Cold Start

[IndyGunner]

Ok, this might be a question for the mech section but then again I think its a general kat question.

I have searched but came up with no info. Why is it so hard to start a cab engine when its cold out.

I was in my garage today trying to start my kat, with no luck. It took a lot of cranking to get her to turn over and eventually run (had it on choke for a long time)

This is probably because I need a carb clean and a valve tune, but just for educational purposes, why does this happen????

[danp2630]

If it has sat for a while like mine, I think the gas evaporates from the carbs and you have to crank the engine to create vacuum to fill the carbs. Or just flip it to prime for a bit before you try it. Just an idea??

[md86]

The gas doesn't atomize the same when it's cold . Fuel injection makes sure it happens right . The choke just dumps extra gas into the chamber to get it to fire initially , since it won't mix right until it gets warm . That's why you don't wanna use the choke for too long .

[IndyGunner]

that makes scence lol. So youll never experience the bs cold start crap with fule injection....

.... i know what my next purchase will be injected gsxr!

[md86]

Because the fuelies know how much gas to add , and do so without you knowing about it .

[IndyGunner]

would the cold also be a reason for the sewing machine sound im getting at idle

[KatanaSoldier]

If you are going to let it sit for any amount of time, put some stabilizer in the tank. Home Depot sells the good stuff for cheap. It is nice for the cold weather and you will notice a huge difference.

[IndyGunner]

I put stabil in before i put it in the garage. I havnt noticed any difference.

[KatanaSoldier]

I put stabil in before i put it in the garage. I havnt noticed any difference.

That is the stuff. How is your battery? If it weak in the slightest, that will make a difference too. Also, a portable heater by the engine block works wonders!

[The CyberPoet]

The gas doesn't atomize the same when it's cold .

Yup. The warmer the weather (& the warmer the engine), the more of the fuel literally turns into vapors (instead of small drops) and the better it burns. Throw in the fact that your oil is cold as well (more resistance for the engine to have to crank against), and that your valve clearances are at their max (since the metal is at it's smallest), and you have a mechanical disadvantage. Throw in a slightly weak battery (and the fact that cold makes the chemical reactions in the battery happen slower too, so it yields up less power on demand) and it could be a real PIA.

Cheater's method: A small shot of starting fluid in the airbox (start fluid is usually based on ether, which will vaporize even in the cold) and poof, the engine usually cranks right up...

Fuel injection makes sure it happens right.

Most fuel injection systems still face the same issues (small micro-droplets vs. actual vaporized fuel), but compensate by dumping extra fuel in during the start process automatically due to the programming -- effectively doing the computer controlled version of the choke (enricher) thing for you.

Cheers,
=-= The CyberPoet

[md86]

Most fuel injection systems still face the same issues (small micro-droplets vs. actual vaporized fuel), but compensate by dumping extra fuel in during the start process automatically due to the programming -- effectively doing the computer controlled version of the choke (enricher) thing for you.

Cheers,
=-= The CyberPoet

Well , yeah , I kinda said the same thing earlier .....

that makes scence lol. So youll never experience the bs cold start crap with fule injection....

Because the fuelies know how much gas to add , and do so without you knowing about it .

[IndyGunner]

good news!!!!

I went out riding today. She turned over on the 4th try. And i had to let it sit for like 15 min because every time id get on ready to go and grab the throttle it would die.

After it warmed up i had no problem (i miss 130 indicated )

[il_ragazzo]

high explosives eh??

so a quick shot of ether in the morning should fire her right up?

[The CyberPoet]

so a quick shot of ether in the morning should fire her right up?

As long as the fuel in the float bowls isn't evaporated off, yup. You'll still need to let her idle away for a while to get her warmed up in cold weather, but it should kick her over with no problems...

TIP: To warm the bike faster and keep her running more reliably until she's warm, with the bike on the centerstand, as soon as you come off the choke, pop it into 1st or 2nd gear and let the clutch out real slowly. The spinning rear wheel will act as additional flywheel weight to help keep the engine chugging along.

Cheers,
=-= The CyberPoet

[misterhipple]

Mine will crank even in 25 degree weather, and I'll let it run on full choke for about 1 min, then half choke for another minute or 2 until I feel heat on the cylinder-- and the idle starts smoothing out considerably--

The motor is usually warm enough in 3 minutes to start riding near normally--

I used to just take off and keep the revs under 5k til my buddy got a TLR and he's all anal about warming it up forever-- So I'm sitting on the couch and he's in the driveway with his yoshi's thumpin for like 5 minutes and it's 12:30am...

After seeing him take such good care of his bike I decided to baby mine on the warmup too..