[Ishibubu]

So just recently, tonight, my bike started to occasionally sputter under heavier acceleration. I wasn't gunning it or anything but I was cruising at 5-6k rpm and gave it a little twist and the bike would pretty much die for a second while I was driving. It was almost instant the bike would sputter, lights go off but then everything comes to in a second. The bike also jerks while doing this, the only reason I can think it would do this is the battery is on its last legs, or at least I hope...

Can anyone help me diagnose what's going on?

 

[rockscaler]

how are you on scheduled maintainence, clean carbs, valve adjustment, have you done anything to the bike lately like exhaust, adding electics like lights or leds. how many miles?

 

[Skaz915]

I have an 01 r6 and I had similar trouble, not as bad as lights going off but if I rip on the throttle it sputters like hell, I was running so rich more than 1/2 my fuel was probably goin out of my pipe. I was only geting about 100 miles to the tank... Problem is solved now, rejetted, cleaned carbs, new plugs and recharged air filter...

 

[Ishibubu]

38000 haven't changed the battery since I bought it over a year ago, it normally dies in the winter. No choke cable on the bike so I have to work with it and the idle screw to get it started, sometimes the battery will die while I'm doing this so I hook it up to a car and jump it off (usually cranks up first try if I have it jumped off).

When purchased from previous owner he said the engine had been pretty much rebuilt, never had an issue with the bike until I figured out the choke cable was stuck on and the shop rigged it to where I didn't need one (at the time it was summer and I really didn't mind). I have pulled off the gas tank and air box and got a look at the carbs, everything seemed clean. I would like to sell the bike and I know I won't get more than ~$2200 for it so I'm tryin not to dump $100s in to it now which is what it would cost to see if my carbs are sync'd. Up till this happened bike rode really well went through all the gears just fine, I'm thinking atm my chain is loose but I can't really tell and can't find anything to help me find out.

EDIT: I don't think it's running to rich, I had that sputter before (when my choke cable was stuck) but it is nothing similar. It's kinda like that but instead of it sputtering because of fuel it sputters because the bike turns itself on and off for a millisecond.

EDIT 2: I believe the bike is in need of an oil change. It hasn't been 3000 miles but it has been 3 months. Could this affect anything?

 

[rockscaler]

the sputtering sounds just like Skaz said but the cutting off and on sound like a grounding issue, if the battery was bad it wouldnt start after turning off, at least without some work(jumping and such). An older bike that is cheap is a good bike to cut your teeth on to get in to the more do it yourself mechanics. You'll get more if the bike is set up in the normal way. Fix the choke, do a valve check and if neccessary adjustment. You will be glad you did years later because the knowledge of things like this will save you more than a new bike costs.

I learned to do a valve adjustment on the side of the road in Wyoming (hitchhiking 20+ mi. to town for parts) while touring around the country, and understanding more about your machine will enhance your enjoyment and decrease the chance of a mechanic overcharging you.

 

[Ishibubu]

Any tips on where to go to learn these things?

 

[enos]

Buy the clymer/haynes shop manual for the bike and dig in. The Honda manual is great too, but it assumes you know the basics. The third party manuals give more practical advice. Also ask on forums like this one if you're still stuck.
But yeah, doing it yourself is the best thing.

The chain slack is listed in the owner's manual, usually it's about an inch to an inch and a half at the loosest point. Usually given as 25-35mm. You measure by pushing up in the middle of the part that hangs down. Hold a ruler behind the chain. Measure on several parts of the chain (rotate wheel) because sometimes chains have uneven spots. That inch of slack should be at the tightest point, but if the difference between tightest and loosest is pretty big you need a new chain.

This isn't a carb sync issue. Carb sync manifests as extra vibration and slightly poorer performance.

It doesn't matter what the outside of the carbs looks like. Like some women claim, it's what's inside that counts.

Choke richens the mixture, and when you got the bike it was always on and you said it ran fine. Now that it's off, why would you think that it's rich? If anything it might be lean.

You say that the lights shut off too. That suggests it's an electrical issue, not carbs. I've had this happen, and it was dirty battery terminals. Just take a file or some sandpaper and clean the battery terminals and the cables that attach to them. Make them shine.
A friend also had it happen, and his main fuse was similarly dirty.

Bad battery may or may not contribute as well. If it's really bad it could be internally shorted and may drop the voltage too low sometimes. The battery is a crucial part of a bike's electrical system and it keeps the voltage in the needed range (>10 volts for the computer to work). You'll have a hard time getting $2200 for a bike that needs a jump. Buy a new battery.

I'm sure a new choke cable would be cheap, too. If not, you can fashion some sort of rope or wire you can tug on to open the choke directly. You should not mess with the mixture screws each time you start. Try explaining that to a buyer.
BTW, there's a mixture screw (one for each carb) and an idle screw (just one).

 

[rockscaler]

I learned what to do from the service manuals, why and how they work from the forums and have become pretty good for my needs from just doing it, buckle down, research just as your doing for problem solving. A couple years youll be ahead of alot of licensed mechanics.

If all electricals cut out momentilary I would try wiggling the harness around, its happening at certain rpms or is it throttle pos. the vibes at certain rpms might be enough to disrupt a connection of a bad spade connector on a ground, at certain throttle pos. the cable/carb shiv might be shifting the harness accenting a short in the harness.
Still I reccomend fixing what you know should be fixed and work from there, it could be connected in a roundabout way to they current issue. A new choke cable is not much and shims arent too much. I think that if you fix everything, do a valve adjustment, clean carbs you find more power and smoother from the bike.

 

[enos]

3 month oil is fine. Do change at 3k miles, but it can sit for a year and be good enough. Bad oil's first symptoms is poor shifting followed by very slow engine damage. Not sputtering.

 

[Ishibubu]

Its funny you say that because I am almost positive it happens, occasionally, at the same throttle pos. When I say occasionally I mean when it does happen I believe it happens at the same throttle pos.

And to Enos I'm not sure if I stated that the bike ran better with the choke cable stuck on? That was actually a problem with my bike I noticed from it stuttering and dying on me 3 or so times.

 

[enos]

If it ran better with the choke on then that means it's lean now. Did the bike sit a while? Carbs could be dirty. That could manifest as a stutter. I find it usually appears like a stutter as you give it gas. If it's really bad it just dies, if it's sortof dirty it can clear up. This can be cured with some seafoam in the gas.

so what throttle pos does it happen at?

 

[Ishibubu]

I'd say a little past a half turn.

 

[enos]

and the electrics die when it sputters or not?

and did the bike sit for a couple months recently?

 

[Ishibubu]

Yes electrics die... Not months no maybe 2 weeks? Max a month but I have been riding it for the past 2 weeks or so with no problems like this.

 

[enos]

like rockscaler said, start with what you know is wrong. new battery, check the terminals and the fuses first.

gas shouldn't go bad in 2 weeks to a month. Wouldn't hurt to fill up at a Chevron next time to get the stuff with techron in it, or use seafom. Just to make sure the carbs are clean.

 

[Papa Rocket]

A lean condition will definitely make it "stutter" and a rich conditon will make it feel "lazy" under acceleration.
It sounds to me like it's an electrical issue too. Like the other guys said, check the battery terminal connections or for something touching the terminals. (maybe from something in the trunk working it's way towards the terminals and grounding.)
One other thing that seems to be a regular issue with that bike. Has it ever been dropped on the right side engine case? If it has and the cover was replaced without using loc-tite, the pickup coil will definitely rattle around on higher revs and certain throttle openings causing the type of stutter you mentioned. Just a shot in the dark, but worth mentioning.

I've been checking out this forum for a few months now and ENOS seems to have a good head on his shoulders when it comes to giving advice! (along with others Ex Liquids,Serpentracer etc.) So, take the advice, do your homework & you'll eventually get to the bottom of your probs.

 

[enos]

Thanks, Papa!

 

[Papa Rocket]

Thanks, Papa!

No problem... I call them as I see them. I've been doing the "motorcycle repair" game for 23 yrs now, So I think I can spot someone with knowledge. :beer

 

[Ishibubu]

UPDATE: Just drove the bike to work today, hardly sputtered at all. Came home changed the oil, went out for a test drive and ooo was it bad. I noticed in 2nd gear it was the worst around 4-6k+ rpm even when I would pull in the clutch and it would still stutter even though it wasn't in gear.

I've now figured out my electrics don't go out anymore I think it may have been my bike jerking that made it seem that way at night time.

EDIT: O and it has mad backfire

 

[Liquids]

why haven't you got the battery tested yet? that's exactly what bad batteries act like... sputtering and backfires are from little/no spark and raw gas going through the cylinders and into exhaust. less likely to be plugs or coils since you say it starts easier when jumping.