MMax 700 loading up/backfire

M

mcuhan

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Joined
Dec 28, 2009
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21
Age
44
Location
Minnesota
I rebuilt a 2001 Mmax 700. Idles according to spec and engages properly too. However when I'm on the gas, let off, then try to get back on the gas, it loads up and sounds like it wants to backfire. It doesn't backfire but I need to let it return to idle speed before I can get after again.

I'm not sure if this air/fuel related or clutching? Any guesses?

It's setup for flatland running. I've been into the carbs a few times and I'm back in there again to make sure the jets and other settings are all stock.

It had a Veriflow system in it but I removed to make it a permanent flatland sled.

I've got other red headed beasts and they are running great. Having trouble with this one though. And am anxious to run the 141 powder special with the rain coming this weekend! :letitsnow

Thanks
Matt
 
Nope on TORS. It's not that kind of limiting. If I get after it initially, it revs right up and I'm on my way. If I'm at WOT and then let off, I can't get back on it mid-range, it bogs and loads up. I need to bring it all the way to idle before I can get it back up to WOT and normal RPMs.
 
Im guessing carbs. Did you check the top hat screens under the float needles? Usually a bog is a lean condition as ive always understood. But yours happens when getting back on the gas from wot. Have you tried to blip the choke when it bogs out? If it jumps back to life that points to carbs. Floats free and correct height. Fuel screw right? Thust thinking out loud
 
If your holding it at WOT then it wont accelerate after you let off this sounds exactly like the TORS system kicking in. Thats the only time my tors would kick in is just after lake runs, Id have to stop before going onto the trail so that the sled would accelerate.
 
Only other thing I could think of is the bushings might be worn in your clutches and they are sticking, did you try engaging your secondary by hand to see if its smooth?
 
check your mains... probably too rich..especialy if it had a variflow you need to jet down!
 
Last year I had a sx 700 that was running like crap i tryed everything with no luck but in the end it was a needle in the carb lost its c-clip.
 
Put the mmax700 back together after checking all carb specs and mains..everything checked out stock. 143.8 and 145 where they are supposed to be and everything is clean with fresh fuel. Still doing the same bog. I messed with TORS too but that didn't seem to matter. What is the trick to override TORS? I thought it was to just unplug the TORS cables and loop them together. No such luck.

On the fuel screw adjustment and setting, is it correct to tighten all the way in and then back out 1.25 times?

Thanks for the replies so far. Clutch tomorrow.
 
Retried bypassing TORS and bingo. No more cutting out. How can I test which side of the TORS is bad? The carb connection or the TORS up in the throttle lever? I'd prefer to set this right instead of keeping the bypass?

Also, to set proper idle and throttle cable, I loosened my cable all the way, then set the idle screw accordingly, then adjusted throttle cable to appropriate free play. Am I missing something in setting the throttle cable and idle adjustment?
 
The gap in the throttle lever should be 2mm +/- 1 mm when you push the lever against the tors switch and take the slack out of the cable. I use the inside jaws on a digital caliper, set it at 2mm then adjust the cable slack from there. Another thing to check is hold the throttle to the bars, make sure the lever touches the grip but the carbs are also against the open stop. If you can still rotate the throttle shaft on the carbs with it pinned to the bars you have too much cable slop and are not getting full travel.
 
If you pulled the connectors for the TORS system on your carbs with no change, my guess would be the problem is on the throttle.
 
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