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Throttle not closing.


imagineer

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I just finished installing new carb jets on my '02 Bandit 1200 and now the throttle doesn't close on it's own.    I didn't kink or over stress the cables when removing/reinstalling the carbs.    I know the problem is not with any of the moving parts on the carb array as it snaps shut smoothly.    The problem presents when the cables are installed.    Are there any tricks to try out before replacing the cables?    Maybe adding an extra return spring?

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I thought you sold that bandit.

 

Routing is almost dummy proof.

As Pauly said, it's likely in the adjustment. Usually the push cable is a little too tight. Those carbs are especially finicky about cable tension. Pm me if you can't suss it out, I'm like a 15 min ride from you, I'll get em done.

 

@2talltim, semi expert? You mean consummate expert. 

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5 hours ago, CrazySkullCrusher said:

I thought you sold that bandit.

 

Routing is almost dummy proof.

As Pauly said, it's likely in the adjustment. Usually the push cable is a little too tight. Those carbs are especially finicky about cable tension. Pm me if you can't suss it out, I'm like a 15 min ride from you, I'll get em done.

 

@2talltim, semi expert? You mean consummate expert. 

I didn’t sell it, rather I (stupidly) traded it straight up for a ’97 Jeep TJ, 4cyl, 5spd.    Although I’ve been enjoying the heck out of the Jeep, I missed having, and tinkering with the Bandit.    About a year after trading the bike away, I was searching Craigslist for another Bandit, or other inline 4 sport bike, to play around with.   I expanded my search to cover Cleveland and what do I see…yup, my old bike up for sale or trade.   The seller even used the same write up I originally used.   Long story shortened, I reached out to the seller, offered a crazy low-ball number…and she accepted (probably helped that she just bought a house and needed cash).     So, for really short $$, I have a fun little Jeep and the Bandit.

When I picked it up in Cleveland, there were only 2 more miles on it than when I traded it away.    Turns out the person I traded it to, had never before ridden a sport bike.    Her 1st ride, she did one inadvertent wheelie, skidded to a stop and then dropped it.    After that, the bike sat untouched in her apartment parking lot for almost 11 months.     There’s a bit of rust here and there and the rattle can paint on the rear cowl cracked, but after getting it home and dropping in a fresh battery, it started just fine.      Ran like $hit, probably because the carbs were a bit gummed up.

Last weekend I cleaned out the carbs, and while apart, I put in a Dale Walker Holeshot Stage 1 Jet kit.   I also put in 5 degree timing advancer.    I ran out of time to get it started again and balance the carbs, so that will probably have to wait a week or two until I have an open afternoon.    In the meantime, I’m hoping to solve the throttle cable problem.   Sounds like the cables are simply too tight.

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You never should have gotten rid of it in the first place, that was a legit sweet build. Glad she found her way back to you.

 

As for the chick choosing a heavy liter-plus torque monster from hell as her first sporty bike, well, that was dumb. 

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Well, I tried getting the bandit started, the carbs leaked fuel all over the place and I can't figure out what I did wrong (and I still haven't solved the problem with the throttle not closing on it's own).

For gas, I'm not using the bikes fuel tank, but was using an auxiliary fuel bottle (think I.V bottle).

I didn't measure the float height while I had the bowls off.    I figured it wasn't leaking before, so the float levels should still be OK.  Could that be the root cause?

As part of the Holeshot Stage 1 kit, after swapping out the jets, I was instructed disassemble the tops of the carburetors and to slide little shims (5 of them) over the pointy end of each needle valve and then reinstall into the diaphragms.      Anyone done this before?   Does the picture below seem correct? 

Also, probably at some point while reinstalling the cabs, a rubber t-fitting the bridges the top/rear side of carbs 3 & 4 got knocked off.   When the carbs were leaking gas, it seemed as if gas was pouring out at this location too.    In the picture below, the T-fitting is installed, but it fits somewhat loose.   I can't imagine this fitting is supposed to be fuel tight?   There are no similar T-fittings between any of the other carburetors.   And this 1 T-fitting is connected to a clear plastic tube that goes nowhere

Any advice? 

 

IMG_0118.JPG

IMG_0122.JPG

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3 hours ago, motocat12 said:

"You haven't put the petrol pipes back wrong way round have you?

One of them works the diagphram, and if on the wrong bit of the fuel tap, will piss fuel out." https://forum.motorcyclenews.com/topic/59931/i-cleaned-my-bandit-1200s-carbs/15

I didn't take the bank of 4 carbs apart so the fuel pipes were never disconnected.    

Thanks for the picture.   That's exactly how I assembled the shims on the needles.    I just tore down the carbs again and confirmed all was assembled correctly and also confirmed the float heights.   I'll be putting fuel to it again in a few minutes, but wanted to check the web first to see what folks think the problem is.

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Only reason for fuel to overflow the bowls is either a float problem or a main fuel valve problem.  Assuming the floats are good, not stuck, saturated or leaking, installed properly and set at the correct level, it's almost got to be a fuel valve not shutting off.  Leaking fuel is not a problem related to the main needle position.  I have experienced a fuel leak from the fuel cross-feed pipes on older i-4 carb racks.  The plastic tends to dry out and shrink if it's not in contact with gas for long periods.  In my case, it eventually (24 hours) stopped leaking after I reassembled and had fuel in the lines.  No issues after that.

I'm no expert at tuning carbs but that 5-shim stack seems like a huge, drastic rise (increase) in needle position, unless you did a lot of porting, head work, and motor mods.  If the motor is still stock and only has aftermarket exhaust, I'd consider cutting that down to 2-3 shims and go up from there.

Edited by Bubba
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Well, it lives . . . and isn't leaking!    I'm guessing it was simply one or two stuck float valves.    During the second tear down of the carbs today, I shot a bit of WD-40 in each valve body before installing the valve.

The test ride went OK, but not stellar.    The bike finally idles well and with a responsible amount of throttle, it runs well.    Should I choose to be a bit irresponsible, at about 3/4 full, and If I gun it, the engine stumbles badly.    I'm not as skilled in carburetor diagnosing as some members here, so I don't know for certain if it's running rich or lean, but I'm guessing lean.   Here's why,

The Holeshot Stage 1 kit had 3 different size main jets, 107.5, 110 and 112 and the instructions clearly state that for my conditions, I should install the 110's.    Stupid me, I installed the 107.5 set.   I just went out to the barn to confirm and yup, the 110's are still sitting in the nifty plastic case.   I know what I'll be doing tomorrow.

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