Jump to content
Sign in to follow this  

07 yz450f fuel mix screw fell out...

Recommended Posts

i still got the o-ring...was wondering if it would hurt replacing the spring with one from a pen that is perfect diameter and a little bit longer than the screw from the threads to the point. and finding a small washer at a parts store? I have new ones ordered from yamaha dealer but i want to ride this weekend. it fell out because i was testing the new main jet and i kept loosening the screw til the cracking/popping went away but then it fell out... /cry

Share this post


Link to post
Share on other sites

You probably need a bigger pilot jet too. The normal range for that screw is three turns out if your less than one go down on the pilot more than 2 go up a size. If you use the wrong spring it may fall out again. Thats up to you if you wanna try it. Just ignore me if you already know what you're doing.

Share this post


Link to post
Share on other sites

well ive got the main jet changed to the one in the dynojet kit for under 3000ft with an aftermarket exhaust. i dont have the exhaust on yet because they sent me the wrong one so it might help when i get it installed? also, why doesnt a jet kit come with jets other than the main??

Share this post


Link to post
Share on other sites

It depends on what kit you get. I have the yfz quad and the gtyr kit for that came with mains pilots and a needle. Some bikes are jetted really lean stock. Do a search for threads about jetting your bike and see what other guys are running.

Share this post


Link to post
Share on other sites

So basically youre telling me that the dynojet kit is a waste of money and i might have to look into buying another, more expensive one? awesome~~~! this stuff is starting to piss me off so much im just gonna put it all back to stock. I mean, "lightly seeated". how do you even gauge "Lightly seated" for a screw that just keeps going in with two fingers. frack. and when i finally get it to where the bike is running great it friggin falls out. im shooting myself in the knee cap right now lol

Share this post


Link to post
Share on other sites

No that kit is not a waste. You can buy pilot jets seperately too. Jetting your bike and getting the most out of it is time comsuming and expensive but well worth the effort. The stock jetting can be improved upon as well. I have to rejet seasonally and have probably 200.00 worth of carb parts. Don't get discouraged. You can screw the fuel screw all the way in and it stops you just have to be easy on it. You don't want it screwed out more than 3 turns you know why. If it runs best at 3 turns out or more up a size on the pilot jet. All you really need is one jet 10.00 or something.

Share this post


Link to post
Share on other sites

So I can't find much in the way of pilot jets, brandwise. Maybe I should see what the yamaha dealer can get me? individual jets too? I did a thread search and can't find what size is stock for an 07 and not much in the way of rejet, but i guess i can take my carb apart again and look. maybe ill just forget about the bike and relax til my new screw assembly and exhaust get it...thanks tech857

Share this post


Link to post
Share on other sites

The dealer can be help full. I changed my airfilter and it leaned my bike right out I went to the dealer and they had the whole range of main jets on hand and cheaper than some of the places on line. Not to rub it in but we just got back from a little afternoon ride. There was a bunch of kids at the pit at the end of our street and they ate a lot of roost off my new tires.

Share this post


Link to post
Share on other sites

damn you i just put new tires on mine too cuz i had studded tires on for ice racing before. wanted to try em out...would a quickshot 3 help me a little as well? i dont have much issue with bog though regardless of season or setup so far... and if i put in the dynojet needle and the 160 main jet...i should be running a little richer right?

Share this post


Link to post
Share on other sites

Your on a slippery slope with all this stuff once you put this pipe on your gonna be forever messing with your carb. Every change requires changes to your carb. I was having issues with it bogging when the throttle was opened quickly. I got the original quickshot and it didn't help. Its more important to get the correct jets in your carb for the mods and weather conditions. The fix for the bog on my bike was mainly having the correct main jet. They have an accerator pump cover that is externally adjustable that would be the way to go.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×