AGH! No power when cornering, massive throttle lag. >

[Eisenfaust]

Well, a few days ago i made a post about a wierd noise my bike was making at 5kish rpm. I figured out where it was coming from... the fairing was loose, and needed to be tightened down a bit. Problem solved.

However, the hole in power that I was complaining about is just getting bigger. Its like I have a lag in my throttle when I roll on. I turn the throttle and... nothing happens, regardless of gear... then I get frustrated and pin it... lo and behold, the bike moves properly.

Its mostly a pain in corners.. I just have no more ability to roll on through a corner smoothly. This is especially annoying as I've recently been able to have reliably dry roads for the first time since I started riding... so my cornering confidence is going up, and I'm wanting to roll on more and more.... I just cant.

Any idea if this is something I can fix myself, or should I just box up my carbs and send them off to srinath for a jetting, cleaning, and tuning? Any idea what it might be? This has just started since someone knocked my bike over a week ago.... I just have no idea what to check.

[Dima26]

Is this your first bike? Is it 2004?

[Eisenfaust]

Yes, its my first bike, and no, its a 1991 that was poorly looked after by its previous owner. I"ve slowly been sorting out all of its various issues... but as soon as I fix one, another crops up.

This is definitely a new occurance, I've done 3000 miles on the bike, and never has the throttle response been sluggish or the fueling felt off.

It basically feels as if the bike is just sucking air when I open the throttle... then it sort of 'catches up' a second or so later. It acts just as it does if I were to start the engine when cold, turn off the choke, and ride around without proper fuel atomization.. IE, horrible throttle response. Its not so bad in a straight line (though pulling away from stoplights is starting to get a bit annoying, with the holes in power), more when cornering... and theres nothing there to power me through the curve.

[Jasco]

At what RPM does it idle at?

[The Buddha]

Sounds lke your float level is off ... a bit high ... or like waaaaay high ... but I am assuming that it was fine before it started doing this and its all stock ... if not ... then I should find out more and guess again...
Cool.
Srinath.

[scratch]

Hmm, I'm getting the same thing anywhere from 5-6k up in the hills Saturday and yesterday. I think it's the weather. 70camguy and I (or was it AR5ENAL and I) had a similar issue last year, with weather being the culprit. I had to keep it in a lower gear to keep the rpm's up. Do check the plugs though. Your bike is jetted, right (3 turns out mix screws, 40 pilots, needles shimmed, 125 mains)?

[Eisenfaust]

No jetting.

The bike idles at 1200 rpm, just fine, after its fully warmed up.

Could be the float levels, that matches with the high fuel consumption...

I think its just time to send the carbs of to Srinath for a nice full body massage.

I'll check my plugs tonight.

[Dom]

I think one of the key points is that the performance is getting progressively worse.  In the case of the plugs it could be running a little rich causing a slow buildup of carbon...my guess is that they will be blacker than white if the plugs are the culprit.  

I'm thinking it might also be tank rust clogging the jets or pilots.  If you havn't taken them apart you should probably do so.  I would then empty the tank and see what comes out...or an easier solution to see what the inside of the tank looks like is to install a clear in-line filter before the carbs.  If little rusty flakes get trapped then you know it's the tank.

[Kerry]

Question:  What does the air filter look like?  Any chance that it's the original item?  How does the bike run without a filter?

[The Buddha]

OK progressively worse ... somehitng is getting clogged and dirty ... and how fast determines how progressive ...
Air filter getting dirty and gas tank with rust clogging the jets is my first 2 guesses ... of which I'll go with 75% on the air filter and 25% on jets clogged with rust ... only because you seem to have rich type issues not lean ... no idle hovering right...
Check float height of course and if the gas in the clear pipe is anyhting other than clear ... you got dirt/rust in the carbs.
Cool.
Srinath.

[pantablo]

a shot in the dark:

check the throttle cable for proper tension and check throttle for slack...

[scratch]

Question:  What does the air filter look like?  Any chance that it's the original item?  How does the bike run without a filter?

Kerry's asking if the air filter is clogged or dirty. I'm begining to suspect the same, as your jetting is stock, which would be lean (thus the lack of power and hesitation in power delivery), but if the air filter is clogged, you're not getting enough oxygen to make power and you're just pumpin' gas through the cylinders.

[Kerry]

Thanks scratch.    I should have been more explicit.

[Eisenfaust]

Oy. I'l check all this out tomorrow. I just had a really great day with my friend at Sears Point doing a track day. No track time for me, but I helped my friend with his bike, and all-in-all, had a great time.

[Hi-T]

No one has mentioned valve clearances.  Several members have mentioned a similiar problem that was getting progressively worse and rather quickly.  They isolated the problems to their valve's being out of spec.  Once those were adjusted the problem went away...

[scratch]

True. One problem at a time.

[Eisenfaust]

Hi-T:

I did my valves about two weeks ago, things definitely improved.

I think this power issue has been there longer than I thought... I'm noticing it more because I'm cornering faster, and at higher RPM... so I never noticed the 'hole' before. Its at about 7k rpm and lasts until... 8500 or so.

Work continues... I'm going to go take the air filter off tonight and check my plugs.

[The Buddha]

7K to 8500 under load and on the gas ... why you chekcing plugs ... unless you rev it into that rev range under load ( not in driveway in neutral ) and hit the kill switch and coast (yea every bit as dangerous as it sounds ) and pull the plugs ... I used to do it on that section of 580 S or is it east past Tracy 5 years ago ... before they built 25,000 houses in Patterson ...
Anyway I'd lift you needle 1 washer if its stock ... 7K - 8500 is mains and needle ... Throttle position 3/4 to 7/8 prolly ... very much needle and mians ... so what you got in there ...
Cool.
Srinath.

[Eisenfaust]

Ok.... I rode again.. its more like 6500, not 7500. Theres a big jerk when I roll on the gas from closed throttle, but the corners I'm talking about involve smooth roll-on at 6500rpm or more... and theres just nothing there.

After going on another little ride, I took the bike apart and had a look see.

First thing I noticed, when pulling my plugs..... they were white, maybe a bit tan, but pretty much white. I really dont know how to read plugs all that well.. but they were white going to tan in a few places. Here are some pics:




After that, I pulled the tank, and removed my air filter... and found.... *dramatic pause* an aftermarket oiled-foam air filter. Definitely not the stock unit, unless Suzuki gives their bikes high-flow foam filters (with lots of reddish oil) from the factory.

Here's a pic of the filter:


I also noticed that, when at extreme left steering lock, my throttle cable was getting pulled tight... so I rerouted that, and now its great... no tight spots anywhere. I managed to get the engine running a little (to test the cable tension), and its no longer tightening (and increasing my revs) when I turn the bars.

I also checked my float height in one carb. Its spot on. The drain screw for the other carb is stuck, and theres a little hose stuck on the drainpipe with a plug in it. Removing this hose shows a small drip of gas coming from the float... I assume that someone put it there to stop the float drain from leaking.

So, all was peachy, until I went to reainstall the tank.

After turning the tank-mounted petcock on, somehow, my old rotten fuel lines decided to tear and spring a leak when I was manuvering the tank into position. Oops.  I lost a bit of gas, then plugged the leak with my fingers and got my roommate to turn the petcock off. The bike isnt going anywhere until I install new fuel lines. I have them... but, blah.

I think I'll be sending the carbs off to you, srinath. I'll send my new fuel lines and vacuum line along with the carbs. I guess I need some kind of jetting that will work with my filter (which looks pretty clean), but without neccessitating an aftermarket exhaust. I have no idea what kind of jetting is in the carbs right now... but I doubt it matches up with the high flow filter.[/img]

[Kerry]

That there is a UNI foam filter.  It's not supposed to be TOO much different from the stock paper filter as far as airflow.  :dunno:



And this here is a Spark Plug Chart.  Unfortunately, your plugs' particular condition is not shown.  The whiteness indicates a lean condition, but they don't look real bad.

EDIT: Added the photo.