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Accelerator Pump Help Timing

By Sasha Rudolfski,
in DRZ400/E/S/SM

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Sasha Rudolfski

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My bike was pulling like a train and I decided to mess around with the AP timing(mistake!).  I tried to put it back to factory setting but the marking that was once there from the factory has rubbed off...Now the bike stalls coming off idle or the rpms drop significantly when I twist the throttle at a stop or low rpms.  Any advice to help me time the AP? I have this RD AP Spring here - will that help me with the AP or equivalent to #78 O-ring?  Anyone change their AP diaphragm / rod?  

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DrzBob

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You can reset the AP timing backing out completely the idle screw (keep track of how many turns), then insert a 0.8mm drill bit in the carb bore under the slide and adjust the AP timing screw so that it barely touches the arm pump. From there it's just a matter of fine tuning riding the bike and turning the screw 1/4 turns at a time (CW and the squirt starts later, CCW and it starts sooner). Don't forget to reset the idle screw to where it was.

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Sasha Rudolfski

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3 hours ago, ohiodrz400sm said:

I missed the R&D spring part the 1st time. No o-ring is required, it is stiff enough

What size is your engine?

My engine is stock displacement. But I have e cams.  AP shot is pretty much there now- no bog and pulls like a train w my jetting.  I got it running nicely from bottom to top.   The only thing is my pilot circuit.  Switched to a 38 pilot and the slight bog in the closed to 1/4 throttle was gone but the fuel screw does not slow the idle when turned in!?!?  I guess I am going to try a 35 pilot??? I dont know what else to do.  I have an adjustable pilot air jet in the bellmouth -- maybe if I up the pilot air jet to a 150?  I tried a 40 pilot w 125 pilot air and didnt help.   Float level is dead on 9mm.  Maybe I should up it to 10mm?  Any thoughts??

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William1

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11 hours ago, Sasha Rudolfski said:

My engine is stock displacement. But I have e cams.  AP shot is pretty much there now- no bog and pulls like a train w my jetting.  I got it running nicely from bottom to top.   The only thing is my pilot circuit.  Switched to a 38 pilot and the slight bog in the closed to 1/4 throttle was gone but the fuel screw does not slow the idle when turned in!?!?  I guess I am going to try a 35 pilot??? I dont know what else to do.  I have an adjustable pilot air jet in the bellmouth -- maybe if I up the pilot air jet to a 150?  I tried a 40 pilot w 125 pilot air and didnt help.   Float level is dead on 9mm.  Maybe I should up it to 10mm?  Any thoughts??

Idle speed is too high. Set the slow air to be a 100. Lower temporarily to where it just idles, adjust the fuel screw at that point, then raise the idle speed back to 1,850 rpm.

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Sasha Rudolfski

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17 minutes ago, William1 said:

Idle speed is too high. Set the slow air to be a 100. Lower temporarily to where it just idles, adjust the fuel screw at that point, then raise the idle speed back to 1,850 rpm.

Idle speed was too high - you're right I read this a couple of weeks ago and dialed it in with the slowest idle possible...even doing this the idle does not slow with fuel screw fully seated...any idea what else i can do?  I did set the slow air back to 100 when I put in the 38 pilot...

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William1

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36 minutes ago, Sasha Rudolfski said:

Idle speed was too high - you're right I read this a couple of weeks ago and dialed it in with the slowest idle possible...even doing this the idle does not slow with fuel screw fully seated...any idea what else i can do?  I did set the slow air back to 100 when I put in the 38 pilot...

You are not looking for it to slow. Only stall if fully closed AND the idle speed is low enough. For are looking for a reaction from the bike to changes in the fuel screw. You set for the smoothest idle and then bring the idle speed back up. Do not over think this.

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Sasha Rudolfski

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1 hour ago, William1 said:

You are not looking for it to slow. Only stall if fully closed AND the idle speed is low enough. For are looking for a reaction from the bike to changes in the fuel screw. You set for the smoothest idle and then bring the idle speed back up. Do not over think this.

Yes, I understand however the bike doesn't stall instead idle speed increases when the fuel screw is fully seated with bike at slowest idle possible..If I raise the float to 10mm it will lean everything out but especially in the lower throttle...Either that or try a 35 pilot and see if that will give me the correct reaction from fuel screw...or go with  40 pilot and a bigger pilot air?  I come up with these ideas (thinking too much), then I put them in action and I don't get the result I was expecting...i understand what your saying but I'm not sure what to do if Im not getting that reaction...

what would you do...

A) Raise Float to 10mm

b) Larger pilot air jet

c) Smaller pilot fuel jet

d) Run it rich and fuhhhgetta bout it

I can't help but keep tinkering until I get it right, i try to stop and leave it alone but it draws me back in and here i am..

I really appreciate your help and taking the time to respond.

 

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William1

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1 minute ago, Sasha Rudolfski said:

Yes, I understand however the bike doesn't stall instead idle speed increases when the fuel screw is fully seated with bike at slowest idle possible..If I raise the float to 10mm it will lean everything out but especially in the lower throttle...Either that or try a 35 pilot and see if that will give me the correct reaction from fuel screw...or go with  40 pilot and a bigger pilot air?  I come up with these ideas (thinking too much), then I put them in action and I don't get the result I was expecting...i understand what your saying but I'm not sure what to do if Im not getting that reaction...

what would you do...

A) Raise Float to 10mm

b) Larger pilot air jet

c) Smaller pilot fuel jet

d) Run it rich and fuhhhgetta bout it

I can't help but keep tinkering until I get it right, i try to stop and leave it alone but it draws me back in and here i am..

I really appreciate your help and taking the time to respond.

 

I'd set the float to OEM specs.

Set the slow air jet to a 100, realize too, your intake adapter may be screwing things up. That looks to have very deep passages. The longer a passage, the more difficulty air has to get through.. The smallest pilot anyone has needed (and that was because of a junk alloy fuel screw) was a 38. If anyone actually rightfully needs a 38, I'd change the slow air jet to a larger one. If fuel passages get too small, they tend to clog sooner.

Set the fuel screw to 1,5 turns. If the bike needs the choke to start and starts hot fine, call it a day.

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Sasha Rudolfski

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The intake bell was from the TT store kit...I have a spare E air intake boot and spare E airbox not in use...maybe I should look at getting a different bell mouth adapter like the E adapter or another bell mouth adapter, any suggestions...any suggestions?

 

I took my carb out and cleaned it with compressed air and come carb cleaner solvent...38 pilot still didn't respond to fuel screw after cleaning...Im convinced I must have a leak somewhere thats causing these problems.  The exhaust is sounding off again, like a Goped scooter not crisp or smooth like before...last time it did this the exhaust valve was tightening up and out of spec and has since been adjusted but I gotta check that again to see if it moved again.  Also there was a leaking connection mid pipe to muffler connection that I sealed with rtv and exhaust tape...not sure what is going on now but I hope it is just an exhaust leak and a jetting issue because the bike is running like complete garbage all of the sudden...

It is that the idle slows all of the sudden in lowers RPMS and it just stalls out if I don't keep the rpms up.  Or all the sudden the bike is idling and it starts surging like 2-3k rpm while stopped... All of the sudden this started happening, seems like a leak somewhere just hope its not in the engine...

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Sasha Rudolfski

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1 hour ago, Bermudacat said:

I could be mistaken, but trying to set a gap is the Honda method, which works only on a Honda, where the linkage pushes the AP arm. The gap on all the other FCR's occurs where the rod sits above the diaphragm.

Yea i set it by measuring gap and it's off. Its causing my idle to dip really low if i crack the throttle slightly while stopped.  Should i advance the squirt or delay it? I also checked it visually.  Just missed the slide from what  I can tell.  Neverused to do this before I messedwith it t

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Sasha Rudolfski

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Anyone here find the powerbowl useful for adjusting  AP ? Just wondering if it would suit me as there are many people who have said it is great and others say totally not needed for TT fcr mx..  I really want to put the carb and jetting behind me at this point.  i had my fun tinkering w the jets and no longer want to chase the ultimate jetting. I got some sm forks and triple clamp that are waiting to get installed next and the carb has taken me away from that project

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