Carb questions RE electronics & jetting..

[SHIFTx450]

I put my 06 trx450r carb on my 06 crf450r powered 400ex hybrid.

It is ripping better than ever mid to top, but has a pretty nasty bog/hesitation at bottom end. Was wondering if it has anything to do with the electronics? There are two sets of wires at the carb: 1 set coming right out of carb, and the other set come from the throttle arm. Position sensor maybe? Not sure, and not sure of there job with making these motors run right if any..

Anyone tell me how they would need to be hooked up so I can rule them out as a problem, or fix the problem? None of the connectors match up from the trx carb to crf harness.

Carb is setup as follows:

170 main
62 pilot
55 leak
needle 5th clip down
2 turns out on fuel screw
Boyeson Quickshot 2 Accel Pump Cover

[DnB_racing]

62 pilot is pretty big ..try dropping it down a few sizes and see what happens..
the wires from carb are.. the ones on the top left are tps and the ones on the right side near idle adjustment are for TORS

what are you using for a cdi?

[SHIFTx450]

Next size down I have is a 48. Would too big a pilot make it bog like that?

Dude who builds my motors says he has a 62 in his 05 trx w/ a 40mm fcr from a CRF450R, but he doesn't run a QS2 or anything like that. Says it the slow jet, and a nice 62 gets rid of that factory bog..

Not sure of your thoughts on that, just telling you so you know my logic in the decision to put such a big one in.

[airmobile101]

Originally posted by SHIFTx450
Next size down I have is a 48. Would too big a pilot make it bog like that?

Dude who builds my motors says he has a 62 in his 05 trx w/ a 40mm fcr from a CRF450R, but he doesn't run a QS2 or anything like that. Says it the slow jet, and a nice 62 gets rid of that factory bog..

Not sure of your thoughts on that, just telling you so you know my logic in the decision to put such a big one in.
Ummm......... the QS2 is a tad to much with a 55 leak. Take off the QS2 and see what happens.

[SHIFTx450]

It worked great on my TRX motor. I was thinking that too though, only I whought it would make it too rich at bottom end with that 62 pilot. I'll try it later on after work, let you know how I make out.

As far as the electronics go, I think I will try and cross reference a crf manual with a trx manual and figure it out.. I really feel they should be all hooked up for it to run right. They are on there for a reason. It idles a little funky, I was told the TPS and other wires not being hooked up will do that.

[SHIFTx450]

stock cdi DNB. Performance wise motor is:

06 CRF, stock ignition, stock cam

Ported Head, Hammer Racing Style

JE 13.5:1 two ring

That's it! Has less than 5 hours on complete top to bottom rebuild.. Been trying to make it run right ever since. Had bigger problems with the 39mm fcr it came with. I took it off and put it on my wifes 400ex. After leaning it out quite a bit that thing friggin rips now.

I should buy the right 40mm fcr for it, just had this one laying around from my 06 trx I wanted to try out. Thought it would run smoother with the bigger carb too.

[DnB_racing]

Originally posted by SHIFTx450
stock cdi DNB. Performance wise motor is:

06 CRF, stock ignition, stock cam

Ported Head, Hammer Racing Style

JE 13.5:1 two ring

That's it! Has less than 5 hours on complete top to bottom rebuild.. Been trying to make it run right ever since. Had bigger problems with the 39mm fcr it came with. I took it off and put it on my wifes 400ex. After leaning it out quite a bit that thing friggin rips now.

I should buy the right 40mm fcr for it, just had this one laying around from my 06 trx I wanted to try out. Thought it would run smoother with the bigger carb too. stock cdi for a trx,crf, or EX? and what year.let me know which harness and cdi and i will be able to help with the TPS connections

[hrc450er]

i would put that 48 pilot in or a 45 and try that. with your a/f screw between 2-2 1/2 turns out 55 leak is what the hrc kit uses i think so that might be good, and i never ran anything larger than a 168 in my 06 trx for a main but you have a crf motor so the 170 will prob be fine

[SHIFTx450]

Originally posted by DnB_racing
stock cdi for a trx,crf, or EX? and what year.let me know which harness and cdi and i will be able to help with the TPS connections

06 crf stock everything motor and electronic wise.

just a sick port job and je piston. 06crf stock ignition, harness, motor

06 TRX carb.

[DnB_racing]

for your TPS... from the crf harness you have blk/blue and yellow and black... from the trx carb you have green/yellow and yellow and pink

crf harness to the trx carb

blk/blue to the green/yellow

yellow to the light green

black to the pink

[SHIFTx450]

Thanks DNB! I'll be heading out to work on it shortly. Gonna make my connections, and gonna swap out that QS2. I'll keep you posted.

[DnB_racing]

Originally posted by SHIFTx450
Thanks DNB! I'll be heading out to work on it shortly. Gonna make my connections, and gonna swap out that QS2. I'll keep you posted. if swapping out the QS2 doesnt get rid of the low end bog, then I would put a smaller pilot in.. the tps wont affect the low end, its has more affect on WOT, but really the tps is barely noticeable if not hooked up,,,

when I was drag racing my times were exactly the same with the TPS unplugged, it works in conjunction with the IPG , and from the way it seams( i tested with resistors and every combo possible to try to get a reaction and tried to see if it changed timing and found no difference) its more of a slight rev limit then a timing curve, it might change the spark intensity slightly at different rpms, but again nothing noticeable when being timed at the drags

from every test I have done it seams the tps is needed more for a aftermarket ignitions with different maps then it is for the stock cdi

[SHIFTx450]

I'm working on it right now. Friggin accel pump diaphram is dry rotted on one side.. What is IPG?

[SHIFTx450]

From my carb @ tps I have green/yellow, green, pink

From harness I have
black/blue, black, yellow

I'm gonna assume that stray green I have, you are indicating as yellow?

[DnB_racing]

Originally posted by SHIFTx450
From my carb @ tps I have green/yellow, green, pink

From harness I have
black/blue, black, yellow

I'm gonna assume that stray green I have, you are indicating as yellow? the IPG is ignition pulse generator


as far as the tps what stray green??

the blk/blue from harness to the green/yellow carb
the yellow from harness to the light green carb
the black from harness to the pink carb

[SHIFTx450]

Disregard the stray green thing, I misread something that is all.

I got it all hooked up, took off that QS2, 2.25 turns out seems to be ticket with fuel screw. She's rippin now! Still a slight bog on bottom end though, feels more like the factory bog.. But it's not bad. Only happens if you give it a quick stab of the throttle.

I'll deal with it for now until my motor Mentor gets back from Hatfield McCoy Trails.

You think it could have something to do with no intake boot or air filter currently hooked up? I'm having another problem, figures you fix some and create others. Got the carb to sit straight and level on motor, but now it's directly facing the damn frame crossmember. I'll try and attach a pic.

Another question regarding the wires. At the thumb throttle assy. comes a small harness of 2 wires, both solid black. I'm gonna assume they hook into the small harness with 2 solid black wires coming from the throttle arm on carb?? But they're different ends.. Both female, one green and one white.

Last but not least, do you know how to get that ball and spring inside the kicker? The old stuff fell out, got a new set from the honda shop and cannot seem to get it into place..

[SHIFTx450]

It says file sizes too big, and I can't figure out how to decrease it within it's limit. F it, I'll figure something out. If anyone is interested shout out your email address and I'll send some pics of what I've got going on.

[DnB_racing]

Originally posted by SHIFTx450

You think it could have something to do with no intake boot or air filter currently hooked up? I'm having another problem, figures you fix some and create others. Got the carb to sit straight and level on motor, but now it's directly facing the damn frame crossmember. I'll try and attach a pic.

Another question regarding the wires. At the thumb throttle assy. comes a small harness of 2 wires, both solid black. I'm gonna assume they hook into the small harness with 2 solid black wires coming from the throttle arm on carb?? But they're different ends.. Both female, one green and one white.

Last but not least, do you know how to get that ball and spring inside the kicker? The old stuff fell out, got a new set from the honda shop and cannot seem to get it into place.. ya no air filter isn't good it will make it run too lean, dont run it long like that you could burn it up


you might have to take a little of the plastic cover off the carb to clear the cross member

the black wires are for the trx only, the cfr doesn't have any safety switch circuit in the cdi. you can completely ignore the safety switch on the carb and throttle housing, you dont need it .
most people eliminate it on there quads anyways... dont even worry about the extra wires from the cab and thumb throttle, the crf cdi doesnt have the kill circuit from the safety

as far as the kicker GOOD LUCK!!! use a small screw driver and a pair of needle nose and LOTS of patience. and make sure you do it were you can find the ball easy when it goes flying 20 feet

[SHIFTx450]

You'll need to see the pic. There's no plastic cover interference. Hang on and I'll try and crop it to a smaller size.

And don't yell at me about the plastic dust cover not being on, I'm still tuning