"Shuddering" at idle?

[Pro_Marinero]

I put off some long-due work this weekend. About six months ago I wrongly performed a zero=zero TB synch on my 02 RT-P. Thanks to a couple of members on here (Ken H and JohnJen), I was able to get the TB's back to stock. In fact, the bike is running I believe better than ever. Granted the bike was on the lift for about a month while I did some other work and waited for parts to show so I may be just happy to be back on, but I'm thrilled with the performance so far.

 

Here's what I'm wondering about. The bike, while running great, seems to have an intermittent "shudder" at idle. I can't tell if something on the fairing or under is loose and periodically rattling, or the motor is doing something funny like a miss or whatnot. It's irregular and will do it for only a second or two. I think the idle is set a hair low right now (1000 rpm or so) and needs to be adjusted. Perhaps that is contributing to the condition? I know it's not much to go on but I was hoping someone else had possibly experienced the same thing.

 

Off the subject, I absolutely LOVE the RT-P alternator! Hooked up two Lightforce 140's on the old light mounts and two El Cheapo 55W fogs off the lower forks just above the calipers. I can now SEE, even in pouring rain. The -P has more than enough power to run all of it, plus tons to spare. With the abundance of extra switches and power sources, it's a snap to hook up new stuff. I had to trace the old switches and cut leads when it was decommissioned, but it was extremely easy to install relays under the radio box right on the box frame. What a great bike!

[Jim Moore]

I think your rpm is a little low and it's causing your bike to nearly stall out. I like to keep mine at 1200 or so. Seems to run smoother and makes for easier launches.

[AndyS]

As Jim says, tweak the idle up a tad and see what it's like then. The book gives 1100 (+/- 50) RPM.

 

Andy

[dan cata]

What the above sayd + adjust the idle while the engine is hot, 5 bars on the RID.

 

And you did clean the BBS, right?

 

Dan.

[Pro_Marinero]

I did clean both of the air screws. Also went so far as to hook up the digital tach to get idle speed right. After a 4-feeler valve adjust and dialing in the TPS, might as well go full anal for the whole thing. I was showing 1100 RPM, but maybe I didn't have it hot enough, though I'm pretty sure I did.

 

Anyway, idle adjustment should be easy enough to see if it changes. I can see where the 1200 RPM would be better as this thing is so cold-blooded. I have over 100k worth of riding and am an MSF instructor, but I actually did a zero MPH laydown of the bike the very first time I took off after buying it from the PO. The bike stalled in a full-lock turn away from the inital parking spot with him watching. Oops. I consider myself an expert low-speed rider and the bike has a very low CG, but ever since that I've had real hesitation about doing low-speed peg scraping. Setting the idle a little higher than spec won't break my heart.

[4wheeldog]

I did clean both of the air screws. Also went so far as to hook up the digital tach to get idle speed right. After a 4-feeler valve adjust and dialing in the TPS, might as well go full anal for the whole thing. I was showing 1100 RPM, but maybe I didn't have it hot enough, though I'm pretty sure I did.

 

Anyway, idle adjustment should be easy enough to see if it changes. I can see where the 1200 RPM would be better as this thing is so cold-blooded. I have over 100k worth of riding and am an MSF instructor, but I actually did a zero MPH laydown of the bike the very first time I took off after buying it from the PO. The bike stalled in a full-lock turn away from the inital parking spot with him watching. Oops. I consider myself an expert low-speed rider and the bike has a very low CG, but ever since that I've had real hesitation about doing low-speed peg scraping. Setting the idle a little higher than spec won't break my heart.

 

I also ride an '02RT. I have owned it since new. My home is at 7200' elevation, and the induction system on our bikes does not compensate for idle speed according to elevation. So I set mine low, shooting for 1,000 rpm at home, and I wind up with about 1150 at sea level.

Anyway, my point has to do with spark plug choices. I have found that the single biggest improvement to idle quality and cold start/cold running is the use of Denso IK22 plugs. These are iridium, cost about the same as buying set of stockers from the dealer, and last virtually forever. Try 'em......I think you will like them.

[Pro_Marinero]

That's a great point. I'm a believer in Iridium plugs ever since I put one in my Husaberg. Starting and cold running vastly improved. I didn't think of doing the same thing for the RT. I just ordered a set off of Amazon for $20. Thanks.

[Pro_Marinero]

Well, it appears to be gearbox/clutch-related as it disappears when I pull in the clutch. I'm hoping that's normal oilhead behavior exacerbated by the idle. I'm going to try to dial in the TB balance a little more and raise the idle. Hope that solves it.

[Quinn]

Well, it appears to be gearbox/clutch-related as it disappears when I pull in the clutch. I'm hoping that's normal oilhead behavior exacerbated by the idle. I'm going to try to dial in the TB balance a little more and raise the idle. Hope that solves it.

 

So, are you thinking the clutch is dragging? Possibly only when warmed up and cable stretched? Easy enough to put it on centerstand, pull in the clutch, pop it in gear and see if rear wheel wants to turn (needs two people).

 

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[Pro_Marinero]

I'm thinking it may just a harmonic nuisance that gets worse when the idle isn't correct. This isn't my first bike that has the reputation of having alarming sounds to the uninitiated, so maybe I'm getting concerned about what may be a normal condition.

 

However, you bring up a good point as well. I'll check for clutch dragging.

[NonComp]

If it is idling in neutral with the clutch engaged and shuddering, then it has nothing to do with clutch dragging. You mentioned that it goes away when you pull the clutch, so I presume that you mean that the problem occurs when idling in neutral. The clutch is full engaged when idling in neutral.

 

You would expect the geabox to be noisy when idling in neutral because the input shaft is free wheeling in the gearbox. It gets worse if you let the bike idle in first gear with the clutch engaged (on the centerstand of course). Driveline slack will make cause this.

 

However, if you can feel vibration when idling in neutral with the clutch engaged and you can't trace it back to the TB sync or other engine-related fueling issue, then maybe you have a failing bearing in the gearbox or spline problem. Change the gearbox oil and look for metal debris.

 

With the engine off and the bike in first gear, how much can you rotate the rear wheel before resistance is felt? This might indicate a spline issue. '02's seem to have more than their share of spline issues.

[Quinn]

If it is idling in neutral with the clutch engaged and shuddering, then it has nothing to do with clutch dragging. You mentioned that it goes away when you pull the clutch, so I presume that you mean that the problem occurs when idling in neutral. The clutch is full engaged when idling in neutral.

 

You would expect the geabox to be noisy when idling in neutral because the input shaft is free wheeling in the gearbox. It gets worse if you let the bike idle in first gear with the clutch engaged (on the centerstand of course). Driveline slack will make cause this.

 

However, if you can feel vibration when idling in neutral with the clutch engaged and you can't trace it back to the TB sync or other engine-related fueling issue, then maybe you have a failing bearing in the gearbox or spline problem. Change the gearbox oil and look for metal debris.

 

With the engine off and the bike in first gear, how much can you rotate the rear wheel before resistance is felt? This might indicate a spline issue. '02's seem to have more than their share of spline issues.

 

 

Oops. My bad. My answer was dyslexic at best. Maybe I should have suggested putting it on centerstand in neutral and seeing how much drag on wheel spin with and without clutch. I'll bow out now.

 

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