bike dies at idle

[notten]

I just finished an oil change yesterday, and I took her for a ride today. Now I can't get her to idle. I get good power throughout, but she dies when idling in neutral or in first with the clutch pulled. Started happening during the ride. Also, I feel like the idle setting might have come loose. Could it be the oil? I used some 10W40 high mileage crap I found at AutoZone. Riding home with the throttle pulled was a PITA. Help me, fellow KatRiders!

[92xjunker]

Oil, no. Dirty carbs and or filters, yes. Did you check the idle adjuster? What oil did you use rated SG jaso MA-2. Regular car oil is not good on the clutch.

[shpielers]

Regular car oil can be ok, energy conserving car oil definitely isn't a good idea. The high mile oils have lots of additives - no idea how well those play with clutches. If your clutch starts to slip, it's the oil. Don't see how that would be affecting rpms at idle though. ...carbs? Stuck open choke? (Would make it run rich. Warm engines tend to bog when rich)

[notten]

Carbs syncd about 600 miles ago along with air filter change. Oil filter changed 800 miles ago. Oil changed yesterday. I do pull on the choke quite a bit, so it might be stuck. I'll see how she starts in the morning. The only thing I changed was the oil. Before that she ran perfect. What are the odds the idle setting went bad or the choke slipped?

[notten]

Forgot to mention this one, but I also see the RPM cycling up and down at certain throttle positions. Specifically, if I bring the engine to about 1700 RPM it will start to wave to 2100 RPM and back to 17000 RPM and continue this cycle until I either apply more throttle or let off. I am thinking this is starting to sound more like a throttle cable/idle setting adjustment than anything else. I'm going to start looking into it in a couple of hours so I don't wake my neighbors.

[Kreylyn]

Bouncy rpms generally are vacuum/air related. Leaks on the carb/engine boots for example. If you were messing with the carbs, pushing/pulling on things in there, it's possible that a previously minor issue has gotten a little worse. I would do the spray test once the bike is warmed up to narrow down where the leaks are at.


Krey

[notten]

So it looks like the problem is gone. I did ride quite hard yesterday, so maybe it's an engine seal issue or maybe carbs. I did a half-hour test ride in stop-and-go traffic and local streets, and everything seems okay for now. The idle adjustment screw is hanging somewhat loose. It is clipped on the side of the frame next to the fairing, but can easily be moved about. Is it supposed to be secured otherwise? I forgot to mention that I changed the plugs about 600 miles ago also, so I doubt it's that. Also, after yesterday's ride I was getting quite a bit of smoke coming out from under the gas tank. Maybe one of the engine gaskets?

tl;dr: It's gone, but might still be engine seals, carb seals, or idle adjustment related.

[92xjunker]

Smoke is never a good thing. Check that asap. The idle adjuster is a cable so, is will move around some, just not sloppy loose.

[notten]

Smoke is never a good thing. Check that asap. The idle adjuster is a cable so, is will move around some, just not sloppy loose.

I'm pretty sure I have a leaky valve cover or head gasket that lets a bit of oil seep out and smoke when I get her too hot. I'm not too worried for the time being. I'm guessing it'll require a new gasket and some metal work to the head to get fixed. I looked at some "sealing" type solutions, but it seems that's all a joke compared to doing it right. I am going to save that for the end of the year when I get the time to do a valve job and some carb tuning. In the meantime, I'm going to take it easy on her and maybe add a fan for the oil cooler since 95% of my riding is on NYC streets.

[notten]

Well, that was short-lived. Now she's acting up again. Won't idle when cold, after about 5 minutes on the choke I still stall. So I take off with the throttle pulled and she rides fine for about half an hour, not dying at lights. Then, after a bit she starts choking in first so I gotta keep her in neutral at lights. Then after a bit longer, she starts dying in neutral so I have to keep the throttle pulled to keep her on. I looked under there to see if my fuel lines are kinked and saw a bit of gas leaking from the petcock, so I'm thinking the petcock is done. I did a rebuild last season because I thought it was leaking then. Now it's definitely leaking. Also, my idle is under 1000 so I'm thinking idle adjust, new petcock, maybe new tank.

EDIT: Found this: http://www.ebay.com/itm/1990-SUZUKI-...e24193&vxp=mtr Looks almost new.

[Kreylyn]

If you can, I would suggest you test the parts you have before buying new.

Krey

[notten]

Thanks Krey. Always good advice. I'm guessing it's actually a vacuum leak that's done it, but my petcock isn't working on prime so I can't tell. Took it to the local mechanic for work.

[REDRUm ALLIk]

I know I'm kinda late but I also had this issue. Kat died at idle when pulling in clutch to stop or slow down. Turns out she doesn't like gas with a high octane rating. Idk why but I'm assuming it's because the compression ratio isn't high enough to ignite all/enough of the fuel at low rpms so the engine craps out because it is fuel starved. Put 87 back in and she ran like a charm. Not a solution that seems to be advised very often but it worked for me.

[arsenic]

I know I'm kinda late but I also had this issue. Kat died at idle when pulling in clutch to stop or slow down. Turns out she doesn't like gas with a high octane rating. Idk why but I'm assuming it's because the compression ratio isn't high enough to ignite all/enough of the fuel at low rpms so the engine craps out because it is fuel starved. Put 87 back in and she ran like a charm. Not a solution that seems to be advised very often but it worked for me.

It's a solution that's advised a lot when the engine is designed for it. I know that most modern, high compression engines run better on higher octane fuel. The GSXF engine is neither modern, nor high compression.

[maniac1886]

I run 93 octane in my pre religiously.