02 Summit 700 Flat spot at 5000rpm

[Mountaintech]

Bought a 02 Summit 700 for the girlfriend. Great sled for her but it has a really bad flat (dead) spot at 5000rpm, which is at about 1/3 throttle. Took apart the carbs and they are clean, intake boots and reeds are good, raves are fine, plugs are good. It had an aftermarket can on it and I put the suitcase back on.....didn't make a difference. Carbs have stock jets (510) and needles. If I run it on half choke the problem all but goes away. Sled runs great above and below trouble point. Any thoughts?

 

[Crasher]

I had the exact same sled, sold it last year. Great sled.

Here is what made mine work better. #20 pilot jets, 490 Main jets

I changed the top gear to a 19. I don't remember the bottom but I think it was 43.

I also installed a 16 x 151 x2 track.


I ride at 7-10 thousand feet.

Oh, I forgot. I took the plastic washer from over the clip on the Needle valve and moved it under the clip. Basicly moved it up. There is no grooves in the needle to move the clip up or down.
I also had to adjust the air/fuel mixture also. The little white knob with the spurs on it on the lower right side of each carb..
I cannot remember if I had to turn in or out.

To sum it up. Mine was too rich on the top end and to lean in the midrange. Hope this helps.

 

[Griff]

It might be dpm. I attempted to fine tune my 02 Summit 7 to eliminate the rich and lean bogs. I finally succeeded by fine tuning the dpm right off the sled and into my tool box. I jetted it like a non dpm MXz 7 and it ran great.

 

[Dopp]

I run a 00 700 for wife and an 03 800 for myself DPM has never faulted once. Is this a great Alt adjusting system. To be safe lift the mid needles a full by moving clip DOWN on needle and see if it makes it better or worse this is checking mid needle setting by fatting it up first, since a plug reading isn't availible.

 

[Mountaintech]

I run a 00 700 for wife and an 03 800 for myself DPM has never faulted once. Is this a great Alt adjusting system. To be safe lift the mid needles a full by moving clip DOWN on needle and see if it makes it better or worse this is checking mid needle setting by fatting it up first, since a plug reading isn't availible.

Not much flexibility in changing clip position on needle as there is only one slot for clip. Presently there is one plastic washer underneath clip.

 

[Crasher]

If I remember the carbs came with 15 pilots. You can get 17.5 or 20. I put 20pilots in mine.

Also, make sure your carb heaters are OFF.

Plastic washer under clip/someone or even the dealer must have done that before you got it. The came with the washer on top.
It was a pretty standard thing to do to help with midrange bog.

 

[Mountaintech]

If I remember the carbs came with 15 pilots. You can get 17.5 or 20. I put 20pilots in mine.

Also, make sure your carb heaters are OFF.

Plastic washer under clip/someone or even the dealer must have done that before you got it. The came with the washer on top.
It was a pretty standard thing to do to help with midrange bog.

Carb heat is off. Stock pilots are 17.5's for the 700. The flat spot/bog is really bad. Basically makes the sled difficult to ride on the trail.

 

[Crasher]

I think there was a different needle # that you could get from the dealer that was thinner and had multiple grooves to move it up and down to help richen the midrange up.

I didn't buy one so I can not be sure what it was.

 

[Mountaintech]

I think there was a different needle # that you could get from the dealer that was thinner and had multiple grooves to move it up and down to help richen the midrange up.

I didn't buy one so I can not be sure what it was.

Anyone know about this different needle??

 

[dansgarr]

I don't mean to go off topic but I finally registered for this site after 3 years of reading great information from everyone. You all have helped me a lot. Anyways I have a 2001 summit 800 that had a mid range flat spot as well. I don't know if the 700's have the same carbs but, I put new needles in (BPR # 404161990) and it did cure 95 % my flat spot. I can still raise the needles more but I think I am going to try going up a couple of pilot jet sizes and see what it does.

 

[Mountaintech]

Thanks for the replies. Installed 490's and 20 pilots. Much better now.