engine rpm's

[borto1990]

I just picked up my new 08 today.. and I have a question right off the bat. When i hit the throttle sittle idle the rpms go up.. then stay up and take a second to taper down. Not sure if that's the way fuel injected is suppose to be.. On my vulcan 750 the carbs needed a good dose of seafoam for that to go away. This bike is brand new.. 0 miles.. well, it has 167 now !!!

[dogdoc]

sounds normal to me.

[Top Cat]

Yeah it is normal. Now go ride the thing.

[macmac]

I don't understand.... What is 'sittle idle '? others seem to understand that typo. and I don't, but I am the King of typo just the same

[borto1990]

macmac... when I'm sitting on it, just idling, then quick hit the throttle on and off the rpm's goes up, as expected. but even though the throttle is now off the engines rpm's have not come down yet. this happened on my vulcan 750 the I bought used.. it took a few cans of seafoam and it worked like a champ. maybe it's suppose to be that way as some people here suggest.. it just sounds odd to me..

[Todd]

Usually stops doing this once it is warmed up (when all stock)......does it act that way all the time, or just when you go out in the garage and start it up to hear it run since it's so new????

[borto1990]

nope, she's all the time.. after 167 miles.. same thing

[macmac]

Well I don't believe this is normal after the last statements.

A all stock bike has ISC's (idle solenoid controlls). When the engine is cold, more air is allowed to the intake by passing the throttle plate.

So with a cold engine rpm should be up when these ISC's are working correctly, and idle rpm should drop down with some warming.

Since you rode 163 miles and the idle didn't drop down, the first thing I might do is look at the so called choke cable, and see that it is IN all the way.

Next would be to remove the right side dog bowl and the backing plate enough to see the throttle cables..

Just might be a PDI tech (pre delivery tech) messed up setting the throttle cables, and so they are holding the throttle open as bit too much.

The check is done engine off and rolling the grip on and off.

Under the right side dog bowl is a black knob hanging down. These are most difficult to break free, and so far it appears all of these need some force to move. The knob itself sould be pulled back stiffly to seat on lugs you can't see, to turn this.

Before you turn it loctate where the cable goes in the first place, and note how it tips the throttle plate linkage.

Then start the engine after tying down the dog bowl backing plate in such away everything will still work. Expect to hear wild assed clicking from the ISC's.

Allow the engine to idle, untill you can tell it is warmed up and or the fan comes on proving the engine is warmed up.

Then turn the black knob you already broke fee counter clockwise and see if idle rpms come down.

Still with the black idle knob in a backed out possition, re-check the pair of throttle cables from the grip, making sure there is no excess cable kinking up, and making sure these cables are routed correctly.

All this in the event you want to know whats what... other wise I'ld take the bike back and bitch.. The problem with that is you don't know what the tech knows and I find most techs wanting...

On the other hand I was a foreign car tech more years than I care to say. This makes me very critical of new guys.

OT: If I was a smarter man I could set up a 3 days stay at any nad owners who need a tech. They would pay me a modest fee for service, feed and shelter me these 3 days, and then i would be going to the next guys place...

The problem there is tooling of course, since i can't carry 6 tons of tools on a Nomad no matter how you make it... Oh well

[Todd]

My guess is the "choke" is still taped up under the bike somewhere and is out.......any takers????????

[blowndodge]

Nope!!!!!!!

[borto1990]

k, maybe I'm missin something or not explaining it right or something.. just to clariy. it idles normal. seems to run normal. so when I am sitting on it.. standing still at normal idle, I hit the throttle for a quick on off. so the rpm's go up like normal, but now the throttle is back in normal idle position, but the engine rpm's take a bit to get back down to idle. does this make sense the way I am saying it?? thanks for the input..

[pooker]

Originally Posted by borto1990

k, maybe I'm missin something or not explaining it right or something.. just to clariy. it idles normal. seems to run normal. so when I am sitting on it.. standing still at normal idle, I hit the throttle for a quick on off. so the rpm's go up like normal, but now the throttle is back in normal idle position, but the engine rpm's take a bit to get back down to idle. does this make sense the way I am saying it?? thanks for the input..

I understand, mine does the same thing. My bike is also new but I have a few more miles on than you.
It bothered me at first but I guess I'm used to it now.
I live in Canada and it's still cold here and I'm thinking it's just the cables sticking.
I mean the cables are probably lubed and because it's so cold out they stick a bit.

[macmac]

So idle isn't overly high then. But when you raise the rpm there seems to be a lag before the rpm comes down?

About how long is that? In neutral there is nothing to take up any of that power increase, and there is a massive amount of metal moving.

So it isn't going to be instant slowing of rpm, but it should be timely.

My impression was you had a higher idle which stayed there a pretty long time before it came down and or you needed to shift and clutch out to drag rpm down with out going anywhere.

I'ld like to ask what the tack read out is, but I already know you have no tach. So all I cn do is guess, and about all you can do it tell me how much time it takes for the idle to settle.


Let me ask this question... When you go to slow down and go to brake does the bike tend to want to resist? Does it seem like the bike wants to stay going faster than you like then?

Almost not caring you applied brakes and shifted down a gear?

Almost wanting to get going faster in the down shifted gear, as if the bike has a mind of it's own?

[VulcanE]

On carbed bikes, when you quickly crack the throttle and let it go, the rpms quickly go up, then quickly down. On my 1600, when you quickly crack the throttle and let it go, the rpms quickly go up, then come down, not as quickly as they went up, and slower than a carbed bike would too. The rpms do "taper" down, and I think it is due to the FI. That would help in changing gears to keep the rpms from dropping too quickly, and causing a "grab" when you let the clutch out (from the rpms being too low).

[borto1990]

vulcanE.. that's exactly what's going on. I guess it's normal... bike seems to run fine, just sounds different than my carbed 750. Thanks everyone