1BigDSRider,

The 45mm carburetor works awesome on machines with just bolt ons! I saw Jiminok (yeah, jimsok!) install one and he gained a good amount of power and he was really whoopin' up some sand dunes at Glamis after he installed it. If you are worried about performance, don't. It will perform even with just bolt ons - however if there are other factors to consider like cash flow, that is more your decision.

 

the 45 i had did not have an accel pump. at first it was hard to get used to, if you hit it hard off idle it would bog. you have to ride it like a 2 stroke almost, get the rpm's up alittle befor hitting off the start. marky nark told me that you can get the 45 with the accel pump from him set up. does the 42 have an accel pump?

 

The 42 does have an accel pump, when you order it tell them you want it activated. The 42 and 45 are the same carb, just a different bore size. All flatslide carbs have the hesitation tendency when you stab the throttle. A properly tuned accel pump will eliminate this tendency but the resistance on the thumb throttle is substantial. If you use a twist throttle, no problem. Or if your Arnold Swartzenegger you may not notice it. I'm not and it torched my thumb and forearm on a weekend of duning. I disabled the accel pump, raised the needle all the way up, dropped one main jet size, and installed a Dial-A-Jet. Works awesome! You really have to work at it to create the hesitation and it is very crisp. It will pull the front wheels in any gear at almost any speed with just throttle.

I don't know if 3mm larger bore is worth almost 300 more dollars, plus the manifold matching. Not saying it isn't, just not to me. If I was going to spend that kind of money on carburetion I would opt for the duals. On the duals you get the best of both worlds smaller initial bore=throttle response, larger overall flow=more top end. But for me I'm waiting for an EFI system that I like before I go any further with carburetion.

 

ok so
with pump = no hesitation but stiff throtal
without pump = hesitation but soft throtal.

without pump with proper jetting / Dial a jet = no hesitation and soft throtal??

 

either way you will have a stiffer thumb pull. i took the spring off inside the factory thumb @ the handle bar, removed the spring on the left side of the carb and installed a softer spring ( supplied by rwr) and it was better but i'm still unbeaten in thumb wrestling[img]i/expressions/face-icon-small-happy.gif[/img] now with my dual carbs i had to go with a twist and i miss my thumb set-up. keep you'r cable lubed and the springs clean and you might be able to keep you'r thumb throttle.

 

MudStud,
You got it. You can tune out 90% of the hesitation on the 42, maybe so on the 45 I don't know. Either way it is easy to modify your riding style to ride around it. Keep in mind, the throttle response on a flatslide 42 or 45 will be WAY better than on the stock carb so you can't really make a mistake. If you try the accel pump and don't like it, you just pull out a rod to disable it. RWR can sell you the non-accel pump return spring to further soften the pull, but don't use it with the accel pump, cause it won't work. If you don't like the performance without the accel pump, put the rod back in... no big. This is no advertisement for RWR but I will say that when I got mine it was set-up almost spot on, just a little adjusting of the accel pump and it was perfect. Whoever you get it from, make sure they know your current set-up, elevation, and riding style so they can be better equipped to set it up for you.

 

JEFFROE is right about the stiffness, I forgot about the crappy cable that came with the carb. It is too long and has alot of resistance. I modified my stock cable and it works smooth. I'l try to explain the mod, but it was much easier to do than to explain on a keyboard.

On the carb end of the throttle cable I cut off the nut that screws into the stock carb. To do that cleanly I put the "nut" in a drill, put the drill in a vise to hold it, held (don't laugh) the cable casing in my teeth to keep it from binding and spining, and held a hacksaw to the spining "nut" to cut it off without damaging the cable casing. The stop ball on the original cable is too small for the new carb so I cut a small piece of 1/4" copper tubing to about 3/8" long. Then I cut a groove in the copper tube to the halfway point, lengthwise, with a Dremel tool to insert the cable ball end into. The I soldered the ball to the inside of the copper tubing barrel that I had made, I could have used JB Weld but I didn't want to wait for it to set-up. The new copper tube barrel fits the new carb linkage perfect and the length of the original cable is right on. Sounds hard but it really isn't. Works much better that the cable that RWR sent.

 

even with the hesitation will it still out perform the stocker? What I mean is it only noticiable on the clock or can you feel the hesitation then does it just rip after the hesitation? why would the pump make it so stiff? why is it so stiff compaird to the stocker?? anyone else make a decent NON stiff carb??? I want a carb but it sounds like it more trouble then its worth...

 

Would the Dual 39mm Keihin Carbs be a good choice for a bike with just bolt ons, or would the 45 be the better choice?

 

In my opinion a TM45 will out run a stocker , you will just get used to any hesitation. I don't think my DS has any problems with Hesitation.

I did some research, the reason the throttle is stiif is because the TM45 was designed for 69ci Harley. The Harley had enough vacuum that it would hold the slide open. Unless you had a push pull throttle you would be stuck at full throttle.

Another $.02