XT660X Engine bogs on quick throttle
 

Hi guys.

I have a problem with my XT bogging when I apply full throttle quickly, Like from cruising to hard acceleration. It's like it skips the first couple of beats.
It's really awkward to brace for acceleration and then being hit with a short deceleration instead.

This problem first appeared (I think) when i fitted new open cans late last year. I figured it was a fueling problem (running lean), so I've just fitted Kev's fuel mod. At the same time I've fitted DNA Stage 1 and Stage 2 filters. I've been messing around with the fuel mod and right now I'm at a little over 6 o'clock.

Do you have any ideas about what I can do to remedy this problem?

Should I install the DB killers in my cans? (Really dig the sound without them)

BTW it's a 2005 XTX.

Thanks in advance

Sounds like fairly typical surging issues?

Have a read of this thread. I think you'll find it useful.

No it wasn't surging, at least not as i understand the surging problem, which is the difficulty of maintaining level rpm when cruising at low speed. This was when I accelerated hard, it would bog the enigne, as in no ignition for maybe 4 or 5 revolutions.

Anyway I seem to have fixed. I just had to go a lot higher on the fuel mod than I thought initially. It was sitting at around 6 o'clock, and now it's cranked up to around 9 o'clock. ECU thinks it's about 27� Celsius colder than it really is ;)

Hey! Only one question for you ...... How are your spark plug ....? New / old ...? The coating on it at a good mixture should look at the hazelnut (n�tbrunt) way ... (and check the gap on it)

Drive safe!

//Jtr71.

It's all interrelated. Surging is a very broad term used for hesitancy, jerkiness and poor pick up off a closed or constant throttle. Most of the components in the thread I linked to will have an effect on the behaviour you describe - TPS, CO, ECU type etc. I'd be checking the TPS (particularly based on what you describe) for both smooth tracking and the correct resistance, setting and voltage.

It may be that, by turning the fuelling mod up, you are just masking the issue, or compensating for a problem elsewhere? I don't know of anyone having to run their fuelling mod at 9 o'clock with a stage 1/2 setup (unless the ambient temperatures were well below zero).

Good call on the spark plug JTR. Always worth checking. Plus, watch out for fake NGK iridium plugs on ebay which breakdown under load. Pre 2007 XTs are harder on plugs than later models as they fire twice as often and do twice the work.

Is your fuel fresh and from a reputable supplier?

I've just checked my TPS sensor and it is indeed one of the faulty ones (starts with 31 on the serial number). How would I go about checking for "smooth tracking and the correct resistance, setting and voltage"?

And do you think it's still possible to get it replaced under the recall from Yamaha?

And thanks for taking the time to answer these questions, it's really appreciated! :notworthy:

Edit: Oh and BTW I don't have a plug wrench, but I will acquire one so I can have a look on my sparkplugs.

Edit2: And yeah the fuel is fresh and from a big gas station chain.

To check TPS throttle angle you need to enter the diagnostic mode:

• Make sure kill switch is set to RUN.
• Hold SELECT and RESET buttons down whilst turning on the ignition.
• Keep holding the buttons down for at least 8 seconds.
• The dash will clear leaving just “dIAG” in the display.
• Let go of the buttons.
• The SELECT button will now toggle the display between “Co” and “dIAG” (leave dIAG selected).
• Press and hold SELECT and RESET to confirm “dIAG” selection.
• Set kill switch to OFF.

You can now select the diagnostic code for the TPS which is 01. You do this by using the SELECT button to go up through the codes from 01-70 and the RESET button to go down from 70-01.

In diagnostic mode 01 you can verify the throttle angle. The LCD display will show the TPS angle as you twist the grip. Closed it should be reading 15-17 and wide open 97-100 and should move through the digits smoothly from closed to open and back again.

To check the resistance and tracking you will need to unplug the TPS connector. Then, using a multimeter set to Kohm, connect the positive probe to the blue wire’s terminal on the TPS unit and the negative probe to the black/blue wire’s terminal. The maximum resistance should be between 4 and 6 Kohms. Next, move the positive probe on the multimeter from the blue wire’s terminal to the yellow wire’s terminal. Now slowly open the throttle and check that the resistance increases smoothly and steadily without any spikes of dead areas and changes in the range of 0 to 6 Kohms. If the resistance drops out of suddenly spikes or there are dead areas in the range then the TPS is faulty.

With the connector refitted you can test the TPS voltage as well by pushing the multimeter’s probes (set to Volts) into the back or the yellow and black/blue terminals of the connector. It should read around 0.7V in the closed position and 5V in the open position.

Unlikely now, but you never know? Those that don't ask don't get!

How's the chain doing? When mine hasn't been checked for a while it gives surging and bogging down sensations. Clean lube and adjust sorts it out a treat.