M7 bog

[Redracer]

I know this has been beat to death, but I cant figure out why I get this bog when I try to get on the throttle real fast. I've searched over and over for a fix but none has fixed it. I've checked the clutches, wiring, ECU tube, tail light wires, AP valves, APV cables, servo motor, exhaust, plugs, coils ect. It runs fine when the bog doesn't happen but it happens a lot. Especially after a hard pull then coast down hill and need to get a hand full fast. It almost dies and you nearly fall over the bars then it comes on hard and you nearly fall off. Any thoughts? Even on ones I think I have checked. I have two M7's one since new and this one I picked up the last of last season. And my first one whips the crap out of this one. They are both stock 153's with A20's except for bar risers and venting. Thanks in advance.

[LucasMX358]

injector perfector man!!! thats all i got to say!!!

[Blk88GT]

I had that issue last year and figured it was the nature of the beast. Do you have a box on the sled?

It was suggested I add "3" down at the lowest setting by a reputable Colorado backcountry rider and the lean bog was gone. Not sure if it'll solve your problem but it's easy to try if it's got a box.

[Redracer]

Originally Posted by LucasMX358

injector perfector man!!! thats all i got to say!!!

Yes I do have the injector perfector installed. I have it on both my M7's. It did seem to help. But still has a bad bog to the point it almost dies. My first M7 had the famous bog but I was able to get rid of it by adjusting the oil pump and add the injector perfector. Neither of which has helped this particular M7. I do not have a box on it. I by passed the throttle over ride switch and that did'nt help. I need to check if the symbol on the ECU and injectors match. I don't know if they do or not. That would do it if they dont match.

[sidehill]

Check your fuel pressure. The 7s with low fuel pressure seem to run good. The ones with higher fuel pressure run just like you are explaining.

[Blk88GT]

Good info, thanks sidehill! What's the acceptable range?

[sidehill]

Originally Posted by Blk88GT

Good info, thanks sidehill! What's the acceptable range?

There is no one size fits all answer for this question. Too many variables like what kind of mods you are running, what ecu and injectors that you have, your riding style and elevation, how your clutching is setup, how much load you have on your motor through the clutching.

It all goes back to old fashion tuning. Check your plugs and wash and keep turning the fuel pressure down till you get it tuned. To many people rely on O2 sensors and egts for tuning. They are good monitoring tools but not tuning tools. Checking plugs on the m series is a real pain in the a$$. Checking wash is really simple, just pull the powervalves and shine a light through the port. Takes about 10 minutes to check your wash this way while you are out riding.

We have one m7 that runs 42psi and it is a basically a stock sled. We have another one that has a few mods on it and it is set a 45psi. If you have a sled that is modded out and you run a fuel controller try turning the fuel down so you dont have to pull any fuel on the box and then just add fuel where needed. The less you have to change the fuel curve with a control box the better your sled will perform. If memory serves me correct cat calls for 42-48 psi on a stock sled.

To change fuel pressure you will need to buy an adjustable fuel regulator.

[Redracer]

I checked the measurement on the secondary white nut and it was about .25" too much. I adjusted it to .52" from .74". Would this cause the bog?

[B C]

I've got the same problem w/ an 05 M7. Granted it has plenty of mods w/ a Dakota Perf 800 kit and PL controller. However, I find it hard to believe it's the nature of the beast as it just came on at the end of last season. I do know it's driving me nuts. What's a good adjustable FPR to use on the M sleds?

[BigRed118]

I have an A/F guage now installed and this is what I have seen. At 0% throttle position (clutch engaged 3500-5000rpm) the sled is very lean. I have been told that A/C has 2 maps installed. An acceleration map and a deceleration map. Not sure if that is true or not. I have a similiar bog and I am going to try adding fuel at 0% throttle position through those RPM ranges to see if that fixes it.