DRZ MRD/SSW jetted carb issues

I picked up a 2009 DRZ 400 SM and it has one or two carb issues I need some help solving. It has MRD/ssw with 3x3 and jetted (not sure which kit, pilot jet is 25 though).

 

issues:

 

1) The power is too on/off when cracking the throttle and when decelerating from higher revs there is plenty of popping.

 

2) The bike stutters at higher rpm under load with 1/2 throttle but runs smooth at low RPM or with full throttle

 

After doing a bunch of reading I was pretty sure I had a gummed up pilot jet. I was also told on another thread to just clean my carb so I took the plunge and did it. To my surprise my pilot looked clean. I was also weary of doing too much to the carb so all I did was clean out the pilot jet with carb cleaner and then soak it in seafoam for 5 minutes. I also cleaned off the needle with the same method.

 

I was worried about what I can / can't spray with carb cleaner (I used generic Gunk Carb Cleaner) so I opted on just those brass parts. What else is safe to use it on? What else should I have cleaned and with what method?

 

The needle clip was on the 3rd position. I tried to lower the needle clip one notch but there is a white spacer on it that didn't want to move. How is that spacer moved properly?

 

I'm also not 100% sure on the order of parts in on the needle, I think it's:

 - washer

 - spacer

 - clip

 - washer

can anyone confirm?

 

My fuel screw was smaller than I was expecting too, not even protruding from the housing. I didn't muck with it though.

 

I put everything back together and the bike runs pretty much exactly as it did before.

 

Any help is appreciated.

 

Oh yeah, in videos I've seen a 4th hose attached to the bottom of the carb but mine did have that. All it has is the fuel line, vacuum line and overflow hose.

drz-carb.jpg

drz-pilotjet.jpg

drz-needle.jpg

Edited by Slappysan

For the needle proper order from top (blunt end) to bottom (pointy end) is:

 

-Thin Washer

-Clip

-White Spacer

-Thick Washer

 

Does the needle have a color on the top (blunt end) of it? Either red or blue? If it does, it is the JD jet kit, if not it is most likely the DJ jet kit (which could be either stage 1 or stage 2)

 

Also it looks like you still have the plug that keeps the fuel screw captive. Here is where the fuel screw is kept prisoner:

100326MikuniBRS36BottomJets_.jpg

 

If it is the JD jet kit, here is the jetting you will want.

Main Jet:   155 (corked pipe)   160 (open pipe)

Needle:      Blue on clip 4 

Pilot Jet:    22.5 (Extended Fuel Screw)   25 (Stock Fuel Screw)

 

As for removing the spacer you just have to get a good grip on it and push/pull it off, it is kind of a PITA.

Edited by Wisconsinite762

The needle had a small blue mark on top.

 

I was pretty sure that the fuel screw was a hex key even though it looks round in the photo.

 

My MRD/ssw has the quiet insert in it, is that what you mean by "coked pipe"?

 

Also the tube my carb is missing can be seen at 12:29 in this video:

http://www.youtube.com/watch?v=4_aZpjFnkLg&t=12m29s

Edited by Slappysan

The needle had a small blue mark on top.

 

I was pretty sure that the fuel screw was a hex key even though it looks round in the photo.

 

My MRD/ssw has the quiet insert in it, is that what you mean by "coked pipe"?

 

Also the tube my carb is missing can be seen at 12:29 in this video:

 

Cool, so that means it is a JD needle.

 

The fuel screw is under that little brass cap, in the photo I posted the cap has been removed but you can see where it is located. Do a search to find out how to remove it, mine was already removed when I got it.

 

 

Sorry I meant 'corked' not 'coked', and and having the quiet insert installed means it is corked.

 

I think that tube has to do with emissions or something like that, smog canister maybe, I am not sure. I'm sure someone else will know what it is for.

So I need to:

- move my needle down 1 notch

- check my main jet size

- check my fuel screw

 

Could that help with the popping during deceleration and the on/off problems though? Seems like it will only deal with the stutter in higher RPMs.

So I need to:

- move my needle down 1 notch

- check my main jet size

- check my fuel screw

 

Could that help with the popping during deceleration and the on/off problems though? Seems like it will only deal with the stutter in higher RPMs.

 

Fuel screw will help with the popping on decel, with a 25 pilot jet and the stock fuel screw 2.75 turns out should be very close to what it needs, so set it there and then fine tune it using this procedure http://www.thumpertalk.com/topic/271735-how-to-confirm-your-pilot-circuit-setting/#!JgM0g

 

The needle position should help with on/off problems.

 

Remember that the fuel screw and pilot jet will only affect idle and small throttle openings (less than 1/4), then the needle affects mid throttle, and the main jet affects 3/4 to WOT.

Is it better or worse with airbox door removed..?

It's been too wet to ride it without the airbox door on past few days but I'll check.

I tried it with the air box cover off and while the bike didn't stutter as much there was way less power.

I tried it with the air box cover off and while the bike didn't stutter as much there was way less power.

 

Less power at mid throttle or wide open throttle..?

Mid throttle, I didn't test WOT.

Mid throttle, I didn't test WOT.

 

Indicators thus far are pointing to a correct or lean condition....

Next .....Replace the air box door , partially tape the 3x3 hole by 1/3, leaving 2/3 open....then ride it under similar conditions .....Better or worse...??

Hard to say how much I tapped off, between 1/3 and 1/2.

 

It runs much smoother with the hole partially taped, and has good power. Still a tiny bit of hesitation mid throttle though.

 

photo 1.JPG

photo 2.JPG

Hard to say how much I tapped off, between 1/3 and 1/2.

 

It runs much smoother with the hole partially taped, and has good power. Still a tiny bit of hesitation mid throttle though.

 

Ok, so we can reasonably assume the needle setting is lean.....If your on clip 3 go to clip 4.....

If you don't have any blue or red colouring on the needle, you have a dynojet jet kit or generic equivalent.....and judging by the info we have , it's most likely the stage 1 kit...

clip 4 should sort it out.....the st 1 kit is designed to be used with stock air box opening , but can be adapted to be used with 3x3 mod...

The main jet size will need to be around 142.5 for the stage one needle...

Check mj size ..and report back....

Edited by Craigo 485sm

Finally got around to pulling the carb again.

 

Moved the needle clip from 3 to 4 and cleaned out the main jet.

 

The main jet is a 160 as I think the previous owner ran it without the insert when he first had it but now I need the quiet insert for sure, so should I go down to a 155 main jet or can 160 work corked?

 

The bike is running much better, smoother on/off, throatier sounding and smoother power. I still get popping on deceleration if I slam the throttle off but it doesn't pop if I slowly turn off the throttle.

 

I took the fuel screw plug out and it checked it and it was near 2.75 already, I reset it to 2.75 but didn't adjust it after that because I'm not sure how I'm going to adjust it with the carb in the bike.

 

There is still a small amount of stuttering though at about 70% throttle in upper RPMs, not sure what to do about that.

photo (1).JPG

Finally got around to pulling the carb again.

 

Moved the needle clip from 3 to 4 and cleaned out the main jet.

 

The main jet is a 160 as I think the previous owner ran it without the insert when he first had it but now I need the quiet insert for sure, so should I go down to a 155 main jet or can 160 work corked?

 

The bike is running much better, smoother on/off, throatier sounding and smoother power. I still get popping on deceleration if I slam the throttle off but it doesn't pop if I slowly turn off the throttle.

 

I took the fuel screw plug out and it checked it and it was near 2.75 already, I reset it to 2.75 but didn't adjust it after that because I'm not sure how I'm going to adjust it with the carb in the bike.

 

There is still a small amount of stuttering though at about 70% throttle in upper RPMs, not sure what to do about that.

 

Is the stuttering better or worse with the airbox door removed>?

Re install the side cover, Then cover the 3x3 with tape by 30% and test in the same manner, better or worse.?

The bike runs much worse without the air box door.

 

With the 3x3 tapped up it runs a bit better.

 

I'm not sure if it's the rev limiter or a carb issue but when I hit around 90 km/h (56 mph) in 3rd with the throttle wide open it starts to bog out.

Still trying to figure things out, but one thing I do notice is the problem is much worse in cold weather.

You are describing a lean condition, What is the actual size of your intake opening..It looks bigger than 3" x 3"

My opening might be a bit bigger, it's pretty messy so hard to tell the exact dimensions.

 

I tried taping up the entire opening and the bike wouldn't even start, I dialled it back to 50% to get it to go.

 

How would I go about fixing this lean condition? Since the problem is only really during deceleration and 3/4 to WOT that must mean there is something wrong with my main jet then right?

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