[WildKat]

the choke in essecense is to help the bike get started???

I always fire it up with the choke and soon as it stablizes I kill it and use the throttle. The previous owner use to leave the choke on for a few minutes before he killed it. The seems to be running better now.... THOUGHTS

When charlie first got her bike, the previous owner used to let it idle and on choke for 20 minutes at a time... definately not good. Fortunately things are good to go now and her bike purs like a kitten, or Kat

[Badkitty]

when its cold..i usually choke it for 1min maybe 1 1/2. When its warm outside, i choke it for as long as it takes to close my garage door and put on helmet.

[Katana600Tao]

My bike needs some work (tune up) so I have to massage her to start in the cold. I usually put the choke on full to get her started then ease it off to about 1/2 way and let her idle at 2k for a minute or two before I turn it off.

Edit: I had a Suzuki Intruder 1400 for about a year, and it was a NIGHTMARE to start in the cold, so I count my blessings with my Kat being so easy.

[Black]

Mine is usually 10 seconds on choke, then turn it off all the way. Then again, my idle is at 1800-2000 still since I havent had the time to take the carbs off.

[harrye]

..and certainly dont ride while the choke is on.

So does anyone know of actual on the spot engine damage from forgetting to put the choke off? When my Katana was new this spring, and I hadn't ridden it for a couple of weeks, I forgot which direction is on or off for the choke. I rode about 2 miles and when I came to a stop, the engine stalled. It was difficult to restart, and when cranking it over, I noticed black smoke from the exhaust. Then I realized I had the choke fully on, rather than fully off.

So any guesses as to what might happen if the choke is actually left on? From my experience, the engine didn't seize, and I never noticed any power loss, or smoking from the exhaust after that.

I'm thinking that there isn't a lot of warranty work being done for new riders who leave the choke on by mistake. The choke lever is not marked open or closed on the handlebar. Think about 2-stroke engines that run on a 50 to 1 ratio of gasoline to oil, and that is the crankcase and cylinder lube, as well as the fuel.

We know that its definitely not good to run with the choke on, but when is the damage noticable? Is it like using regular oil, rather than synthetic oil. Your engine will last for only 500,000 miles, rather than one million miles?

Come to think of it, I left the choke on by mistake for a few miles in 1983, when riding my Yamaha XS400 twin cylinder 4 stroke bike. The bike has about 8,000 miles on it now, and is just as powerful now as it ever was.

So I'll let you all know about Katana engine damage from leaving the choke on one million miles from now, or less.

[JoeCool]

I choke my bike at 2K RPM's for 30 seconds, while I'm putting on my gloves (everything else is on already)...then get on the bike, turn off the choke and let it idle for 2 minutes...then ride at an easy pace through my housing track and to the freeway entrance (keep engine around 3K RPM's)...this takes another 5-6 minutes and the bike is running perfect by the time I get on the freeway and let loose...
My bike is a 05 Kat 750 that I've only had for 5 weeks, so I may have to extend times as it gets older and more tempermental

Hope everyone has a great Thanksgiving tomorrow...
Peace out 8)

[The CyberPoet]

So does anyone know of actual on the spot engine damage from forgetting to put the choke off?

Well, Harrye, that's a tosser of a question...
The choke (a misnomer on the Kats) is an enricher circuit on our bikes. It dumps extra fuel into the carbs. Some of that extra fuel that becomes excess carbon build-up, both on the plugs and on the various combustion chamber surfaces...

So the question then becomes does anyone here know of any engines that have been damaged by carbon build-up? It'd foul the plugs before it caused any other anxilliary damages (because they'd load up to the point of not firing reliably). And I know I've seen my share of riders with that issue. But let's say the rider ignored the plug issue and simply kept swapping plugs regularly for some reason rather than tearing into why they were fouling so rapidly...

So the question then remains does anyone here know of any engines that have been damaged by carbon build-up -- aside from just the plugs? I have, and I suspect that a number of our mechanically inclined (esp. professional mechs & those who rebuild) have... But that's also a finger-pointing problem: was it that the owner running the choke constantly that caused it, or was it a situation of the carbs' mixtures being so far off was inducing the overly rich situation (or some other reason, such as an air-blockage at the intake, say a clogged air filter or unseated donut on a K&N kit)?

We have three potential problems aside from the bike running like crud related to excess carbon build-up:

1. Cylinder wall scouring, and rings getting torn up. Our left-over excess carbon is exceptionally hard, and if it breaks loose from the surface it formed on (either from shockwaves from the detonations, and/or due to chemical additives such as some fuel system cleaners or detergent-rich fuels), of the loose particles that don't sucessfully get blown out immediately, some will be the right size to fit between the piston crown and cylinder walls, held up by the rings. Those will scratch the #$% out of the cylinder walls, causing a loss of pressure retention in the detonation camber and burning oil -- and I've seen engines that display that problem. But can I definitively say that it was carbon and not fine sand from the inbound air or impurities in the fuel that did it? Hard to tell definitively (although carbon build-up to this point is usually visible on the other surfaces -- but all engines normally have some carbon build-up).

2. Pre-detonation/Pre-ignition (aka Knocking). As the carbon build up loads sufficiently, it displaces combustion chamber volume, and acts as a localized hot-spot(s), both of which can cause detonations to occur at times prior to the spark event (either through dieseling via raising the pressure too fast due to displacement, or via pre-ignition from the hot spot). I've seen a couple engines torn down with this, and moreover I've heard a lot more of them running while doing this.

3. If the problem still goes untreated (not spotted by a mechanic at a valve adjustment, etc), you could build up enough carbon to actually start an interference event between the valves and the piston crown, or the valves and the valve seat. When this happens, something has to give -- either the engine seizes, or parts break (valve stems are common, valve edges at times depending on where the build-up occurred, tappets and cam shafts, cam shaft retainers and bearings, and the connecting rod bearings or support pins -- connecting rods are rare to go these days). I've seen both car and motorcycle engines that have seized or broken parts which could only be explained by either carbon interference or metal failure... But again, it's a question of was the rider actually cruising around with the choke on all the time, or was it some other cause involved making it run that rich?

Cheers,
=-= The CyberPoet

[AtlantaKat]

the choke in essecense is to help the bike get started???

I always fire it up with the choke and soon as it stablizes I kill it and use the throttle. The previous owner use to leave the choke on for a few minutes before he killed it. The seems to be running better now.... THOUGHTS

as he seems to like to make me look bad, i used to leave it choked until the RPM's jumped, you know from the low rpm to the screaming rpm, then immediately turn it down. as far as it running better...umm yea, sure if that makes you feel better about yourself in the morning....UNLIKE metal, i didn't EVER ride with the choke on, but he does a lot...so lets not make this into something that its not cousin o'mine.

[Kat-A-Tonic]

When I originally purchased my Kat I often had the choke on for a minute or longer. However, after my first tune-up I would only put it on for 10 to 20 seconds during the warmer months and about 30 seconds when things got cool.

When I took the Kat out yesterday (during sub 30 degree F / below zero weather ) I had the choke on for over a minute with the RPM's from 2 to 3 K. Even after that the Kat seemed to resist the throttle until another couple of minutes passed.

I guess the short answer is when the weather is nice follow the manual but when things get cold think about extending the time.

PS: Does anyone know who makes good snow tires for the Kat?

[The CyberPoet]

When I took the Kat out yesterday (during sub 30 degree F / below zero weather ) I had the choke on for over a minute with the RPM's from 2 to 3 K. Even after that the Kat seemed to resist the throttle until another couple of minutes passed.

Actually, carb icing can be a problem for Kats -- and many other carb'd bikes (where the linkages want to freeze solid, or the smaller passages want to freeze over). Some carb'd bikes have pre-heaters as part of their technology package, but injectors work much better, so carbs are generally going the way of the dodo bird.
In sub-30 F (negative degrees C), I'd seriously let the bike choke for a minute or two, and then let it idle (or hold it at a high idle) for a good five to ten minutes after that... you want the oil to come up to a decent temp before you put any load on that engine; this will also help warm up the carbs. Even after the engine is warm, carb icing can still be a problem, especially if there is fog or very small ice crystals in the air.

PS: Does anyone know who makes good snow tires for the Kat?

Yup. I was looking at some the other day... you have two basic choices: enduro style tires, and real snow/ice tires with studs. Which do you want?

Cheers,
=-= The CyberPoet

[Black]

A 650lb sport/touring bike in the snow is a scary, scary thought.

[harrye]

Cyber, thanks for the explanation of the possible consequences of riding with the choke on. I always chringed at the thought of what I had done. It sounds like a person can get away with it once or twice.

[JoeCool]

I just wish I had 10% of the knowledge/wisdom that Cyberpoet has...
I can't tell you Cyber how much I have learned from you alone on not only Katana's but motorcycles in general.

Thank you and everyone else on here for your help and wisdom8)