Need advice on bog/gas consumption????

MM 700

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Jul 29, 2005
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Location
Iowa
A stock 2001 Mountain Max 700 with around 5000 miles. Has a bog the minute you go off the trail into the powder, not even powder over the hood. Runs like its flooding out. Hope on the trail takes 15-30 mins to clear back up. Then it comes and goes randomly.

About the same time this happened, it started using gas bad. We have a group of 5 Mountain Max's and this one ran out of gas when the rest of us had 1/2 tanks left???? I have cleaned carbs, checked the floats.

I THINK the bog in the powder is due to exhaust/pluging not sealed, sucking exhaust into the air box. Not sure on the fuel consumtion. Has the stock snow deflector for exhaust outlet.

This has me stumped.......Reeds bad, using more gas????

Have had this sled for 4 years without any problems
 
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maybe start by checking your reed petals and carbs to make sure everything is as it should be?
 
Ultimax said:
I had a similar problem with the same sled model a couple of years ago. I replace the float bowel needle & seats and its worked great since then.


Are you talking the pilots jets?? Never thought of the needles them selves, I guess they are out??

What was your problem you were having?

This sled has cost us some nice meadow riding......
 
I have done compression check, and it checks out fine. Doesn't rule of rings though. When it runs right, it runs great.....
 
Gas needle & Seats

I'm talking about the needle & seat that the float is attached to that lets gas into the float bowels. Mine were leaking past the inlet and was flooding the engine enough to make it run rich. It was most noticable when going down a bumpy road. It would also be loaded up after you would start it following a short break when riding.
 
I found a pic in the "Tech" section. I see what you are talking about. That is something for me to look at.

Thanks

Any other ideas????
 
Ultimax said:
I'm talking about the needle & seat that the float is attached to that lets gas into the float bowels. Mine were leaking past the inlet and was flooding the engine enough to make it run rich. It was most noticable when going down a bumpy road. It would also be loaded up after you would start it following a short break when riding.
what he said x2 - i just replaced mine in my viper. my reed petals were actually wornfrom having so much gas run through them.
 
When replacing the needle/seat. What do you need, the needle assembly or just the 0 ring and filter????
 
Is this correct. I need to order the complete needle and seat assembly???Not something I can clean? Is there a way the check them to see which one is faulty??
 
Needle & Seat

When I took mine out they looked fine, but it was the only thing I could come up with considering the way it was acting. I replaced all three of them, both the needle and seat assembly. They weren't cheap but it fixed the problem.
 
OK, so I changed all 3 needle and seat assemblies.

This thing is still acting up. The stock 01 Mountain Max 700 with around 5000 miles, still seams to run rich as can be. We have to lean it out with the Vari-Flo way past where it should be, other wise it runs to rich and bogs/sputters.

The funny thing this problem started around the time when I changed the jetting. ( I have checked the floats...twice. Looked at the reeds thru the carb boots, and they look OK. All are seated to the cage)
It was jetted for sea level and we used Vari-Flo to adjust the jetting to the 6000 feet(which is the lowest elevation we ride at. It had a slight bog on the low end, was the reason to jet to the 6000 feet. So I jetted to Yamaha specs 5000 to 6000 feet and 0 degrees.

Also, where the Vari-Flo is set to with the 5000-6000 feet jetting set up, is almost the same as we had it when running the sea level jetting.

I am worried about putting the jetting back to sea level, and having to change jetting on the hill. And that would not make sense...


Any suggestions :o|
 
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Variflow

I'm not real familiar with the variflow system. I know a lot of people on this forum have used them with good results. They might have an answer to your problem or similar problems resulting from the variflow. There are a lot of smart Yamaha techs on here with years of experience. See if you can TURK to answer you on this forum. He seems to have a lot of experience with the Yamaha triples. I've read a lot of his posts and he would be one of the first on this forum I would contact with a possible answer. Good luck!
 
We have 4-5 other triples with vari-flo, and this one is at a way different setting then the others.

This sled has always had the vari-flo on it with good results. I do not think the Vari-Flo has anything to with the problem.

Thanks
 
MMax 700

Sorry, I guess if it was me I would start looking at an ignition problem. It sounds like you gone through the fuel system pretty thoroughly. If the spark is weak you will be using more throttle to get the HP from the engine and use more fuel due to the lack of combustion. I'm not familiar with testing those components, but like I said I would contact TURK. Good luck!
 


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