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Discussion Starter · #1 ·
Anyone have this problem. The bike is my 95 Suzuki Katana 750. The bike is fine under acceleration, but even moderate to heavy braking and it just wants to stall -- kinda embarassing stopping at lights and having to fire up the bike every time.
Is this a problem with my carb floats? It seems weird why it would affect all the carbs (in other words hard to believe 4 floats could all have the same problem). I'm thinking fuel delivery, but what would cause this only under braking?

Anyway, I'm clueless as to what to start looking at.

Buying new carbs at $379 each is not a cost effective option for me. I'm pretty good mechanically speaking, but I don't want to get into my carbs and not know what needs replacement (if anything).

Bike has 32,000 or so miles on it.

The problem progressively got worse over time (about a 2-3 month period), it was NOT sudden. At first is was just very heavy braking, then heavy braking, now moderate braking will cause it to stall.

Thanks for any help.



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Cheers, Rob.
 

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Rob, I'm pretty sure we can eliminate carb problems, and I'm also pretty sure that this isn't going to cost a lot of money.
A couple things come to mind right away - How is your clutch adjustment? Has your clutch been "grabby" lately, especially when cold? Do you have to pull the lever in almost to the bar to release your clutch? Secondly, is your kickstand spring holding your kickstand up tightly. Look at the base of your kickstand. See the switch? Is the electrical connection to this switch tight and clean? Lastly, have you been experienceing any kind of electrical problems lately. Are your battery connections tight.
Check these out, and let us know what you find. Try to provide as much detail as possible, and I'm sure someone out here has the answer to your question. Good luck.

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Discussion Starter · #3 ·
Thanks for the response. The kick stand switch is in good shape. The clutch is in good shape and I keep it well adjusted (no slippage). No electrical problems either, battery is well connected and secure.

All good questions. I'll expand more on what happens. I can have the clutch in and brake hard and the bike will start to stall. If I give it enough gas while braking I can keep the bike going -- splutters a little but so long as I keep the rpm's up it will continue running. But this is hard to do since I have to be on the front brakes hard and throttle while coming to a stop. This only happens when I'm coming to a stop. Under high speed cornering where I'm braking and blipping the throttle to match gear/rpm the bike is fine -- but I'm usually well into the rpm range while doing this. It only happens when I'm coming to a stop and the rpm range drops below about 4K.

If I brake very gently (use less front brake) the bike does not exhibit this problem at all -- runs and idles fine.

I've been having some problems with my choke cable getting sticky (hard to open hard to close). But still no problem getting the choke to disengage eventually and return the bike's idle back to normal.



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Cheers, Rob.
 

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My Ninja kills during stoppies...not that I do stoppies. I did one on accident and now when I try it kills under hard braking.

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Dan...Comfortable enough with his manhood to ride a 600.
 

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Clutch in, braking hard , sputtering starts once revs drop below 4k? If you let up off the brakes before coming to a complete stop, does the engine come back to life? If so, does it come back right away, or does it continue to sputter, and gradually come back?

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Discussion Starter · #6 ·
It will continue to splutter and gradually come back to life.

I really appreciate you guys/gals taking the time to read/help me with this.

Thanks again all.


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Cheers, Rob.
 

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It's very challenging, diagnosis using the Force, but lets see what we got. Those carbs have been around forever, and I've never experienced or heard of braking-induced fuel starvation occuring in all four carbs at once. When you're decelerating with the clutch in & the throttle closed, your fuel requirements are minimal, and it seems unlikely that the carbs could "run dry" in those few seconds. Course, I could be wrong. Does the Suzuki motor have the clean air injection system like Kaws? If so, that's also a possible culprit The check valve could fail. When you have the clutch in and the engine is sputtering, do you feel it through your drivetrain, as if the clutch were partially engaged? What I feel you may find is a short, which may have happened by a wire rubbing against the frame. It doesn't actually short until it's pushed forward by braking inertia. As the insulation wore away, more and more electrical current was diverted from your ignition system until it began to misfire. The only way you can verify this is by removing the gas tank & bodywork, and carefully checking the routing of your wiring.
Try this - if your bike has a fuel switch, run up to a good speed & brake hard. When the engine quits, shut off the fuel switch & attempt to restart. If the engine starts, and runs for 4 or 5 seconds with the fuel cut off after stalling, you can be pretty sure that your fuel system is not the problem, which leaves the electrical system, or the clutch. Good luck, Rob, write back & let us know what you find, or any service or modifications that were done prior to this problem starting.

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Discussion Starter · #8 ·
I just appreciate any responses since I have no clue how to resolve this issue.

What is the clean air injection system? How would I determine if it did? And, if it does, what/where does this check valve live?

I do NOT feel it thru the drivetrain at all.

I'll double check my wires. The bike did have a short about 2 years ago after my 20K mi full service. The Suzuki dealer/mechanic trapped some wires when he put the tank back on. I got stranded because the mechanic was so lame. Anyway, after that I make sure my wires are out of the way and full protected. But when that did happen the short caused my fuse to blow immediately -- it was not a "temporary" type of thing.

Could a bad choke cable cause something a weird as this?

Rob.

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Cheers, Rob.
 

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i try to think of simplest stuff possible. how's this for stupid but maybe over-looked. see if your fuel line is in a position that under hard braking your body moving against the tank can be cutting the fuel supply (shouldn't be the problem because of how fast it's eating up fuel, a pinched line would likely flow fuel longer, but maybe it's starved for fuel slightly to begin with).

one more quick thought, vance and hines powerpak? my f2 wouldn't idle with it sometimes. ran great, but had a mystery problem kinda similar to yours, wouldn't always idle. put in the stock box, ran good 'til i sold it.

hey leon, ever go to mikata japanses restuarant on jordan and independence. great food. went there last night.

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Tony

the views and opinions expressed by tony (cbrf2boy) are the ramblings of a total idiot. sbw.com, it's administrators, moderators, and members don't necessarily agree with and are not responsible for anything this idiot has to say.

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Discussion Starter · #10 ·
At this point I'm thinking of taking the bike to a service shop, but there are so few good ones in my area (like none). The only issue I have with that is the cost -- I don't want to dump tons of money into this bike especially since I plan to get a new one soon (Hyabusa, V-Max, or CRB1100XX).

I'd like to get the bike in running reliable order so I can sell it. Either that or sell the bike for $500 and let whoever gets it deal with the problem.

My bike is my daily "reliable" transport (which the Katana has been since I got it new in '95 ... until now that is) -- rain or shine. My car is strictly for racing these days and the wife's car is for groceries :)

Rob.


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Cheers, Rob.
 

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Does your bike have ram air, or little snorkle like things on the front? If so, it will send more air to the air box than it can handle at low RPM. So the bike is still flying down the road, and your engine is only producing so much gas, which stalls the engine.
Maybe?

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Discussion Starter · #12 ·
Unfortunately no such feature for the 95 Katana 750. But thanks for the input.



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Cheers, Rob.
 

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I am going with the starved fuel theory, all 4 carbs can have low float levels (equivalent) if you have a clogged fuel filter, clogged or restricted fuel line(s) or a weak or intermittent fuel pump.

You also may want to check the petcock assy. (calm down RCJohn!)

I am going to stand behind this one, your fuel level is LOW in all 4 carbs. Under braking, the forward G forces will "pull" the fuel forward within the carbs and viola, youve got mains sucking air. Check that fuel flow and everything associated with it. This is not electrical.

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Fear Green.
 

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Discussion Starter · #14 ·
I thought fuel filter myself when this first started happening. I went to my dealer to order up a new fuel filter. Well, he searches the database and nothing comes up as being a fuel filter. Apparently the bike doesn't have a fuel filter (at least not in the traditional sense). I've checked the fuel hoses and didn't see any problems. About the only thing I haven't checked is the fuel valve (Off, Fuel, Primer, Reserve).

Actually this kinda reminds me of a weird happening. My bike will stop when in the standard Fuel position even though there is plenty of fuel in the tank and my fuel guage is well above the empty red zone. What I did (this was about 2 years ago) was just leave the bike's fuel valve in the Reserve position -- this seemed to cure the problem. I wonder if this is related? Maybe my fuel valve got clogged or is faulty. Hmmmm...

Sorry for coming up with this info so late, but I totally had forgotten that I always have to leave the fuel valve in the Reserve position.

Everyone has really some good suggestions, I'll definitely follow up on the fuel valve.

Rob.

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Cheers, Rob.
 
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Put it on reserve then try your braking problem and get back to us..

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If somebody sounds as though they might know more than you, talk more and louder.


Adam
 

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Sounds like crap in your tank. Remove the petcock thing and clean it. Should be a filter in the tank, or a tube that's broken because it's become brittle.


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I thought about it some more over the weekend, and I'm going to go with my old favorite - water. Completely drain your tank, and then refill with new gas. After reconnecting fuel line remove the drain plugs at the bottom of the carbs, 1 at a time, and let flow for 4 - 5 seconds. Try to make arrangements to catch the gas that is going to spill - some bikes have tubes leading from the drains, others don't. If this doesn't work, at least it's free, and it only cost you 10 minutes. It may be that the deceleration forces the gas toward the front of the bowl, and then lets your motor get water. I feel that it is highly improbable that you have a fuel level problem, as fuel level changes very little over time, if at all. The electrical things I mentioned earlier are just too rare to be probable. Fuel starvation usually manifests itself at high rpm, where the need is greatest. When you said the motor slowly came back, that is usually something caused by a slow return to the proper mixture, as opposed to the more instant recovery you would expect if it were an electrical problem. I would also take a moment and check all of the vacuum hoses for cracks or bad connections. You will find them leading from the rubber manifolds between the carbs & the engine. Good luck. Let us know.

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I'll put my money on the Idle speed adjustment.

give that a few twists in one direction or another and see how that plays for ya.

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Yes mom, I promise this is the last bike I'll buy (this year....)
 

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I am interested. I have the same problem with my bike at the track. It only started doing lately. I ahve tried both reserve and main tank, no difference. I have rasied my idle to 2500rpm...still does it. It mainly happens when I brake for turn one, whcih I must brake hard and downshift form 6th to third. I can resolve the problem if I blip the throttle 5th thru 3rd, but id rather solve the real problem. A tuner at the track said I should try moving the clips on needles up one. i believe this would make it run leaner. I still havent done it though. Does anyone second the notion that making it leaner would solve it stalling after braking????

Trevor

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I wish I could remember... Oh .. i knew a guy or read something ?? That he had the same problem as this.
What had happened was he had his valves adjusted by the dealer... The clearance for his bike (I think it was a ninja) let's pretend it was "0.09 - 0.19" as an example.. If you don't take the lowest number "0.09" the bike acted weird .. But like I said I can't remember ...
Anyone can help me out ??

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Watch out where those Huskies go , Don't you eat that yellow snow ....


Adam
 
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