Coils and Plugs and TCIs and no start - OH MY!!!

Well, I'm back from lurking again. I have spent the spring working on the bike (an '82 XJ650J) here and there between household projects. Now I have time to get the bike running so I can enjoy the 90 mile round trip for work this summer. To the problem:

I have rebuilt the carbs per Rick's instructions (which were idiot-proof - thanks again for putting the how-to out there for us) and the carbs pass the clunk test, all starter circuits are clean and approved for use, the jets and emulsion tubes have no obstructions, and I pulled the petcock, cleaned and reassembled it and used new fuel line and a filter. Fuel is into the carbs, the exhaust is rich with the unburnt gas smell and with the new battery, the engine is spinning without a problem.

Here is where I am at a loss - The wires to the TCI read the same ohms - similar between the pairs, however, the wires are not in the normal two on two situation. There is the orange and black on top but there is only a grey pin on the bottom.


When the engine cranks I have no "choke" and it will spin without firing but as I release the starter button the engine will sputter as if to catch, but then the starter dis-engages and unwinds. No continuation of running. I have checked the coils and plug caps and they all ohm out properly, but could the coils be bad while still being "within" spec?

Also, I know that I have not verified the float levels are as required, but I wanted to ensure I have spark before diving back into the fuel side of things.

Sorry for getting long winded, but I have burned out the search engine and wanted to get bike specific on this one. Thanks again for all the advise to now and I'm sure that by the weekend we'll have this problem nicked.

 

see if your plugs are wet with raw gas.

MN

 

Sorry, forgot to mention. All the plugs were wet, so some fuel is getting into the cylinders. I'm sure the floats will need adjustment, but i want to ensure the bike can fire before diving in elsewhere, again.

 

Did the bike run before????
Why would you start trying to look for an electrical problem when you know by your own admission the carbs are not right?
Spark plugs will not fire in raw fuel. They are fouled.
Stop and get the floats set before you go any further.

MN

 

There are several other recent threads where this topic has been covered:

http://www.xjbikes.com/Forums/viewtopic/t=14844.html
http://www.xjbikes.com/Forums/viewtopic/t=19297.html
http://www.xjbikes.com/Forums/viewtopic/t=19151.html

 

Common. Starter takes all the battery juice and there is none left over for spark. Try roll starting or jump starting.

 

+1


grz Thijs

 

Unfortunately, the battery is new, fully charged. I'll check the float levels tonight or tomorrow.

For additional history on the bike, I got it for nothing about 5 years ago and replaced the fuse block with new mini fuses. Got it running and rode it for a part of the first summer. Since then I put in pods filters, rejetted with a stage 3 dynajet kit and have a 4:1 exhaust. I rode it for another partial season, then it sat for a couple of years. I decided to rebuild the carbs because of the many tips and tricks on the site concerning tuning and proper operation. I guess I got a bit overzealous about testing the coils and ignition system.

Another thing that I recall, the diode block smoked out when I first tried to get the bike running and after I removed it I was able to ride for the next couple years. Might I have fried something else?

Thanks again for the help.

 

Diode block is integral to a couple of the safety circuits. There are conditions where the bike will turn over but not start because the TCI is being grounded. Do you have spark? I have to assume some of your safety circuits have been by passed. MAybe something has come undone...

 

I would suggest that the items that are known to be not right be taken care of first. If the engine is flooded with gas and ignition system is still giving spark.
Let olinrj sort that out first and then work on the other issues. One thing at a time and soon it will all come togeather.


MN

 

A quick update:
I was cleaning out the garage over the weekend and a friend came by to say hi. While discussing things he wanted to hear the bike turn over. So I reconnected the battery and fuel lines and hit the starter button. With no starter enrichment circuit help if fired and kept a solid idle for a few minutes before I turned it off and disconnected everything. This progress made my weekend.

I'm planning to go through the carbs to verify/correct the float issue, then work through things over the next week. Luckily, I have a 4-tube vacuum balancer that I'm going to use to get her dialed in and a friend is going to help with the final tune.

Thanks again for the tips and encouragement and I'll keep you posted.

And, sorry for not saying so before, but I'll fix my signature to show my first name.

Thanks,
Bob

 

In the middle of checking/adjusting the float heights, and from the gasket surfacr to the mold line on the float, 2, 3, and 4 are at 9.32, 9.88, and 6.50 mm respectively. Had to come in and check the 17.xx mm measurement again and wanted to let you all know how far off these are. Be back in ten minutes.

Bob

 

You need to measure from the gasket bump surface to the bottom of the float. Now just to make thing abit more difficult. You need to have the carbs at an angle just so the tab on the float just touches the float pin. Then when you are all done with that you need to set the carbs up on a level and plum surface you can clamp them to. Then fill them with gas and use the clear tube method to double check the levels in the float bowls.

MN

 

Got the tabs adjusted to 17.5mm +/- and refilled the carbs. Got it fired up and idling well, but the battery needs to go back on the charger, was reading only 12.6 volts. I also need to replace the vacuum line for the petcock, I think it is collapsing or leaking, every time I turned the valve from prime to run the fuel line would run down, even at higher rpms (2500). When back on prime it would fill up without a problem. I'm going to get more line as well as a longer piece of clear tubing to double check the floats.

More updates tomorrow, hopefully.

bob

 

Did you check the voltage at the battery while the bike was running? You should get around 14V if the charging system is working properly (and the headlight should brighten when you rev it off idle).

 

The charging system was in good shape the last time I had the bike on the road, and the alternator brushes are well within spec. I didn't have the headlight installed last night but will put it on to check tonight. I believe the battery is down mainly because I have been working on getting the bike started for a few nights now and haven't had the chance to let the bike recharge it.

 

Wouldn't hurt to put a volt meter on there just to see what the charging volts are.

MN