2008 Nomad Idle Speed Dilemma

[billyboy]

Totally stock 2008 Nomad purchased new in January 2009.

Last season was my first season with the Nomad and the idle speed seemed too high. I'm NOT going for that H-D loping idle cadence (some Harley owners set idle WAY too slow). The RPMs just seemed a bit fast to my ear.

So, after returning from a ride with the engine at operating temp, I lowered the idle speed by ear since I didn't have a tach. But on the next ride the engine RPMs between shifts would drop to idle speed very quickly.

Maybe it's the way I shift, but the bottom seemed to fall out of the engine RPMs as soon as I pulled the clutch lever in. It would drop to idle speed very quickly when the clutch lever was pulled in, instead of a nice slow drop in RPMs to give you a chance to shift. So, I kept tweaking the idle speed up until it didn't do that.

So, fast-forward to spring 2010, and I hated not knowing where the idle RPM was actually set, so I bought an inductive tachometer.

Last week, I returned home from work on the bike after a good half hour ride and the tach registered idle speed at 1250. The manual suggests 900 - 1000, so I lowered it to 950 as a starting point. That idle speed sounded more normal to my ear, but when riding the RPMs plummet very quickly between shifts as they did when I was adjusting idle speed the previous season.

So, using the tach I adjusted up to 1000 RPM or the top end of the range. Same thing. Idle sounds right, but the engine still wants to drop to idle too quickly between shifts.

Is the intake just too restrictive for the suggested idle RPM range? Or is something else going on?

[cactusjack]

Get some spray carburetor/throttle body cleaner (I use Berryman B12 Chemtool) and give your throttle body bores and butterfly plates (both sides) a good scrubbing with an old toothbrush. If the throttle body bores and plates get all gunked up (and they will), it can play heck with your idle. I perform this procedure every time I change my oil and filter.

[macmac]

I agree with Cj. I bet there is gunk, and it is holding the throttle plates in a too open place, and the readings for fuel are wrong.

[redjay]

Has the idle always dropped real fast when you close the throttle or just since you changed the idle speed ? It sounds from your post that bike has been like that from day one ? Are you used to a bike with more cylinders ? Maybe they take longer for the rpms to drop ?

[billyboy]

Originally Posted by redjay

Has the idle always dropped real fast when you close the throttle or just since you changed the idle speed ? It sounds from your post that bike has been like that from day one ? Are you used to a bike with more cylinders ? Maybe they take longer for the rpms to drop ?

Only does this when I lower the idle speed to where it "sounds" right, or between the recommended 900 - 1000 RPM. If I increase the idle speed back to over 1000, it's fine.

I just now rode it home from work on the interstate and checked it again. Idle was 975 and would drop a little when the fan came on, so I raised to 1000. We'll see what that does..

[billyboy]

Originally Posted by cactusjack

Get some spray carburetor/throttle body cleaner (I use Berryman B12 Chemtool) and give your throttle body bores and butterfly plates (both sides) a good scrubbing with an old toothbrush. If the throttle body bores and plates get all gunked up (and they will), it can play heck with your idle. I perform this procedure every time I change my oil and filter.

It's so new and just hit 3,000 miles. I can't imagine the throttle body is gunked. Always use Shell 93 and put Seafoam in as stabilizer when I winterized in December. Ran that out in March and through several tanks already.

The weird thing is that it drops right to idle speed, not like it's gonna stall, but it drops so fast on downshifts that it feels like it might stall. It's almost as if you cut the engine, but then it hits 900RPM and is rock steady.

But tweak up the idle a bit and it's fine. I lowered the idle initially NOT because it seemed like the idle was racing, but that it was just a little high. That was confirmed when I put the tach on it

[ringadingh]

Even though you just turned 3000 miles Id still clean the throttle body, I do mine regularly and sometimes you can really notice a difference, especially in the idle.

[blowndodge]

I just think your shifting too slowly. I time my left hand and left foot and right hand so that my Nomad sounds like an automatic when I execute a shift and my idle is 850.. That's the RPM's the mirrors are glass smooth. Lower rpms also allow me to slow down quicker when I chop the throttle; therefore, using the brakes less.

[cactusjack]

Originally Posted by billyboy

It's so new and just hit 3,000 miles. I can't imagine the throttle body is gunked. Always use Shell 93 and put Seafoam in as stabilizer when I winterized in December. Ran that out in March and through several tanks already.

The weird thing is that it drops right to idle speed, not like it's gonna stall, but it drops so fast on downshifts that it feels like it might stall. It's almost as if you cut the engine, but then it hits 900RPM and is rock steady.

But tweak up the idle a bit and it's fine. I lowered the idle initially NOT because it seemed like the idle was racing, but that it was just a little high. That was confirmed when I put the tach on it

You'll notice I said I repeat the cleaning procedure every time I change my oil. That's every 3,000 miles. You may not have a lot of miles on the Nomad, but the throttle body could need cleaning.

[billyboy]

Originally Posted by Blowndodge "Darksider"

I just think your shifting too slowly. I time my left hand and left foot and right hand so that my Nomad sounds like an automatic when I execute a shift and my idle is 850.. That's the RPM's the mirrors are glass smooth. Lower rpms also allow me to slow down quicker when I chop the throttle; therefore, using the brakes less.

That's a definite possibility - I might just be taking my time while shifting. Dropping to idle that quickly could be the nature of the Nomad beast, but I'm lazy shifting as if the RPMs are falling more slowly.

That's the other thing I noticed when the idle was higher - downshifting coming off the interstate doesn't slow me down much.

I'll clean the throttle body anyway and see if that improves things.

[billyboy]

Originally Posted by cactusjack

You'll notice I said I repeat the cleaning procedure every time I change my oil. That's every 3,000 miles. You may not have a lot of miles on the Nomad, but the throttle body could need cleaning.

No, I did catch that, but I'm just really surprised that the throttle body would be that dirty. I'll take a look tonight.

Thanks!

[redjay]

I think maybe your Nomad is as it should be and that you are just not used to its traits ?
My Ford Taurus had absolutely no engine braking and when you took your foot off the gas pedal it took forever to slow down and the revs to drop. I think the Nomad has lots of engine braking and maybe the reason why the revs drop so fast as you describe. I have never really noticed it though in the way that you describe. I will check it next time I am out on the bike.

[billyboy]

Originally Posted by redjay

I think maybe your Nomad is as it should be and that you are just not used to its traits ?
My Ford Taurus had absolutely no engine braking and when you took your foot off the gas pedal it took forever to slow down and the revs to drop. I think the Nomad has lots of engine braking and maybe the reason why the revs drop so fast as you describe. I have never really noticed it though in the way that you describe. I will check it next time I am out on the bike.

That's what I'm thinking. I cleaned the throttle body and adjusted the idle to 950 tonight. No riding tomorrow due to t-storms, but I should be able to ride to work Friday. I'll work on my shifting then.

[timebandit]

Which inductive tachometer did you get?

[billyboy]

Originally Posted by cactusjack

Get some spray carburetor/throttle body cleaner (I use Berryman B12 Chemtool) and give your throttle body bores and butterfly plates (both sides) a good scrubbing with an old toothbrush. If the throttle body bores and plates get all gunked up (and they will), it can play heck with your idle. I perform this procedure every time I change my oil and filter.

Everything was spotless in there, but I sprayed it out real well anyway. I rubbed the inside of the throat with a rag and it was spotless - no dirt on the rag and the plates were gleaming. Used carb cleaner then followed up with Deep Creep.

I'll follow your lead and do that at oil changes.