Bike won't idle?

So I just picked up a 1980 Yamaha Maxim 650 a couple of weeks ago and it has been running great. Then one day out of no where it just couldn't idle properly. I'd start it up with the choke and it would hover around 3k-3.5k then I'd turn it off and it would just drop to 800 or so then drop further until it stalled.

I really don't know much about bikes, so I didn't think to adjust the idle screw first, but instead I just took out the carbs and cleaned them. They were decent. Not "clean" but there was nothing in there that should have caused huge issues. All the jets were clear, and there was no blockage anywhere. So I placed them back on the bike, and started her up. Now for the first few minutes the bike runs quite great. Sounds a lot better, and the throttle is less sticky due to cleaning up some springs down there. The bike just feels a lot better... but once I get on the road the bike still continues to die. Then I've noticed how the throttle just feels choppy. It almost feels like I'm running out of gas. Adjusting the idle screw does nothing. It works, as I can tell when I use the choke and before I ride when it runs perfect, but with it off and once it's warmed up the bike just does not want to run.

I'm very stupid when it comes to mechanic things like this, but I made sure the carbs were cleaned correctly and placed back on the bike correctly. I would like to fix everything myself, and not waste any money, but I'm not against bringing it to a shop for a diagnosis. Any ideas?

 

Well, first off, welcome, next, gotta do some reading....

http://www.xjbikes.com/forums/threads/the-information-overload-hour.27544/

http://www.xjbikes.com/forums/threads/in-the-church-of-clean.14692/

 

Thanks for the response. Sounds like the bike is running rich. Fits the symptoms.

So I guess the fix to that would be to check the floats and spark plugs? I did clean the carbs and took my sweet time on them so I'm pretty sure those are fine. Also going to check the intake tubes to from the carbs to the airbox. One didn't fit quite right when putting them back on, and I didn't think much of it because... well I don't know much about this stuff. So I might have to replace those.

Just remembered all these problems happened a day after switching the fuel from 91 premium to 89 or whatever because apparently the 91 octane isn't needed in this bike. I really highly doubt that had anything to do with it, but ya, that's a whole other topic with the correct octane to use.

Might just take it to a mechanic who knows what they're doing and fix what they tell me to fix. Spend something around $300 at a shop just for the peace of mind.

 

just gonna throw this out there because it will not cost anything to check. there is a vent in the gas cap open your gas cap when it starts to feel like its running out of gas. vent could be pluged up
there is a thread on rebuilding your gas cap

your gas cap and you
http://www.xj4ever.com/gas cap.pdf

and because you mentioned it
setting your fuel levels.
http://www.xj4ever.com/setting fuel levels.pdf

 

idle is controled by the pilot jets. when you spray carb cleaned in the jet does it come out the air jet on the top of carb and out the mixture screw holes?
this link showes the paths traveled by your fuel and where it needs to be clean
http://www.xj4ever.com/inside your carbs.pdf

 

I haven't checked the gas cap yet. I'll add that to the list.

And when cleaning the carbs I made sure that there were no blocked holes. Basically I sprayed carb cleaner though all the little holes, and made sure the cleaner came out somewhere else. Then I did the same with compressed air. So I'm fairly certain there's nothing being blocked. But who knows. It was my first go at cleaning carbs so it wouldn't hurt to pull them out again and go through the cleaning process one more time. Worse that could happen is that I gain a bit more experience cleaning the carbs haha.

Also, XJ550H those drain bowl screws look just like mine haha. I should definitely replace those.

 

NO! If it was that easy everyone would be riding one of these timeless classics.
You most likely won't find anyone that works on these, or if you do they will never be as meticulous to detail as you yourself will be.

Do not fret, there are smart and patient people here that will guide you through the 're-furb' process. Did you read through the two articles completely? Did you break your rack when you cleaned your carbs? Did you check valve clearances? There is a lot to do and easily twice as much $$$ as you thought you could pay a decent mechanic, plus your time that needs to be invested to make your Maxim a safe and reliable ride.

It is worth the effort, as you start to learn your confidence grows, your pride of owning an XJ grows and then you end up like some of the guys here that have Yamaha's all over their property . . .

FYI when I started off my knowledge of motorcycles was that most of them have two wheels. Thanks to this site and people here I know enough to listen to the advice that is given and then parrot it back to others.

 

Good advice.

 

YEP!!!!! GREAT ADVICE!!!!! You are gonna find out really quick, there are some really smart folks on this site, do what they say, and I promise you won't be sorry

 

[QUOTE="Warheroguy, post: 462816, member: 17969"
Just remembered all these problems happened a day after switching the fuel from 91 premium to 89 or whatever because apparently the 91 octane isn't needed in this bike. I really highly doubt that had anything to do with it, but ya, that's a whole other topic with the correct octane to use.[/QUOTE]

A lot of gas stations have Ethanol free 91 gas. I run it in my bike because the Ethanol eats up the rubber in the carbs and causes a lot of gunk and corrosion I don't care to deal with. If you downgrade to the 89 or 87, then you're potentially harming your bike by allowing it to corrode the insides of your carburetors and eat away at your rubber components. E10 is not approved for use in small engines or motorcycles and can be really harmful, because it can make the bike run lean. You haven't really been using enough 89 to have this be an issue, but that doesn't mean it won't become one.

Here's a map of every gas station that has Ethanol free gas. http://pure-gas.org/extensions/map.html

 

@Stumplifter : It's not parroting when you've done the work too and understand what you did.

Gary H.

 

10% ethanol was around when our bikes were new. They are in fact rated to use E10, and E10 has been approved for motorcycles and small engines for decades. Continue using ethanol free gas if you wish, but please don't keep spreading that sort of misinformation.

 

The Environmental Protection Agency has approved gasoline with 15 percent ethanol for use in cars year 2001 or newer, yet it prohibits its use in mowers and other power equipment, stating it may cause damage. A Department of Energy study found that E15 caused hotter operating temperatures, erratic running, and engine-part failure. But even gas with the usual 10 percent ethanol (E10) could help destroy small engines.

"Ethanol has inherent properties that can cause corrosion of metal parts, including carburetors, degradation of plastic and rubber components, harder starting, and reduced engine life," says Marv Klowak, global vice president of research and development for Briggs & Stratton, the largest manufacturer of small engines. "The higher the ethanol content, the more acute the effects." Servicing dealers are reporting similar problems, even with E10, according to the Outdoor Power Equipment Institute, the industry's trade group.




It can make the bike run lean, and it will f*** shit up even if it doesn't.

E10 is a minimal level of gunk that they allow you to run through your bike, but it's still nasty awful gunk that I don't wish to use.

I agree I was in the wrong when stating E10 was not approved, because it is, but it's still not recommended.

 

I will close with saying that I have been using E10 since 1986 without any issues. As with all things, your mileage may vary.

 

I run a landscape business and have been using E10 in all my equipment for over 7 years with no fuel related problems in any of my small engine equipment. Keep your engines tuned, keep your gas fresh and your mix consistent and you won't have any problems. I have a chipper and a splitter with Briggs engines that have tons of hours on them with E10. I also always run my gas out if I know I won't be using it again within the month.

 

I won't get into this, but my bike runs 2x better on eth free gas.

No hiccups or burbles, easier starts, better mileage.

If it doesn't eat rubber, even better!

I know the added octane does 0 for our engines (predetonation), but the other benefits make it worth it.