high revs

[GZ250]

for sometime like a week i am experiencing that when i come to a stop the engine keeps going on at high rev (not very high) but i can feel that it takes like few seconds when it comes to normal (rev) speed. I have oiled the cable and it is not sticking. Is something sticking in the carb? where to start to find the fault.

Please suggest. Thanks.

[Moedad]

Does it do it after the engine is good and warmed up? I'm no GZ mechanic, but choke cable lubrication or idle setting might be a couple of things to play with. Check and make sure your fuel valve is not set on "PRIME" too. Try running some Berryman's 12 through a tank of gas. That about exhausts the things I know to check.

[GZ250]

yes it happens when the bike is warmed up and hot. choke seems to be ok because when i close the choke initially the revs go down and idle setting is also not very high where the engine seems to be running high. otherwise i do not feel any thing wrong, the clutch is working fine and bike is running good. i am using the a carb treatment additive. i looked the berryman site but how do we buy that because it does not sell or any anything.

Thanks for the reply.

[Easy Rider]

i am using the a carb treatment additive.

Which one? One at a time, please!

This could be a sign of a vacuum leak. Check the air filter element to be sure it is not loose or otherwise damaged. Check the rubber boot between the carb and engine.
And, believe it or not, the drain tube coming from the bottom of the air box MUST have the plug in place. If not, this effectively makes a vacuum leak and might cause your problem.

Also need to be sure there is some slack in the throttle cables; no slack can mean a subtle sticking that is hard to notice. Same thing for pinched or kinked throttle cables.

[patrick_777]

Have you adjusted the idle speed?

[Easy Rider]

Have you adjusted the idle speed?

IIRC, he says it drops back to "normal" on it's own after a few seconds:
" i can feel that it takes like few seconds when it comes to normal (rev) speed."

I guess this could mean that the idle speed is set WAY too low.......but I doubt it.

[Canuck]

I had that problem when my Enricher circuit cable was reinstalled infront of the Front Left signal

it was yanking on the cable when i would push the left handle bar forward causing the enricher circuit to open or (choke)

maybe that helps??

[jonathan180iq]

So, as you come to a stop after riding the revs stay high for a bit before dropping back down to normal?

If that's the case, this is a sympton of having a lean mixture. I would suspect a vaccum hose has come loose somewhere. Most of them aren't held in place by anything other than friction. Check all of your little rubber hoses and make sure they are properly attached to something.

[GZ250]

Still the same issue. The idle speed is ok because it idles ok. no leaks that i can find and rubber boot is ok, tight and fix in its place. the air filter element is good (only smells gas), the plug on drain tube is there. i did not remove the cable but looks ok. now i lubed again. fuel valve is at its normal place. and i used once the GUMOUT additive bought from walmart and its the first time. previously i have been using the Suzuki brands. did NO adjustments or changes to anything. Just an oil change but after that it was ok.

i also feel that for a couple of fill ups i am getting less mpg (63) than i used to get (65-67).

Thanks to all.

[michaelp]

Thanks for the chatter. I was having a similar problem but mine did not return to normal after a few seconds of idling. I adjusted the idle and that seems to have fixed it.

Question: Does the idle adjustment tend to move on its own over time

[Badbob]

Question: Does the idle adjustment tend to move on its own over time

It moves with temperature. I think that is why it adjusts so easy. When I make adjustments I'm usually at a traffic light. Mine seems to be less sensitive to temperature changes as it gets more miles on it. Or maybe I found some happy medium.

I adjust by ear. I if it sounds to fast I just reach under there an turn the knob until I get something I like. I idle slower than the Suzuki recommended idle speed.

[Easy Rider]

the air filter element is good (only smells gas),

i also feel that for a couple of fill ups i am getting less mpg (63) than i used to get (65-67).



Taking those 2 things together......and not being able to SEE the bike, I would suggest that you get a new air filter. It might be clogged with something you can't see, making it run rich. Might want to remove the cap and see what comes out of that drain tube too.

If that doesn't help, it's probably gonna have to go to the shop. Probably not anything major wrong; just hard to find for the untrained eye.

[alantf]

When you say that the idle speed is low, don't forget that it should be set at 1200 - 1400 rev/min.
A cold engine will idle at lower revs,then when it warms up it will increase,so set the idle speed when the engine is good & warm. So don't forget, the proper idle speed will sound faster than a car.

[Easy Rider]

When you say that the idle speed is low, don't forget that it should be set at 1200 - 1400 rev/min.


OK, fine, that's what the book says....however:

It is not really necessary to have the idle speed that high. IMHO, the ideal idle speed is the lowest one where the engine still sounds smooth and you don't tend to kill the engine when starting out. An idle speed that is too high gives you virtually NO engine braking (which the little pup doesn't have much of under any conditions) and may make shifting jerkier.

Idle speed should be set when the engine is fully warmed up; then maintain about that same speed when cold with a tiny bit of choke, if necessary, until it warms up.

Having said all that, I don't actually KNOW what my idle speed is because I've never bothered to hook up a tach. to check it. I just set it to the point where everything works the best. That may vary a bit for different riders.

:)

[Sarris]

My only concerns w/ a low idle are engine cooling and oil pressure.

:??: :??:

[Easy Rider]

My only concerns w/ a low idle are engine cooling and oil pressure.


Not THAT low !! It starts making knocking noises about the same time that oil pressure would be a problem.
AND.....cooling ??? Does your's have a fan ?? :biggrin:

[GZ250]

UPDATE:

So I was having the "high revs" problem. Now the probem is gone and am enjoying again. Looked through all the suggestions. What I did; put a lot of oil in the throttle and moved it back and forth so that the oil penetrates deep inside, moved the idle know to too high and to low just in case if something was sticking in there but I think oiling the throttle helped as my bike remains outside.

[Easy Rider]

What I did; put a lot of oil in the throttle and moved it back and forth so that the oil penetrates deep inside,

That's the good news. :)

Now for the (potentially) bad: What kind of oil did you use? If it was motor oil or 3in1 oil and the bike stays outside in the sun and wind and rain, that oil will probably thicken up in a few weeks and you will be right back where you started.

You need a thin oil for the cables; a penetrating oil or MMO or even ATF will do. I would have suggested silicone or teflon but after a good dose of oil, that might not be a good choice.

[GZ250]

i used WD-40 oil this type. I also have "Cable Life" oil that is specifically for cables.

[Easy Rider]

i used WD-40 oil this type. I also have "Cable Life" oil that is specifically for cables.

WD-40 isn't really "oil". It is mostly solvents and a protectant that actually gets a little sticky when it dries.
SO.......
It is a good thing for freeing up a stuck cable and maybe flushing out the old lube but you definitely need to follow up with a "real" lubricant........like the Cable Life.

[Badbob]

I set my idle speed the same way as Easy Rider. Its worked perfectly for 27,000 miles.