Jetting help for 2006 TE 610 LeoVince X3

[MotoSteve]

I need some help with diagnosing and possibly re-jetting my bike.

I have a 2006 TE610 with a LeoVince X3 slip-on, no air-box mods. I live at sea level(coastal CA) and ride primarily from sea level to below 2,000 feet. The previous owner stated the exhaust was installed and jetted at motoexotica in Vacaville (I know they are a knowledgeable dealer and I only include this for atmospheric reference as Vacaville is only 200 feet above sea level).

1) I am experiencing excessive backfire/popping on fully-closed-throttle deceleration. Not just a few pops; the bike backfires rapidly until I give it partial throttle or pull in the clutch and relieve the engine braking.

2) There also seems to be a momentary lag in acceleration when I quickly go to full throttle, then after a moment and a few more rpm the power comes in again and builds as normal. That lag in acceleration is more noticeable now that I have installed a set of SM wheels/street rubber as the back tire is not spinning in the dirt. A local motorcycle mechanic suggested the power lag may be due to the fuel pump not keeping up with the throttle and an O-ring should be placed on the fuel pump to fix this(I’m guessing like a rubber band to help it open faster, but I’m not fully sure what he’s talking about)? I figure I’ll start by sorting the machine gun backfire then see about the flat spot.

Can anyone tell me what jet sizes and position I should be running to eliminate this continuous popping on deceleration?

Thank you in advance.

 

[K7MDL]

There is no fuel pump on the carb bikes. Only on the FI bikes beginning in 2008 in the US. So do not waste time looking for one :-).

You might pull the plastic side cover off the carb and see if you have a rubber O-ring on the pump actuator. Whe you crack the throttle, a stock carb setup will delay hitting the pump actuator and delay the squirt of fuel into the intake. The O-ring mod and adjustment removes all delay.

On the intake manifold there is a vacuum port that should be plugged well. Make sure it is not leaking.

Check your actual jet sizes and idle mixture screw setting, and jet needle clip setting. The LV3 pipe with JD jet kit is used by very many and runs well with the right settings. I put an aftermarket mixture screw in with the numbers for easy adjustment on the bike.

Also be sure your exhaust outlet clamp is not loose or leaking.

There is the 610 jetting thread on ADV and also see the Cafe Husky forum section on EFI/Carb

 

[MotoSteve]

Thank you for this! Great info. I noticed on the back of the airbox there is an opening that looks like a hose once went to it. It let's dirty, unfiltered air right into the intake. It doesn't look right. It think that's what you were referring to? I'll try plugging that and then check the rest of the items mentioned. Many thanks!

There is no fuel pump on the carb bikes. Only on the FI bikes beginning in 2008 in the US. So do not waste time looking for one :-).

You might pull the plastic side cover off the carb and see if you have a rubber O-ring on the pump actuator. Whe you crack the throttle, a stock carb setup will delay hitting the pump actuator and delay the squirt of fuel into the intake. The O-ring mod and adjustment removes all delay.

On the intake manifold there is a vacuum port that should be plugged well. Make sure it is not leaking.

Check your actual jet sizes and idle mixture screw setting, and jet needle clip setting. The LV3 pipe with JD jet kit is used by very many and runs well with the right settings. I put an aftermarket mixture screw in with the numbers for easy adjustment on the bike.

Also be sure your exhaust outlet clamp is not loose or leaking.

There is the 610 jetting thread on ADV and also see the Cafe Husky forum section on EFI/Carb

 

[MotoXotica]

i would say just get the jd jet kit and you should be good.with that kit i would say the 48 p jet is right for this time of year.dan

 

[rajobigguy]

The 610 is a little finicky about jetting but after a few trys I got mine dialed in pretty well from sea level up to about 4800' . This set up works real well in most situations and has a minimal amount of decel popping. I have also found it helpful to run the sparky with the LV can.


main jet--------178 If you modify the airbox cover and aren't running the sparky you might try a 180
pilot jet-------- 45
starting jet---- 85
main air---------200
low air ----------100
needle----------JD red Or a OBDVR Keihein they are virtually the same thing.
position--------- 4 from top
mixture screw ---- 1.5 out Mixture screw is a Zyp Tye Racing type with extended reach.

I don't remember the sz. of the leak jet that I installed, I believe it was a number 60.

I am using the heavy O-Ring on the accelerator pump. Once you pull the tank and air cleaner watch the linkage for the accelerator pump while turning the throttle and you'll see where it needs to go, it basically ties the two levers together so that you don't have to get to the half throttle position before the AP begins to work. Merge Racing makes a heavy spring that does the same thing and is a bit cleaner looking than ties the two together with a rubber band.

 

[MotoXotica]

there could also be some debris clogging up the pilot jet.or if the bike sat a few months build up in that jet will occur and the bike will run lean and pop on decel badly.plus it has been pretty cold lately to make matters worse.manifold could leak as well from cracks.dan

 

[rajobigguy]

Thank you for this! Great info. I noticed on the back of the airbox there is an opening that looks like a hose once went to it. It let's dirty, unfiltered air right into the intake. It doesn't look right. It think that's what you were referring to? I'll try plugging that and then check the rest of the items mentioned. Many thanks!

That in the back of the airbox should be you're engine breather and there needs to be a hose that goes there. The hose may go directly from the engine to the airbox or may go from the engine to the frame and then to the airbox but it needs to be there. Misssing that hose can also have an effect on how the engine runs because you are drawing light hydrocarbons off of the crankcase, it needs to be there. There is even a possibility that having the hose there acts like a crankcase ventilator and reduces windage in the crankcase, It needs to be there.
In short that hose plays a big role in keeping you're bike alive and running well, did I mention how important it is for it to be there?

 

[MotoSteve]

Ok, I see where a tube exits the posterior crankcase and vents into the frame. I'll have to find where the missing tube exited the frame and went to the back of the airbox. I guess it's just venting to the atmosphere right now without the vacume of once being attached to the airbox.

That in the back of the airbox should be you're engine breather and there needs to be a hose that goes there. The hose may go directly from the engine to the airbox or may go from the engine to the frame and then to the airbox but it needs to be there. Misssing that hose can also have an effect on how the engine runs because you are drawing light hydrocarbons off of the crankcase, it needs to be there. There is even a possibility that having the hose there acts like a crankcase ventilator and reduces windage in the crankcase, It needs to be there.
In short that hose plays a big role in keeping you're bike alive and running well, did I mention how important it is for it to be there?

 

[MotoSteve]

thank you dan.

there could also be some debris clogging up the pilot jet.or if the bike sat a few months build up in that jet will occur and the bike will run lean and pop on decel badly.plus it has been pretty cold lately to make matters worse.manifold could leak as well from cracks.dan

 

[CrankN]

You might pull the plastic side cover off the carb and see if you have a rubber O-ring on the pump actuator. Whe you crack the throttle, a stock carb setup will delay hitting the pump actuator and delay the squirt of fuel into the intake. The O-ring mod and adjustment removes all delay.

Just pulled my carb apart and realised it has stock jets. Am going to try a #178 main, #45 pilot and #60 leak jet as per Rajo (and plenty of others) advice.

Where do I get this O-ring from? Haven't found a thread on this although the above sound like something i'd like to try.