No Power on intial throttle

C

Clif

Member

Jun 19, 2014

3

0

• Jun 19, 2014

• #1

Hello. I am new to this site. I have a YZ250 2002. The problem I have is the initial power on the throttle. The powerband is fine. I have completely cleaned the carb, replaced all the items with stock parts but the initial throttle is sluggish until I pop the clutch once or twice. Any ideas? I just replaced the exhaust, pipe, and seals.

 

Rich Rohrich

Moderator / BioHazard

LIFETIME SPONSOR

Jul 27, 1999

22,839

16,904

Chicago

• Jun 20, 2014

• #2

Start with basic stuff like repacking the silencer, cleaning the coil ground strap connection, verifying the compression and the power valve operation. Once you have verified it's in proper mechanical working order you'll likely have to look at cleaning up the jetting.

 

C

Clif

Member

Jun 19, 2014

3

0

• Jun 20, 2014

• Thread starter
• #3

thanks bud for the guidance. I replaced the exhaust with FMF silencer and replaced all the head in exhaust seals. I replaced all carb componets with new stock and reset the float. I am certainly going to replace the reeds and clean the PV with carb cleaner this weekend. Its just annoying that the powerband is huge but the intial throttle suks wind.

 

C

Clif

Member

Jun 19, 2014

3

0

• Jun 26, 2014

• Thread starter
• #4

Ok, so the bottom end power is very poor. I removed the the PV cover on the side and discovered that the actuator arm is broken. Since I have rebuilt the carb, replaced the exhaust then I will assume this is the culprit.

Thoughts from the experts?

 

Okiewan

Admin

Dec 31, 1969

29,550

2,238

Texas

• Jun 27, 2014

• #5

Clif said:

Ok, so the bottom end power is very poor. I removed the the PV cover on the side and discovered that the actuator arm is broken. Since I have rebuilt the carb, replaced the exhaust then I will assume this is the culprit.

Thoughts from the experts?

Click to expand...

I'm no expert but I play one on the internet.

But, yeah, that would do it. What's the purpose of a power valve?

In simple / general / mostly accurate terms :

 

jaguar

~SPONSOR~

Jul 29, 2000

1,508

82

South America

• Jul 4, 2014

• #6

Make sure engine compression is good and raise the carb needle one or two notches.
Also adjust the timing a bit more advanced since partial throttle needs more ignition advance. Advance it till Paul is happier but Peter is a little disappointed. (Paul is low range power and Peter is high range power)
Also put in an iridium plug.