New to me yz426f a few questions


20 replies to this topic
  • slasher729

Posted February 15, 2016 - 04:55 PM

#1

I bought a clean 02 yz426f for a good price. It's been cold as hell here and he couldn't get it started for me but it was so clean I bought it anyway (I know). It took me a ton of kicks to get it started. (30+) I know it was too many by far. It's 30* at the warmest. Will that temperature effect the carb and engine that much? I can change the jets but is it really worth it all?

  • 0bigsilver6

Posted February 15, 2016 - 04:58 PM

#2

I bought a clean 02 yz426f for a good price. It's been cold as hell here and he couldn't get it started for me but it was so clean I bought it anyway (I know). It took me a ton of kicks to get it started. (30+) I know it was too many by far. It's 30* at the warmest. Will that temperature effect the carb and engine that much? I can change the jets but is it really worth it all?


Shouldn't take nearly that long. I would ensure the valve clearances are good and get the carb jetted right. Bike should start and run like a champ if you get those two things right and know the proper starting procedure. The temperature shouldn't have that much of an effect on starting it to where it takes 30+ kicks. Mine starts in 3-4 kicks. Granted it's like 50 degrees here, but my valve clearances are out a bit too.

  • grayracer513

Posted February 15, 2016 - 05:16 PM

#3

In thirty degree weather, I would expect trouble starting cold.  Cure it by giving the throttle 2-4 twists before cranking it. 



  • slasher729

Posted February 16, 2016 - 04:42 AM

#4

Fouled plug? When he was trying to get it started he was twisting the throttle 3 times about every two times he was trying to kick it. For about 25 kicks, that's a lot of gas.

  • grayracer513

Posted February 16, 2016 - 07:09 AM

#5

That's a little excessive, yes. 



  • Baldwin

Posted February 17, 2016 - 03:33 AM

#6

I've had a similar issue a couple times in warmer weather and a fresh plug got me going in two kicks. 2002 YZ426.

My bike started up right away and ran great when I bought it used. If not for the hanging idle it developed, I wish I had never opened up the carb. I also went up a size on the pilot and think it's probably on the rich side now. This spring I'll be going back to the stock pilot size.
I've had a similar issue a couple times in warmer weather and a fresh plug got me going in two kicks. 2002 YZ426.

My bike started up right away and ran great when I bought it used. If not for the hanging idle it developed, I wish I had never opened up the carb. I also went up a size on the pilot and think it's probably on the rich side now. This spring I'll be going back to the stock pilot size.

  • slasher729

Posted February 17, 2016 - 10:38 AM

#7

Put a new spark plug in and still won't do anything. Local shop suggested just waiting for warmer weather. Last thing I'm going to try is fresh gas. On the carb there's a brass screw holding a few cables into it. Any idea on how to take that off? I almost stripped it by trying to turn it once.

  • Baldwin

Posted February 17, 2016 - 10:49 AM

#8

I remember kicking it forever in the cold once and it finally went, but I haven't done much cold weather starting to be honest.  They're notoriously finicky bikes to start, but once you get them dialed in and set up they seem to start pretty easily.



  • slasher729

Posted February 17, 2016 - 11:22 AM

#9

It's supposed to be 55 on friday so I'll give er a go then.

  • Baldwin

Posted February 18, 2016 - 03:23 AM

#10

Put a new spark plug in and still won't do anything. Local shop suggested just waiting for warmer weather. Last thing I'm going to try is fresh gas. On the carb there's a brass screw holding a few cables into it. Any idea on how to take that off? I almost stripped it by trying to turn it once.


Are you referring to the throttle cables?

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • slasher729

Posted February 19, 2016 - 04:09 AM

#11

Are you referring to the throttle cables?

Yeah i was, i had to shock the screws with a phillips. Carb looked clean as hell and all the jets were correct. The black screw on the side of the carb for the idle, how far out is everybody have these set? I think my problem is the carb is out of tune. Or the valves are out of adjustment but they were done by a shop along with a new top end so i'm doubting that's the issue. 



  • slasher729

Posted February 19, 2016 - 04:13 AM

#12

We also pull started it with my buddys quad and i got it to run but as soon as i let off the gas or pull the clutch in it would just die. We have to fuel screw 3 turns out, way too much from what i've been reading and was shooting flames while trying to start it. Would that cause it to not start? Sorry i'm new to this and am learning as i go.


Edited by slasher729, February 19, 2016 - 07:39 AM.


  • slasher729

Posted March 09, 2016 - 04:40 AM

#13

Another quick question for you fellas. I was riding around my block to get some needed seat time and it started spitting coolant out of the overflow. I got home and noticed the head gasket was leaking just sitting and idling. So i looked up the torque specs on the head bolts and one of the bolts was hand loose, once i tourqed everything down it was fine. The base gasket looks like it was leaking coolant but it could just be from the overflow while riding? Does the base gasket leak oil or coolant or possibly both?



  • grayracer513

Posted March 09, 2016 - 07:45 AM

#14

Possibly both. And it's clamped by the same head bolts.  If you had loose head bolts, you're going to need to replace the head gasket at least, and should replace the base at the same time.  The head gasket will almost certainly continue to leak combustion pressure into the coolant.  



  • slasher729

Posted March 09, 2016 - 02:21 PM

#15

It has a brand new top end put into in and the head gasket is definitely new. Even after I tourqed it down it will still leak?

  • slasher729

Posted March 09, 2016 - 02:37 PM

#16

Yeah base gasket is &%$#@!ed. This should be fun

  • 0bigsilver6

Posted March 09, 2016 - 05:10 PM

#17

Yeah base gasket is &%$#@!ed. This should be fun


I just did all this on my bike for the first time. New piston/ rings, cam and cam chain. Wasn't bad actually. Kinda fun.

  • slasher729

Posted March 09, 2016 - 05:12 PM

#18

It's just annoying knowing that someone was that far down to do the head gasket and wouldn't bother changing the cylinder gasket. I know what I'm doing next week!

  • grayracer513

Posted March 09, 2016 - 09:52 PM

#19

It has a brand new top end put into in and the head gasket is definitely new. Even after I tourqed it down it will still leak?

 

If they had never been torqued down, you might have a chance.  Maybe



  • slasher729

Posted March 10, 2016 - 05:18 AM

#20

If they had never been torqued down, you might have a chance.  Maybe

It looks like the head gasket is fine but i'm just going to put all new gaskets in when i go to change the base gasket. I took it for a quick ride and it was leaking oil and coolant from the base gasket. It wasn't new like the head gasket and i think when it was loose it ruined the base gasket. Some green almost paper looking gasket. 







Related Content

Wiki
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info


Articles
  • 0 replies
Forums
Photo

Megabomb Fitment by 288yz450


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply
Forums
Photo

Snake pit oct 30th by The Anvil


Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies
Forums
Photo

Michigan Motocross Tires by 288yz450


Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply
Reviews

Yamaha YZ450F 2017 by Chris.GVS


Yamaha YZ450F 2017
  • - - - - -
  • 0 reviews
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.