Backfiring XRL

[rawsonboy]

I have had problems with my XRL backfiring and popping on the over-run since I bought it. I finally got round to fitting a new pilot today and the bugger still backfires

Details:

Fitted dyna jet kit - I don't have details of the sizes in front of me but it was basically a new needle, new spring, new main jet. No pilot though.

I just fitted a 55 pilot up from a 50. Didn't seem to make much of a difference to be honest. It might have made a little difference but that might just be me wanting it to be better.

Air filter is a foam after-market which I just cleaned and oiled.

Exhaust is after-market.

Mixture screw is 2 1/2 turns out.

Aside from the popping, bike runs fine. Pulls pretty good from idle and it will run at 65 all day long.

As it's popping and farting, if I just put the choke on a little, it goes away so clearly the mixture is off - either too much air or not enough fuel.

HELP

At this point, I don't know what to do - I really thought the new pilot would fix it but it really didn't seem to do a thing so I'm not sure going up even higher will help.

What should I try next ?

How far out can you go with the mixture screw before going to a bigger pilot ? Will a bigger pilot make that much of a difference (50 to 55 realliy didn't appear to do much). My side panel (air box side) is not a great fit so I'm wondering if the bad seal there is allowing too much air in ? Clutching at straws I know....

__________________

[martinfan30]

I wouldn't go more than 3 1/4 turns out. I'd say you need a 58 pilot.

[rawsonboy]

I wouldn't go more than 3 1/4 turns out. I'd say you need a 58 pilot.

Thanks. I actually ordered a 58 when I got the 55 so I might try that - I will try 3 turns out and then 3 1/4 as a max and see if that does anything.

[martinfan30]

Read this too.

https://www.thumpertalk.com/forum/showthread.php?t=327405

[DT1]

Mine did the same thing. You need to richen up on the main jet and raise the jet needle.

[rawsonboy]

Mine did the same thing. You need to richen up on the main jet and raise the jet needle.

Well, I'm no expert but as it was explained to me, the main jet and needle have no bearing on the carb when the throttle is closed - which is when I get the backfiring. With no throttle, the only thing that comes into play in the carb is the mixture screw and the pilot jet.

I will say I am no expert though....

[martinfan30]

Well, I'm no expert but as it was explained to me, the main jet and needle have no bearing on the carb when the throttle is closed - which is when I get the backfiring. With no throttle, the only thing that comes into play in the carb is the mixture screw and the pilot jet.

I will say I am no expert though....

You are correct, but don't just address the low speed circuit with out fattening up the high speed circuit for a complete package.

[rawsonboy]

You are correct, but don't just address the low speed circuit with out fattening up the high speed circuit for a complete package.

Understood

Right not though, the issue is the low speed circuit and as and when I figure that out, I'll work on the high speed circuit if I have to - does that sound like a good approach ?

Right now it pulls fine - the only real issue is the backfiring (which is substantial).

[martinfan30]

Understood

Right not though, the issue is the low speed circuit and as and when I figure that out, I'll work on the high speed circuit if I have to - does that sound like a good approach ?

Right now it pulls fine - the only real issue is the backfiring (which is substantial).

I just read the OP and remembered you did a DJET kit. So you are good on top. Just get the 58 pilot and see what she does.

Don't forget to follow the instructions on confirming your pilot setting in that link I provided.

[XR650L_Dave]

The DJ kit may leave you a little lean if you are getting 10% ethanol in the gas.

Dave

[rawsonboy]

I just read the OP and remembered you did a DJET kit. So you are good on top. Just get the 58 pilot and see what she does.

Don't forget to follow the instructions on confirming your pilot setting in that link I provided.

Thanks, will do. I actually have the 58 so I will fit that and see how she is.

One thing's for sure....I am getting good at getting that carb off and back on again

[DT1]

Well, I'm no expert but as it was explained to me, the main jet and needle have no bearing on the carb when the throttle is closed - which is when I get the backfiring. With no throttle, the only thing that comes into play in the carb is the mixture screw and the pilot jet.

I will say I am no expert though....

Ok, let me rephrase that. You mention Popping and backfiring. Popping is usually caused by a lean condition. Mine popped unless I slightly pulled the choke lever in. Backfiring is usually a timing issue. So I guess I have to ask you...Is it backfiring, popping, or both?

[martinfan30]

I'm sure he is experiencing the typical lean L pig condition. Timing issues (backfiring) is a rare issue without serious drive ability problems.

Just rejet fatter and do Dave's mods.

Although you do bring up a good point DT1.

How many miles and what year on this pig?

[rawsonboy]

I'm sure he is experiencing the typical lean L pig condition. Timing issues (backfiring) is a rare issue without serious drive ability problems.

Just rejet fatter and do Dave's mods.

Although you do bring up a good point DT1.

How many miles and what year on this pig?

Good point, my bad. It's popping - it's not backfiring. What can I say, I'm English, common language and all that....

It's a 99 and it's done about 23K. As I said, aside from the popping on the over-run, it's runs great. Starts first time (hot or cold) and runs like a champ.

I'll re-jet tomorrow and see how it is.