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Low RPM stumble?

Started by 1990dtgl98, June 27, 2014, 05:14:36 PM

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1990dtgl98

So I have a problem and I need some help.

My wife has a 2002 gs. I bought it for 800 and have replaced tires, chain, sprockets, fork seals, etc. When she'd drive it, there would, however, be a stumble at lower rpms. At around 1800-2200rpms with a partially opened throttle, there would be a distinct 'shudder'  and 'studder'  where it would almost act like it was missing. Additionally at around halfway engagement on the clutch, the bike would shake almost like it was grabbing too hard.  This caused the bike to shudder and sometimes stall. If it did stall there's been a few times it's been at a stoplight or stop sign and she dropped the bike turning because it stalled on her.

So I replaced the jets, cleaned the carbs, redid the fuel lines and adjusted the clutch both at the transmission and the lever.

However it still has this surging RPM at around 2k, and a point in the clutch engagement where the bike will stumble and shudder pretty hard. Just today she dropped it after it stalled turning out of work. Her coworkers poked fun at her and now she doesn't want to ride it anymore. (a pretty crappy thing to do but I digress)

So I could really use your help figuring out the problem and the way to fix it. I finally got her around to riding, and feel Ilet her down by buying a bike sshe's not comfortable with. I thought it might just be her, but trying it compared to my sv650, there's definitely a stumble and jerky clutch engagement.

So help me fix this... Anyone have any ideas? It'dbe aawesome if she would trust the bike again.... But I'm worried I might have to start shopping for something newer, maybe with fuel injection. But finding a naked, fuel injected, sub 450lb bike is also pretty hard.

So any help you could provide would be greatly appreciated!


1990dtgl98

Also, the previous owner left it outside, uncovered and said he was generally cheap with maintainence. He could have went with the cheapest oil on sale... Would running energy conserving oil cause a cclutch to go bad? Would replacing the clutch be the next step?

Bike only has 13k, but I've seen stranger things happen.

Also,  sorry for any typos or run ons.... I'm using my cell phone to type all this.

gsJack

#2
My 97 GS needed about 4k rpm to launch smoothly and I learned to rev it to about 4k slipping the clutch until the bike caught up to the engine.  Worked for me.

My 02 GS with the 3 circuit carbs was/is better and only needed about 3k rpm to launch quickly and smoothly. Can't imagine running a GS at only 2k rpm.

Both my 97 and 02 had clutch chatter when engaging at low speeds on steep up hills which could be avoided with plenty of clutch slippage.

I never rode a SV650 but a buddy rear ended me once with a SV1000 when I hit the brakes if that counts. :icon_lol:

Energy conserving oil can cause wet clutches to slip.

407,400 miles in 30 years for 13,580 miles/year average.  Started riding 7/21/84 and hung up helmet 8/31/14.

robfriedenberger

I ride a ton in traffic so I find my self riding at 2k-3k range more than I'd like to. I surging is normal at at that rpm, if you drop a tooth on the front it will help with that, also check the chain adjustment

gsJack

#4
A screaming GS is a happy GS. :icon_lol:  My first new car after several old jalopies was a 60 VW so I learned not to lug an air cooled engine long before I got my first bike in 84.   :icon_lol:  I saw the clutch plates from my old 97 after my son took it for a commuter after I totaled it at 80k, bought the 02, and restored the 97 after waiting a few months to get insurance settlement.  Had a broken collar bone from that "incident."

So I think a GS clutch will take a whole lot of clutch slipping without serious wear but I never used any Energy Conserving oil in it and don't know how clutch might be after changing back to non EC oil.  I've never seen EC oil in 10-40 or 15-40 grades.  Had a 15T front sprocket in the 97 for most of the miles I used it, like the stock gearing in the 02 with it's more docile engine.  Think the clutch chatter is mostly due to weak clutch springs rather than worn friction discs, some put in heavier springs.
407,400 miles in 30 years for 13,580 miles/year average.  Started riding 7/21/84 and hung up helmet 8/31/14.

JAS6377

Yep. That sounds about right for a GS. I've got an '04 that needs about 3000-3500 before it'll launch smoothly. Like Jack said, you just have to slip the clutch until the bike catches up to the motor speed. I don't mean to say anything harsh about anyone, but perhaps a day of launch practice would help? Take her out to an empty parking lot and just practice smooth launching and clutch slipping.

That's actually one of the things that I love about this bike, believe it or not. It teaches clutch control.
Blue 2004F with some fun stuff
Lunchbox, 22.5/65/147.5, Jardine, 17/39, R6 throttle, R6 shock, .85 springs, GSXR1100 rearsets, Clubmans+Rox 2" risers, T-Rex sliders, flush mount fronts, integrated LED tail, integrated LED fronts, HID Projector, blue gauge LEDs, 12V outlet

And 96.5% more wub wub

robfriedenberger

Haha a 74 Yamaha with a messed carb in the dead of winter teaches clutch control

ace50

#7
.

BockinBboy

Like others have said, the GS needs revs to get going... at least 3k.  If I hadn't read that on here early on, I'd probably have gone through what your wife has gone through on this matter.  The only bikes I had really ridden before the GS were those in the MSF course mostly... and all of those you can get going using only the clutch and no throttle below 2k rpm.  It can be done with the GS, but you really have to work it compared to most other bikes... they just need the revs!

- Bboy


Sonic Springs, R6 Shock, R6 Throttle Tube, Lowering Links, T-Rex Frame Sliders, SW-Motech Alu-Rack, SH46 Shad Topcase, Smoked Signals, Smoked LED Tailight, ZG Touring Windscreen

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