Thumb Throttle On A 2002 CRF450

[Miller2706]

Hey Everyone-
I know this is weird, but I've used thumb throttles for years since growing up on 3-wheelers. In the past I've outfitted my 97,98,99,01 and 02 CR250's with thumb throttles by using one from on old 86 trx250r, just had to shorten the end of the throttle cable.

I'm lookin at buying an 02-04 CRF450 and wondering if a thumb throttle off of a trx450r would work on it? If so, would the throttle cable need to be modified or would that bolt right on too? If not, any clues what would work on there?

I've gotten weird looks and laughs at the races for years for using a thumb throttle, and I wouldnt want to disappoint anyone just cuz I bought a thumper.

Any advice or help would be appreciated!

[Aus_Rider_22]

I've read about people putting the thumb-style throttle on motorcycles and have wondered how they would. Obviously you're comfortable with it as you've done it to your previous bike.

I thought it would be hard trying to rev the bike in the air when you are hanging on with your whole hand wrapped around the grip?

Anyway back to your question. I guess the biggest difference would be having 2 cables instead of 1. I've read about some 4-stroke owners reverting back to just one cable and ditching the push/push setup. I guess there could be a risk of the carb slide getting suck wide open from the pressure. That could be a problem with removing the return cable.

Try here, perhaps the kits are for CRFs as well.
[Only registered and activated users can see links. ]

[Woody_393]

Agree with Aus, the biggest problem (with using the older setup anyway) is the dual cables. You'll have to find a new one that will accommodate both throttle cables. Otherwise it should work fine. Not sure about the length question though.

[cowboyona426]

I can't imagine riding a dirt bike with a thumb throttle... that would be an interesting experience for me Good luck with the conversion, let us know how it goes.

[Miller2706]

Well I picked up a 02 crf450 yesterday, so after a good bath I'm ready to tear into it. My old fourtrax thumb throttle definately wont work because of the dual cables, and I'm nervous to remove the return cable..


Do you guys know if the new trx450r's have dual cables for their thumb throttles? I'm guessing I could find one cheap as most atv racers convert their quads over to twist throttles, i'm just wondering since the trx's and the crf's have similar engines if that would work?

[cowboyona426]

Originally Posted by Miller2706

Well I picked up a 02 crf450 yesterday, so after a good bath I'm ready to tear into it. My old fourtrax thumb throttle definately wont work because of the dual cables, and I'm nervous to remove the return cable..


Do you guys know if the new trx450r's have dual cables for their thumb throttles? I'm guessing I could find one cheap as most atv racers convert their quads over to twist throttles, i'm just wondering since the trx's and the crf's have similar engines if that would work?

No idea, but there's one way to find out

[Woody_393]

Good question. I'm not sure to be honest.

I tried to find a picture, but didn't have much luck. I bet the parts fiche would show it though.

[dogger315]

I checked the diagrams and it appears the TRX450R uses a single
throttle cable. The TRX uses the same FCR carburetor but it looks
like Honda replaced the return throttle cable used on the CRF with
some kind of linkage at the carb that is controlled, both ways by
the single cable.

You may be able to adapt this linkage to your CRF or, buy a used
TRX FCR carb and throttle assembly.

dogger

[FFRacing11x]

I know this has been stated at least 100X, but the dual cable deal is a liability issue with the bikes. The TRX and YFZ use basically the same carb as their bike counterparts but use just one cable. Your bike will not mysteriously blow up or stick wide open if you only use the pull cable.
Use the Throttle off a TRX on your CRF and you will be fineTdub

[Miller2706]

Well I got the bike tore down today, and after adjusting the valves, I removed the return cable on the carb to see if the throttle would display any problems.. It didnt.

The slide in the carb has a spring on top of it, holding it down the same as any old mikuni or kehein on the CR250's. The linkage on the side of the carb also has a spring on it, helping hold it at a stop.

I ordered a standard Moose thumb throttle, and other than possibly having to adjust the end of the cable for the correct throw, I dont see any problems.

I appreciate everyones help!

I'll post some pics when I'm all finished if you guys wanna see how retarded a MX bike looks with a thumber..

[Woody_393]

ha ha, all that matters is that you are happy with it. Glad you found a solution.