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drz400E running rich but surges, fuel screw not effecting anything.

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after and adventure build on my drz440E , my bike slightly surges in power during a constant speed. not during acceleration at all. My bike had a 165 main jet and i swapped it for a 155 main jet. it runs better now but it still does it. many people say this is what happens when the bike runs lean but my spark plug is black, i think it is running too rich. when my bike is warmed up and idleing, i can turn my fuel screw all the way in and the bike still idles and will rev. This, as i understand it, means i have too rich a pilot jet. The odd thing is, the engine/ exhaust is stock except i opened up my air box, which if anything, would make my bike run lean. before i buy a smaller pilot jet, could anything else affect this? timing?  anything? i know the carb has three jets, could it be the mid jet (name?)? should i lower my needle (raise the clip) one notch to see if it helps? i have the JD kit with blue needle on third clip from top. FCR carb. 0-200 ft elevation on average, 90degrees F in summer and 45-60degrees F in winter.

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About a 45 pilot, 2 turns fuel screw, check the coast enrichner on the l/h side of the carb (if your bike is a full blooded earlier E model with the factory FCR), get rid of it and link the carb pipe with a fuel hose, this may be your issue, tonnes of TT threads on this mod, just Google it, cheers

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thanks, i have seen that mod and was considering it, but dod not know it could cause this. ill do this asap. thanks.

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after and adventure build on my drz440E , my bike slightly surges in power during a constant speed. not during acceleration at all. My bike had a 165 main jet and i swapped it for a 155 main jet. it runs better now but it still does it. many people say this is what happens when the bike runs lean but my spark plug is black, i think it is running too rich. when my bike is warmed up and idleing, i can turn my fuel screw all the way in and the bike still idles and will rev. This, as i understand it, means i have too rich a pilot jet. The odd thing is, the engine/ exhaust is stock except i opened up my air box, which if anything, would make my bike run lean. before i buy a smaller pilot jet, could anything else affect this? timing?  anything? i know the carb has three jets, could it be the mid jet (name?)? should i lower my needle (raise the clip) one notch to see if it helps? i have the JD kit with blue needle on third clip from top. FCR carb. 0-200 ft elevation on average, 90degrees F in summer and 45-60degrees F in winter.

 

Re instate your air box to stock, ....just run with snorkel removed,  it is adequate as an air intake for stock and Big Bore...

 

Use blue needle clip 4 , run your 155 main jet and install the next size smaller pilot jet...

 

Use this procedure to tune your pilot circuit....http://www.thumperta...ad.php?t=327405

 

With modern fuels trying to read the spark plug is not a good way to tune your engine...

 

CE removal is a good idea...

Edited by Craigo 485sm

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Nobody has mentioned checking the float level. Anytime you close the fuel screw (are you sure it's not an air-mixture screw?) and it revs, you're getting gas from the main and not the pilot jet. The intermediate is called, for obvious reasons, a needle jet. A flooded float bowl will cause surging anytime you set throttle to cruise, level off main jet demand and raise the vacuum at the venturi. Under acceleration, vacuum is at its lowest but air flow is highest and fuel metering is at a minimum. Check the float level and make sure you're using the correct air filter oil.

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By opening up airbox, I just mean the snorkel is off. I will remove CE today. I don't mind dropping the pilot jet it justseems very odd I'm giving it more air but it is too rich on stock jet. I'll follow link to adjust pilot. So your saying the float is not adjusted low enough? Thanks guys, I understand concepts, but still new to MC carbs.

Air filter oil is this green stuff made for it, I think it is OK.

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Oh,and my understanding is 4strokes have fuel screw and 2stroke have air screw. Correct?

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I just got off the phone with jdjetting. They recomended going back up to a 162 main jet but switching to the red needle clip 5. Sound legit? I'll try it tonight

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I just got off the phone with jdjetting. They recomended going back up to a 162 main jet but switching to the red needle clip 5. Sound legit? I'll try it tonight

 

Do want you wish.....I have already posted my thoughts

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yeah, your advice sounds better. i will try it. thanks. i know they make the kit but i dont know if the lady knows whats up.

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Oh,and my understanding is 4strokes have fuel screw and 2stroke have air screw. Correct?

No as general rule (with very few exceptions) if the screw is in front of the slide it controls fuel, if the screw is behind the slide it controls air.

Edited by Kioti

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So while waiting on a leaner pilot, I tried the JD recommended setup they gave me of red needle clip 5. Won't even run. I raided it to clip 3 and idled but died and wouldn't restart. So I removed carb and did the Eddie wire mod and deleted the cost enrichener. Put the blue needle back in on clip 3 and 4 and bike won't even run still. I'm done for tonight but any suggestions or advice?

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I also just saw my original post claims a drz440. That is a typo, it is a 400E

I also just saw my original post claims a drz440. That is a typo, it is a 400E

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So while waiting on a leaner pilot, I tried the JD recommended setup they gave me of red needle clip 5. Won't even run. I raided it to clip 3 and idled but died and wouldn't restart. So I removed carb and did the Eddie wire mod and deleted the cost enrichener. Put the blue needle back in on clip 3 and 4 and bike won't even run still. I'm done for tonight but any suggestions or advice?

 

I also just saw my original post claims a drz440. That is a typo, it is a 400E

I also just saw my original post claims a drz440. That is a typo, it is a 400E

 

Your OP said it was a 440 so I instantly thought big bore.....use a 160 main jet for BB

Use the Blue Needle clip #4...

What method did you use for CE removal, ports capped or joined..?...use a 100 or 60 pilot air jet respectively

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Yeah, sorry about my typo. I capped the bungs. While waiting on pilot jet,l have 162 ( im going to maybe drop it to 160 or less today) the pilot air jet is stock. I havent touched it. Shouod I? I need to read up on what it's function is. I heard some people remove it?

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Yeah, sorry about my typo. I capped the bungs. While waiting on pilot jet,l have 162 ( im going to maybe drop it to 160 or less today) the pilot air jet is stock. I havent touched it. Shouod I? I need to read up on what it's function is. I heard some people remove it?

 

.I believe the stock pilot air jet for US of A "Real E" models is a 60 as with Australian models..Noble may correct me here about the paj size....

 

If the 60 is installed you should link the carb ports with a piece of hose and cap the port on the head...

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My 45 "seems" too rich. But I'll see soon. I still REALLY appreciate the help/advice. I'm stumped. I'm adjusting float level Now

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