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2000 XR400R Edelbrock carb trouble

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History on the bike: 2000 XR400R has new rings, all four valves + guides are new, new Hotcams stage 1 cam, new FMF powercore 4 muffler, CNC port job. The problem is it has an old school Edelbrock carb on it. The one without jets or an accelerator pump. I cannot get this bike to start reliably. Since the carb doesnt have an accelerator pump there is no way to really prime the carb except for the enrichener and it seems to want to start better with no throttle, no enrichener. I know how to tune it with turning the screw in the top of the carb but that doesnt seem to be helping the starting issue. I called edelbrock and they informed me that those carbs havent been made for 12yrs and the current tech support doesnt have ANY experience with them.

So what should i do? Is there a procedure i should follow while starting it or is the best thing to just change to a mikuni or stock carb with jet kit? Literally kicked it for 30 minutes yesterday before it started...

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I'm not familiar with this Edelbrock without jets. If you can't adjust this one, you can do a search for other carbs that work well on the XR400's.

I am running a Mikuni BRS42, that came off a Polaris 500 with outstanding results.

Perc

Its not that it cant be adjusted its just that the adjustment is by raising or lowering the needle by way of a screw in the top that you access by taking a plug out. If it needs more adjustment than you can get out of it you have to go to a different needle. At least thats what the instructions say... I have had the carb apart and made sure the float needle is working properly.

Is the carb you have a flat slide or round slide? I have a brand new mikuni VM32 round slide laying around if itll work...

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A 32mm carb is much too small for these engines. They came with a 38mm Keihin and I went up to, (first) a BST40 then a BRS42 because I believed it needed a larger carb to reach it's potential.

Both of these carbs are constant velocity Mikuni carbs. The BST40 comes from a Suzuki DR650 and the BRS42 from a Polaris Predator or Outlaw 500.

Perc

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A 32mm carb is much too small for these engines. They came with a 38mm Keihin and I went up to, (first) a BST40 then a BRS42 because I believed it needed a larger carb to reach it's potential.

Both of these carbs are constant velocity Mikuni carbs. The BST40 comes from a Suzuki DR650 and the BRS42 from a Polaris Predator or Outlaw 500.

Perc

Thanks. Ill check into it. I really wish there was a way to make the edelbrock work but i dont have high hopes for this carb...

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Can you find a schematic on your particular model Edelbrock carb? Does it have a starter jet or air jet? If so, a smaller air jet would create a stronger vacuum signal to the starting system(enrichener).

I agree with the others tho. You're better off putting something on there that you can find support for.

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Can you find a schematic on your particular model Edelbrock carb? Does it have a starter jet or air jet? If so, a smaller air jet would create a stronger vacuum signal to the starting system(enrichener).

I agree with the others tho. You're better off putting something on there that you can find support for.

There isnt much of anything i can find for this carb... Im pretty sure that it doesnt have ANY jets in it. The needle and emulsion tube work as the only fuel metering devices in the entire carb.

I agree about finding another carb though.

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I had two Edelbrocks like yours (no pumper) both on XR600s. I too had starting problems in the beginning. The procedure I finally stuck with is: 1. Turn the enrichener on full. 2. Hold the throttle open and hold in the manual compression release and kick the engine over 2-3 times. 3. Turn the enrichener off, let go of the decomp lever, slowly use the kicker until you feel compression. 4. Pull the manual decomp and push the kicker gently about 2-3 inches. 5. Let of the decomp lever, return the kicker to the top of the stroke and give it a healthy boot.

If you decide to give up on the Eddy, you might want to consider a Minuni TM34 flatslide. I have one (non-pumper) on the XR400 that I am currently riding, it works great, easy starting, great throttle response, strong steady pull all the way through the RPM range.

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I had two Edelbrocks like yours (no pumper) both on XR600s. I too had starting problems in the beginning. The procedure I finally stuck with is: 1. Turn the enrichener on full. 2. Hold the throttle open and hold in the manual compression release and kick the engine over 2-3 times. 3. Turn the enrichener off, let go of the decomp lever, slowly use the kicker until you feel compression. 4. Pull the manual decomp and push the kicker gently about 2-3 inches. 5. Let of the decomp lever, return the kicker to the top of the stroke and give it a healthy boot.

If you decide to give up on the Eddy, you might want to consider a Minuni TM34 flatslide. I have one (non-pumper) on the XR400 that I am currently riding, it works great, easy starting, great throttle response, strong steady pull all the way through the RPM range.

Problem is with the hotcams cam in it, there is no more compression release... I actually was able to start this thing easier before when it had two bent exhaust valves by following that procedure...

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Problem is with the hotcams cam in it, there is no more compression release... I actually was able to start this thing easier before when it had two bent exhaust valves by following that procedure...

When you installed the HotCam you lost the "Auto-decompressor" but you should still have the manual lever and cable to the right side exhaust valve.

Or was this already gone when you got it?

Perc

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When you installed the HotCam you lost the "Auto-decompressor" but you should still have the manual lever and cable to the right side exhaust valve.

Or was this already gone when you got it?

Perc

Hmmm. Good catch. The cable is there but disconnected. I just assumed since the cam didn't have the decompressor that the manual lever wouldnt work.

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Look on the right side of the cam cover. If the decomp lever is still there, hook up the cable and give it a try.

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Oh good! :bonk:

Hook that cable up and get it adjusted. The manual de-compression lever works by pushing on the rocker arm that opens the right exhaust valve and has nothing to do with the cam, so... this will make starting much easier!:smirk:

Perc

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Oh good! :bonk:

Hook that cable up and get it adjusted. The manual de-compression lever works by pushing on the rocker arm that opens the right exhaust valve and has nothing to do with the cam, so... this will make starting much easier!:smirk:

Perc

The cable, and lever is still there. Ill hook it up and get it adjusted. This should make the edelbrock able to prime and save from needing another carb hopefully, although i suspect the adjustment in the needle is just about all the way richened up... The headwork and cam DEFINATELY made it flow a whole lot better, and it has the exhaust and K+N filter on it with no snorkel.

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Well, i got the compression release hooked up and it starts better but is running lean and i have the adjustment on the needle(edlebrocks version of jets) richened all the way. The only way to go richer is to go with a larger needle and im not even sure where to get a larger one from...

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This is the correct carb from polaris predator 500? What needs to be done as far as jetting? I know i had to richen the edelbrock WAY up and its still running lean... With the cam, and CNC headwork this bike really flows. Also has FMF exhaust and K+N filter.

http://www.ebay.com/itm/03-07-POLARIS-PREDATOR-500-CARB-CARBURETOR-/360416897395?hash=item53ea856973&item=360416897395&pt=Motors_ATV_Parts_Accessories&vxp=mtr

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If you can't find a richer needle, try installing an air filter that doesn't flow quite as much as the K&N. A UNI foam filter is still a good filter, just not quite the flow of the K&N. That will help richen things. Do you still have the air box snorkle?

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Well, i got the compression release hooked up and it starts better but is running lean and i have the adjustment on the needle(edlebrocks version of jets) richened all the way. The only way to go richer is to go with a larger needle and im not even sure where to get a larger one from...

What size needle is in it now? Are you turning the needle adjuster the correct direction? Clockwise for richer, counterclockwise for leaner. The link below is the owner's guide for Eddy off road carbs. The next link is parts.

http://www.edelbrock.com/automotive_new/misc/tech_center/install/off-road_carbs/Off-Road_install.pdf

http://www.edelbrock.com/offroad/mc/carb_parts/carb_parts.shtml

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If you can't find a richer needle, try installing an air filter that doesn't flow quite as much as the K&N. A UNI foam filter is still a good filter, just not quite the flow of the K&N. That will help richen things. Do you still have the air box snorkle?

No airbox snorkel, and i would rather take advantage of the performance work done to this bike instead of restricting the airflow to richen it up and choking the engine down.

With no support for this carb i believe id just be better off to change to another, more traditional carb that i can rejet easily as necessary

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