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Mini-Raptors (250, 80, and 50cc) => Mini Motor Mods => Topic started by: GRAPTOR on May 26, 2008, 03:01:51 PM
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OK, Here is the latest I think I have my main jet figured it ran great at full throttle. My problem now is at 1/4 throttle or when I jab the throttle I get a slight bog/stutter. If I am putting while going thru some tight trails then hit the throttle it will do this also gets worse as I ride longer ( motor gets hot). I have changed my stock pilot jet to a 25 stock was a 22.5 and I am 3 turns out on my air mixture. Should I go back down on the pilot? or adjust my air mixture screw in. Thanks for any suggestions.
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Im no jetting pro but I'd say you running rich. I would drop back to the 22.5 unless your running in colder temps. I have 27.5's but I ride -25 to -30 in the winter up here. What's your stats? temp, alt, quad setup?
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HERE IS MY CURRENT SETUP
PITTSBURGH, PA 1200FT. ASL
TEMP. WAS ABOUT 60 - 70 DEGREES
2005 RAPTOR 350
WHITE BROTHERS E2 EXHAUST
K&N FILTER
152.5 MAIN JET
25 PILOT JET
HOTCAM STAGE 1
Do you think I should go down in my main or just mess with the pilot?
My problem only appears to be at 1/4 throttle.
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Most guys go with a larger main jet. Have you tried a 155?
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Tried a 155 it ran worse and the plug was black so I figured I was too rich. I when to the 152.5 and it appears to run better I just have this stutter any thoughts.
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HERE IS MY CURRENT SETUP
PITTSBURGH, PA 1200FT. ASL
TEMP. WAS ABOUT 60 - 70 DEGREES
2005 RAPTOR 350
WHITE BROTHERS E2 EXHAUST
K&N FILTER
152.5 MAIN JET
25 PILOT JET
HOTCAM STAGE 1
Do you think I should go down in my main or just mess with the pilot?
My problem only appears to be at 1/4 throttle.
If your problem is at 1/4 throttle I would try adjusting the air/fuel screw first. It's the easiest to mess with, try to atleast get rid of the blimp and then read your plug to get a better read (throw a new one in there)
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OK, Here is the latest I think I have my main jet figured it ran great at full throttle. My problem now is at 1/4 throttle or when I jab the throttle I get a slight bog/stutter. If I am putting while going thru some tight trails then hit the throttle it will do this also gets worse as I ride longer ( motor gets hot). I have changed my stock pilot jet to a 25 stock was a 22.5 and I am 3 turns out on my air mixture. Should I go back down on the pilot? or adjust my air mixture screw in. Thanks for any suggestions.
Have you tried turning the mixture screw back a half turn?
~Brian
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Brian,
I have not tried anything yet my first thoughts were to adjust the air/mixture screw a 1/2 turn back in and see how that goes. My other thought was to change the pilot back to the 22.5 ?? I'm going to wait until I mess with the air/mixture. Sound good? Any suggestions would be appreciated.
Jon
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Brian,
I have not tried anything yet my first thoughts were to adjust the air/mixture screw a 1/2 turn back in and see how that goes. My other thought was to change the pilot back to the 22.5 ?? I'm going to wait until I mess with the air/mixture. Sound good? Any suggestions would be appreciated.
Jon
I would crank it back a half turn to see what happens first.
Your main sounds a bit small too.
I would have installed at least a 155 main with that set up. If you are jabbin' the throttle, and getting it to above 1/2 throttle when this occurs, the main jet is the problem. The main opens from 1/2 to full.
~Brian
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I had a 155 installed an it didn't run very good the bog was more like 3/4 throttle and my plug was pretty black so I assumed that I was too rich. Now that I changed the main jet down to a 152.5 the bog is not as drastic and the plug is more brownish/black then just black. I will post a picture of my plug tonight let me know your thoughts. Does this make any sense?
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Is your lid on or off?
~Brian
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I was just going to post my airbox lid is on and everyone tells me they run a 155 with it off. So I kind of figured with my problems I figured less air need less fuel so I went with a 152.5 next size down.
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I was just going to post my airbox lid is on and everyone tells me they run a 155 with it off. So I kind of figured with my problems I figured less air need less fuel so I went with a 152.5 next size down.
Yank that bitch off yo!!! :grin_nod: seriously, you'll never look back :thumbs:
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Try removing the lid and see if that clears up your problem. Chances are you're not getting enough air to your engine with your mods.
Check out a high flow lid, or modifying your airbox with vents.
A great lid modification is the lid EHS Racing offers to mod your exsisting lid.
http://www.ehsracing.com/
If not, www.RockyMountainATV.com sells 2'' foam filters that snap into your drilled airbox. Pretty good add for not a lot of cash.
http://www.rockymountainatv.com/productDetail.do?navType=type&webTypeId=177&navTitle=Filters&webCatId=27&prodFamilyId=6786
~Brian
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Brian,
Need some help this is where I am at. I just ordered the uni-filter air box vents so I will install as soon as I get them. Now let me ask you this, while I was riding on Sunday I checked my plug it was brownish black looked ok. After riding I just unloaded off the trailer and ran it down to my garage and let it set I just checked it tonight and the ceremic is white ?? is that normal or am I still running lean? From our past comments what should be my next step I am going to install the unifilters should I go back up to a 155 main? Leave at three turns out? ?? any thoughts or instructions would be helpful.
Jon
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Did you change the plug after you re-jetted or is that the original plug before your rejet?
The true and correct way to make 100% sure you're not too lean is install a new plug after a rejet. After the install, get it up to speed, ride for a couple of minutes, kill the bike. Pull the plug, then read.
If the plug was black before and now it's white could mean a number of things. You could have burned off excess carbon on the plug, or if you had a change in your climate while riding could affect the plug color too. Usually a white plug will indicate a lean mixture, but it's hard to say on an old plug.
As far as the next step, did you try removing the airbox lid to see if it still bogs at 1/4 throttle?
~Brian
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No, I did not that is kind of tough with the Raptor because the lid hold the filter in place. I ordered the unifilters and will have them Thursday. My plan is to install the unifilters, take my main jet back up to a 155 and leave the pilot at 25 and three turns out on air/mixture. Does that sound where I need to be or should I try a different approach.
Jon
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Have you cranked the mixture back a half turn yet to see if that clears the stumble? If that didn't work, my next step would be
to try running without the lid just to see if the bog goes away. If the lid off clears the stumble in the throttle, then install the filters. Changing the main would be up to you, but this is the main I've used on a previous application. Give that a shot and if it doesn't work, buzz me back.
I think the issue of your bog before with the 155 main is due to lack of air flow.
I would spend a couple of bucks on a new plug too, just to make 100% sure I wasn't too lean.
Just remember, It's better to be rich than lean.
~Brian
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Yes,
I have installed a new plug with every jet change. I think I will try to adjust my air/mixture in 1/2 turn tonight to see if that takes care of the bog I have not done that yet. Are the unifilters worth the install do you see any increase in performance (any experience with them)
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The uni-filters just flow a little better if you decide to leave your lid on. They will help!
~Brian