400ex thumb throttle conversion?

[socal]

First let me start by saying i did a search and found topics on this but no explanation.What exactly is done so the push of the thumb opens the carb fully?Also,I have a 38mm carb.What cable will I use?Thanks...

[DnB_racing]

when I used the 300-400 ex thumb throttle i was able to just swap it out on the stock carb, I used the stock cable and had some issues with wide open throttle,

but when I got a 38mm carb I got a new cable,
I used stock length,and was able to adjust enough to have wide open
but the end that goes into the carb was different...
the 38mm that I have is threaded into the cap, and the 34mm one I had was more of a pressed in fitting,

I just cut off the brass end that presses into the cap and used the threaded one from the 38mm.. if that makes any sense at all

[K-Dub]

If you look inside the 300,400ex and 450R thumb throttle there is a stop that doesnt allow the level to go far enough. You take a drimmel and grind out that stop, on side toward the grip. Then adjust your cable. This worked for my 38mm AS, I just did this saturday to my R. Do it with the air box off so you can make sure you have enough travel and that the slide fully closes and opens.

[86 Quad R]

the above mentioned technique works great and will work up to a 39.5mm carb. the cable used will need to be a OEM 250r to a PWK carb from motion pro.

[socal]

Great,thanks!Ordered a 400ex version on fleabay.Now will be getting a cable.Still unsure on which cable to get?86 quad r,you said a OEM 250r cable from motion pro?

[86 Quad R]

Originally posted by socal
Great,thanks!Ordered a 400ex version on fleabay.Now will be getting a cable.Still unsure on which cable to get?86 quad r,you said a OEM 250r cable from motion pro?


when ordering a cable from mo-pro, ask for either a cable for stock 250R thumb to PWK carb or a stock 400EX to pwk carb ect. :cool:

[jcs003]

i tried the 400ex thumb throttle and it was terrible. put a 250r one on that was in better condition than the original i had, and problem was solved.

[86 Quad R]

Originally posted by jcs003
i tried the 400ex thumb throttle and it was terrible. put a 250r one on that was in better condition than the original i had, and problem was solved.

what was the terrible part about it? just curious.

[socal]

I heard they are much lighter action.Maybe he did not have it setup correctly???

[jcs003]

Originally posted by 86 Quad R
what was the terrible part about it? just curious.

there was too much freeplay in it initially. when set to specs. after it was adjusted to where it would open the throttle where it needed to be it made the pressure on my thumb more than what i consider comfortable. also, it wouldnt open the carb fully. another thing. the action on the 250r throttle is much better than the 400ex anyway.

[86 Quad R]

i see. if setup correctly and you were blind folded you wouldnt know. lol juss saying.

[jcs003]

Originally posted by 86 Quad R
i see. if setup correctly and you were blind folded you wouldnt know. lol juss saying.

i tried everything in my repertoire without success.

[socal]

Dam,hope it works for me!

[jcs003]

Originally posted by socal
Dam,hope it works for me!

well, randy(86quadR) knows the trick. im sure he will help you get it figured out. he is a knowledgeable guy.

[K-Dub]

I have 450R thumb throttles on both my 250Rs and love it. I tried the 250R thumb that came on the Roll R I just bought and couldnt ride for more than 20 min. Put the modded 450R on and no problem. The thumb push part is farther away from the bars on the 250R than the 450R, I notice this to be the biggest difference. My thumb can push all day close to the bars, but to even get my thumb to reach down to the 250R thumb push is my problem. With the 250R TT I barley had to shave a dirt bike grip, with the 450R TT I had to shave it clear to the bar.

[socal]

Thats something to consider,the 450r version.Well,I ordered the 400ex and a Mo.Pro 250r cable.Hope it works!