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Discussion Starter · #1 ·
Hi,
I am a new Raptor member and am loving this sight, lots of good info.

My Problem - I live at 7000 feet in Flagstaff, AZ. I am having issues starting my Raptor at this altitude and I mean I consider myself luck if I can even get it started before the battery dies. When I go to Glamis, California (at sea level) it will start with no issues.

What I have tried - I have completely rebuilt my carb. and jetted at 7000 feet by Dyno Jet stage 2 specifications. I cleaned every jet and port. Fuel level is good in bowl and it sounds like it wants to start. I had this problem before rebuilding and jetting at 7000 feet. The Raptor should start but run like crap. I would think anyway.

Has any buddy had this issue and or can give me an idea of where to start.

Thanks,
Steve
 

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I am unique
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Hi,
I am a new Raptor member and am loving this sight, lots of good info.

My Problem - I live at 7000 feet in Flagstaff, AZ. I am having issues starting my Raptor at this altitude and I mean I consider myself luck if I can even get it started before the battery dies. When I go to Glamis, California (at sea level) it will start with no issues.

What I have tried - I have completely rebuilt my carb. and jetted at 7000 feet by Dyno Jet stage 2 specifications. I cleaned every jet and port. Fuel level is good in bowl and it sounds like it wants to start. I had this problem before rebuilding and jetting at 7000 feet. The Raptor should start but run like crap. I would think anyway.

Has any buddy had this issue and or can give me an idea of where to start.

Thanks,
Steve

Did you adjust the valves, tight intake valves will cause a no start...........
 

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Discussion Starter · #3 ·
I was thinking about that. Could they be out of adjustment and flood the motor. The spark plug is wet.
Thanks I will give a look Monday.
 

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I was thinking about that. Could they be out of adjustment and flood the motor. The spark plug is wet.
Thanks I will give a look Monday.
If you don't have enough compression, then possibly your plug will look wet due to the fact it wont start because the valves may be too tight........:)
 

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Master of the Electron
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I would definitely check your intake valve's adjustment - they tighten up as they wear and will cause difficult cold starting due to reduced compression especially at higher altitudes (less air, lower compression still).

I can't imagine this being carb related (starts in Glamis but not in Flagstaff) because, when cold, the engine should prefer to start a bit rich (and you ARE at 7000 ft).

Check the valves.
 

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Discussion Starter · #6 ·
Well it is coming to life, the intake valves was the key. It starts and idles with out issues. The valves were way tight. Thanks for your guys help.

My new issue is when the Raptor warms up it chokes out as soon as I throttle up. It idles great. So, I just totally rebuilt the carb. and now that I am able to start and idle, I am assuming I need to dial in main jets and pin.
 

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Glad to hear you got the starting issue sorted out. As for your next issue, what are your current mods, and your current jetting?
 

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Master of the Electron
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At 7000 ft, even with the open airbox, I'd be running very close to stock jets... the unwritten ruls is about a reduction of 5 per 2000 feet. Starting at recommended 160L/165R with an open airbox at sea level, you should be down about 15-20 per side at 7000 ft, or around 140L/145R - which is stock. I'd also run stock needles and 22.5 pilots with screws at around 2 turns out (also all about stock).

These will just be starting values that you'll need to tweak to optimize.

THe numbers I'm quoting are Mikuni - you currently have DJ jets and they don't match numbers... but the stage 2 is probably around 146L/148R (DJ numbers). Don't know what stock would be in DJ numbers - I'd suggest getting the proper mikuni jets (140/145) so we can all speak the same language.
 

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Discussion Starter · #9 ·
Tried a couple of things and no luck. It is idling great, but at 1/4 to full throttle it is stumbling horribly. The funny thing is when I finished adjusting intake and exhaust valves it seemed to run great. I shut it down re-installed my plastics and started it and let it idle for 10 min. when I got on the throttle it started stumbling and popping.

Spark plug is black and dry
Fuel level is 6mm above bowl rim, both sides ( clear tube method)

My only mods are.
Open air box w/k&n filters
Off road exhaust assuming high flow.
Rebuilt carb (with dynojet kit installed left 142 and right 144. Needle 4th position down. 3 turns out on pilot screw. 22.5 pilot jet.)

Carb settings are dynojet recommended settings for above 6000 feet, I am at 7000 feet

what is the recommended fuel level? Could timing be an issue? Any opinions would be welcomed. Thank you.
 

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Master of the Electron
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it starts out lean when cold and richens up as the engine warms up - so you are too rich (as we expected at 7000 ft).

Follow the jetting suggestion. Stage 2 is way too rich for 7000'.
 

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Tried a couple of things and no luck. It is idling great, but at 1/4 to full throttle it is stumbling horribly. The funny thing is when I finished adjusting intake and exhaust valves it seemed to run great. I shut it down re-installed my plastics and started it and let it idle for 10 min. when I got on the throttle it started stumbling and popping.

Spark plug is black and dry
Fuel level is 6mm above bowl rim, both sides ( clear tube method)

My only mods are.
Open air box w/k&n filters
Off road exhaust assuming high flow.
Rebuilt carb (with dynojet kit installed left 142 and right 144. Needle 4th position down. 3 turns out on pilot screw. 22.5 pilot jet.)

Carb settings are dynojet recommended settings for above 6000 feet, I am at 7000 feet

what is the recommended fuel level? Could timing be an issue? Any opinions would be welcomed. Thank you.
Engine timing can not be altered unless the woodruffe key is sheared and the flywheel has turned in relation to the crank............

Cam timing can be changed by one or two teeth on the cam gear if you do not time the cam to crank properly when you install the cam.....
 

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Discussion Starter · #12 ·
I see what your saying. Get stock jets and needles for 7000 ft elevation. I wanted to make sure that it was just a carb issue. I ran it last night cold and it went right into hesitation and stumbling. What is the proper fuel level for aa 660 raptor? Is 6 millimeters above seem at bowl and carb too high and cause over fueling?
 

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Is it defenately throttle position or could it be your PB limiter?
 

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Master of the Electron
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Is 6 millimeters above seem at bowl and carb too high and cause over fueling?

That high will cause it to run even richer. Everything you have described to date can be attributed to running too rich at 7000'...

#1 - reduce the main jet size;

#2 - you may have to lower the needles some (raise the clips on the needles), or replace the DJ needles with stock, but wait till after you replace the mains to decide.

Get the engine running well at 3/4 to wide open throttle by changing mains. Then get 1/4 to 3/4 right by adjusting needles.

Your pilot circuits are at least running ok for the moment - start and idle are good - but this might change a bit after the main and needle tweaking.
 

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Discussion Starter · #16 ·
ok my plan of attack is this, i am going to clean my exhaust screen and adjust my floats on the carb (using clear tub mod). Test my changes. If that does not work I will use my stock needles (which are thicker then dynojet) and then if I am still running to rich I will step down main jets or jump to stock mains.

This Raptor was not maintained very well and is my first Rapter. Thank you guys for your input.

Am I on the right path?
 

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Master of the Electron
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Sounds close enough to get you there eventually.
 

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Discussion Starter · #18 ·
fuel level in bowl was to high. Runs great, other then it pop a little on deceleration. would that be air mixture screw or do I need to raise my needle?

Thanks Maniac.
 

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fuel level in bowl was to high. Runs great, other then it pop a little on deceleration. would that be air mixture screw or do I need to raise my needle?

Thanks Maniac.
Open the air screws another 1/4 to 1/2 turn............
 

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Master of the Electron
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Agreed - you're a bit lean on the fuel screws. CCW 1/4 to 1/2 turn each.
 
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