I have been reading on this forum trying to catch up on all the great info now that I own a P650. I have noticed all the neat modifications you folks are doing to improve your machines and I have a question.

By putting on a freer flowing air cleaner, and then adding a new, larger intake (either making one or buying the one that is being developed) I understand that this would allow more air into the system, changing the air/fuel mixture, and essentially leaning out the machine. To compensate, I would have to change jets. Is that right? How big of a jet change would I have to make?

I also understand that by taking my Minnesota machine to the Colorado mountains, up high, the machine gets less air, thus changing the air/fuel mixture, making it too rich, and that to make it run right, I would have to change jets to lean out the machine. How much would I have to lean out the jets to operate at 10-12,000 feet altitude?

Now, my big question. I'm not very bright, but I do think alot. If the adding of a new air cleaner/intake leans out the machine at lower altitude, and a machine needs to be leaned out at high altitude, could I get by with running stock at lower altitude and changing the air cleaner to a freer flowing model, and enlarging the air intake when I go to high altitude, without changing jets or without hurting my engine? Does anyone have an opinion on this or on how much this change might lean out the engine? I was just thinking that for one week per year in the mountains, it might be easier (cheaper) to change the air cleaner and intake rather than re-jetting. Especially since I am satisified (for now) with the performance of the stock machine. Inquiring minds! Thanks
Todd M.
Minnesota

 

Just my opinion

I'm going to leave mine alone...I'm happy with it stock. I am a hands on guy, but jetting is just not something I want to play with...out of all engine related items carberation is the one thing I can't stand. Now if I had a DYNO and all the computerized stuff kawasaki techs have then I'd be all about it...IMO that's the only way your going to be able to see a differance anyway is on a computer screen.

 

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Now, my big question. I'm not very bright, but I do think alot. If the adding of a new air cleaner/intake leans out the machine at lower altitude, and a machine needs to be leaned out at high altitude, could I get by with running stock at lower altitude and changing the air cleaner to a freer flowing model, and enlarging the air intake when I go to high altitude, without changing jets or without hurting my engine? Does anyone have an opinion on this or on how much this change might lean out the engine? I was just thinking that for one week per year in the mountains, it might be easier (cheaper) to change the air cleaner and intake rather than re-jetting. Especially since I am satisified (for now) with the performance of the stock machine. Inquiring minds! Thanks
Todd M.
Minnesota >>


Hey you've got a good handle on it already. You're absolutely right. If you don't want to fool with the jetting at all then run stock intake until you head for the high country and then put the stuff on that increases air flow. You will run rich at altitude but you are in no danger of damaging the engine with a rich mixture. You may however foul plugs if it's really rich.
Since the machines are jetted a little lean any way for emissions I would consider rejetting richer at lower altitudes if I was gonna run a modified intake there. If you do that then you have set yourself to have to re-jet at altitude.
I live and ride at 6500-8000 feet and I feel that the intake mods I have done have me only slightly rich compared to the WAY rich I started with. I have yet to touch a jet. Plug reads and white glove in the exhaust pipe say that I am close to being optimized for this altitude.

Craftsmen sucker hose and a UNI filter are my only mods so far.

 

Thanks for the info. I would rather do the increase air thing than have to rejet the carbs for just one week in the mountains. I certainly can put up with a little rich, a little loss of power, and increased fuel consumption in the mountains if the thing starts and runs OK. I can also take a spare set of spark plugs. I'm not looking to race around up there, just want to be able to motor up the mountain faster, and with less energy expended, than I was if I was walking. Last year, one foot, I had 1.5 hour and 2 hour walks each way to the hunting areas from the camp, and that is on top of hunting on foot all day too. Makes for a long day. This is at 11,000 to 12,000 elevation, and takes a lot out of us flatlanders. I won't hunt off the quad, but just want to save myself some time and energy for the hunt itself. Of course, I would also use the thing to pack out the elk.

Now the additional question, what is the Craftsman hose you were talking about. I was thinking of the UNI or the Duo something air filters and I think Nyroc said some company was going to be selling an air intake that was larger.

Todd
Minnesota
P650 and Bayou 220
Ford F350 Powerstroke

 

That company would be http://www.diamondgracing.extremegarage.com/ I e-mail them and it is going to go for about 50 bucks plus shipping it should flow way better that the air hose off a shop vac due to the sides of the hose. and it will also have a drain hose for water.

 

The Craftsman sucker hose is nothing more than about an 8-9&quot; piece of shop vac hose installed in place of the factory snorkel. It fits perfectly in the rubber grommet on the airbox. For me it made a large difference in mid and high range power. Don't do this mod if you ride in deep water or even cross the ocassional creek as the water trap that's built into the factory snorkel is lost and any water you encounter, even small splashes are gonna get sucked right in to the airbox. I made mine just long enough to protrude through the rubber damn. Any longer and the stiff hose was interfering with all of the wiring running up the steering shaft.