Hi all I've got a few problems I was hoping someone could point me in the right direction. First I have an 04 700 efi sportsman with about 2700 miles an 350 hrs.
the problem is when it gets hot. if I've been in low for awhile and the fan is doing its thing it will eventually will start missing and sputtering and die if I shut it off for 10 min or so it will run fine seems like after it cools.
I have read that sometimes the fuel gets to hot n these machines only onetime has it refused to run right on start up I thought it would clean out an run but it didn't I put it back in the garage shut it off a min fired it up and it ran fine. Its not throwing any codes. yesterday it would just backfire when I went to start it but It has been really cold the last few days anyway if any of you all can point me a direction it would be greatly appreciated I can turn wrenches but know nothing about atv's thanks again.

 

Guessing the fuel pump is going out on you. If you have a pressure gauge, test the fuel pressure when its hot and see what you get. Without looking at a manual, I think it should be like 41 psi, give a take a pound or so. Ive also seen when the pressure fluctuates-its time for a pump as well. Should stay steady.

 

I don't have a gauge but I think I can borrow one[lots of tools but always need one more] thanks for the reply. Where do you buy parts from any favorite suppliers [forum sponsers maybe] I also need a few boots that are worn.

 

I dont stop here a whole lot anymore, too much to do at work so I dont know the site sponsors. There are aftermarket fuel pumps from all sorts of suppliers, from cheap, to expensive. Take your pick. Not saying any are any better than others, I like epi for cv boots. Various reasons. I've personally had good luck with high flow fuel system pumps. Hope it helps.

 

94harley Thanks I'm gonna try a carter pump I think I've read some about other guys having good luck with it Thanks again.

 

Well I got the machine out out last rode about 4miles it ran fine but it backfires when you let off the throttle fuel pressure is running high 48 to 50lb [ regulater maybe?
when I first started it it would backfire as it turned over but would not start but when it finally did start it ran fine.

 

Valves may need adjustment.

 

The 700 motor has hydraulic lifters. No valve adjustment.
48 to 50 psi is a little high in my opinion. I would guess the regulator myself. Did you look at the intake boot? Between the throttle body and head? They were famous for cracking and sucking air.

 

Thanks guys, I made a post on here somewhere but there ia no telling where I posted it SORRY if it comes up on someone elses thread.

I worked on the 700 today first the fuel filter the gas that was in it came out clean but it seemed to help just a bit. it took just a wee but of pressure to blow it out by mouth but

after that it was normal. {air filter too}
Second I changed the plugs [NGK ]they looked good but were kinda black and sooty
Third I remembered I had a pk of CRC throttle body and MAF sensor cleaner get it at WM a can of each.
I Cleaned the MAF or that's what I thought it was no difference then the throttle body it was kinda dirty but it done wonders idle came back to normal 1180 sounded better and ran better. Sometimes you forget the small stuff I also taped some wires.

94harley the boot you mentioned was cracked I siliconed the cracks awhile back just trying to make it last awhile longer I need to
get a new one for it do you know of a good supplier for this kind of stuff.
One more thing the machine has about 450 hrs on it instead of 350. Thanks again for the info.

 

Spend the money on an OEM in my opinion. Make sure your throttle freeplay is correct to(etc switch) approx 1/16 to 1/8 play at the end of the lever.