Bucking?

[kevdog3019]

My buddy has an '02 V11 Lemans that he got last year. One issue it initially had was stalling occasionally upon stopping. He went through the bike this Winter and did a TPS check and found it was up at 350. He set it at 150 and overall the bike runs better. However, now it stumbles (Bucks) around 3000-4000 RPM, but runs smooth and hard above that. It also doesn't do it when cold.

Yesterday we thought we'd experiment a little and take a TPS off my '03 Lemans which runs perfectly. We hooked up the wires and got nothing. We used two different volt meters and nothing coming off mine. He went home and tried his again and no problem getting a reading. What's up with that? Also...why would his be bucking after warm-up but running so smooth above 4000 RPM? He changed the intake boots, so they're new and snug. He changed to a K & N filter, but did take off the intake tubes to the filter box to breathe better. No apparent exhaust leaks. The original owner took off the breather tube to the carbs (I think that's what it's called?), but he has since reconnected a tube from one to the other, however, it's a little smaller than it should be. Would this make a difference? Now...his CPU is different than mine also. It says 2000 V11 sport and mine says 2002 V11 lemans and has different numbers. This shouldn't make a difference unless someone knows if there's an issue with this CPU.? We are just plain stumped and wanting to get this bike running smoothly throughout the rev range. It has very few miles on it and really does run smoothly for the most part.

 

-Kev

[stucatz]

Now I don't claim to be an expert on the V11 but something similar happened to me last year and it was entirely my fault.

 

I had removed the tank and when I put it back I somehow managed to "kink" the fuel hose in such a way that the pump was starving of fuel.

 

Check the hose could be as simple as that.

[BRENTTODD]

My 2000 does the exact same thing but not all the time just every now and then it will hickup. if you get it figured out post the fix. Mine does it around 3000 if you are lugging the motor and tends to be more predicable the hotter it is outside.

 

Good luck wish i could help

Brent

[Steve G.]

Loosen up the tappet clearance to Eropean specs, and put the TPS back to where it was before.

Steve

[kevdog3019]

Why is my TPS not registering anything...and it runs great. No hesitation ever anywhere!

-Kev

[gstallons]

Can you define "not registering anything" ? Are you using a DVM to check tps voltage?

[Ouiji Veck]

Brentt.....

I think your TBs are out of sync. Mine was doing the exact thing. Hiccuping

around 3.5K at flat throttle. It also popped and barked loud on deceleration from higher Rs

(Does yours do this too?)

 

At risk of derision I'll again post my cure.

I simply ran the bike @ the offending RPM range, reached down and twisted the spigot

(white knob that connects the throttle plates) in tiny micro turns one way then the other

until the offensive hiccup was gone. It took about 10 - 15 minutes of fiddling..

running in 3rd gear(2nd? maybe...whatever is safe) on a secluded road.

Once I got going in the right direction there was noticeable improvement

and it was obvious when I got "there". I made about 6 or seven 1/32nd turns in the

wrong direction. Got off and zeroed back to my starting mark and tried the other direction. It was soon obvious I was on to something.

 

Disclaimer.....

No halfway decent mechanic would use this method. I think there would be

a possibility of back firing and bending a throttle plate or at least blowing a boot off.

I'm more like Goober from Mayberry. Maybe I just got lucky but my bike runs flawlessly through all RPMs and I get about 40+mpg. (In the summer ) for the last 30Kmi.

If you are a reckless idiot Goober like me and decide to try it, keep in mind ..

tiny turns, mark your starting point. It should be clear if it's improving after 4 or 5 turns.

I accept no responsibility if you blow it up, but will happily accept accolades if it works.

This may be some truly diz-astous advice but it's what I did and it worked for me.

I've read many a post about putting a V11 on a Dyno and squeezing out the n'th degree

of HP only to still have an annoying stumble @ mid 3K. What's up wit dat?

Oh yea... Euro Specs on the valves first...the only way to fly...it's the single

best thing you can do to get a Guzzi to run happy.

 

Now to suffer the slings and arrows........

[BrianG]

Loosen up the tappet clearance to Eropean specs, and put the TPS back to where it was before.

Steve

 

+1

Mine was doing this same thing and I wasted a whole day messing with the Fi system, thinking it had to be that. Nothing made much difference.

 

I then thought to check the tappet clearance. It was way too tight, so I se it to Euro Specs and the reset the FI specs....

 

NO MORE BUCKING!

 

THEN I read the instructions..... "Set valve clearance before setting FI ....."