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Discussion Starter #1
I bought a new 2016 KLR 650 two months ago. I didn't like the sound so installed Two Bros SR1 exhaust, UNI air filter, KLX needle and jet kit and snorkel removed, AIS system removed.
After lot of testing I have this setup: 145 main and clip on 3rd slot with screw 1.75 turns out. Anything less was way too lean!
It was running good especially i had issues with 1/2 to full throttle (i changed from 142 main to 145 and it worked better ..not sure if i need to go up more).

Yesterday I removed the air box door to see if I need to do L mod. Didn't notice much difference but sound was little better. But after a day of riding it sounds horrible from 1/4- WOT and sometimes it stall the moment i push throttle . Now I don't know if something is wrong with air filter because i ran it with door open or if I burnt glass wool in the exhaust (because i was running it too lean even when i was trying out jettings) and need to repack it? How do I know what exactly is wrong with it?
 

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Those settings, in general, should be good. Slightly rich. perhaps.

Can you describe how you determined that it was too lean at the normal setting of a 142 and the second clip?

Proper setting of the idle mixture screw varies from bike to bike. 1 3/4 turns out is a good starting place, but fiddling needs to be done to get it right. Usually this is done by turning the screw out until the RPM peaks, then bringing it out just a bit further. By doing this what you should have found is the slightly lean spot where RPM is the highest. It will probably stumble a bit when hitting the throttle, so turning it out a bit more richens it up so that it is correct for idle to about 1/4 throttle. You want to play with this to find the spot that has the highest RPM, yet doesn't stumble when the throttle is opened. You may have to go back and forth with the idle mixture an the idle speed screws until you find the happy spot.

But again, what lead you to believe that it was lean at the recommended settings?

Tom
 
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Discussion Starter #3 (Edited)
Those settings, in general, should be good. Slightly rich. perhaps.

Can you describe how you determined that it was too lean at the normal setting of a 142 and the second clip?

Proper setting of the idle mixture screw varies from bike to bike. 1 3/4 turns out is a good starting place, but fiddling needs to be done to get it right. Usually this is done by turning the screw out until the RPM peaks, then bringing it out just a bit further. By doing this what you should have found is the slightly lean spot where RPM is the highest. It will probably stumble a bit when hitting the throttle, so turning it out a bit more richens it up so that it is correct for idle to about 1/4 throttle. You want to play with this to find the spot that has the highest RPM, yet doesn't stumble when the throttle is opened. You may have to go back and forth with the idle mixture an the idle speed screws until you find the happy spot.

But again, what lead you to believe that it was lean at the recommended settings?

Tom
Tom, first of all thanks for your detailed reply!

Two Bros pipe is wide open compare to other exhausts. So I started with the KLX recommended settings first. clip on second slot, 142 main and two turns out. With this setup pickup was not good and lot of decel pooping. So I turned the fuel mix screw out to 2.5 turns and felt little better pickup and popping was almost gone but still not great so turned it out to 3 turns.
At 3 turns out, No popping and pickup was much better and I liked it. But from mid-range throttle position to wide open throttle bike was struggling. Pushing it beyond 60 mph didn't feel good throttle didn't feel smooth at all compared to stock bike with stock pipe. So I tried clip on 3rd slot and notice noticeable difference in mid-range but still it didn't like it when i push it beyond 70 mph lot of vibration and throttle felt heavy. So I changed main to 145 and and it was all good.
But I wasn't sure how to set the fuel screw perfectly and find sweet spot. I tried this trick: increase the idle speed to 3000 and then turn fuel screw in until engine stumbles and then move out until rpm stop rising then stop and turn it 1/4 out and set the idle screw. I noticed when fuel screw was completely closed (all the way in) bike was still running it was surprising because it should die! also when i turn out the fuel screw it dint raise rpm like after 1.5 turns so set it to 1.75 and it felt better at that settings.

So 145 main, KLX needle with clip on 3rd slot and air screw 1.75 turns out was my final setting and it running good even though i dint test ride it beyond 80 mph .

Two days ago I wanted to see if my settings are rich enough and if I need to do L mod. So to verify i opened air box window and rode for a day....didn't feel much difference but sound was better (deeper and throaty) but next day I notice something happened from 1/4 throttle position to wide open, exhaust sounds horrible ..don't know how to explain but sounds like phrrr phhrr and (no thump! ) and also decel popping!

So closed the air box door but still exhaust sound is same and little decel popping. Fuel screw is 2.5 turns out but it some(very little) decel popping is still there !
It runs good but i can feel it that something is not good but cant figure out what.
Dont know what i did by opening air box door or if its something else?!

Thanks
G
 

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OK, that's good info that folks can use to help you.

I can't diagnose the problem over the internet, but I can share some stuff that might help your thinking

My bike is set up with a ported head with big valves and I'm running a GSXR750 pipe. That's a pretty wide-open pipe that probably flows similarly to yours.

What I have found is that the generally accepted KLX settings of a 142 main with the needle at the second position gives me a good AFR in the mid 13s range. I could go back and check, but I recall that it was about 13.5:1. I tune with an LM-2 wide-band analyzer. I have the L-Mod done and the snorkel is out.

I did find that I needed to go to a #42 pilot jet. The idle circuit affects running from closed throttle to about 1/4 throttle. I found the additional flow in the exhaust needed a larger pilot to beat the lean pop into submission and give the idle circuit enough adjustment to provide a proper AFR out to 1/4 throttle.

My first thought, since you've gone to a 145 and the third position on the needle, is that you're running too rich. That can be the cause of a 'heavy' throttle feel. The 'snorkel-out, 142, 2nd position, L-mod' set up has worked for me and for many others for a long time. I have run it with stock displacement and with a 685, with stock exhaust, SuperCrapp, and the Gixxer pipe, stock head and modded head. As long as your intake and exhaust flows are balanced (which they really need to be!) it just works. More flow through head and exhaust, as a balanced system will do, simply draws more air, and the tried and true KLX settings manage the AFR. With different engine configurations the AFR changes somewhat, but it always seemed to work and provides a slightly rich AFR which is what you want for good all-around general purpose performance.

Taking the door off should not have upset anything, so don't discard the possibility that something may have happened, coincidentally, in the carb.

I just finished increasing my displacement to 678 with a Wössner high compression piston. Even with the added displacement and the increased compression, I don't expect the tuning to have changed, but I'm going to go through the tuning process anyway.

To do that, I'm going to start with a newly cleaned air filter in place and I'm going to disassemble and clean the carb. I want to start by knowing I have no issues with either.

I'll start at ground zero and reset the idle mixture and then start playing with the needle position. Of course, I will have the advantage of using the analyzer, but the idea is the same. Start from ground zero with a known good filter and clean carb, then go back through the tuning process.

I would suggest that you make sure your filter is newly cleaned and properly oiled, and that you pull the bottom off the carb and clean the main and the emulsifier tube (watch out for the silver needle jet falling out) and blow the passages, at the very least. Do the L-mod (you've increased the potential for exhaust flow; you need to balance that with an increase in potential on the intake side. If you do it by drilling four 1" holes and don't like it, you can use 1" plugs to reverse it.) Then install a #42 pilot (good source is the Harley store), put a clean 142 in, and start over with the needle set at the second position. Reset the idle mixture and see how it goes.

It can be frustrating to have to go back to zero, but it usually works better than trying to work form the middle of a situation and trying to find the solution.

Let us know how it goes; it's how we all learn from others.

Tom
 

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Discussion Starter #5
Great Info Tom!

I did start with ground zero and basic setup suggested for KLX. 142 Main, KLX needle on second clip and screw two turns out. But as I mentioned lot popping and not that great pickup made me jump to clip at 3rd and 145 main. But yes I never tried upgrading pilot jet and you have a good point when you say with wide open pipes it needs richer pilot system.

So you are suggesting:
142 main
clip on 2nd slot
Upgrade Pilot to #42
L Mod

I'm going to try this new setup this weekend
 

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Yes, and let us know how it works.

Also, since your bike is new, check the torque on the exhaust manifold nuts. They should be at 15 ft-lbs. It would be silly to be chasing a pop that was caused by a leaking exhaust gasket ;^)...

Tom
 
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Discussion Starter #8 (Edited)
Yes, and let us know how it works.

Also, since your bike is new, check the torque on the exhaust manifold nuts. They should be at 15 ft-lbs. It would be silly to be chasing a pop that was caused by a leaking exhaust gasket ;^)...

Tom
Upgrading to Pilot #42 may resolve popping issues but when i go back to clip on second and 142 main I'm afraid my '1/4th to wide open throttle' response will go down. Thats what happened when I was trying with 142 and clip on second slot in the beginning!
 

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Discussion Starter #9
Also, replying to question you asked me in the beginning "what lead you to believe that it was lean at the recommended settings?"

pipe was turning blue slowly and I suspect its running lean!
 

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Also, any good suggestion/tips on how to reset the idle mixture?

Thanks,
G
Pretty much the procedure I outlined in my first post. That usually will get is set pretty well.

Tom
 

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Discussion Starter #12
Yes, they are tight enough. Its not just the popping second issue is bike response between 1/4 to wide open throttle position
 

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Well, now you have two expert opinions that basically say the same thing (here and the "other" site). Your jetting isn't the problem; it's something else. IMO you are too rich and the fact that the pipe is more "open" than some others is irrelevant. My FMF Q4 is also wide open. The exhaust isn't the biggest restriction on these bikes.

My KLR's:

- KLX needle, 142 main on second clip with no washer, 2 turns on the fuel screw
- snorkle-ectomy and 4 - 1" holes in top of airbox
- uni filter
- FMF Q4 on one, LeoVince X3 on the other

bikes run perfectly.


I'd start with the carb and expecially the diaphram. Check the exhaust for leaks; just because the acorn nuts are tight doesn't mean the gasket is in good shape and seated.


2 cents,
Dave
 

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Discussion Starter #14
Well, now you have two expert opinions that basically say the same thing (here and the "other" site). Your jetting isn't the problem; it's something else. IMO you are too rich and the fact that the pipe is more "open" than some others is irrelevant. My FMF Q4 is also wide open. The exhaust isn't the biggest restriction on these bikes.

My KLR's:

- KLX needle, 142 main on second clip with no washer, 2 turns on the fuel screw
- snorkle-ectomy and 4 - 1" holes in top of airbox
- uni filter
- FMF Q4 on one, LeoVince X3 on the other

bikes run perfectly.


I'd start with the carb and expecially the diaphram. Check the exhaust for leaks; just because the acorn nuts are tight doesn't mean the gasket is in good shape and seated.


2 cents,
Dave
Yes, one school of thought says I should use 42 pilot jet and other says I don't need to change pilot jet. I ordered a new gasket anyways so will put it back
 

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Yes, one school of thought says I should use 42 pilot jet and other says I don't need to change pilot jet. I ordered a new gasket anyways so will put it back
I said "basically the same" ;-) From your description, I don't think it's your pilot jet but it shouldn't hurt. Both experts have said that the 142/KLX needle/2 clip position should be spot on for your bike and that your silencer choice doesn't matter. Try the jetting tom recommended but I bet you have another problem.

Good luck.

Dave
 

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I bought a new 2016 KLR 650 two months ago. I didn't like the sound so installed Two Bros SR1 exhaust, UNI air filter, KLX needle and jet kit and snorkel removed, AIS system removed.

(lonsomecrow,
Did you cap the AIS port by the spark plug? And if yes, could your cap possibly be Leaking Air?)



How do I know what exactly is wrong with it?
Trial and error is most common way to learn the 'what'.
We have all been there before ya'.
 

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Discussion Starter #18
Trial and error is most common way to learn the 'what'.
We have all been there before ya'.
Good to know that...I was almost frustrated with removing tank and messing with carb setting infinitely. I'll just do this final standard klx setup with L mod and look for any other issues that might be causing this
 

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Check for air leak at the AIS block off port next to the spark plug.
 
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