Regardless of what it is, it gives me an opportunity to experiment and learn. And I've learned a bit between these forums and hands-on experience..

Sooooo.... I put the "recommended" jet (#150) in for my area.. I took the bottom bolt out of the float body and had a hard time getting the screwdriver on the groove of the jet, so I gave it a lil' pressure, and the jet slightly sank up and into the carburetor, if this is possible ... I'm wondering if the jet is able to push the needle up and therefore the top of the diaphram up?

I'm asking because after replacing the 155 jet with the 150 jet, the bike semes to sputter around 1/4 throttle... I ran out of time and now it's too dark out to take the top of the carb off right now....

Now, I'm learning here, but what I gather is that the MAIN jet is for 3/4-to-FULL throttle, so what I'm guessing is that I inadvertantly offset the needle by pushing in the jet and disforming the diaphram and therefore changed the lower throttle parameter.... if that makes sense?

 

Its possible to break needle jet stop where main screws in. Main jet should have sleeve or washer underneath to limit travel. look in carb to see if needle jet flush in recess area. If jet "sank' up into carb are you missing spacer or washer? Also open end of needle jet should face forward toward front of carb.

 

Thanks for the information. I didnt apply a whole bunch of pressure, so I couldnt imagine breaking anything. It ran great with the #155 in and I'm certain nothing fell out (spacers, etc)..

I'll tear it apart this weekend and figure it out..!

 

I was able to remove the diaphragm and needle and see the top of the jet. I applied a slight amount of pressure with a wood dowel, and it sank back down.. it only moved a tad.

With the #150 in, it appears that I have a little more top end, pegging my ATV out over 60mph. Before I could only hit about 55mph. Safe? No. Practical? No. Was it worth the money? Probably not.

It doesn't seem to be eating the gas like the #155 did though, and I don't smell gas (rich) anymore.

I just wanted to share this information in case others might be considering, and thanks for your feedback.

 

drewbad with only doing a jet kit getting a tad better gas mileage along with the experience-- that alone should be worth it as you said. Dont forget to also do a proper plug reading now that you did the kit - Just because its the right thing to do-- different motors&different conditions as you mention above give you different results, so whenever changing the jetting&needle position you should make it a SOP-standard operating procedure- just as a added precaution, some will disagree with me BUT I always prefer to err on the caution side when it comes to motors, its a lot cheaper and only a few mins more time.

 

Maine,

Thank you for your input.

Do you have a link on how to read the plug? I hear this can be a whole other can of worms! [img]i/expressions/face-icon-small-blush.gif[/img])

Drew

 

First let me say that it is good that your willing to learn,its hard to beat that satisfaction you get from doing your own stuff. 2nd and most important, when you think you know it all - you know nothing, learning is a constant never ending process so don't get discouraged as easy as it could be to at times. LOL- yes plug reading is another whole argumentative thing and some people take it as a science, I myself think its just a decent quick way to see how your motor is performing. This link I'm posting is a excellent source of information about plugs it describes in detail on what the plug numbers mean, how heat ranges work and has over 25 pictures showing what plugs look like in different conditions and I've found it to be very helpful. let us know how you make out.---
http://www.totallyamaha.com/sn...tion%20%20Overview.htm

 

Picked up a new plug on the way home and swapped out the old.

The old looked great--compared to the pictures in the link... not to oiley... not too burnt.. just right.. I think I did good.

I'll pull the new plug in a few weeks after a get a little time on the bike and check it out again.

I hope this thread helps others..

 

You guys sound like you got some experience with carbs so maybe you can help me out, I've got an 04.5 SP 500 that I put in a bigger jet, 155 to 162, for better cold weather running, and now when I accelerate on an uphill slope I get sputtering and backfiring. If I back off the throttle and don't open it up too much it will pull the hill but if I open it up to 1/2 to 3/4 throttle it's starts to sputter. Since this is the throttle range where the needle supplies most of the fuel, I'm wondering if it's a lean backfire situation and I'm thinking I need to raise the needle a notch to get a little more fuel. Any ideas?

 

STILL LEARNING HERE!!

I am experiencing two issues from my jet change (I think). I can easily put back in the stock jet/needle that I took out, but I'd rather learn a little...

1.) the bike, when in gear and idleing, creeps forward or reverse. Would you think that this a mixture/idle issue? It seems to idle pretty low now, but maybe not enough.

2.) Stall, stall, stall! It idles in neutral just fine, but when putting in gear... instant STALL! Prolly related to #1 above?

Thanks to everyone/all. You guys make this forum rock!!

Drew