I have a 2002 suzuki eiger quadrunner 400 2x4 when idling it will run fine and I can rev it up full throttle no issue but when I go down the road it wont go past 30 mph before it starts spitting and sputtering like its starving for gas I had the carburetor cleaned I changed the sparkplug I checked the fuel valve to see if its dirty idk what else it could be

SOURCE: no acceleration

I had the same problem with one exception. It would rev higher than 3500 but the higher it revved the more it bogged. I had the catalytic converter replaced. I thought I bought a new car. Acceleration is just like new. It was easy enough to test. My mechanic cut a hole in the exhaust pipe in front of the catalytic converter. It sounded like a truck but the acceleration difference was immediate. Easy diagnosis.

The car is hard to shift because the more you press on the accelerator the more the computer for the transmission won't let it shift. Which in turn causes the car to bog more sending more unburned fuel into the catalytic converter. Which in turn causes more carbon build up and more back pressure. Vicious cycle. It will only get worse.

My thermostat caused the entire problem. Thermostat was stuck open, engine never got to operating temp most days. Car burned rich. Bad gas mileage. A lot of unspent fuel being dumped into the converter. Probably have some underlying cause that needs to be addressed. Bad plugs, wires, coil, fuel filter.

Posted on Jan 21, 2009

SOURCE: Motor spits and sputters

If it is old enough to have points then I would check them and make shure they are clean and gapped at .020. if that is noth the problem then it sounds like a fuel issue. Either a weak pump or a dirty carb.

Posted on Aug 06, 2009

SOURCE: 2003 suzuki rm 85 wont start cleaned carburetor,

if it has reed valves, check them for either cracked or broken pedals. also try starting it with the air filter removed. also make sure the choke is operating properly

Posted on Oct 22, 2009

mark woodring

• 496 Answers

SOURCE: 2001 Honda Shadow ACE 750 idles, but won't rev up

vac leak craked boots

Posted on Jan 05, 2010

Joe Stanch

• 755 Answers

SOURCE: My Suzuki Eiger 400 starts hard then once running is great.

Clean and keep a spare pair of plugs , use better octane gas , 92 is the best for bikes , cost a little more but stops the problems you have starting , make sure you wires are not grounding out and carb has no vacuum leaks , ck hoses and air filter

Posted on Feb 21, 2015