Do I have a combustion problem?

[VanRiver]

Hello experts, sorry this is probably a very novice question to ask, but I know you will be kind to me if it is.

 

My 1986 Venture appears to be running ok (in the garage) I have not been able to take this bike out on the road since I purchased it in a non-running condition (stupid winter weather), and have been able to get it idling and revving fairly nicely in the shop. Anyway, the 2 front engine cylinders (cyl #2 and #4) seem to heat up really quick while the rear cylinders (cyl #1 and #3) stay relatively cool to the touch for a long time while the bike runs. Also when I pull the spark plug wires off of Cyl #2 or #4 while it is idling, the bike immediately stalls. But if I pull the plug wire off a rear cylinder (cyl #1 or #3) the bike continues to idle with no evident hesitation. I have only tested it this way at idle, I have not revved it with a rear spark plug wire removed

 

Does this mean that I'm not getting fire in the rear cylinders?? But it sounds like it is running fine and strong, not like an engine missing a cylinder...that is why I'm confused and reaching out.

 

Also, on initial start up it appears that I'm getting exhaust fumes coming out of the Airfilter box....it's difficult to tell and the light needs to be just right to see it. Is this related in anyway?

 

Any thoughts or insight from you experts would be greatly appreciated.

Edited November 24, 2014 by VanRiver

[Prairiehammer]

If you hold throttle open at a higher than normal idle rpm, say 3000 rpm or so, do the rear cylinders then become hot? If so, then the pilot circuit of the carb is likely plugged.

Be cautious when pulling the spark plug wires from the running engine. The spark should be grounded to avoid damage to the TCI.

IS there spark at the rear cylinders?

[MiCarl]

Three possibilities I see right off the top of my head:

 

1) No spark at rear cylinders.

2) Idle mixture wrong or jets dirty on rear cylinders.

3) Carburetors not synchronized, fuel/air cut off to rear cylinders at idle.

[VanRiver]

Houston we have a problem....Yup, I just did a test....one by one pulled the spark plug wire on all cylinders and grounded a plug to engine block to test.....I get one single spark as soon as I hit the starter button on #1 and #3 then NOTHING. Spark looks proper and consistent on #2 and #4.

 

Does this mean I have a bad TCI??...or is it worth me troubleshooting anything else?

 

The TCI is a mysterious Black box to me......Should I just go with a "Ignitech TCI" setup I have been reading so much about on the forum from member "Dingy"?

 

Thanks for the help!

Edited November 24, 2014 by VanRiver

[Marcarl]

Pull the TCI, open it and show us what you find.

[VanRiver]

I pulled the TCI, It looks good with no visible moisture or corrosion issues...but there is a visible crack in the board near the pins for the plugs and a small chip missing near the corner screw. Now when I plug the TCI in again relocated on top of the Air box I get no spark at all on any cylinder. :crying: Looks like I need a new TCI, and the member Dingy is sold out of his Ignitech kits.

[VanRiver]

Hello Experts...My bike is a 1986 Venture Royale....what other year TCI's are compatible with my bike? Is it the same TCI for all MKI bikes from 1984-1989? Need to know for my search on eBay.

 

I hate buying 25+ year old electrical parts on eBay...Like gambling in Vegas.

[MasterGuns]

Hello Experts...My bike is a 1986 Venture Royale....what other year TCI's are compatible with my bike? Is it the same TCI for all MKI bikes from 1984-1989? Need to know for my search on eBay.

 

I hate buying 25+ year old electrical parts on eBay...Like gambling in Vegas.

 

 

If you are interested, I have a good used TCI from an 86 I will sell you. Make me an offer.

[VanRiver]

Thanks MasterGuns...I'll send you a PM shortly.

[flyday58]

I pulled the TCI, It looks good with no visible moisture or corrosion issues...but there is a visible crack in the board near the pins for the plugs and a small chip missing near the corner screw. Now when I plug the TCI in again relocated on top of the Air box I get no spark at all on any cylinder. :crying: Looks like I need a new TCI, and the member Dingy is sold out of his Ignitech kits.

I must have got the last Ignitech Dingy had. Mine had the same issue, #2 and 4 not firing, but when I opened it the corrosion was unbelievable. None of us could believe it was running at all. Hope you get a suitable replacement soon.

[VanRiver]

Well my working replacement TCI arrived in the mail today, plugged her in and my Venture started right up and she is firing on all 4 cylinders again!! Yippie!!!

 

Thanks to everyone for your advice and comments. But I would like to give a BIG shout out and THANK YOU to two members:

 

1. MasterGuns (Herb) for selling me his spare TCI box and at a very fair price. Really appreciate your kindness to help a Newbie Member like myself!

2. Neil86 (Neil) for taking the time to walk me through all the step-by-step troubleshooting and testing of my electrical system. I learned so much from you!

 

So many more task to complete on the bike before spring, but this is one big step toward hitting the open road on my 86!

[Neil86]

Good to hear the "new" TCI cleared up the issues.