellow button or knob for on the crf throttle body?

 

[DL700]

whats the yellow button or knob for on the crf throttle body?

choke/idle

 

[boost addict]

Chris used a WK 54mm tb on his build with the xr650 head. Ehs tried that 50mm on my XX a year ago, good luck with that.

 

[smo0oth1]

I'm thinking the 54 would be to large for my goal and not sure how trail friendly it would be. Also still debating on actually going 50mm on the taper, I may only go 48mm.

 

[chris]

The wk 54mm throttle body is alot of money for the average quality of machine work you get.

 

[boost addict]

You will need a 450 wiring harness to make it work. The TPS and IAC connectors are different, that's just to get started.

 

[smo0oth1]

You will need a 450 wiring harness to make it work. The TPS and IAC connectors are different, that's just to get started.

I done a little homework on it, Hadn't seen any deal breakers as of yet. I ordered some CRF plugs and will de-pin mine

 

[smo0oth1]

The wk 54mm throttle body is alot of money for the average quality of machine work you get.

How much of an ordeal was it to wire up the WK?

 

[chris]

How much of an ordeal was it to wire up the WK?

I bought a raptor 700 harness and cut the pigtails off it for the tps and map. Wiring was the easy part making the air intake tube to my liking was the hard part mine still is'nt completly finished. I removed part of the top cross frame rail that the battery box mounts to. I cut it off flush with the right frame rail and cut it about 2-3inches out from the left frame rail so the battery box mount is still their. I also moved the fuse box to the back side of the battery. I still don't have the room to run as big as air filter as I'd like thats the sacrifice of having irs it takes up alot of room in the back.