I am in the process of modifying my 2011 KLX250S FI Version from Thailand by installing a Bill Blue 331cc Big Bore Kit and the Mikuni TM33 which he supplies bored to 34mm. After removing the FI unit, it seems the TM33 does not fit right with some gap. Anyone got a solution to this problem, i know there are many here who have converted from FI to Carb without problems, so i hope someone can help me out. Is there a bracket which i need to install to mount the carb?

 

If you haven't done it yet, I would pull up the airbox/carb and airbox/FI parts diagrams from Bike Bandit or the like. Then compare parts and part numbers and their order of assembly. It might show you what is wrong, might...

And it will help if you are more specific about where the gap is, pictures would really help too, if you can.

 

Hi Max, thanks a lot for your feedback, i sent the bike to the workshop to do the installation and they told me the problem over the phone, something about one part measuring 42mm and the other part is 50mm so it doesnt fit. Anyway, great idea, i will get them to take a photo and send it to me so we have a better idea of the problem.

 

If the airbox boot is 50mm and the carb flange is 47mm, they usually make adapters for things like that to step up the size of the smaller carb flange. If it's the other way around, that's more difficult to address.

 

After talking to my mechanic again today, i managed to find out where is the problem. Referring to the photo, the problem area is highlighted in red circle, one side the diameter is 42mm and the other side the diamter is 50mm, so the carb doesnt fit the cylinder head. anyone who installed a TM33 faced this same problem? Is there an adapter or holder that can solve this problem?

 

Look on the Sudco site and see if any of those available intake manifolds will work for your application...or, will the OEM carb manifold from Kaw fit on there? Is the KLX head the same for FI or carb?

 

yeah thats what im wondering myself, whether the carb manifolds are the same for the efi or the carb models. anyone here fitted a mikuni TM33 on their efi model?

 

I'm curious on the FI replacement with a carb. Isn't the FI supposed to be a decent performer on the KLX? I certainly understand people replacing the CV carb with a pumper, but doesn't the FI work pretty well? I don't know because I've never even seen an FI KLX.

 

i believe Joel had mentioned a ways back that efi to carb conversions were pretty common over there on big bore installs since it was easier and cheaper than messing with all the extra gadgets needed for tuning the efi.

i dont believe he went into much more detail though, i just remember finding it interesting since alot of people seem to regard efi as the holy grail of motorcycling.

 

Actually i would have no problems just using back the FI but i couldnt live with the stock tank size and all the bigger after market tanks requires carb, thats the reason i wanted to convert from FI to carb. Unfortunately now im stuck and the bike is just lying at the workshop. Im starting to regret getting this bike now with the problems im facing, first i got a leak on the rear shocks and now this....