Raptor 660r jetting help

288 Views 7 Replies 5 Participants Last post by QuadManiac, 9 d ago

Laneperkins15

Hi I have a 2001 raptor 660 and I am having trouble getting the jetting right after a rebuild/ modifications.
Bought the quad blown and completely went through it and replaced everything. Im running stock carbs with mikuni jets, stage 1 hot cam, minor head porting, pro flow cone filters with air box but no lid, and stock pipe with no baffles/ spark arrestor. I was running 170L and 172.5R jets and 25 pilots, but I can’t get it to run correctly. Do not remember current needle position. Bogs sometimes and seems like it has no power on the top end. I’ve changed jets a few times bigger and smaller but I can’t make it any better. Any recommendations would be appreciated

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Motoswan

· #2 · 21 d ago

Are you sure it's the carbs and not one of the safety switches/rev limiters?

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Laneperkins15

Discussion Starter · #3 · 21 d ago

Motoswan said:
Are you sure it's the carbs and not one of the safety switches/rev limiters?

Yes sorry I should have put that in the description the park brake and reverse limiters have been disabled

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Motoswan

· #4 · 21 d ago

If your sure it's not one of the rev limiters I would start with thoroughly cleaning the carbs again, make sure the floats aren't sticking open, are at the right height, and that you're needles are in correctly. These carbs are extremely sensitive to even the slightest bit of dirt or residue in them. Also I would check your compression it may be an exhaust leak or carb boots leaking. What's your spark plug looking like?

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Montana

· #5 · 21 d ago

Do the “clear tube method” to set the floats.

Read thru this

Jetting that works, collecting info

Would like to collect the jetting that people are using and know to work well. With any luck others will be able to find a simillar setup and have a starting point for thier carbs. A standard format would be easiest to follow. Elevation and region of the country or world. Including this since...

www.raptorforum.com

And this

The Basics Of Jetting This Expains It

Pilot Screw - Idle Pilot Jet - Idle to 1/4 throttle Needle Jet and Jet needle - 1/4 to 3/4 throttle Main Jet - 3/4 to full throttle 1) Idle Screw Allow the engine to reach operating temperature. turn to smooth idle. If unable to obtain smooth idle, go to...

www.raptorforum.com

And this very helpful thread

Carb mods and Clear tube method explained

It’s my 1st post, so I hope you guys find this useful. I have spent years messing about with the carbs on the 660 raptors, and I picked up a few tricks in the process. The basics on how to set up the carbs have been posted, so I am not going to explain more on that. What I will tell you is how...

www.raptorforum.com

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QuadManiac

· #6 · 12 d ago

DJ kit for for its jets and needles - DJ 156 in left, 158 in right, (or Mikuni 160 L, 165 R). DJ needles at 1 notch rich of center... you'll never get open airbox tuned right without the DJ needles.

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Supermike

· #7 · 12 d ago

QuadManiac said:
DJ kit for for its jets and needles - DJ 156 in left, 158 in right, (or Mikuni 160 L, 165 R). DJ needles at 1 notch rich of center... you'll never get open airbox tuned right without the DJ needles.

I'll second that, that's from experience, been there, done that, got the whole wardrobe. Also do clear tube method for float height as floats are set too low from factory

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QuadManiac

· #8 · 9 d ago

In the troubleshooting world, where I come from, the mantra is "Only change one thing at a time!"

Do the jet/needle change to get it running... THEN change float height if you need to - and then you may have to change jetting again, but you'll know WHY now.

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