07 Yzf 450 Tps?

Just picked up an 07 450, noticed there was an issue at steady throttle, there was a spot about 1/4 - 1/3 into a slow roll on that was quite rough. After posting in the jetting section and getting feedback from Eddie I switched the 45 pilot to a 42 pilot and that reduced the problem significantly.

There is still a spot in the same place in the throttle that seemed as if someone just cuts out the spark for a split second then its smooth sailing. Just to see what would happen, I unplugged the TPS and that spot went away immediatly.

What does that point to. Do I need a new TPS, new CDI?? The bike has 30 min on it around my subdivision so if there is a major issue I can drag it back to the dealer but if its just some minor wrenching I'd preffer to do it myself.

My 04 YZF 250 never had an issue and the TPS is still connected.

Ideas??

What are you local conditons in terms of temps/elavation? If it was somewhat cold outside perhaps it is too lean. Might just need some more run time to break in a little. I think Yamahas have a 30 day warranty also so maybe just contact the dealer to let him know.

Sea level to +500' perhaps, conditions are fair lowest it gets say 40 higest 100 deg. Houston Tx

I am just trying to picture a time when this would be a problem. If mine does this i will never know. I never ride at a steady 1/3rd throttle, not what the bike was made for. It is a dirt bike not a street bike. I am either on or off the gas.

I am just trying to picture a time when this would be a problem.
Rolling down a desert access road at 70mph springs to mind.

The TPS performs the same function on your engine as the vacuum advance does on older car engines. It increases the spark advance at part throttle. Disabling it causes the CDI to assume teh engine is at full throttle at all times.

In your case, when you unplugged the TPS, you retarded the ignition timing at 1/3 throttle, and that had an effect on the jetting issue you were having. Basically, it covered up the problem.

The kind of sputtering you mentioned is usually a part throttle mixture that's too rich, or too lean. Rich is usually a regular miss, where as lean is more commonly erratic and irregular, and often accompanied by popping in the exhaust.

Since you have gone to a 42 pilot already, which is leaner than most of us run in an '06, but you say that helped, I'd try dropping the needle a notch to see what that does. Did you install an aftermarket exhaust?

I'll try dropping the needle one spot to the 3rd position and see if that clears it up w/ the TPS connected.

Sea level to +500' perhaps, conditions are fair lowest it gets say 40 higest 100 deg. Houston Tx

Sometimes a 4 stroke will to do this a little when they are fresh, the majority of street bikes I used to service out seemed to do what you described. If you have any time at all on the bike though I would not doubt you have jetting problems. I would hate to be you jetting a bike where you live, sea level and the humidity changes would be a nightmare. Most of the new bikes are lean, we had to do a 48 pilot and 165 main, I wan't to say you are too lean causing the problem but the humidity could be making it rich.

I think I have a headache already, good luck.

Just picked up an 07 450, noticed there was an issue at steady throttle, there was a spot about 1/4 - 1/3 into a slow roll on that was quite rough. After posting in the jetting section and getting feedback from Eddie I switched the 45 pilot to a 42 pilot and that reduced the problem significantly.

There is still a spot in the same place in the throttle that seemed as if someone just cuts out the spark for a split second then its smooth sailing. Just to see what would happen, I unplugged the TPS and that spot went away immediatly.

What does that point to. Do I need a new TPS, new CDI?? The bike has 30 min on it around my subdivision so if there is a major issue I can drag it back to the dealer but if its just some minor wrenching I'd preffer to do it myself.

My 04 YZF 250 never had an issue and the TPS is still connected.

Ideas??

in my 2007 I run

45 PJ

NFLR - 4

165 main

Power nows front and rear

Disconnected TPS

Yoshimura titanium pipe

Wired Accellerator Pump

It runs as as good or better than the 06.

the 06 was exactly the same but it had a 48 PJ

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