over-heat and 6k idle?

[JunoAF]

ok so im definetly a noob when it comes to bikes. this is my first bike that i bought for 400 bucks. (see other threads with my name to get full story) anyway, FINALLY got the thing running and it idles at 6k! is that normal!? i have an 88 ninja 600R by the way. Also i noticed that my exhaust lines going into the engine are turning red hot, temp is damn near H, and the coolant is sizzling. are bikes and cars the same when it comes to the coolant process? any thoughts? thanks guys

Nate

[bigred875]

sounds like your choke is on..

[JunoAF]

nope, pretty sure its not. when i do hit the choke on the RPM jump to almost redline (11-13K)

[nilez]

i bought for 400 bucks.

there's your problem

[Thunderbisciut]

Maybe the throttle is sticking somehow, either in the carbs or in the lines.

Work on the idle first before worrying about the other issues. Only run things for a short time to see if any changes get the idle under control.

[stoinkythepig]

I'd guess you have a vacuum leak and the heat is caused by a very lean condition. I imagine there's other issues as well...

[JunoAF]

Maybe the throttle is sticking somehow, either in the carbs or in the lines.

Work on the idle first before worrying about the other issues. Only run things for a short time to see if any changes get the idle under control.

ok im only going to assume that the overheating is caused by the sparatic idling. i got it to maintain idle at 1200-ish for a little while then it died. i started it back up and it shot up to 6g, tried the choke and it jumped to 11000. When you say that its sticking, are we talking about internally? i.e. braiding of the cable inside the rubber housing?

[butcher bergs]

Have you tried turning the idle adjustment down?

Running an engine at 6K while at a standstill can be taxing on the cooling system. I'd say, on that bike in particular, there's no way it could keep up with cooling duties while the motor is spinning that high.

Another thing is, those carbs are vacuum actuated. If the diaphrams have hardened because of their age, then there might be a chance that at least one of the slides are sticking in an up position. Strictly a guess.

Keep an eye on your oil too. If the motor's hot, give it 3-5 minutes to let the oil trickle down to the sight glass before checking the level. Don't wanna burn a motor before you get it to idle.

[JunoAF]

this might be a dumb question, but is that the knob on the left side? lol if so then yes i tried that many times, almost brought the whole adjustment all the way out. I brought it way down to 1200 at one point by doing that. I never thought to check those diaphrams...what are the odds that would be the problem? is that common?

[butcher bergs]

this might be a dumb question, but is that the knob on the left side?

It's highly likely. Hard to say without actually seeing it. Should be a black plastic knob somewhere just below the gas tank/ seat area.
Can you see where the adjustment screw contacts a tab located in between the carbs? If so, back it out so it's not touching at all and see if you can "idle" the engine using the throttle.
If you can manually idle the engine then what you wanna do is turn the idle knob in by half turns. I suggest blipping the throttle in between each turn. You don't need to rev the engine, just a simple blip will do. What the bilp does is move the tab away from the idle adjustment screw so the pressure from the screw being turned is relieved....that's about the best way I can explain it.

I never thought to check those diaphrams...what are the odds that would be the problem? is that common?

Not for nothing but the bike's 20 yrs old. The chance does exist. Do you know if the bike's been sitting for an extended period of time? I mean years...

[JunoAF]

its hard to say, the kid i bought it off of said he was just riding the day before but not sure how much of that is true. ive owned it for about a month. ill have to try that tomorrow, seems like you have to be very meticulous with it. and yes its the knob going into the carb, you tighten it or loosen it to adjust the idle right? sooo yeah dumb question on my part lol.

[GixerJockey]

Leaking intake boots... They're 20 years old and very prone to dry rot and cracking.

[stevecbr900rr]

Give Mark TLRMan a PM he'll set ya straight. He's a bike guru...

[Sheppo]

Leaking intake boots... They're 20 years old and very prone to dry rot and cracking.

+1

[JunoAF]

hmmmm.... ill take a look at the condition of the boots when i get home. from what i could tell, they seemed to be in ok shape. no cracks and plyable... is it something that is very obvious?

[TheIglu]

Spray them with WD-40 when the bike is running. If it dips in RPM, that means the WD is sealing an air leak temporarily and you need to replace the boots.

[JunoAF]

ok that sounds easy enough, ill try that. we are talking about the boots that connect the air box to the carb? or carb to the engine?

[Sheppo]

ok that sounds easy enough, ill try that. we are talking about the boots that connect the air box to the carb? or carb to the engine?

The Carb to the Engine.

[JunoAF]

thats what i thought, ill have to check that out when i get home and IF the rain stops...its pouring down here

[stoinkythepig]

Gunked up pilot jets will make the bike slow to drop to idle speed from throttle input (I know is sounds weird, and I cannot explain why this is, but I have seen it) so perhaps it's possible they could make the bike stay at high idle as well. Did you ever take the carbs out and clean out the pilot jets?

[JunoAF]

Gunked up pilot jets will make the bike slow to drop to idle speed from throttle input (I know is sounds weird, and I cannot explain why this is, but I have seen it) so perhaps it's possible they could make the bike stay at high idle as well. Did you ever take the carbs out and clean out the pilot jets?

no i did not, that might of been a part that i couldnt get to.

[stoinkythepig]

no i did not, that might of been a part that i couldnt get to.

Pull the carbs off, remove the float bowls and the pilot jets should be plainly visible in each carb as a brass, slotted screw with a hole in the center, in a tube that would hang down in the fuel. A flat bladed screwdriver can remove it easily and at the other end of the jet, you'll find some tiny holes and, on at least one of them, some crud. Clean it out with carb cleaner, compressed air and a strand of wire if necessary. You chould be able to see from one end to the other and through each side hole. Any crud is unacceptable. Reassemble and try again.


This is what my bike has, yours will be somewhat different.


Bennie


And the jets...

[Kurlon]

Any chance the prior owner screwed up a carb sync, forcing one or more carbs to be open too much even with the idle set screw backed all the way off?

[JunoAF]

thats definetly a possibility, in fact i know that the carbs need a sync. but would that be enough to completely f*ck up the idle? i would imagine that would just cause small spikes? i dunno, im def no expert. as far as what i pulled out, it did look very similar to the jets shown above. i cleaned them out about 5 times just in case. i did not pull out the starter jet or pilot jet though...

[TriumphIsMyBaby]

Pics please.