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Author Topic: Carburetor Installation  (Read 1968 times)

Offline sraney

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Carburetor Installation
« on: March 07, 2016, 06:56:34 AM »
I'll be reinstalling the carbs on my 2001 1200 today after cleaning the jets.  I always have a terrible time reattaching the rear/open throttle cable end to the "throttle wheel"--you can't really see it or feel it with the carbs loosely in place.  The last time I did this, it involved at least an hour of fiddling and cursing before I finally got the cable secured on the wheel.

If anyone has a technique for this, I'd love to hear it.  Your method has to be better than mine!

Thanks,

Steve

Offline txbanditrydr

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Re: Carburetor Installation
« Reply #1 on: March 07, 2016, 10:25:13 AM »
Nope... pretty much the same method I use.  While I've never tried it I have read that loosening them at the throttle will help.  Good luck and stay patient.

BTW...  :welcome:
'01 B600S ... sold
'05 B1200S ... Top 20 mods... #20 through #2 - All The Usual Ones, Yada, Yada  & #1... 150,000+ Miles and Counting!!!!

Offline CanaBandit

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Re: Carburetor Installation
« Reply #2 on: March 21, 2016, 08:42:27 AM »
I just went through this as well.  The thing that worked for me was to slide the carbs in from the right side of the bike about half way.  Then I put a pair of vice grips between carbs 1 & 2 so I could rotate them downward and use them to open the throttle valves.  I then held the vice grips down with my so the throttle valves were full open which allowed me to get the cable in place.

Might seems obscure but it was what worked me for after messing around for nearly 20 minutes and getting no where.

Offline sraney

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Re: Carburetor Installation
« Reply #3 on: March 27, 2016, 09:14:26 AM »
Thanks for the reply.  After a lot more than 20 minutes, I ended up removing the fuel hose from the rack for better access, sliding them in from the right all the way until one carb was completely clear of the frame on the left and then tilted the rack "nose down" as much as possible to finally finagle the "rear" cable onto the wheel working from the left side of the bike.  This is the second time (since 2001) I've had the carbs off the bike, and I swear I'll sell the sucker before I do it again! (After 15 years of sitting in fuel, the fuel T fitting on the rack can get a little brittle and will break when you clumsily attempt to remove the hose.  Ask me how I know this.)

As an ironic side note posted for the benefit of future Internet searchers, the real original problem wasn't clogged jets this time, it was a leaking petcock flooding the crankcase.  I'd never seen this before in 40+ years of motorcycling, and my preconceived notion of clogged jets prevented me from believing my lying eyes that the sight window was over the top with black liquid.  For future searchers, here are the symptoms I observed:

1.  Relatively normal startup but with miss.
2.  Idles at 3000 rpm, then dies away after 2-3 minutes.
3.  Cold cylinder (#4 in my case) as determined by header temp after a few minutes.  (At least I now know that the primary and secondary circuits on both coils are within spec--more wasted time checking ignition.)

Symptoms I didn't observe, but should have:

1.  Oil level way beyond full.
2.  Relatively fresh oil completely black through the sight window.
3.  Thrashing and bubbling liquid visible through sight window with engine running.
4.  Somewhat faint fuel smell detectable through oil filler hole.  (Strong fuel smell in pan of drained oil.)
5.  There was no oil beneath the bike from the crankcase overflow, which would have forced me to consider the possibility of fuel leaking into the case.

Parting thoughts:  The inside of the carbs on my 2001 low mileage Bandit looked almost new, and the float valves looked great.  I think this led me to stubbornly believe that good float valves would prevent fuel from getting to the crankcase even with a leaking petcock.  (Back in the day when men were men and petcocks didn't need no stinkin' vacuum hose, I'd leave the petcock on--inadvertently or otherwise--for extended periods with no ill effects.)  I was wrong.  Even with good float valves, the pressure of the fuel can manage to seep by and fill up the crankcase, particularly in the winter when the bike sits for a while between rides.

Resolution:  Being tired and disgusted with myself after all of the above, I just removed the petcock, opened the vacuum diaphragm side, and stretched the spring, ops checked it several times off the bike with a vacuum hose attached, and put everything back together.  All back to normal now.  Maybe someday I'll pop for a petcock rebuild kit, but I doubt it--the diaphragm was flexible and looked like new, and I'll bet a simple hardware store spring will do the job if this happens again.  In the meantime, I have really clean jets and I'm now paranoid about checking the sight glass before I hop on the bike.  Another lesson learned....

End of dissertation.




Offline China Greg

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Re: Carburetor Installation
« Reply #4 on: April 19, 2016, 12:45:35 PM »
First of all, if your bike has been sitting for any length of time, SH*T STARTS TO HAPPEN. Modern gasoline, especially with it's high Ethanol levels, CORRODES your INSIDES. This is because the alcohol results in water in the lines, seals, etc.... and you get corrosion and rubber drying-out and hardening.

Now... if you are getting fuel into the crankcases, that can really only meanone thing: Gas has worked its way past your petcock (could be corroded seals, see above, or maybe someone left the tap on Prime), run down into the float bowls, and overflowed into your combustion chamber, where it sits and slowly drips past the rings, down into the cases.

I had this problem BIG TIME with a '96 Kawasaki 1100 that someone gave me a few months ago. The bike had sit for 2-3 years, the rubbers decayed, adn gas flooded the cases over that time. I had a b*tch replacing all the corroded seals in the petcock and carb fuel rail... and had to reset all the carb specs again.

INSTALLING THE THROTTLE CABLE-
You'd do yourself a huge favor by istalling the cable BEFORE you plug the carbs into the manifolds! Pull the carbs OFF. You can do this most easily by pulling them UP and out the TOP frame rails. It's a WHOLE lot easier than trying to wiggle them out the side, (believe me).

But if you're having fuel problems, first suspect the age of the fuel.... modern gasoline breaks down VERY quickly, much faster than gas, say, 20 years ago. This causes a lot of problems... clogged pilot jets for starters.
« Last Edit: April 19, 2016, 12:48:55 PM by China Greg »
Black '98 B12S, JE 1216cc bore kit, light port work, Yosh RS3, Ivan jetting, drag bars, Corbin Gunfighter, Progressive shock, Racetech front end, stainless lines, Wave rotors, six-piston calipers, polished wheels, fender eliminator, bar-end mirrors, smoked shield, NEP throttle lock...110,000 miles as of late 2014.. two complete tear-downs. Fresh as a Daisy.

Offline bluebandit02

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Re: Carburetor Installation
« Reply #5 on: April 22, 2016, 04:23:23 AM »
I feel for you. Just went through the cable thing tonight.

Wanted to ask you guys a similar question to one asked below. I took my bike (2002 1200S) out of storage 2 weeks ago and it would barely start. I winterized it as usual except I decided to fog the cylinders with Sea Foam as well. Now Cylinder 3 and 4 are not getting hot at all (only residual heat from 1 and 2). I have spark on all four plugs and I just cleaned and reinstalled my carbs thinking I had a stuck float or something. I did notice when I changed the oil it smelled of gasoline and after changing it I also noticed it was much fuller the next day and darker colored. When I do get it started it sounds like its missing a couple cylinders and it back fires as it starts and when it finally dies it back fires again. Anyone have any thoughts. Could the petcock cause my right cylinders to not fire and for it to backfire. Also when I pulled the plugs to check spark cylinder 3 and 4 smelled of un-burnt gas.

Im at the end of my diagnostic abilities and unless someone has some great suggestions I think I'm going to have to take it into the shop and spend the money to have someone fix it  :banghead:

Sean
2002 1200s, ART exhaust, mra windscreen, givi bags, stage one jet kit

Offline bluebandit02

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Re: Carburetor Installation
« Reply #6 on: April 22, 2016, 01:10:43 PM »
And now this morning I found a puddle of gas under my bike. The air filter box was also full of gas. Petcock issues ????

Sean
2002 1200s, ART exhaust, mra windscreen, givi bags, stage one jet kit

Offline China Greg

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Re: Carburetor Installation
« Reply #7 on: April 22, 2016, 02:13:05 PM »
MODERN GAS GOES BAD QUICKLY.
It is DIFFERENT than it was 20 years (or less!) ago. It breaks down quickly, and can leave a host of problems, including corrosion inside fuel systems (due to methanol)... hardened/crumbling rubber seals, and numerous jet clogging issues.
Many years ago when I worked in Suzuki shops, many guys would come in in the Springtime and say the same thing:
"Uhhh, my bike won't start, and I can't understand, because it worked FINE last fall!"
yep. They'd sign the work-order for a "tune up" and the first thing we'd do is drain the float bowls. 85% of the time: PRESTO! Ran like a champ.

But now the gas is far worse.  I just inherited a Kawasaki 1100 that had been sitting for two years; what I expected would be a simple carb douche-out turned into a nightmare... full rebuild of the petcock with new seals...full gas-tank rinse with muriatic acid... repalcement of fuel-rail seals between the individual carbs....and THREE attempts at cleaning out all the green powder and Mung in the various fuel passages.

Okay.. SO.
If you have gas in the airbox, it most likely means that your petcock FAILED somehow, (or you F-d Up and left it on Prime), the fuel leaked into the flaot bowls... filled THEM up... ran over into the intake manifolds and into the comb. chambers... then seeped past the rings and slowly-but-surely filled up the crankcase. When you went to start it, there was so much hydraulic pressure from too much fluid (gas and oil) in the crankcase that it pumped out the breather tube up top.. and down into the airbox.

Bad news, but not terrible:
First, make sure your petcock is sealing properly... put a tube or hose on the end of the petcock spigot and turn it to "Reserve". NOTHING SHOULD DRIP OUT. If it does, then that means you'll need a petcock rebuild kit (seals.. pretty cheap on Ebay).

Next, take your sparkplugs out and hit the starter motor. If you're lucky, you won't get a spray of wet gas come shooting up. If you do, make sure the petcock doesn't leak (again), and turn the motor over enough times that you're sure it's mostly free of wet gas, which could cause HYDRAULIC LOCK and bend a con rod.

Now you'll have to CLEAN the oil out of EVERYTHING.
This means fully draining everything in the oil system, including the oil cooler and filter. You can't take a chance on running with any fuel left in the lubricating system, as it will dilute the oil and damage the bearings, including the Mains. You SHOULD run some cheap (supermarket) oil in the bike for ten minutes, after it's all been cleaned out, and then dump THAT, (and Yes, i did all that with the Kawasaki).

THEN you'll need to clean out the carbs completely... that means EVERY MOTHERF***ING ORIFICE YOU CAN FIND. remove all jets, spray every hole, big or small (don't forget the tiny holes in the carb bores where the butterfly comes down, AND the little jets in the edge of the bellmouths)  with good carb cleaner, and blow it all out with high pressure air. Don't forget to clean the little rubber-tipped float needles and their seats, (for that use a Q-tip with a tiny shred of steel wool on the end).
DO IT AGAIN.
If the bike has been sitting, especially outside, there most likely is JUNK in there... and what sometimes happens is that MOLD actually grows in there. (Look for greenish powder coating).

All that done properly, you shouldn't have any more problems.
If it still won't run on all four evenly, then you've still got blockage in the jets somewhere.
« Last Edit: April 22, 2016, 02:18:12 PM by China Greg »
Black '98 B12S, JE 1216cc bore kit, light port work, Yosh RS3, Ivan jetting, drag bars, Corbin Gunfighter, Progressive shock, Racetech front end, stainless lines, Wave rotors, six-piston calipers, polished wheels, fender eliminator, bar-end mirrors, smoked shield, NEP throttle lock...110,000 miles as of late 2014.. two complete tear-downs. Fresh as a Daisy.

Offline bluebandit02

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Re: Carburetor Installation
« Reply #8 on: April 22, 2016, 04:38:25 PM »
Thanks I'll try all that. I did just clean the carbs 2 days ago and re-installed them last night ( checked every jet and orifice, ran air and wire through the holes very carefully)... but I do think I may have turned it to prime by accident last night when I tried it again. ( I wasn't sure if "PR" meant prime or not on the petcock but I guess it does). Despite that I believe it was leaking into the crankcase over the winter because my oil smelled like gas when I changed it in the spring.

So do you think my two carbs not firing despite spark is because of the hydraulic pressure in the crankcase from the leaking gas?  It would make sense that that is what's causing the back fire as the bike stalls.

I'm going to try what you suggested and I'll post an update. Thanks for the advice.

Sean
2002 1200s, ART exhaust, mra windscreen, givi bags, stage one jet kit

Offline China Greg

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Re: Carburetor Installation
« Reply #9 on: April 22, 2016, 05:46:28 PM »
So do you think my two carbs not firing despite spark is because of the hydraulic pressure in the crankcase from the leaking gas?  It would make sense that that is what's causing the back fire as the bike stalls.

Okay, first of all, if there's any hint of gas in the crankcases / oil, DO NOT run your motor. There's two dangers:
1) If you have liquids of any kind (fuel) inside the combustion chambers, you are at big risk of HYDRAULIC LOCK.. meaning that the liquids cannot compress like air does in there when the pistons rise and compress. This is a good way to BEND A CONNECTING ROD, or worse. Take the plugs out and make sure there's no liquid in there. Also, it will give you a good chance to see which cylinders are firing... and which aren't.. by the wetness or deposits on the plugs. This will help you narrow your problem down.
2) Any fuel in the oil will result in SCORING OF THE BEARING SURFACES.

It is unlikely that fuel in your oil supply (cases) would prevent the engine from starting (although as I just said, you wouldn't want to try).

Question: when you DID start the bike (at least partially) what did you see coming out of the exhaust pipe? If it was WHITE smoke (as I expect) that means your combustion chambers had wet gas in them. If it happened to be BLUISH smoke, then there is oil getting into the com. chambers.

First, pull those plugs. That will give you a very good indication of what's going on in there. Hit the starter with the plugs out and see if any gas comes spraying out. Very important.

If the plugs are clean and dry (I doubt it), then put them back in.. and your problem will be back in your carbs... something is still blocked. There are FINE HOLES in the venturi (carb bore). Be very cautious about poking wires etc. around in jet holes... you're liable to change the size and flow. REMOVE ALL THE JETS and check that they are all clear. The B12 Pilot Jets are notorious for loading-up, because they are so fine. Hold each one up to the light and make sure that each one has about as much light coming through as the others. You HAVE to take them out to do this... otherwise you are wasting your time. (PS the Pilot jets are the little ones). No offense, but if you did not remove the pilot jets to clean them I seriously doubt that you could "get a wire through them"... they are very small. And it's not a sure fire cleaning method.

Make sure your floats are working properly... bouncing up and down happily on the little float needle springs, and that the float needles are clean. If you know how, re-check your float heights (13mm, I believe). If you had, or have, a float not working properly, that could be an excellent reason why fuel is leaking inside.

The more experienced you are with removing the carbs the faster you will get at it. I can get my carbs out on the table inside of ten minutes... back in in another 10. Practice makes Perfect.

Also, check your air filter. B12's a famous for disliking dirty air filters, and if yours has been soaked (gas) or gotten very dirty, it will greatly effect your running.

Unfortunately there aren't too many short cuts here. Sweat the Details and do it right the first time and with luck you won't have to go back in. Don't ask me how I know this.
« Last Edit: April 22, 2016, 05:57:57 PM by China Greg »
Black '98 B12S, JE 1216cc bore kit, light port work, Yosh RS3, Ivan jetting, drag bars, Corbin Gunfighter, Progressive shock, Racetech front end, stainless lines, Wave rotors, six-piston calipers, polished wheels, fender eliminator, bar-end mirrors, smoked shield, NEP throttle lock...110,000 miles as of late 2014.. two complete tear-downs. Fresh as a Daisy.

Offline RDUBandit

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Re: Carburetor Installation
« Reply #10 on: September 25, 2016, 12:43:45 PM »
I've always attached/detached drained carbs while removed from the boots and "hanging" out the right side of the bike.  There's plenty of slack in the throttle cables to turn the carbs upside down and install the throttle cables.
Dave...
2004 Bandit 1200S (>92k miles; lotsa mods; SOLD)
2002 Bandit 1200 (>13k miles; more mods)
1997 Bandit 1200 (>3k miles; most mods)
2005 Ducati Monster S4R (>48k miles; ditto)
2003 Triumph Speed Triple (SOLD)
2013 Yamaha FJR1300 (5k miles)
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