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DRZ400sm surge

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Hi Eddie and all.

Please excuse my english.

I have a "situation".

Bike = 06 DRZ400sm.

Mods = Full Arrow exhaust + 3x3 + SM specific DJ kit.

Environment = Sea level.

Problem outline:

After opening the airbox and installing the exhaust system, I had my mechanic install the DJ kit as per DJ's specs (155mj, Needle @ 2nd clip).

The bike now surges (feels like out of gas) when cruising at around 4.5k-5.5k RPM (just guessing, no tach to be sure) at any gear and at around third-to-half throttle. When I go beyond half throttle it pulls like a champ.

I noticed that a 25pj instead of the 22.5 stock one is recommended everywhere. I also tested my pilot circuit as per Eddie's sticky and noticed the idle smoothes out at around 1.5 turns out.

btw... my mechanic also tried 150mj, 1st clip, 3rd clip and all available combinations... DJ's recommendations prooved to be the best compromise for now.

Jet's (which are not OEM) are hard to come by out here so I ordered a couple of pj's (25 & 27.5), they should arrive by this weekend and will hopefully solve my problem.

So, here are my questions:

1. Does the surge and the rpm/throttle position I am experiencing it in really sound like a pilot circuit problem or am I hoping for too much from these jets?

2. If yes, should I go to the 25pj or go directly to the 27.5pj?

3. If no, what else can I do to get rid of that annoying surge? (maybe 160mj?)

Thanks in advance for any input you may have for me.

It's really annoying to have invested so much in these mod's (prices are ridiculously high here) and still have the bike feel unstable at some rpm's.

Ralph.

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so when you do the fuel screw tests the idle smooths out at 1.5 turns?are you sure your counting full revolutions?

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so when you do the fuel screw tests the idle smooths out at 1.5 turns?are you sure your counting full revolutions?

Well, I'm pretty sure. maybe it's 1.75 turns... I will re-check in the morning.

You seem pretty surprised that it smoothes out at that point, any specific reason?... What are we looking at here doc?

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Yes it does.

To the point that it shuts down if I stay fully closed more then a few seconds.

I'll be going down to the bike in a few minutes and will make sure once again how many turns it takes to smooth it out... I'll report soon.

Thanks.

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OK, now I'm sure. the idle is nice and smooth at 1 3/4 turns.

I kept turning it out to make sure it doesn't get any smoother and it doesn't.

I left it at 2.5 turns for the time being according to your recommendations.

What do you think Eddie?

Will a 25pj solve this surge I have in mid RPM or is it something completely different?

Thanks.

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no,you dont need a 25 pilot jet.

does the surging problem get better or worse with engine heat?

did you reuse the stock needle spacers?

I can't say I feel a difference with engine heat, feels the same regardless.

Yes, my mechanic reused the stock spacers.

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Mine does the same exact thing, I did just upgrade too and asked the same question about the pilot in DRZ400 section. A gent told me to put the needle in the 3rd clip postion and it solved it for him. I am going to try that, and it makes sense. I think that range of yours and mine 20-30 percent throttle you are off the pilot by a long shot.

But what you describe is the exact same thing mine does. other than that it pulls much harder just surges with a little throttle opening.

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Mine does the same exact thing, I did just upgrade too and asked the same question about the pilot in DRZ400 section. A gent told me to put the needle in the 3rd clip postion and it solved it for him. I am going to try that, and it makes sense. I think that range of yours and mine 20-30 percent throttle you are off the pilot by a long shot.

But what you describe is the exact same thing mine does. other than that it pulls much harder just surges with a little throttle opening.

The thing is, we tried 150mj and 155mj, both in combination of 1st, 2nd and 3rd clip... DJ's recommendation of 155mj and 2nd clip proved to be the best compromise.

I'm confused.

I honestly thought this would be a simple swap and all will be fine.

If only I knew... *sigh*

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well, that honestly sucks. I love the increased acceleration and I was pretty sure the 3rd needle setting would do it(stop surging) by richening it up(needle higher) at that throttle position.

I will still try it tonight, but it kinda is a shame knowing it did not work for you.

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Thanks Eddie, I'll try it on my way home from work and I'll report back.

In the meanwhile, should I leave the mixture screw at 1.75 turns or 2.5 like it is now?

Thanks again.

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umm...

I was just down looking at the TPS.

Please excuse my ignorance, do I disconnect it simply by unscrewing the little screws that hold it in place and pull it out or is there another way?

Thanks.

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actually there is a connector about 8 inches up the loom in a bundle tie-wrapped together. near where the frame is.

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I have a 06 sm with the S kit in it and I am running:

3X3 mod

yoshi pipe

S DJ kit

needle on 3rd clip

152.5 main

3 turns out on screw

sea level

goog luck i was fighting a hesitation off idle for a long time

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well mine is hooked now!! :ride: no more surging for me. I only did a 30 min ride but I'm calling it. I can't believe you didn't notice a differance on the 3rd clip. It definately took the surging away on mine but I am running the stock pipe so there is a diff I'm sure

So I am very happy and am 3x3, DJ SM kit... needle 3rd w/spacers, 150m 22.5p

stock pipe. It feels way better than stock, and I keep the original exhaust :banana:

also 3.5 turns out

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actually there is a connector about 8 inches up the loom in a bundle tie-wrapped together. near where the frame is.

Thanks solorsix. I'll trace back from the carb and disconnect it in the morning.

Just wondering, what will disconnecting the TPS prove if the surge stays or whether it goes away?

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goog luck i was fighting a hesitation off idle for a long time

Thanks!

Looks like I'll need some :ride:

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Just wondering, what will disconnecting the TPS prove if the surge stays or whether it goes away?

I'm not sure with a carby setup, but I would imagine the ignition curve changes based on throttle position. So maybe if you disconnect it there is a default curve or something like that. I don't know this for sure on a DRZ. fuel injection systems rely on TP sensor as well as a host of other sensors to determine fuel and ignition timing, thats why I'm guessing.

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