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Discussion Starter #1 (Edited)
I installed an inexpensive ($26) Mikuni copy in place of the stock carb and it works wonderfully. The stock carbs seem to be the bane of the Tdub. Starts instantly, idles way lower than stock, smooth, really fast warm-up time, etc. It's a whole new bike, now. No comparison. I posted the details in the classifieds area. Can't decide whether to burn the stock carb at the stake, use it for target practice, or bury it at sea.
cnc200
 

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Are you sure? It says only Big Wheels up to 88. Different monkey altogether. CNC200 could you let us know where you got it at?
There are lots of vendors for this carb on Ebay.

It does say that it is for the BW200, but from my research I have found that this carb (a Chinese copy of a Mikuni TM24/26) is used on 50cc pit bikes up to 250cc Chinese scooters, motorcycles, and small ATVs.

I believe you will need a different throttle cable and throttle sleeve to make it look and operate like stock, but CNC200 can address that.

My only concern is the slightly different sizes of the carb intake and outflow diameters.

jb
 

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I have seen that and wondered how well it might work. For $26 how could you go wrong?

If CNC200 would post the parts # etc. for the throttle sleeve and cable and save everyone from doing the searching along with a quick explanation of what he did that would all be great!!! Tony
 

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$26?? a rebuild kit is more than that., curious minds want to know more.
 

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Discussion Starter #8
Here is what I posted in the classifieds. I was trying not to cross-post, but here it is:

I works! I was totally frustrated with the stock carb on my 87 Tdub. From the sound of things on the group, even if it is set up perfectly, it's finicky with altitude. Enough, already! I bought a new carb off of ebay for a whopping $26 (delivered) and it bolted right on. I didn't want to hack up the existing dual cable setup, so I took it all off and scrounged a twist grip and throttle off of a dead Honda-like Chinese bike at a junkyard. It worked perfectly! Hooked it all up and hit the start button. It sprang to life in 1 second and purred. Choked at first, then half choke in a few seconds, and after maybe 30 seconds, no choke. Threw a leg over and roared off. Very smooth, no flat spots, same power (by feel). Goes up hills the same as before. Idles right down to thumpa-thumpa speed and has no hesitation when gassing it. This carb looks like a copy of a Mikuni to me. Didn't even have to adjust the needle or jets or anything. It just runs. I'll keep the carb around for the next owner (some year), but I've apparently found the holy grail of carburetors for the Tdub. The carb I used can be found on ebay item number 380442144936. I recommend purchasing a Domino throttle assembly and a single cable, 36" long. The carb end of the cable has to have a small, cylindrical nub on the end. I also removed the angled tube on top of the carb. Grab in a vise and drill the end of the tube until it falls off. Used a threaded cable adapter from a junked scooter. Tapped the top of the carb with a 7X1.0mm tap to accept the adapter. The adapter allows some adjustment of the cable. Can't tell you how thrilled I am that I'm finally free from that stock carb.

Looking at the same seller's other stuff, it looks like http://www.ebay.com/itm/TWIST-Thrott...item3cdc0d39a3 would work, or at least be close. Still need to add a cable end on the carb end and whack off the angled tube. I may just burn my old stock carb at the stake....
 

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If it sounds too good to be true then it usual is. A $26 carb may be a quick fix but it will inevitably lead to more problems. You may get lucky but I would be a bit apprehensive. This is just one man's input. Take it as you will.
 

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Are you sure? It says only Big Wheels up to 88. Different monkey altogether. CNC200 could you let us know where you got it at?
I've been pondering your skepticism that this carb would work for the TW. In my mind the BW and TW engines are similar...4 cycle, same displacement, low compression.

This carb is used on a variety of displacement vehicles, but my best guess of why this is advertised for the BW200 and works for the TW is the jetting.

This carb used on a different bike would need different jetting.

The main and pilot jets in this carb have no identifying numbers, so replacing them is pot luck unless you can measure the openings and match them to known jets.

I have examined all the parts of this carb and IMO they are of no better or worse quality than the TK. This is actually a simpler carb than the TK's...less fiddlly small parts.

I see no reason for this carb not to be as long lasting as a TK.

As for spare parts, it would probably be less expensive just to buy a new carb.

I will reserve final judgement until I put it on my TW and see how it performs.

jb
 

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If someone does repeat this. Be sure to take pics and do a writeup so we can put this up as a sticky for those with carb. problems as a possible solution.
 

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Here it is:





And in pieces:



First impression is that this isn't a high performance pumper carb.

But it is a simple carb (less things to go wrong) , and if it proves reliable, perhaps will give those with old unfixable/broken carbs an inexpensive option to get their TW's running again.

jb
 

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FWIW I used on of those ebay MIKUNI copies (different size) same style and price on a little 90 that was missing carb parts and all sorts of other problems and I had the same luck. I had to do a little creative linkage on the top end also but in a year or so of owning it never failed to crank, even my 11 year old busted it off with ease. As a matter of fact that same bike just took second in a local MX race.
DO it folks, do not wait for an expensive TW carb to come along, hack it up!
 

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Discussion Starter #16
Good plan on the spare parts. Just buy a second one and stash it. Who knows when these will disappear. I made one other mod today. The manifold side of the carb is a little longer than the stock unit. 4mm, to be exact. That prevents it from seating like it really should. Solution: Mark a like 4mm from the end, stuff a rag in the hole and push it up against a belt sander. Bingo. Snaps all the way into place, now. I'm soaking the boot in DOT3 brake fluid now to soften it up. It was more like plastic than rubber. Had to really work at it to get it out of the air box. One other thing that needs doing is to replace the existing start button and kill switch. Planning on just getting a couple of kill switches and strapping them on the handlebars somewhere. They were part of the original twist grip, which I'm no longer using. For now, it's just stuffed over by the speedometer.
cnc200
 

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CNC, any chance you have a photo of the carb mounted in place?

jb
 

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Discussion Starter #18
No. Not yet. Rerouted the single throttle cable so it doesn't stretch out and rev the engine on a right hand turn. Tried soaking the intake boot in DOT3 to soften it up. Soaked for 4 hours at room temp and got no effect. I'll try it later but for now, it's back together and ready to ride. A new boot would be a good move, anyway. I temporarily used duct tape (yay!) and tie wraps to bridge the gap. It would probably hold fine for 10 years but it looks just a tad redneck...:p

CNC, any chance you have a photo of the carb mounted in place?

jb
 

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I had to replace the boot on my 87 and it was around $25 if memory serves. I couldn't believe the difference in the elasticity and condition when side by side. Thanks for the OP and let us know how it pans out.


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