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View Full Version : 84 big red 200es wont rev up



gravismaximus
07-22-2016, 12:43 PM
hi, HELP im about to rip my hair out. thought i had her fixed this time (maybe i did) last time i found that my coil wire cap was open not allowing spark. found that after testing the cdi, stator, coil, pulse gen, and everything else that has to do with making spark. after testing everything was good i still replaced the coil wire cap plug, pulse gen and got a cdi form dratv. and she ran again. woot :Bounce . my buddy and i went out for a ride and she started do the same old thing after a hour of riding, losses power and eventally dies. wait 30 sec and itll start back up (sometimes) and you can go 1 min to 1 hr without a problem again (not this time). just at random times weather wet, dry, pavment, rocky terrain itll loose power and pushing on the throttle only makes it die quicker. got it home -towed

so again went for the previous fix and behold the new spark plug cap was open again ??? ok it was a cheap chineese one so i got a ngk for it just to have it not fix it this time. ok what else did i do sense it started running, o yeah i added half a can of sea foam to a full tank of gas(more than what it calls for) but it ran for over a hour befor it died. but just to be sure i removed it from the carb and tank and put in fresh gas, which got it so i would at least run for more than 3 seconds like it did after it died on me. so i turn the carb mixture screw to find hey i can make it run better, but still cant give it more then 1/4 throttle with out it dieing. so i was thinking spark to start but maybe it is fuel, but isnt sea foam spouse to get the gunk out not put it in. (cleaned carbs 2 years ago with maybe 10 hrs of riding time sense then) so find it hard to belive that it was gunk in the carb seeing how it was running perfect, died (spark plug cap) ran again fine and died again now. IDEAS ANYONE my source coil ohm is 280 and it produces 30acv at idle and 70acv at 1/4 throttle (befor it falls on its face) all the other spark parts have been swaped and cross checked with the like parts and produce the same voltages (not bad parts).

so is there something im missing or did the sea foam really gunk up the carb somehow and i should get a rebuild kit again.(gas tank is clean)

RubberSalt
07-22-2016, 01:03 PM
Brain storming here:

Gunk in the carb sounds possible. As gasoline dries, it turns to varnish and begins to gunk up carbs.

As for your spark, would rust under the coil be possible? bad ground=weak spark. dirty connection = weak spark.
Do you have any air leaks going from the carb to the head?
Whats your valve clearance at?

Sea foam is over rated in my opinion. I'd rather spend the time and clean parts right.

fabiodriven
07-22-2016, 04:02 PM
You have to do a bit more diagnosis I'd say. First of all you have to narrow it down to either fuel, or spark, or both. It sounds like right now you're unsure. If it will run fairly well on ether, you most likely have a fuel problem. If that's the case, start with making sure your gas tank is venting (doesn't sound like that's your problem because you said you changed the gas, that would have released the vacuum), making sure your petcock is flowing (many of them have screens), and cleaning your carb again. You can bet your britches there's a chance it could be dirty again with the gas they sell now. If you've done everything you say to the fire system, one might suspect it's something other than spark. Doesn't mean it's definitely not spark, but you must explore more.

Also, if there is rust in your tank it can easily clog a screen or filter and then do it again minutes after you've just cleared the clog. If the tank is rusty that would need to be addressed.

Gasoline additives are good preventative measures, almost a requirement these days. However there is no such thing as a "carb fix in a bottle" and not many true octane boosters, not that you'd ever need one. Get er in ship shape the right way and she'll treat you to another 30 years.

HoldMyBeer
07-31-2016, 05:34 PM
I had a very similar condition going on with a different bike and found the butterfly in the carb for the choke was loose and not opening and closing fully. No power, died when throttled up. Tightened up the screw on the butterfly and problem solved.

Methyl Ethyl Keytone (MEK) is the best carb cleaner I've ever seen. Anything cleaner really