Help - Not running on all 4?

[Guest Buck-0-5]

I am looking for some help with a problem I am having with my bike. I have an 84 venture. I was out for a ride with some guys and one of them suggested to me that they think my bike is only running on 3 cylinders. This did not come as too much of a shock to me as my dad had had the problem two years ago. (The bike was his) He took it in and they replaced the "ignition unit". He seemed to think that the problem was fixed. Being that I am a new rider I realy didn't notice any lose of power, the bike has run the same the whole time I have used it.

What I am wondering is how do I know if it is only running on 3 cylinders and what should or can I do to try and fix it. I don't want to have replace that ignition unit again, it cost pops about a $1000 bucks. Also when riding the bike seems to ( for lack of a better discription ) cough when in 2 and 3 gear at about 3500rpm. It doesen't lose power or jerk or anything like that. It just makes a noise. Could this be related to the cylinder problem?

 

Any help or suggestions would be greatly apreciated. Thanks in advace and ride safe.

[hipshot]

Dan , the simplest way to determine if you have a dead cylinder, is to start it up, COLD.

as the engine warms up, hold your hand close to the exhaust pipes , one at a time. they should heat up quickly, to a point that they will BURN your bare skin!

be careful, there.

if one of the exhaust headers doesn't get as hot as the other three, then that one is your problem.

now, sooner or later, the "big guns" will jump in here, and diagnose your problem.

just jt

[Gearhead]

Yup, what he said. You can also lick a finger and quickly touch a pipe as the bike warms up. An IR thermometer is more sophisticated!

 

The TCI problems are usually not a bad TCI itself but the connectors or solder joints, esp. if yours is not that old. Don't cross the TCI bridge until you've elimintated ALL other possibilities.

 

I've heard alot of people say these bikes can miss one cylinder and it's hard to tell except you lose the top end power and the gas mileage suffers. What mileage are you getting, under what kind of riding conditions?

 

On the ignition side, you have plugs and wires to check. Then of course there's the possibility of gunk in the carbs and / or bad slide diaphragms. Question: did the bike sit for a long time between your dad riding it and you starting to ride it?

 

Jeremy

[Venturous Randy]

Buck, it is not that bad to pull the plugs and change them. As you look at each one, if you see a wet or oily one, that one is the problem. It may be the plug, a bad plug cap or even a carb diaphram.

That may be easy to fix compared to the cough problem. I suspect that is 2nd gear and you are looking at that getting worse until you fix it. It is actually ratcheting loose on the gear locking due to a thrust washer being worn and the gear dogs not engaging deep enough.

RandyA

[Marcarl]

Check the sliders to make sure they are working properly, and do a carb sync. Either issue will give you what you are experiencing.

[Guest Buck-0-5]

Thanks guys for all your help. It looks like I have my work cut out for me. At the very least, some things I can check myself before I take it to a shop.

 

To answer some off the questions, Yes the bike sat for quiite a bit. It was in the shop for 3 months in 06, then sat for the winter. It was only out a couple times a month last season, and then down for the winter again. I have had it out twice this year.

I am getting about 250km on a tank of gas. From what I have read that is about 2/3 of what I should be getting.

 

I will try the thing you all have suggeted, hopfully it helps.

Thanks again and ride safe.

Dan

[GigaWhiskey]

if it has been sitting for that long, those carbs are long over due for a cleaning. You can do a big part of it while they are still in the bike.

 

You said "Being that I am a new rider I realy didn't notice any lose of power, the bike has run the same the whole time I have used it." Maybe you do not know what it is supposed to have because you have not experienced it yet.

 

Take all the above suggestions, read the tech forum, search for posts and ask lots of questions. Forget the idea about taking it to a shop.

[Yammer Dan]

Sea-Foam it!!

[BJB]

250 Km on a tank is about all I get and that'sat about 42 mpg canadian!

[DonB]

I occasionaly lose a plug and to find it I use a thermal sensor. The cold plug will show up right away. I bought mine at Harbour Freight in Detroit for $10. One of my better investments.

 

Regards

 

db

[Condor]

I occasionaly lose a plug and to find it I use a thermal sensor. The cold plug will show up right away. I bought mine at Harbour Freight in Detroit for $10. One of my better investments.

 

Regards

 

db

 

Yep, bought one of those from Harbor Freight too. Accurate, and no more burned fingers...

[Gearhead]

How much gas do you have to put in after 250 km?

 

Carbs that have sat as much as yours are often gunked up. Strong doses of Seafoam work for some people, but you may be looking at a thorough carb disassembly and cleaning.

 

Jeremy