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Dave Scarce Posted on Jun 25, 2012

Bike cuts out and misses when you open throttle

Bike runs good at low speeds but on the road if you open the throttle slow it builds up speed but if you open the throttle fast it misses and back fires

5 Related Answers

Anonymous

  • 1 Answer
  • Posted on Mar 21, 2009

SOURCE: kawasaki gpz 1000 rx 1987 model

Running well at high revs would indicate that all the fuel and air it needs are getting to the engine and you also have a good spark. Probably no problem with air and fuel filter ( if fitted) or sparkplugs.

Running hot, and bad idling are signs of a lean air fuel mixture. The engine is probably not getting enough fuel at low revs.

This could be caused by an air leak between the carburettors and the engine. Check that the vacuum line to the fuel tap is properly secured at both ends. It is behind the fuel line at the tap.

Get a a short length of hollow plastic tube and use it like a stethascope - put one end to your ear and move the other end around your carburettor mounts with your engine revs as low as you can get, and listen for any sucking noises that would indicate a leak. Look for cracks in the rubber inlets.

The other possibility is that there is an internal blockage in the idling jets or idling fuel circuit. This is where dirt tends to lodge because the jet dimensions and passageways are very fine - The high speed jets are much bigger and dirt often just passes straight through.

Try a little bit of choke while the engine is warm to see if you get a stronger low speed response. If so that would point to an internal blockage.

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Anonymous

  • 3 Answers
  • Posted on May 05, 2009

SOURCE: misfiring at speed on gilera 200 scooter

This sounds more like a lean fuel condition than ignition. If it was stored over the winter without the gas being drained or a fuel stabilizer being added, you'll likely have varnish build-up in the fuel system that is not allowing sufficient fuel flow.  If your engine is fuel injected, it's likely your injector is partially clogged.  If it's carbureted, your carb jets may be partially clogged or your carb float may be sticking and not allowing the needle valve to fully open.  Fill the gas tank with fresh gasoline, but leave enough room for a can of Sea Foam.  The Sea Foam may be able to break up the deposits and allow fuel to flow again.  However, there's no guarantee and the fuel system may have to be disassembled to be cleaned.

Knight 007

Murtaza Akberali Versi

  • 767 Answers
  • Posted on May 10, 2009

SOURCE: honda cb750 f2 1978fault on old bike ! electrical problem

From your explanation it sure sounds electricals, but surprising to hve a total failure to the electricals and thn it reappears after 30seconds!
Best would be to go through the wiring especially frm the battery onwards, the fuse box .
Since it is totally disappearing it should be a fault to those main wires could be lose connections somewhere!.
Hope this helps.

lapum0nz

  • 18 Answers
  • Posted on May 11, 2009

SOURCE: gear box oil my bike cuts out at top speeds

the gear box oil does not go anywhere.it helps to lubricate the gear surface.its located at the rear .pls check your carb and spark plug.if two item is o.k check your engine block is there any crack at your engine

nova2nv

Bill Linda Rivard

  • 197 Answers
  • Posted on Jan 23, 2010

SOURCE: I have a 96 arctic cat zr 580 efi that runs good

Remove handle bar cover,find 3 wires that come out of the right side throttle,follow them down to where they get just about under the cowling and disconnect them there.Find a wire to jump the 2 outside wires of connector and plug harness back together.This will disable your throttle saftey switch which is most likely the cause of your problem.The center wire is for the kill button on top of bars.

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2011. Why has cruise control failed?

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Did tune up but still acts like it's missing once in a while

skipped filters?
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How do I adjust the carburator?

There are two needle screws that can be adjusted to make the engine run properly. Be certain that the carburetor is clean and the diaphragm is in good condition, and the fuel is new. The two needle screws mentioned above should initially be adjusted at one turn open from turned in all the way (lightly seated). Each of these needle screws performs different functions. One is for idle and throttle response (this screw is marked "L" and the other screw is marked "H". L and H are marked on the carburetor body and also on the plastic "shroud" near the adjustment screws. These screws are not interchangeable, being foolproof since the thread sizes are not the same. When properly adjusted the low speed screw (L) allows the engine to idle properly and throttle response will work properly. When the high speed screw is adjusted properly the engine will have correct power at full speed. Adjust the low speed screw so that the engine idles and when you squeeze throttle all the way to wide open the engine should not hesitate and should come up to full speed and when you drop the throttle it should idle nicely without stalling. Now adjust the high speed screw. Hold throttle wide open, holding it there while you adjust the high speed screw. If this scares you (be carefully so that the spinning chain does not cut you!) you may adjust the high speed screw at idle, turning it just slightly in or out. The high speed screw should be adjusted so that the engine does not run clean at wide open throttle but sputters slightly, slightly adjusted open from running clean to slightly sputtering. When under load (cutting a log) the engine should run clean. Good luck!
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Hyosung avitar 650 wont stay running

Maybe this will help. This is a common problem that I have had with my GV250. Almost the same bike mechanically by Hyosung.

If the battery is low on charge and you are lucky enough for the bike to start. As per normal when first started it revs higher because the bike is cold, this turns the alternator fast to give you the electricity you need to keep the bikes computer working properly. Bike will warm up and revs drop down, alternater not turning as fast, not as much electricity being made. Bike will either stall or rev up and down irradically to try to produce its own electricity. This will occur when the battery charge is low and bike is at low revs, for example when you slow down for traffic or you stop.

If this is your problem. To resolve it when you are out on the road, keep the revs up, twisting your throttle gently when you are going slow or stopped. Give the bike a good long run on the open road to give the battery some charge from the alternator.

Make sure your battery is maintained. If you dont use your bike for a while it will lose charge just sitting there doing nothing. Give the battery a good deep cycle charge or take the bike for a good long open road ride.
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