scratching head big time!

OK guys I'll try to be as detailed as I can about this issue have followed some advice from here and from a local dealer but still having issues. (82 750 maxim)
I have cleaned the carbs (twice now) replaced the plug caps (this did return my spark) ended up paying local shop to synch the carbs. Most of my backfire problems have been resolved (once in awhiule still a loud pop now and then from left side pipe, on deceleration) It idles and sounds good, and on the low end (1st - 3rd gears) seems to have good power, but on the hiway seems to loose power in the 50mph and up range, and absolute max speed I got out of it yesterday and today was 63mph. I originally cleaned carbs due to a float problem, but had tons of power and cruised home when bought it at 75mph with about a quarter throttle left. Has anyone else ran into this or similar issue? or have any other areas to look I am at a complete loss since it sounds and idles so good.

 

Sounds like it's running lean - backfiring and lack of power. Check your plugs - if they're white that is where to start.

Lean condition can be caused by carb setup and damaged carb boots... you say it is on one side so I don't htink it would be as far back in the air supply as the filter.

Another cause of lean condition is float heights - but you set those?

Woot.

 

hey there woot, all boots are in excellent condition, air cleaner is new, carb floats (I beleave) are set correct, I actually was thinking of it being lean as well, but have now put 3 new sets of plugs in, and everytime I pull them they are a bit different, first time left side (1 and 2) were normal wear, and 3 and 4 were black, now (last two sets i put in were all heavily black, not wet but completely black, which lead me to beleave i was wrong and it is rich, thats when I decided to have the carbs synched, I have not put new plugs in since synched, was trying to wait as long as I could for that since now have bought 5 new sets of plugs, but maybe I should I guess it may help to have a clean plug again. From another post was wondering if the ignitor mentioned would act up like that? but since it doesnt seem to be a heat problem, more of a speed range problem not sure if that would be true.

 

is your tank clean. It sounds to me like your running lean due to blockage in the fuel tank on the petcock. If your tank was creamed in its past, the cream might be peeling off and into your petcock.
Sean

 

Hey Regulator,

I would really look at the ignitor box (alias TCI, I think). If the plugs are burning black it can be to either too much fuel available or too little fire (spark) to burn it. This thing is an electronic device and they can present strange symptoms when they start to act up. Like I said earlier, I think it is located on the RH side behide the side cover (or at least the wiring harness or plug for the box). The way I narrowed to the ignitor box, I rode the bike without the side cover and moved the wiring around. The bad wire made contact in the movement of the wires and the bike let me know when it did. You can put the bike on the center stand and put it in 5th gear and run it while moving the wiring around. Mine seemed to mess up more under a load and doing this will allow you to put it under somewhat af a load and leave all your bones intact. I would look long and hard at the ignitor box and aas I said earllier, I didn't replace mine, I fixed it

Kelly

81 XJ 550

 

I am thinking along the same lines kelly, but unfamiliar with repairing this and cant find much about it, if no problem send me a message with how to go about or a link if you know of one, read your other post on how you did it, but have to say was a little lost LOL

 

some links to look at for TCI information, troubleshooting, and repair

http://www.xz550.net/tci_english.htm#a3p0

http://www.jetav8r.com/Vision/TCIRebuil ... build.html

 

I agree with bikerlife relug colour... black is rich due to too much fuel, not enough spark, or too little air. As the symptoms happen at higher speed wider throttle openings you'd expect good battery power.

A fuel system clog you would think would cause it to run lean... The caveat there is when do you check your plugs? If you hit the kill switch during the symptoms you'll get a read of what it is doing then - not what it is doing generally. When have you been checking them?

The TCI is a possibility in that it's just a black box to me - I do know that they fail in strangeways - a bad solder connection on it (crack/dry) could cause a weak spark I suppose. Worth looking at I suppose.

 

I have been checking them after a short ride, 15-20 minutes after i put them in, thanks guys will be checking in to this more this weekend and let you know what i find

 

Ok - if you can (safe to do so) hit the kill switch when the symptoms occur - check the plugs then.

Cheers,
woot.

(called for supper!)

 

yeah you should do the plug reading when the stuff is happening, so that may require you to take the tools to pull the plugs with u on the ride and hit the kill switch then come to a stop with the motor off then read the plugs, thats the only real way to read the plugs.
cheers brenton

 

find a long hill, git on it, & where you know you can pull over hit the kill & haul in the clutch @ the same time. If you hit kill & dont haul in the clutch, youll get the plugs covered w/ raw gas from the overrun vacuum... the heat on the plugs will burn some off, & darken them.

 

Well guys finally got half way decent enough wheather to do some more checking into my problem, and well feeling a bit STUPID about what I found but hopefully it will help someone else from making the same mistake. I took the carbs out again to investigate and found that I had put two secondary jets in two carbs, and two primary jets into the others. Althou the numbers on the jets are a bit worn and hard to read I still chalk this one up as a major bonehead move on my part, another thing I learned is that the two jets are completely the same thread pattern and thread size. So to top it off leaves me with another question, the jet sizes are 40 and 120 which of these is the actual primary?

 

Haynes manual says - main jet is the 120

 

Thanks Nick, just found that a few minutes ago, got it all back in place and took out for a test ride (cold one too 36 deg here) and WOW it's back tons of power and torque!!! cant wait for warmer wheather!!! thanks to everyone for helping me get this fubar move of mine figured out

 

Bravo!! Cheers, roar, happiness! Have a great time with it Regulator. I wrote the jet numbers in my Haynes exploded view one by one as I removed them and I am bloody well glad I did. Never had that mix up happen as a result. Thanks to everyone, this troubleshooting effort was interesting.

 

Thanx robert, worst part of this whole mess was I am usually extremely ANAL as my friends would say when it comes to marking things I work on, but this time I let it slide (either due to excitment for the new bike or the 15 degree temp i was working in LOL), goes to show taking your time and writting things down makes it a shorter job in the long run. Good rides wished to all!

 

I'm glad to hear you fiquired it out. I hate making dumb mistakes. But as it's been said, If you don't make mistakes, chances are your not doing anything at all.

Happy motoring

Kelly

81 XJ 550 Maxim

 

LOL I like that saying kelly