My sick bike

[Puckman123]

Just back from cabot trail east coast tour about 3000 miles for me. Here is the problem, mike bike (2002 midnight Venture-65000 miles) will run great for about 10 or 15 minutes then something happens and the floor boards, bars and even the seat sometimes start to shake or vibrate, sometimes very badly. performance also drops off, it is as if you are dragging a parachute behind the bike. It will go but you have to push it to make it go, normally this bike just wants to run with my little 165 pound body on it. The bike will run this way until you stop for gas or a drink at the side of the road then the cycle starts all over. The bike runs so fine for the few minutes it does and so badly the rest of the time (I would think it is dropping 1 or even 2 cylinders when it is running running its worst). The bike will also come back alive after running like crap for an hour, but usually only for a few minutes. Here is what I have done so far- Replaced coils, 3 sets of plugs, pulled carbs 4 times-last time I took out every valve even float valves soaked it over night, set floats according to Goose instructions,ran 5 cans of sea-foam (a couple of strong ones), sync'd carbs with morgan carbtune a dozen times or more, changed the fuel filter twice, new plug caps (NGK), Air filters have 5000 miles on them, ran with gas cap cocked a little, Any ideas you guys have would be greatly appreciated, I really love this bike, but I have spent more time working on it than riding it. If I can't come up with something there will be a wing or an ultra in my garage shortly. By the way I broke down and took it to the Yamaha dealer they said GET THIS- that's normal, that is the way those bikes run- UNBELIEVABLE! Most people would not last 1 hour riding down the hiway on this bike. All I can think of is maybe the fuel pump or the ignitor box. Any help from the great minds here would be greatly appreciated, I would really like to keep this bike. Thank you..

[flb_78]

Almost sounds like a weak fuel pump.

[Squidley]

This is just a wild guess, but have you tried a different ignition box? It almost sounds like electrical cutting out, fuel pump is another option as Forest mentioned. How old is the battery and when was the last time you checked the charging system? The Venture is hard on batteries as the electrical system is just barely adequate. Check all your connections at the battery and solenoid/frame for tightness and corrosion.

[V7Goose]

Your description certainly sounds like a heat related problem causing cylinder drop. Since you already changed coils, that primarily leaves the ignitor (and maybe the pickup coil). I doubt seriously that the fuel pump has any possibility to cause this, but that would be very easy to check just by bypassing it with a direct gravity feed.

 

Thinking while I type here, I even have doubts about the ignitor. Your description says the problem has varying degrees of severity (sometimes bad, sometimes really bad), so that says more than one cylinder drop, just like you suggested. Electronic circuits can do strange things as heat changes, so that potentially could still fit the symptoms, but I would also check for any plugs in the wires between the coils and the ignitor. Bad plug contacts are classic causes of intermittent problems.

 

But I'm really leaning towards the pickup coil here - it would affect all cylinders the same, so if was just flat bad, the engine would not run at all, but what if it is weak or intermittent? Maybe the problem is not just one or two specific cylinders dropping, but all four missing a lot? If that is the case, you should be getting a lot of afterfires unless you made the huge mistake of plugging the AIS. With your symptoms, the only viable check of the pickup coil would be to replace it. Maybe you can locate a used one that someone would let you try as a test? Anyway, those are my best guesses at this point - do not forget to check the plug contacts on the ignitor as well as the plug that connects the pickup coil; like I said above, bad wires or plug contacts are just as probable as a bad part.

Goose

Edited August 2, 2010 by V7Goose

[Oldslow]

I like to read these kinda posts in case I run into a problem that's similar down the road. Maybe I'll remember and be able to diagnose it.

One thing I find is weird tho. Every so often, (more than it should be) someone takes their bike to a dealer and gets told, "it's normal"

Man that would make me angry!

My question is this: If you were riding a Harley, would they come at you with "that's normal"? Or would they take you seriously?

[flb_78]

Just another thought, but you may also want to check the fuel tank vent and if the bike is a California model, the roll over valve.

[Puckman123]

If I may ask, where is the pickup coil located? ( I am assuming it is different from the 4 coils)I had the ignitor out and cleaned all the contacts. There is absolutely no backfiring or popping of any kind going on. Thanks for your replies.

[Pictonian]

I have the stock ignition box out of my 07 RSTD if you want to try that.I'm in Mississauga .

Steve

[V7Goose]

If I may ask, where is the pickup coil located? ( I am assuming it is different from the 4 coils)I had the ignitor out and cleaned all the contacts. There is absolutely no backfiring or popping of any kind going on. Thanks for your replies.

The pickup coil is mounted with the stator. Tartan Terror can give you lots of info - he just went through a problem with his. See this thread:

http://www.venturerider.org/forum/showthread.php?t=49836&highlight=pickup+coil

 

Yes, the pickup coils is very different than the spark plug coils. The pickup coil is what replaces the old ignition points - it triggers the spark by providing the input signal to the ignitor.

Goose