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Discussion Starter · #1 ·
I just bought a 05 Raptor 660 used from Craigslist. The Raptor wouldn't start because of a dead battery and the previous owner hadn't started the Raptor in over a year. This is what the bike has that I know of, Alba full pipe, K&N filter, air filter lid off and some kind of computer mod.

So I replaced the battery and started the bike. It ran but not very well. Ran better with choke on, but the exhaust seemed to get really hot. Also if the gas was left on, gas would pour out of the bottom of the carb. So I figured the pilot jets were plugged at the very least and I would tear the carbs apart for a inspection.

Removed both carbs, pilots were a little plugged but mains looked ok. Also found the floats were out of specs. So I cleaned the jets, adjusted the floats and reinstalled the carbs. Bike runs alot better at idle, exhaust header temp seems normal and the bike sounds good. But the mid range seems to have a hesitation or dead spot, once the bike gets thru the mid range it really hauls the mail! But it also pops and backfires on decel. And I stiil have the gas running out the bottom of the carb problem if the gas is left on.

At this point I've already pulled all the magic tricks from my bag and was hopping that someone had a fresh idea.

Carb specs
Left has a #155 main, 22.5 pilot and 5 groove needle with the clip in the middle.
Right has a #160 main, 22.5 pilot and needle is the same

Thanks in advance, Caddyman
 

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Master of the Electron
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The o-rings under the float valve seat often get hard and leak, especially after a good cleaning. Probably the source of your continued overflow.

Did you remove and clean the emulsion tubes (the main jets screw into them)... clogged holes in these will cause problems somewhere between 1/2 throttle and wot.
 

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I would also think that with a full exhaust and modified airbox you will need #25 pilots instead of the stock 22.5's. This may help the popping on decel. I'm no expert though. Willykiller will probably chime in soon and correct me if I'm wrong. LoL
 

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Git-R-Done
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yes with a modified airbox you will need #25 pilots.
 

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I am unique
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I just bought a 05 Raptor 660 used from Craigslist. The Raptor wouldn't start because of a dead battery and the previous owner hadn't started the Raptor in over a year. This is what the bike has that I know of, Alba full pipe, K&N filter, air filter lid off and some kind of computer mod.

So I replaced the battery and started the bike. It ran but not very well. Ran better with choke on, but the exhaust seemed to get really hot. Also if the gas was left on, gas would pour out of the bottom of the carb. So I figured the pilot jets were plugged at the very least and I would tear the carbs apart for a inspection.

Removed both carbs, pilots were a little plugged but mains looked ok. Also found the floats were out of specs. So I cleaned the jets, adjusted the floats and reinstalled the carbs. Bike runs alot better at idle, exhaust header temp seems normal and the bike sounds good. But the mid range seems to have a hesitation or dead spot, once the bike gets thru the mid range it really hauls the mail! But it also pops and backfires on decel. And I stiil have the gas running out the bottom of the carb problem if the gas is left on.

At this point I've already pulled all the magic tricks from my bag and was hopping that someone had a fresh idea.

Carb specs
Left has a #155 main, 22.5 pilot and 5 groove needle with the clip in the middle.
Right has a #160 main, 22.5 pilot and needle is the same

Thanks in advance, Caddyman
With the open air box you will need aftermarket needles, most of these needles have six grooves, you will also need number 25 pilot jet both sides and mains in the area of 155 to 165 depending on the air box mods...........
 

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Discussion Starter · #6 ·
I will replace the o-rings and also check the emulsion tube's (I don't think I removed them)

I need to order the pilot jets, now should I still replace the pilot jets and needle's if I'm going to reinstall the air box lid?

Thanks again for all the help!
 

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I am unique
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Another question I have is,

I know the main jets are for WOT and the pilots are for idle, but where does the needle and needle clip setting come into play?
Pillot jets main area is up to 1/8 but delivers fuel throughout the whole throttle range............
Needles are from 1/8 to full and the mains are from 3/4s up but will affect the needles performance if they are too small or to large............
 

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Master of the Electron
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If you re-install the lid, the main jets will now be too large. 25 pilots, aftermarket needles should make it run good with lid off, and you'll see significantly more power with it off than with it on.
 

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Discussion Starter · #10 ·
Ok, just back from Chaparral with new float valves (because you can't just get the orings), main jet orings, float bowl orings, #25 pilot jets but they didn't have a #165 main jet. I'll just leave the air box lid off for now. I hope the #155 left and #160 right main jets are going to work.

Thanks again
 

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Master of the Electron
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THey may be a bit lean - why not try drilling holes (3/4 or 1") in the airbox, start with just a few and add until the bike is running perfect - then, if you do go to 160/165, take it off altogether.
 

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Master of the Electron
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Run. You will know if they're rich enough by the way the bike rides... I suspect you will be changing them, unless you follow my drilling suggestions above.
 

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Discussion Starter · #15 ·
Ok here is where I'm at. I replaced both float valves with o-rings, replaced both pilot jets with #25's, reinstalled #155 main jet in left carb and #160 in right carb, both needle's have 6 grooves and clips in the #4 groove from the top, air box lid off. Fuel is leak gone!!! Thank you. Engine idle's great and runs better overall, but engine still back-fires and pops on decel, has little hesitation in mid-throttle. Overall it's a lot better than when I started. Thank You all very much!!!

What else can I try now for the hesitation and popping on decel? Is the clip in the correct groove? What is the positioning of the clip for?

Thanks again for all the help.
 

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I am unique
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Ok here is where I'm at. I replaced both float valves with o-rings, replaced both pilot jets with #25's, reinstalled #155 main jet in left carb and #160 in right carb, both needle's have 6 grooves and clips in the #4 groove from the top, air box lid off. Fuel is leak gone!!! Thank you. Engine idle's great and runs better overall, but engine still back-fires and pops on decel, has little hesitation in mid-throttle. Overall it's a lot better than when I started. Thank You all very much!!!

What else can I try now for the hesitation and popping on decel? Is the clip in the correct groove? What is the positioning of the clip for?

Thanks again for all the help.
Popping on decel ............open the fuel screws another 1/4 turn...........
hesitation in midrange.............depends if it is bogging or hesitation, bogging requires more fuel, hesitation requires less fuel...........
 

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Discussion Starter · #17 ·
Popping on decel ............open the fuel screws another 1/4 turn...........
hesitation in midrange.............depends if it is bogging or hesitation, bogging requires more fuel, hesitation requires less fuel...........
Is the pilot screws the same a the fuel screws? Should both screws be turned out the same amount or will they be different?

With more fuel or less fuel, how is that achieved? Needle clip position, main jet size or pilot screw?
 

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I am unique
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Is the pilot screws the same a the fuel screws? Should both screws be turned out the same amount or will they be different?

With more fuel or less fuel, how is that achieved? Needle clip position, main jet size or pilot screw?
First question........yes
2nd..........close to the same
3rd............open fuel screw for more fuel...........
lift needles for more fuel..........
bigger mains for more fuel..............
 

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Master of the Electron
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Turn both fuel screws (pilot screws) CCW 1/4 turn for popping. Raise needles one notch (clip lower on needle) for mid hesitation, if it gets worse move it down one notch instead.

You may end up wanting 160L/165R with the lid off, but see how it runs so far.
 

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Discussion Starter · #20 ·
Left carb pilot screw was turned out 2 1/4 turns
Right carb pilot screw was turned out to 3 3/4 turns

I adjusted them both to 4 turns out, still back-fires and pops a little or stall when the clutch is pulled in. Should I turn them out more? What is a good starting range for the screws?

The clip on the needles were at the 4th groove from the top, changed them to 5th groove from the top, ran much worse. Changed them again to 3rd groove from the top, seemed better than the 4th groove but still little stumble. Should I try the 2nd groove?

Thanks again, you guys are helping to understand this a lot more!!!
 
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