Unusual Throttle Behavior

1982 Maxim xj650, on my way home today I made a turn around a roundabout and when I came out of it I lost my throttle briefly in the next block off and on three times. I suspect the spark plugs I put in weren't firing the cylinders off perhaps? It's the first time it's happened and the spark plugs have been on for about 800 miles. I was also curious if the lean I had the bike in moments before may have encouraged the issue.
It was a bright sunny day here in Portland (believe it or not) so that eliminates water as a possible cause for the sudden loss of throttle and consequent surprise engine braking. Any ideas on what may cause this?

 

I doubt it's the plugs. Could be anything; start with the fusebox and the sidestand switch; and give us a little more history on the bike.

Might also be fuel-related, but from the tone of your description it seems like you think it's electrical, so we'll stay with that.

 

I haven't had a repeat of this issue yet. When it did happen the engine didn't shut off, the throttle just ceased to have an effect on anything for a second or two. I'll revisit if it finally does happen again. My current fun problem is getting the bike turned on. It's pretty clearly a battery issue this time. If the replacement I have doesn't work tomorrow i'll look into the solenoid or get more help on the new flooded battery I purchased. It's resting at 12.77 volts right now and it's been off the charger for some time so hopefully I'll be riding tomorrow.

 

Do your carbs go clunk? (referring to initial pickup hesitation problem, not the starter issue)

 

First question-

How much/little gas did you have in the tank? If you were running low, you could have "faked" the bike into running out of gas for a couple seconds.

Next question-

How far were you leaning over? If it was more than you normally do, it may be that you did two things: 1. starved the carb on the high side of the angle, and/or 2. at the same time swamped the carb on the low side of the angle. This would indicate that you may need to go in and check the float levels.

If everything seems fine there, then we have to look at electrical, like a loose wire somewhere.

Dave

 

If you mean there is an audible noise while I'm riding then no.

 

I aught to check the float levels regardless I bet, but I was leaning in a roundabout close to the extent my engine guards allow.

 

Todays update, I put the battery, reading a solid 12.7v after leaving it overnight, into my bike. No difference in behavior so my suspicions have shifted to my solenoid. The lights in the control cluster don't dim like they did with the previous battery while attempting to start, though without the crank, engaging that might not be a fair comparison. I also stumbled on the thread about checking the drum brakes for de-lamination late last night and really want to get my tire off to take a peek. I don't have a torque wrench or another clip to replace the one I remove. (referring to my manuals instructions of proper removal and replacement of the rear tire.) So I may be stuck sending it to a shop.

 

Buy a CRAFTSMAN Torque-sensing Wrench.
Cotter Pins are a Dime-a-dozen at any Hardware Store.

http://cgi.ebay.com/ebaymotors/Craftsma ... veQ5fTools

 

Well, if you were leaning that far over, I'm gonna stick with the"you either starved a couple carbs, or you swamped a couple other carbs,or a combination of the two" scenario. Lets see what a float level check shows.

Dave

 

12.7 Volts is NOT a "solidly charged" battery.

Take the "solidly charged" battery to your local auto parts and have it load tested.

Although it is probably unrelated to your issue...

 

Honestly man I hope it's just the battery. I've been struggling with it for days now. A consistant 12.7 is the highest i've gotten it to rest so far. I must have foiled something in the earlier flooded battery starting procedures.

 

Ok I now have a torque wrench and cotter pins and another new battery that will be charged properly. Thankfully I was told I should be able to get my money back on the first new battery that I apparently overcharged. All I need to track down now is the appropriate lube to place on the connection between my wheel and shaft drive when I put it back together after taking a peek at my brake shoes.
Actually having fun sorting this out on some level. My wallet isn't super happy but paying for life experience and head knowledge isn't that awful.

 

also, sorry for driving this thread away from my previous issue and just sort forcing it into general "new rider XJcolby talking out loud to anyone that will listen" I really do appreciate all of your input though, it makes it a lot easier to learn.

 

Two separate issues ...

Number One, starter not working, bike wont go

Number Two, once going mild hesitation when throttle opened with no loss of ignition ...

Once you have the engine going again see if you can replicate the hesitation, with the bike upright in a straight line. After all it only happened coming out of the corner, not while in it.

I'm going with sticky carb slides or holes/tears in the boots. Either way, it's bound to be fuel related so back to those carbs !

 

IF, ... the Starter won't spin after you short the two main Solenoid Terminals:

Battery has insufficient Charge.
+12Volts showing Not good enough.
You need to ck Batt for Cranking Amps.

Starter won't spin.
Battery OK:

Carbon Dust from Brushes contaminating Commutator
Shorting Starter to Ground

Clean Electrical End with Heavy Squirt Sprayer
Elect Parts Cleaner
Isopropyl Alcohol.

 

Today I had my second new battery load tested because the resting voltage is quite small (12.55v). Cycle Gear that sold it to me tested it and said its cold crank was good to go. So I diverted to replacing the starting motor and I went and salvaged one for 60 bucks with the option to return it and pick another one out if need be. They could not bench test it at the salvage garage for whatever reason so that's why he suggested I bring it back if there is an issue.
I then placed the salvaged starter on my bike and put the battery in and attempted to crank over. I got maybe 3 rotations, albeit slow labored ones, before the starting system returned completely to it's previous behavior of just a single click at the starter solenoid switch. I now, despite strategic multimeter testing that seems to disagree, believe that my solenoid switch may be the culprit.
Corrosion is at a minimum throughout the system. Though, I did find the short bolt that mounts my starter engine (the one closer to the airbox) was quite heavily corroded so I cleaned it up a little, but I'm in need of a better abrasive to really shine it up.

 

you also could have dirty contact in the handlebar start switch. Or one of the safety has intermittent problem. I have a honda that sat for 7 years that the contact in the start button was not making good contact did you try jumping the sol.

As far as the loss of power at different times could be lots of things make sure everything is right in your carbs float height. Try opening the fuel lid probably not the problem but easy to check. How does the inside of the tank look could the petcock screen be just about plugged . If all is correct in your fuel system you could have a bare wire in the ignition touching intermittent or solder in the tci might have broken off and not making good contact. Hopefully its in the fuel system its much easier to trace

 

OK, I've got to agree that you're looking at two different issues.

First off, the starter: This one's easy. You should be able to apply 12V directly to the starter, and it should spin, even if not installed in the bike. It's possible your salvage unit has a problem too.

Use your multimeter and follow the starting circuit diagnostics in the book; if you don't have a factory manual, PM me with an email address and I'll send you a scan of the factory manual pages for that.

The other issue does sound fuel-related, however; do you have an in-line fuel filter installed? Tried popping open the gas cap when it happens? How about running on "PRI" for a while to see if it repeats?

 

I recently bought a 93 XJ600 Seca II. The front end of the bike was rebuilt becuase the previous owner layed it down, therefore i have no tacometer, and cannot tell what my RPM's are exactly. This is my first post on XJ bikes, and i am not very experienced with bikes, so any help will be much appreciated! One question is that when i pull back on the throttle hard, the RPM's will soar, but there is little if no output in speed, just high RPM's. Thanks for any help!