Major stutter after rejet. Help.


46 replies to this topic
  • JCORMI

Posted March 29, 2006 - 09:27 AM

#21

I went through the same thing as you, all of the same mods same problem but when I switched to a 168 main ,48 pilot, red needle at the 4th position, and Zip-Ty 1.5- 2 turns out depending on temp and altitude. The bike runs fantastic and no more stumble. James Dean gave me these settings because I was having such a hard time with my jetting :thumbsup: I think the blue needle is just too rich for some bikes. Good luck...


Sounds like I have some experimenting to do, I never considered going to the red needle just because it's so cool here right now. Were averaging 45 degrees right now.

  • JCORMI

Posted March 29, 2006 - 10:09 AM

#22

Are you sure the fuel screw is in the whole way?
With the stock 45 PJ and scew in and engine on a 'fast' idle, you should see some difference from a few turns out to the whole way in.
The first time I installed it I thought it was in teh whole way and it wasn't. I took it out completely (don't loose the sprong, washer or O-ring !) and ran it in again. That time it went the whole way.
The know should almost touch the bottom of the carb bowl when its in the whole way.
If your sure it is, don't crank it too hard. You can damage it or the carb.

I am pretty sure it is all the way in, I don't dare to crank it any harder. I will try taking it all the way out and then screwing it back in. What would the reason be for it having no effect if it is all the way in?

  • J_DOGG

Posted March 29, 2006 - 10:10 AM

#23

Why the blue needle?

I just pulled mine and put in the RED on clip #6 I think (almost near the bottom on the needle)..with a 170 main..
I have all the free mods done, with no after market pipe and the bike runs great.

I was just wondering why the Blue and not the red, it's going to get warm real soon.

  • JCORMI

Posted March 29, 2006 - 11:21 AM

#24

I guess the reason I went with the blue is because I just went by the directions that came with the JD jet kit. It did say in the kit that I could use red needle on #5 as well, I guess I just wasn't sure.
Oh yeah, indys jetting chart suggested the blue needle as well.

  • odonnks

Posted March 29, 2006 - 11:44 AM

#25

I originally used the blue needle too because the JD directions said to. Eventually tried and stayed with the red needle because the weather is getting warmer.

I'm not sure why the needle on mine initially felt like it was in all the way when it wasn't. But after I removed it and reinstalled it I bet I got a good 4 more easy turns. I never found debris or anything that obstructed it. It just went back in further.
I have seen other threads that suggested that their Zipty screw wouldn't go in the whole way and that they saw a spot on the anodizing that indicated it was hitting something along the shaft. They used fine emery paper and polished it at that spot and it worked.
I never had this problem but ??

  • yamageezer

Posted March 29, 2006 - 11:59 AM

#26

The temps here are the same, in fact in the month of February I was riding while it was snowing and the bike still ran like a raped ape. There is allot of testing and experimenting, sometimes it get to be a pain having to take the carb off time and time again but the good thing is, you eventually get it down to where you're in and out in a flash. :thumbsup:

  • tony1970

Posted March 29, 2006 - 12:45 PM

#27

I went through the same thing as you, all of the same mods same problem but when I switched to a 168 main ,48 pilot, red needle at the 4th position, and Zip-Ty 1.5- 2 turns out depending on temp and altitude. The bike runs fantastic and no more stumble. James Dean gave me these settings because I was having such a hard time with my jetting :thumbsup: I think the blue needle is just too rich for some bikes. Good luck...

Had the same problem. Went to the red needle and everything cleaned up. Expect to remove your carb a lot to get your jetting just right. Good luck

  • JCORMI

Posted March 29, 2006 - 12:57 PM

#28

Tonight going to try the set up that is in now 170main 45pilot and blue #3, after my test I will install 48 pilot and try again with same needle and main setting. If I am still not satisfied I will try the 170main 48 pilot red needle on #5. Can't wait to get home!!

  • JCORMI

Posted March 29, 2006 - 01:54 PM

#29

Look over this link.
The graph / map is pretty handy to figure out which jet to adjust based on where the problem is.
This is a really good article and applies to both the 250 and 450.
http://www.thumperfaq.com/jetting.htm


That was a great page. Excellent breakdown on how everything works, and it is simple enough for even less experienced people to grasp.

  • JCORMI

Posted March 30, 2006 - 05:10 AM

#30

Alright, I tried 170main blue #3 and 45 pilot, still stuttering in the mid and what was worse is the header pipe was glowing orange, VERY hot, I thought it was an indication that I was lean on the bottom because I was riding at around a 1/4 to 1/2 throttle. I changed to a 48 pilot with everything else the same, better off the bottom but it still ran horrible in the middle.
I changed the needle after that to red #5 but did not have time to test it, I am praying that this is the combination. I am beginning to worry that this thing will never run smooth.
Took fuel screw all the way out, put it all the way back in, can't see any places on it that it was rubbing or hitting. Bike still started right up with screw turned all the way in. I am really considering putting the stock screw back in at 1.5 turns out and seeing if that does anything.
If the setting that is in there does not work tonight I am going to return to stock settings and start over. Normally I am a patient person, but I have to admit this is pissing me off a little.

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

Posted March 30, 2006 - 05:17 AM

#31

I'd be getting pissed to.
Your right, the red header is lean at idle or part throttle.
The stock fuel screw way be a good test.
Did you look at the plug yet?
Before all the mods, did the bike have the same problem?
It seems odd that after all this testing the problem still exists.
Is ther a way to run it in the bad zone for awhile and hit the kill button. IF so. hit it leave off the throttle at the same time. That'll give you the best plug read.

  • Matty05

Posted March 30, 2006 - 05:22 AM

#32

Your bike will run with the fuel screw all the way in! Nothing wrong with it!
If your bike studdddders, it is rich. Just keep on dropping the needle!
Leave the 48 pilot jet in there. Leave the 170 in there too, for now.

  • JCORMI

Posted March 30, 2006 - 05:40 AM

#33

I'd be getting pissed to.
Your right, the red header is lean at idle or part throttle.
The stock fuel screw way be a good test.
Did you look at the plug yet?
Before all the mods, did the bike have the same problem?
It seems odd that after all this testing the problem still exists.
Is ther a way to run it in the bad zone for awhile and hit the kill button. IF so. hit it leave off the throttle at the same time. That'll give you the best plug read.


I have not looked at the plug yet, before all the mods there was not a studder like this, it was just flat and kind of powerless. Is it possible to run it in the bad zone? The answer is YES, last night it was impossible to run it when it wasn't in the bad zone. The bike was running horrible, felt like it was just cuttin out like every 1 or 2 seconds. I will try the plug test if the setting in there that I am testing tonight isn't at least close.

  • JCORMI

Posted March 30, 2006 - 05:44 AM

#34

Your bike will run with the fuel screw all the way in! Nothing wrong with it!
If your bike studdddders, it is rich. Just keep on dropping the needle!
Leave the 48 pilot jet in there. Leave the 170 in there too, for now.


Matty, right now I have red on #5, if I still get studder move up one clip you think. So you don't think the mixture screw could be causin an issue? Or is it more likely a combo of the needle and screw?

  • odonnks

Posted March 30, 2006 - 05:44 AM

#35

If its cutting out is there a chance of debris in the fuel that could be plugging the jets. This is fairly common. The WR has no fuel filter.

  • Matty05

Posted March 30, 2006 - 05:49 AM

#36

Matty, right now I have red on #5, if I still get studder move up one clip you think. So you don't think the mixture screw could be causin an issue? Or is it more likely a combo of the needle and screw?

It won't be fuel screw! It is for fine adjustment only!
Leave it at 1.5 out untill you get the needle right.

Go to #4 if it still studdddders in the 1/4 to 3/4 throttle range.

  • JCORMI

Posted March 30, 2006 - 05:51 AM

#37

I think anything is possible at this point, I have had it apart so many times something could have gotten in there I guess. I don't know though?

  • JCORMI

Posted March 30, 2006 - 05:53 AM

#38

It won't be fuel screw! It is for fine adjustment only!
Leave it at 1.5 out untill you get the needle right.

Go to #4 if it still studdddders in the 1/4 to 3/4 throttle range.


Will try that, sucks to have to wait, god I wish it was saturday!!

  • Matty05

Posted March 30, 2006 - 06:23 AM

#39

Learn to feel what each adjustment does, and the difference when you change it again. It takes a while to get it right, but it is worth it.

I would suggest you only change one thing at a time. Untill you know what is going on.
When you lowered the needle, you said it got better but not there yet. Well you are on the right track! Keep on going!

If it gets better, keep on going. If worse, go back to the last setting.

I have found that red #5 is about the same as blue #3. Others have too.

You will be happy to know that when you get it right, it will be easy to make minor adjestments (depending on weather variation) to get it right, plus you will know how to jet your bike!

The cut out feeling is definately rich!!!!!

  • yamageezer

Posted March 30, 2006 - 09:20 AM

#40

I agree with Matty, lower that needle. Keep the 168-170 main, and the 48 pilot. I would also blow out and clean the inside of the carb. Also look for any air leaks around the carb. I'm running a YZ pipe, and opened air box plus all of the other mods. I believe that unless you have completely opened up your pipe, I mean like the YZ style pipe no baffles at all, you are definitely running to rich. One last thing, make sure that you still have the spring, washer, and O-Ring in, and in the right order on the fuel screw.




 
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.