Choke on, 100 degrees outside

[kjcorduan]

So yesterday I start my bike up and let it warm up for a bit (even though I'm in the San Fernando valley and hell feels like a breeze compared to here!) I pretty much always have to use the choke to start it so I open it up and and let it sit. Well I go inside and get a little side tracked, meanwhile the choke is all the way up and it's running at about 4 grand on the tach, sitting. So its obviously not cooling the oil down to cool the engine. I step outside after 5-10 minutes and there is smoke coming up from the front of the engine. POOP. I cut it off and say a few french words, then head off in the cage. Come back later that night and take the fairrings off and move the tank over. Nothing leaking, all looks well. I start it up and everything runs fine, phew. put it all back together and take it out for a few minutes, no more smoke, runs great. Guess I was as close to overheating the bike you can get without blowing it. So all that to say, don't leave the choke on long at all when you are warming it up, most of you probably know that, but to those that dont... now you do!!

[berube600f]

lol i learned that the hard way too lol... i forgot i had started mine with the choke on, and i had walked away. Same thing def dont do it, and remember to take the choke off...

[Wheel]

another good idea is to stand by the bike when you start it, then back the choke down to about 2500 rpm instead of leaving it up at 4k...

[The CyberPoet]

One of the great joys of oil-air cooled bikes is that overheating damages are normally limited to ruining the oil and possibly the spark plugs -- unless you keep pushing it further once it's already overheated and the oil turns to crud. Personally, I wouldn't ride it without swapping oil and checking the plugs for fouling/glazing.

Meanwhile, if you need choke in 85+ degree weather, you need to clean or enrichen your carbs. There is no reason it should ever need choke in 100 degree weather to start (1/4 turn on the throttle & hit the starter, should start right up).

Cheers,
=-= The CyberPoet

[kat6hundo]

I usually get her started without choke, but she'll putter out if i'm at a stand still for the first 5 minutes of riding or so. Is it bad to ride before it's completly warmed up? I may have to tinker with my carbs also if that's the case. Usually I get it started then give it choke to around 1.5-2k rpms for about a minute, then I head on my way. What would the most time you would want to keep the choke on be?

[eak0703]

Same issue here. I've got stock carbs, air filter, exhaust on...they've never even had the A/F mixture screws drilled out. No choke, no start...or rather..very tough start.. Also will sputter out if not warmed up for about 5-10 mins. Once the bike warms up, idles just fine either at 1k or 1.5k

If i need to ride it "cold" i can be on my way almost right after starting the bike, but i've got to give some throttle to prevent stalling....also i kick on the choke every stop light until the bike warms up...

[The CyberPoet]

You have one or more of four things happening:

(A) The fuel in the carb's float bowls are evaporating off their lighter compounds while parked (or boiling 'em off in the case of parking the bike hot). Unfortunately, the alcohol mixed fuels common now evaporate & boil off a whole lot easier than pure gasoline fuels... AND/OR

(B) The smaller passages in the carbs are not perfectly clean/clear, and so it's not getting enough fuel into the air at cold idle. The correct answer is a fuel system cleaner and/or higher detergent fuels to clear out any dried fuel residues (I prefer techron for this purpose); drilling out the A/F (pilot screw) covers and resetting the pilot screws to 2.5 turns out will normally help a lot as well (great time to check the pilot screw seals as well -- alcohol-rich fuels are eating these things up much faster than normal). I do have extra seals in stock now. Note that again, alcohol in the fuel screws with the settings -- alcohol-mixed fuel needs richer settings than pure gasoline fuels to hold a healthy idle when cold.

(C) The idle is set too low. Warm idle for a 98+ should be 1250 - 1350 RPM (1300 - 1400 for a California model). If your cold idle on an 80 degree day is below 1100, odds are your warm idle is set too low.

(D) The vacuum to the petcock is too weak at idle to get enough fresh fuel to the carbs. Check for minor vacuum leaks, esp. if it sounds really lumpy at idle even after warm.

Other Tips to try:

Hot start: open throttle 1/4 way manually and hit the starter button. This also applies to any bike in 85+ degree F weather.

Pre-fill the carb bowls to replace any evaporated/boiled-off fuel - switch petcock to PRI for 30 seconds, then back to ON or RES (whatever it was at previously). Then start with the hot-start method above.

Holding idle: if the bike is on the centerstand, after you get it running for 20 seconds, put it in 1st or 2nd gear and slowly let out the clutch. This will add the weight of the rear wheel & tire to the flywheel weight and help keep it running until it burns through the old fuel.

If you don't burn through a full tank of gas at least once every couple weeks, I suggest adding some Stabil or other fuel stablizer to your fuel.

Naturally, virtually all of these problems go away if you install a good jetkit

Cheers,
=-= The CyberPoet

______________________
CyberPoet's KR Specials
SuzukiStratosphere.com - 6 Cylinders, wet dreams...
The Best Motorcycle Tire Valves in the World, plus lots of motorcycle & Katana (GSX600F / GSX750F) specific help files.

[kjcorduan]

Thanks for the info, I appreciate you putting the time in!

[whitecl0ver]

Ehh sorry for the hijack

Whos that???------>

[Nero]

Yeah, I was just thinking the same thing, whitey. -I couldn't read the posts for all the distraction.

[The CyberPoet]

MD86 in drag!



Cheers,
=-= The CyberPoet

______________________
CyberPoet's KR Specials
SuzukiStratosphere.com - 6 Cylinders, wet dreams...
The Best Motorcycle Tire Valves in the World, plus lots of motorcycle & Katana (GSX600F / GSX750F) specific help files.

[Catcha23]

another good idea is to stand by the bike when you start it, then back the choke down to about 2500 rpm instead of leaving it up at 4k...

[Enjay386]

5 to 10 minutes in 100 degrees, yikes.