Jittery Throttle

[artwu]

1st off, hello everyone.

I bought my 650 about 2 years ago in Hawaii. It was used, broken and generally neglected so I, being the good guy I am, rescued it for about 2K and put another 1K into getting it up to spec. Now it's dying again...I think.

I had to mothball it for a while recently. I moved back to Texas from Hawaii in December. I'm military, so the bike was shipped with my household goods. When it got here, there were no new scratches, dents or other damage and with a bit of coaxing (choking), the bike started fine.

That was in February. High op-tempo has kept me from riding but I got a few days off and took it for a spin this morning. Again, the bike needed a bit of choke, but started fine and even ran great for about 1 mile. After that, things got odd.

The speedometer and tachometer started jumping up and down and the bike started getting jittery at low and high speeds. From a stop to about 25 mph with steady throttle pressure, the bike jumped..I don't know how else to describe it..it felt like it was nervous. Like it would it accelerate, then hitch up for a split second, then accelerate more, then hitch up again until about 25-30 mph. Then it would ride normally, then the hitching would start again at about 50 mph. The tach and speedometer jumped every time the bike hitched. I tried applying the clutch and revving, and the tach dropped to zero. All this time, the engine seemed ok except for the hitching. The bike shifted well, too.

Is this from a long period of inactivity or what? Any ideas?

[Rockhead]

You said the bike was dormant for a while; maybe the fuel went bad and clogged up your carbs. I would suggest starting they’re.

[Clint]

Sounds electrical to me. Check the battery connections.

Welcome to M-J. We have quite a few Texan members.

[bigE]

Originally Posted by RowdyRed94

Sounds electrical to me. Check the battery connections.

Welcome to M-J. We have quite a few Texan members.

+1

Check the fuses too. Sounds like something has a poor connection.

Are the lights flashing/getting dimmer when the hick up occurs??
The speedo is totally analog i believe (I could be wrong) so I'm not sure how it would jump unless youre doing wheelies or something....

Does the problem occur at the same RPM interval in different gears? If so, then it could be a carb issue

[artwu]

To all the repliers: Thanks, good to be here.

1) RowdyRed94: Battery connections are sound; I checked them before I rode today. Alternator maybe? Does the SV even HAVE one?

2) bigE: Fuses are another matter. For one, I have no idea what to look for. The manual will tell me where to look, but that's as far as it goes.

3) All: (Carb) I think the bike's fuel-injected. Does that mean no carb? If so, does mean that just running it for awhile will clean it out? When I went out, I filled up with hi-octane gas (13.50 for four gallons...gimme a freakin break). Not sure if that will make a difference. Do I just drain the whole system and put in new fuel? I could use the old stuff for my mower, I guess.

4) bigE: No lights flashing or dimming that I could tell. Then again, it was midday w/ full sun and I was busy just trying to maintain positive control. The problem occured at all gears in all RPM intervals (I usually don't let it get above 6000), although it was MUCH worse in gears 1-2 and 4. Gear 3 saw a decrease in the "hitching" phenomenon.

My amateur opinion: The throttle or throttle cable went bad. This only happened when the bike accelerated. Idling was no problem, and once the bike started and was decently revved (did it to 7000 a few times), it started without any kind of complaint.

Any help you can offer is greatly appreciated, and thanks in advance, guys.

-A

[Easy Rider]

Originally Posted by artwu

1) RowdyRed94: Battery connections are sound; I checked them before I rode today. Alternator maybe? Does the SV even HAVE one?

The problem almost HAS to be electrical. The gauges dancing around at the same time as the power loss is a solid clue.

Could be the battery going bad. If it hasn't been changed since comming out of moth-balls, that's what what I'd do first.

Second, even if they LOOK good, remove, clean and re-seat the cables on the battery posts (automatic if you change the battery) AND check/clean/tighten the connection at the other ends of the battery cables (away from the battery). Pos usually goes to starter (or solenoid) and Neg usually goes to frame.

Yes, it has an alternator but testing charging might be misleading unless you know you have a good battery and solid main connections.

Could also be a pinched wire shorting out and dragging down the voltage to everything but that's probably a long shot since that should blow a fuse rather quickly.

The (loose) fuse check is a good idea too.

After that, things get a little dicey.
With FI and electronic tach and speedo, there is probably a "main" computer board somewhere that controls all of that. A loose or corroded connection to that board will cause all kinds of wierdness........as will a fault on the board itself ($$$).

Good luck!

[bigE]

If the bike is a 2002 its carburated.

If you dont have a manual, go to www.sv650.org - UK based SV650 resource and search for "service manual." Read through the trouble shooting section for ideas and use it to see how to check your fuses

Might want to take it for a short spin at night to see if your lights are getting dimmer/flashing. If theyre not, I would bet its a simple carb issue

Remember, its always a good idea to check the easy/free stuff first (like fuses and battery) then work your way towards the more difficult (starter, reg/rect etc)

[artwu]

It was the cables. At some point between my initial inspection the my last one (the bike was test-ridden 3 times), the positive battery cable came undone. Bolted it back on and rode it for an hour with no problems at all.

Thanks, guys.

[Clint]

Cool.

[bigE]

Love it when its something easy and free

[Louis]

Glad to be of help...

[SVZuki]

Good work trouble shooting your bike. Ride safe!