Hi Guys, My 700 Sportsman starts and runs great for a while, but when it gets hot, it acts like it is starved for fuel and backfires sometimes. When you put it under a load it won,t hardly move. I have put insulation under the tank but it did not cure the problem. Also, I noticed that the speedometer does not work but the rest of the instrument panel does, not sure if that has any bearing on the problem.

 

Not registering speed/mileage is usually caused by a dirty or shorted out hall effect sensor located on the right front brake caliper.Item #28 in the parts breakdown. Dirt Cheap Yamaha, Honda, Arctic Cat & Polaris OEM Parts & Accessories – Cycle Parts Warehouse If you check this forum or just google Sportsman 700 ignition problems you'll find quite a bit about problems people have had. The whole system on the 2002 to early 2004 carb models changes out to a Kokusan complete ignition system from the Ducati that's in it now.Symptoms range from back firing,hard starting,won't run when hot plus some people have killed the machines then they wouldn't crank back up. Kits are available at Cycle Parts Warehouse,Cheap Cycle Parts,Partszilla,etc. Around $450 for the complete ignition.Not worth trying to repair what you have as the parts are NLA. Here's the pdf instructions along with what's all involved in the kit.http://www.google.com/url?sa=t&rct=j...71778758,d.aWw
Plus videos are out now that may help on installation.

 

Thanks, I changed the complete ignition system last year and it ran great. It still runs and starts great until it gets hot--about 15 to 20 minutes into the ride. I will check the hall effect sensor today.

 

Another thing to check on the 700 is cracked intake manifolds if you've already done the ignition upgrade. They usually crack under the clamp and are hard to spot unless you remove the clamp. Just a small split can cause problems on running. If the fan is kicking on,the radiator sensor is good and probably has trapped air. Just elevate the front end up with the radiator cap off and let the fan cycle on and off several times to purge any trapped air,then top off the radiator and coolant bottle. These models were bad on this also. Make sure the hall effect sensor is plugged into the speedo. Some people would unplug them just to keep from racking up mileage. Check for dirt/mud that might be blocking the signal from the aluminum cap covering the hall effect sensor and the rotor slots are clean and open where it get the signal from.If all this checks out just replace the sensor. If it still bogs down when it gets hot,even after the extra insulation around the fuel tank,could be a weak fuel pump,carb or tank vents partially blocked or collapsed.

 

Thanks for all the info, I will check it all out