How long can the bike sit unused?

[edromero]

At what point do you know tha the bike has been sitting so long that it's better not to try to start it up without removing and cleaning the carbs?

Also, if its only been sitting a moderate amount of time, is it sufficient to drain the tank, add carb cleaner additive to a fresh tank of fuel, and run it through?

Is there a rule of thumb for length of time, or are there indicators to watch out for? Thanks

[edromero]

What is your diagnosis?

Seller says its been sitting for a while. He said it "starts, runs and drives fine but breaks up at high speed" ...does that sound like carb cleaning issue to you? Fuel filter?

Thanks

[steves]

You don't need to start a new thread half an hour later.

http://www.motorcycleanchor.com/motorcycle/how_to/mc_buyingused.html

[edromero]

2 different questions. That was a good link you posted, but it didn't answer either of them. Thanks

[arsenic]

Seller says its been sitting for a while. He said it "starts, runs and drives fine but breaks up at high speed" ...does that sound like carb cleaning issue to you? Fuel filter?

Thanks

That doesn't sound like a dirty carburetor issue even a little bit. A dirty carb problem is dirty pilot jets 95% of the time. Pilot jets control idle RPM. If it "breaks up" at high speed, it's on the main jets. If there are dirty main jets but clean pilot jets, that's a special kind of issue I've never seen in the history of forever. The other 5%is dumb shit that people do because the think they know what they are doing. Like installing a DJ kit in a set of 98+ carbs and putting the DJ main jets where the starter jets go, and leaving the stock main jets in place. I have seen that, twice.

[edromero]

Would it act like that if the guy put a k&n air filter in it? The reason I ask is because it sounds similar to the way my bandit acted when I opened up the air box and it was getting too much.

Could it be as simple as a fuel filter?

[arsenic]

All depends on dudes definition of "high speed". Anywhere but Florida, I'd say no, but there, who knows.

[91_gsx600F katana]

Seems to me like perhaps ignition break up or something for the upper rpms. could be a fuel issue or a combo of bad fuel and timing (if it was advanced). There really shouldnt be a fuel filter on these, if there is take it off.

Usually if the bike sits things that go bad are the fuel/hoses deterorate. Perhaps even some fresh oil is good in case fuel got past the needle/seats and entered the engine/oil. Also might be a good idea to pull the plugs and squirt alittle oil in the cylinders.

K&N should only affect lower RPMs and idle as it affects the vacuum/restriction to operate the carb slides, in the higher rpms theres little to no vacuum anyway.

[arsenic]

Seems to me like perhaps ignition break up or something for the upper rpms. could be a fuel issue or a combo of bad fuel and timing (if it was advanced). There really shouldnt be a fuel filter on these, if there is take it off.

98+ Kats DO have a fuel filter. The picture he posted is a 98+. In other words, don't "take it off".

K&N should only affect lower RPMs and idle as it affects the vacuum/restriction to operate the carb slides, in the higher rpms theres little to no vacuum anyway.

Not exactly.

[91_gsx600F katana]

Not exactly.

ok, didnt know they had a filter.

how would less of a restriction affect WOT performance? since the vacuum part of the slides would be wide open anyway...

[arsenic]

There is a shit load of vacuum at WOT. It's not "slim to none". Obviously you've never bliped the throttle with a manometer hooked up to the carbs.

[canucme3]

Yes the carbs run on pressure differences, but they work using pressure differences between the air moving through the carb and atmospheric pressure. Putting a filter on wont change that. The issue more then likely is some one put on the aftermarket air filter and didn't jet for it and you are running way lean on the top end.
As for if how long can it sit before carbs should be cleaned all depends. Did you leave them full of gas? If they were definitely take them apart and clean them if its been sitting more then a couple weeks. If they were drained its still probably in your best interest to pull them apart quick and check them, but there is no real time period put on how long they can sit.
Gas tank depends on how long its sat and care of the PO. If you fill the tank completely it will keep the tank from rusting as long as every so often you drain out the water that will settle to the bottom and top off the tank. Basically just look in the tank and if you don't see rust you should be okay. Personally I would take any tank that sat for any period of time with or with out gas in it and clean it.

[edromero]

Thanks this helps. I was wondering if it could be something simple as an air filter. From reading this site, I've learned that the katana does not do well with aftermarket filters. I appreciate the advice and will report back my findings if I end up buying it on saturday

[91_gsx600F katana]

There is a shit load of vacuum at WOT. It's not "slim to none". Obviously you've never bliped the throttle with a manometer hooked up to the carbs.

Im pretty sure that all carbs are basically the same... And if thats the case my race car/all car carbs should have 0 to very slim vacuum at WOT! If you still have vacuum at WOT then your carbs are too SMALL! Essentially with the butterflies fully open there is no restriction to create a vacuum and its sucking in air as fast as it is consummed. I guess the entire carb world and ppl like holley got there $hit all messed up... well that and my car vacuum gauge must be broken cuz it reads 10" at idle and 0" at WOT...

Blipping the throttle creates a sharp rise in vacuum, hence why cruising your vacuum should be at its highest, on a car carb you tune for highest vacuum at idle, my race car gets 10" at idle but 18" at cruise and when I blip the throttle but at WOT she screams at 0" vacuum.

[arsenic]

Im pretty sure that all carbs are basically the same....

Do you know what CV stands for? As in "the Katana stock has CV carbs." No race bike or race car I've ever heard of uses CV carbs. They use slide carbs which do not depend on vacuum at all. You twist the throttle (or push the accelerator pedal) and the slide opens, period. CV carbs or "constant velocity" depend on vacuum the ENTIRE RPM range. In which case, I'm "pretty sure" you're wrong.