Question about Honda CB 250 Motorcycles

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1979 cb 250 flat spot

It idles find but when you take off it has a flat spot, but it cleans it self and rides fine up to 5000rpm and cuts out then you roll for 500m it will start and ride if you don't go over 5000rpm or stop it is hard to get going. can some one help please

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Posted on Jan 02, 2017

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SOURCE: 1983 FLHS starts and idles fine,pops and backfires when riding

In 1983 the carb used on this model was a kehin. They can be made to work well, with a couple of tweaks. First, on the top about midway, you will see a boss sticking straight up. Unless it has already been done, use a jabsaw and cut the top 1/8 inch off the top. Using a tiny improvised screwdriver, back out the idle adjustment screw which is down inside about a half a turn. Then remove the float bowl. You will see 2 tubes hanging down. Remove the rubber plug from the larger one and remove the low speed jet. The jet and the mixture screw are soft brass, so make sure you don't shred them. The jet has a number stamped on the end. Go to a knowlegble shop and get the next size up. For example if you have a 52 and they say the next size is a 54, that's what you want. Take the old jet with you and compair the size of the air holes along the side. They should be the same size. If not, they are selling you a jet for a cv carb and that will not work. (common mistake) Don't forget to shove that rubber plug back when you reassemble it. If I have your problem pegged correctly, the bike will be less cold blooded and the driveability will be much better.

Posted on Jan 06, 2009

  • 36 Answers

SOURCE: bike keeps cutting out

sounds like either your fuel vent on the tank is clogged ( the rubber hose coming off the top of the fuel cap) or #2 your spark plugs are fouling out which is probally the most common thing with a 2 cycle engine.

Posted on Jan 27, 2009

  • 408 Answers

SOURCE: my zx12r cuts out while riding them wont start

You should measure the fuel pump's supply first to check that the pump works ok.
When it dies, do you hear the pump pressing your ear against the fuel tank and turning the key to on position and your kill switch to on too?You should hear it working for 3 sec.If not working at all start by checking the pump's relay and then the pump itself.

Posted on Jun 08, 2009

  • 12 Answers

SOURCE: rmz 250 04 model wont idal or kick start

Like I told somebody earlier to day lower the octane rating of the gas you are using....repost if you need anything futher......

Posted on Jun 22, 2009

  • 377 Answers

SOURCE: aprilllia rs 125 wont idle

some things to try,
adjust the idle using the black knob on the carb,
check air filter is clean,
remove and clean carb

Posted on Oct 24, 2009

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