Just curious...what would you guys recommend to get for the best performance, the 42m TMX carb or the HPD Air Box/Carb mod? The HPD mod is cheaper ($110 vs. $299) but is it just as good? Does anyone know of a good place to find the 42mm carb cheaper than Aaen($299)?

Thanks.

 

I think you would probably get a bigger inprovement with the carb, the flatslide does alot for the Scramblers. The air box mod would give some improvement, but I just wouldn't see alot without other improvements along with it, like a pipe.

 

The flatslide on a four stroke does not work, unless your get one with a pump. The regular flatside goes lean when the slide opens and leaves a flat spot off idle. everyone tried the TMX 38 on the sportsman 700's and could not get it to idle and run correctly.

 

The flatslide will work, It is just a bear to get jetted correctly. I have friends who have run the flatslide on their 500's with great success. It is all in the jetting.

 

I, personally, have never messed with jetting on a carb before. If it is as hard as it sounds to get right on the TMX, I think if I were to do any of these mods, I would go with the HPD, mainly because it is also cheaper. No one knows of any other places,besides Aaen, to get the carb from (cheaper)?

 

I would have to hunt around for a better price for the carb. I know I have seen it, but have forgotten where. The HPD kit is good, I have one on my 400 and It makes a big difference, but you have to be prepared to re-jet with it also. But, they can probably give you recommendations on it.

 

Stay away from the 42mm tmx, nothing but problems with jetting. hot seat performance used to sell the same carb but discontinued it due to calibration problems, too many people having flat spots and bogging. I have the hpd airbox mod with there jet kit along with a dg xcellerator exhaust system and am happy with the results. I know yost performance is working on a new carb for the 500ho along with their power tube kit which may be out mid-summer. some people i've talk to said the 42mm tmx is actually a carb for a two-stroke and that's why it is such a bear to set-up. I have asked the same question about this carb way back and I'm glad I stayed away from it. some people have had luck with the kihein 39mm fcr carb but I'm going to wait and see how yost performance makes out. good luc

__________________________________________
2002 scrambler-x 500 2x4, dg xcellerator exhaust system,
HPD airbox and jet kit mod, H/L water temp. gauge,HSP
chain tensioner, super cooler, radlites, K&N filter, heelclicker clutch kit.

one fun and fast trail machine!

 

OK first of all, yes the TMX series carbs are hard to jet, so unless you are good at it or willing to learn, It probably is best to stay away from it. Secondly, I have heard that the PWK carbs are much easier to tune than the TMX. The major difference between the stock carb and the 42 is that the stock carb relies on vacuum to build up before the diaphragm pulls the slide up. With the 42, you are manually pulling the slide up when you pull the throttle, the slide raises instantly and therefore the theory is of more throttle response. Yes there is alot of tuning that has to take place in bottom to mid range there because of that and if done correctly should give good results. Now, the difference between 2 stroke and 4 stroke carbs is another story. The difference between a 2 stroke and 4 stroke engine is intake velocity. 2 stroke engines have a lower velocity so the needle jet has a half moon shaped hood protruding into the venturi to produce a low pressure area that aids in drawing the fuel up through the needle jet. 4 stroke carbs need to atomize the fuel more than a 2 stroke carb because so much of the fuel shears along the intake port and separates from the mixture stream. 4 stroke carbs have more jets and finer adjustment screws plus they usually are equipped with an accelerator pump. The reason behind the TMX carb is that it is a flatslide carb and it offers a greater peak flow rate. Now if you are unsure whether you are looking at a 2 stroke or a 4 stroke carb, then look inside of the venturi or throat of the carb and if you see a little tube sticking up in the middle where the needle goes, then that is a 2 stroke carb. 4 stroke carbs won't have that. Also the differences in the 42TMX 2 stroke and the 42TMX 4 stroke carbs is not only the price, but the 4 stroke also has an accelerator pump. So, there is no way that the correct 42TMX carb can be for a 2 stroke. Hope this helps everyone understand the differences. [img]i/expressions/face-icon-small-smile.gif[/img]

 

Offrder15, the answer to one of your questions about price?? Well, that same carb here is $360.00, so your best price probably is Aaen.

 

Thanks.