hey guys i have been messing around throwing large quantities of money at my old 88 600 hurricane. i have had the carbs cleaned and set up twice.... doesn't seem to fix it, basically what it is doing is, when it idles it has a bit of a miss to it, when you get on and start riding it hesitates and studders it will drive but until it gets nice and warm it has no nuts.
so when it does get warm and it will run though the rev, it will drop off for a split second while revving up, then come back.
the only way i can describe what the bike is doing is, think of the sound when it works good as a crisp music note, then for no reason it just goes flat for a second or two then comes back, goes from a weeee!!! to a baaaaa... goes fast then power droppes right off.
and yes this is terrible analogy.
so the only thing i can think to change next is the coils. i took them off i don't see any damage to the coils.
i want to do the stick coil converstion but i dont know what bike i could pull them from...

if any one can help that would be much appreciated, if this doesnt fix it i just cant justifie putting anymore money into a problem i cant find, its my first street bike so i have gotten kind of cozy with it.

thank guys.

 

Not really sure. But some common things I'd always check with this type of thing are:
- spark plugs - best to replace them if you haven't (they need gapped though!)
- HT leads
- You can test your coils with an ohm meter. Grab the service manual from the sticky and see how
- check to make sure there are no vacuum leaks. Insulators are tight with no cracks
- Check for exhaust leaks - never know
- Check valve lash
With you bike cold, take the tank and air box off. Start it (you might need full choke, and to chock it with your hands a bit to get it to idle) See if you can see the slides all most in sync with a bit of revs. See if it does its stutter and if that can be attributed to one cylinder not pulling vac.

Not sure if any of this will help - but you have come to the right place to find out.

 

Lots of things it could be.

If the carbs have been torn down, did you sync them? Is the problem always the same or intermittent. If intermittent check for loose or damaged wires...may be a short in the ignition. Are the plugs new? What do they look like. Clean fuel. Fuel filter. Fuel pump. Have you checked compression...could be valve issue.

 

thanks alot for the reply guys. its much appreciated, i had the carbs cleaned and synched on a bench twice, thats why i am thinking its not the carbs.
i did have the spark plugs replaced at the same time, i had the bike in a shop.. cost me like 800$ but they reset the timing and valve lash, timing chain, tune up basically, the only thing i havent fiddled with is the coils and wires, and any of the ignition system. i will defiantly try all the suggestions, thanks.

 

Is the bodywork on the bike? How old is the battery?

 

right now the body work is half on the bike, just the front fearing and what not, i am making a naked version, and the battery is good, i acctualy just had the old girl running, pumped some stabil to it.

 

Is this your first carb'd bike? Are you saying it runs like garbage in comparison to another carb'd 4 banger or in general?

Im in a very similar situation with mine but being my first bike I'm not sure what to expect. Again very similar situation, picked it up and had the carbs cleaned, oil changed, and gone over. It keeps failing emissions at idle for HC's and is hard to start, doesn't run great at the beginning, etc. but as I get used to the bike and learn the nuances it runs better. Based on my limited experience, it sounds like you have a similar problem. You're just getting too much fuel when the bike is cold and as it warms up the mixture leans out, or it's simply getting hot enough to detonate everything in the cylinder.

My car experience tells me it could be a lean misfire (as did the uneducated emissions tester) but one look at the results (that he handed me!) told me that I was running very rich at idle. Especially with the choke on, when I run it cold it misfires, stutters and bogs. When I pull the choke it runs like a champ.

It is very possible that a newer, stronger ignition would correct this rich mixture when cold and the bike would be a little easier to manage. You just have to decide if it's worth the investment.

 

ya that really does sound about right, it does change alot when i play with the choke while driving.. it doesn't completely go away but i can get it to hold the ( sounds like a good working crotch rocket ) note a lot better, not perfect but better.
its not my firs rodeo with carbs, it is however my first 4x carb machine. and im not really having luck with the bloody thing lol .

as long as i can get away with doing the stick coverstion to the bike for under 100$ im sure i will be doing it, but the next question is what style stick coils fit the 88 600,

 

Just to clarify since I'm not sure how to edit, when the bike is warm and I turn the choke all the way off it runs great, even though its a little rich. Idle quality isn't perfect and the jet crossover (3.5k RPM ---> 4.2K RPM) is very noticeable but it runs solidly.

I think the new ignition would help, but eventually you just realize it's an old bike and it won't run perfectly, especially considering their age and in my case lack of rebuild. After knocking around for 20 years near 10k RPM and sitting for months at a time, the fact that it runs at all is amazing. When I want something better I'll just get a new bike.

If you find one post it up here because I would definitely be interested at that price range.

 

An old bike is no excuse for a bike not working properly. Mine is smooth all the way up the rev band, and I am sure its been bagged on in its earlier days. Does your airbox have those 2 pipes going to the air holes in the frame? Makes a huge difference.

Best way to tell how your mixture is is to look at your plugs