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petrosXR650R

which pumper carb for my XR650R

12 posts in this topic

Which pumper carb for my XR650R SM? I tried the mikuni TM42 pumper carb and now swiched to keihin FCR42.5 MX. I'm very happy with its performance,but it fits in place semi-lying cause it's tall and hits the tank...The problem is that when i park my bike with the stand looses gas from the overflow fuel line :) what about TM45? and ELDERBROCK too. My exhaust is a full ti-acrapovic system wide open and have no airbox- just a venturi velocity stack. Thanks!!

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Thank you frankstr! I forgot to mention that i'm mostly interested in performance.. I managed to try the TM and FCR, but the EDELBROCK is hard to find here. I was told the FCR performs better,and if so i'm gonna modify the tank with a heating tool to fit everything ok. Does the EDELBROCK worth to order it from the US?? - despite having the FCR.. my bike now has 56PS and 6.2kg-m measured on DUNOJET 150. Thanks again

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As much as I like my Edelbrocks on various bikes, you also need to consider your logisic issues. I doubt there are any Edelbrock dealers near you and there's probably nobody near you that has an Edelbrock carb for their motorcycle. The FCR is a very good carb and if I were living in another country where there were no Edelbrock parts dealers and if there were Keihn dealers in my area, then I would have been working to modify my fuel tank to make the FCR fit. The Edelbrock comes as a complete bolt on kit and everything fits without any clearance issues. Performance is very good for either a stock or uncorked bike with the selection of needles it comes with. If however you go to a 680 kit, higher compression piston, porting, higher performance cam, larger diameter header, rev box, etc, then you'll probably want the Edelbrock bored out so it will work even better with those mods. If you go with the Edelbrock, make sure you find a dealer that will pre-inspect for you to make sure all the parts are in the box and have them pre-test it for you just to make sure you don't get a carb that's missing parts or has a problem. They don't have a history of issues like this, but if there was a problem, it's not like you can hop over to your nearest dealer and have them fix it. If your bike is losing fuel from the overflow, it may have to do with the angle your carb is sitting at. Once you modify the fuel tank so the carb is sitting perfectly upright, it should not loose any fuel from the overflow. If it does, then you'll probably need to inspect your foat needle / seat for dirt or wear, etc. If the float needle and seat check out perfect, then the only thing left is to check the height of your float and see if it's in spec. If it's too high, then bring it back down to spec. If it's at spec, then drop it down just a few mm's and that should do the trick if everything else checks out fine.

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What was the problem with the TM42? I have had both the TM40 and HSR42 (Up dated TM42) the XR650R. Once tuned right they rip! For the FCR42.5 MX you can heat the tank with a heat gun and push the tank in making the Carburetor fit so you do not have to have it leaned over. You would have to have the Edelbrock bored out to be 40mm X 42mm instead of the stock 36mm X 42mm that it comes as. I have this setup on my 680cc XR650R now (4omm X 42mm and it works good. Not as smooth as the Mikuni 's but, it works. You might want to look into a TMR42 mikuni.

What jetting were you using on the Mikuni? That carburetor is way fat for our setup. My 42mm Mikuni came setup with a 160 main jet. 140 is what works. Y-4 needle jet, 9ohj1 needle. 1.2 air jet (major important) and 25 pilot.

http://xr650r.borynack.com/

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Gadsan you're right its the angle the carb has that creates the problem.I'm so curious about EDELBROCK cos fits well,as the TM, but everywhere all the bikes run FCRs.And i mean DIRT BIKE & RIDER, and MX ACTION, US magazines and thought if its so good they'd be using it. BWB63 i had no problem with the TM, but the person who treats my bike told me to switch to FCR for better results..Didn't tell me does not fit! So first i bought it for 850euros, and then having given that money wanted in any way possible to run this part..It performs better but has this only problem and will be solved finally. dont know about the TM jetting, and yours might be faster,but i'msure mine got the looks!! ciao

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I've got a TM40 on mine, which is a great improvement over stock - but given the money I would have gone for a TMR. Easier to fit than an FCR and just about as good, from what I've read.

Or get a WR450, which comes with an FCR. :)

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That was a good one stoo!! I'm not an FCR maniac, i am an XRmaniac!The improvement you experienced installing the TM over stock is the same i did installing the FCR over the TM. Now,the TMR is something between these two that's why HUSQVARNA and HUSABERG switched from one to the other.

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That was a good one stoo!! I'm not an FCR maniac, i am an XRmaniac!The improvement you experienced installing the TM over stock is the same i did installing the FCR over the TM. Now,the TMR is something between these two that's why HUSQVARNA and HUSABERG switched from one to the other.

:)

Also - They're all only as good as the time spent setting them up... A properly jetted stock carb is going to be nicer to use than a poorly set up FCR..... but as long as it pours plenty of fuel into that engine .... :)

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I am getting a TM40 for my 650R because that is what xrs only recommends and I am wondering what jetting I should run. I live at 7700 ft in Colorado. Any help would be much appreciated.

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135 - 137.5 main should work. Y-4 needle jet, 9ohj1 needle, I think your MT40 will come with a Y-8 needle jet and a 8DHJ1-1 (or something like that) some like most don't. 1.2 air jet (major important) and 22.5 pilot.

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