Stutter when full throttle in mid range

[packruler]

I searched around but couldn't find anyone with this problem. I recently bought an 08 FZ6 (last week) and everything was running amazingly until today when I went to pass someone. I was in 2nd at about 6-7.5 RPM and when I went full throttle the bike lurched around. I have recreated this many times. The bike wasn't near 200 but had been cruising for an hour. So I got home researched the issue and couldn't find anything, then went out again to see if I could figure out any more info. So I did another full throttle second gear and it reved perfectly. Assuming all was well continued to cruise for a while and checked again and the problem was back. Any ideas.

Edit:
The lurch isn't a slow down and go its like 50% throttle- 0 - 50% - 0 continuously. If I go about 50% it doesn't seem to do it as much if at all

 

[PB4UGO]

Kind of sounds to me like a secondary ignition issue. Maybe a wire or coil opening up under load when they get hot.

 

[ChevyFazer]

Start with the easy stuff 1st, KISS (keep it simple stupid) since you just got the bike what do you know about it? Has it sat for a while? Check you air filter mice like to make nest in the air box, plus if it has sat a while the fuel could be bad and you could have some fuel gumming up. Can you see any rust in the tank? I would also go ahead and put some fuel treatment in it like seafoam

 

[packruler]

When I bought it from the dealer they said the previous owner had it sitting in a shed for 3 years but they changed the fuel pump and put in fresh fuel. I have not let it sit for more than a day since to much fun to ride :BLAA:

 

[ChevyFazer]

Well I'd say that's the cause of the problem, sitting three years, but what all the dealer did is another story. I would probably believe them that it has a new fuel pump but they might not have cleaned the tank in the process, can you open it up and see any signs of rust? I would personally ride the bike back to the dealer and park it on top of the salesman's desk and tell him to get the **** fixed, or you could keep going at it yourself. I'd say its definitely a fuel issue and after sitting 3 yrs it could be the entire system has gummed up in different spots. You could keep running fuel treatment in it and until it clears it all out, it might take only 1 try or 10 just depends on how bad it is.

 

[TownsendsFJR1300]

+1 ^ Big time... And WELCOME!!!!!!!!!!!!!!

Chevron Techtron is a very good cleaner, Seafoam a good cleaner / stabilizer. I suspect the injectors /fuel system are gummed up with varnish starving the engine when under load. If rust isn't involved, the cleaners, with time may/should help quite a bit.

If its lurching that badly, I'd definitly bring it back and have them clean the system with whatever commercial grade cleaners they use, (or replace injectors if needed, etc). The last owner traded it in as it wouldn't run, dealerships don't replace fuel pumps unless they go bad/need replacement and why did it go foul (rusty tank?)

Fuel goes bad in as quick as a month. A fuel stabilizer is a must unless ridden often. I ride about everyday (pleasure) and use Seafoam on a regular basis(bike runs like a top)..

There have been numerous posts where a bike was left without a FULL TANK, it'll rust big time, especially in humid conditions. Three years is a long time for water /steel to rust.... It gets in the fuel pump and fries it ($400+ fix just for the part)...

 

[FinalImpact]

Edit:
The lurch isn't a slow down and go its like 50% throttle- 0 - 50% - 0 continuously. If I go about 50% it doesn't seem to do it as much if at all

From off idle to 50% throttle the demand on the ignition system is greater than the demand on the fuel system. From that I would be looking at the ignition system first. However there could be an overlap in that bad fuel which is hard to burn could play a role from off idle to 50% throttle.

If you like to tinker and you're up for that (vs taking it back), I'd pull the plugs and check the plug wires for being poperly seated into the caps. I went looking for an ignition problem and found all 4 wires to be loose in the caps. One had to be cut back and before it snugged up like the others (hint the wires screw into the caps).

http://www.600riders.com/forum/gara...d-your-kit-when-doing-spark-plug-changes.html

If it doesn't have fresh gas in it, pump it into your auto and run that out. Put some fresh in there from a trusted source and some Techron as Scott mentioned.

 

[packruler]

I rode today with no issue so I think it was just a bit of bad fuel but I'm going to take it to dealer tomorrow to get the title anyway so I'm just going to have them check on it.