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Discussion Starter · #1 ·
Hello, Longtime listener, firstime caller!



So I bought a used 1994 tw after a wreck destroyed my Ninja and have been having a heckuva time keeping my hands off the carb. I noticed a fuel leak at the carb a week after purchase--a leak that would turn into a gush after I picked it up from a lowside. I first pulled the carb at this point and did a total disassembly and cleaning, quickly and spazzily and most unlike the suggested method. First, the snorkel at the beginning of the intake was all crudely hacked out--more on this later. All the carb parts looked good, but the idle screw plug was removed and the screw was way out, like 6-7 turns. Started up until this point was a little finicky, but the kickstarter would do it in a couple tries, cold,hot whenever. I replaced all o-rings with the Keyster kit, kept all the "original" parts (I think), reset the idle screw to 2 1/2, and couldn't start her. Unscrewed to 6-7 and she starts up.



At this stage she's a little hard to start, and very sensitive at first, usually dying out and requiring a few restarts before I can get the revs up. After that hump, she's golden. At speed, totally fine, though I don't know how a stock 200 should feel, but no weird noises or hiccups. Idling started making an unhealthy slappy ticky after getting warmed up. I haven't found a good sample of pinging to compare it to. But she got me around.



The idle thing really bothered me so I started looking for vacuum leaks, because the effectiveness of the idle adjustments seemed to have a definite limit. Using the hose-in-ear trick, found a hiss at the o ring between the engine and carb, fixed it, no improvement. Got a new airbox-to-carb hose, no improvement. Noticed the airbox was missing a hard to reach screw and the front cover, the big one, wasn't mating to the main body.



While the cover off I tried holding a piece of foam over airbox-to-carb hose and it would start with idle set at 3 turns! At higher revs it would stumble and die very quickly though.



I get the airbox back together as best I can, not perfect, and nozzle still hacked off, return the idle screw to very rich mode, and not it's even harder to start and more finicky about applied throttle. Idle had not improved. All the adjusting I can do can either make it really lean, or maybe ok-ish. Have not experienced any signs of richness. And today it was a little chilly and would start at all, regardless of idle screw adjustment, choke, no choke, prayer, etc.



So, the poor bike has been messed with by the Previous Owners, and messed with by the Current Owner, and I'm sort of lost as to what to do other that start replacing whole components.



If anyone can help I'll stencil your name on the tank with hearts around it.



Thanks,

Darren
 

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“unhealthy slappy ticky after getting warmed up.” This could be the signs of valves & cam chain out of adjustment. This can cause poor running conditions. Easy to check & correct, and take that off the list.

How many miles are on the bike? I’ve seen worn out valve faces cause problems like this too.

I think you need to re-examine the carb again, pull it off & get it on the bench. Make certain everything is clean & clear. Check the float level. Look at the carb thread & follow the instructions for shimming the needle. Check that intake boot that fastens the carb to the cylinder. Make sure it’s in good shape.

Your bike seems to be exhibiting the classic symptoms of a lack of proper air / fuel mixture at idle. Your statement about “ While the cover off I tried holding a piece of foam over airbox-to-carb hose and it would start with idle set at 3 turns! At higher revs it would stumble and die very quickly though.” Seems to indicate that it can pull fuel through the idle circuit. The reason it would run poorly with the foam covering the intake & increasing throttle is because you were restricting the necessary air to achieve proper combustion at higher RPM’s. The trick here is to get the carb cleaned, modifications made, & follow qwertys post on how to properly tune your carb. Hope this helps. m.
 

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The hacked out snorkel at the intake, is this the connection between the air filter box and the carb? Worse yet, we’re not talking about the connection between the carb and the cylinder?

If it’s the one between the air box and the carb, this can cause strange running conditions, although one might think otherwise. The carb is set to run with a certain amount of intake suction pressure. That is why you have to change jetting if you go to a K&N type air filter, these things change the flow dynamics.

Just an afterthought. m.
 

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Discussion Starter · #4 ·
Thanks for your thoughts.



The snorkel I'm talking about is at the very beginning of the intake, right under the seat. I just assumed the fuel system was reallly sensitive to minute airflow fluctuations or something. Can the bike run with just a universal filter replacing the airbox. Can airbox shennanigans cause the symptoms I'm experiencing or am I chasing wild geese here? There's a great chance that I effed up the carb cleaning/reassembly too, though I blew out all visible holes with air. Pilot jet is clear too. I located a tiny crack beginning in the carb-to-engine hose and rtved it but saw no improvement there.



I also was thinking the PO may have changed the main jet to compensate for this airflow mess, hence the stumble at high RPMs when I increase restriction to get the idle screw into spec. This bike has about 3k on the clock and has not been pampered. Off road beater I reckon.



Thanks!

D







The hacked out snorkel at the intake, is this the connection between the air filter box and the carb? Worse yet, we’re not talking about the connection between the carb and the cylinder?

If it’s the one between the air box and the carb, this can cause strange running conditions, although one might think otherwise. The carb is set to run with a certain amount of intake suction pressure. That is why you have to change jetting if you go to a K&N type air filter, these things change the flow dynamics.

Just an afterthought. m.
 

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So far so good. Be suspicious of the carb to engine intake boot, if it has any cracks, that can indicate problems, and you may want to replace it just to take it off the list, as it is only going to get worse.



The air box damage can cause strange running problems, as that can change the intake dynamics. At this point you may want to try & do a little repair to the box with some gorilla tape, if it is repairable. If this changes the running condition at all, it will be a valuable clue.



Can the bike run with just a universal filter replacing the airbox? Yes, it’s done all the time. If you want to go with an aftermarket air filter, like a K&N type, then you will probably have to change your main jet anyhow. There is information on this forum to guide you with this.



On the side of the main jet, it should give the size, this would be good to know. It is possible that the PO may have drilled the jet out larger thinking they would improve performance. This usually has the opposite effect. Or they may have installed a larger jet, which can change things all around.



Try these things, & then if something changes, it may point us in a proper direction. Otherwise, you may want to replace the intake connection tube, remove the air box & go with a good aftermarket air filter, & research the jets necessary to tune the carb with the aftermarket air filter, & hopefully that would fix it. But exhaust all the simple things first. m.
 

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Classic signs of a lean low speed circuit. I'd expect a pilot screw 5-6 turns out would pretty much unscrew itself and fall out. At 5-6 turns out, the pilot screw itself could be a vacuum leak. I'd be double-checking the size and condition of all parts of the pilot circuit and the various rubber parts inside the carb. Wouldn't surprise me a bit if the pilot jet is the wrong one.



Anywho, I'd check all other adjustments first, clean the tank and petcock, check for cooties in the intake and muffler type stuff. Then I'd resign myself to a slow, careful carb rebuild with a magnifying glass inspection of each component. I'd pay special attention to passageways in the carb body and the various rubber and plastic parts, especially diagphrams and such. It is possible somebody hit the partially disassembled carb with cleaner that damaged ruber parts. Ditch the Keyster and other aftermarket parts and stick with OEM.
 

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Discussion Starter · #7 ·
Thanks, guys.

Replaced the Keyster pilot (38) with the old "stock" 40 that I had taken out. Runs better but idle still has to be turned out 5 or 6 turns. Can I up the size of the pilot at this point? Most of the sites mentioned here have either "stock" or "obsolete" for pilots. Would anyone know the equivalent hole size in inches?



D
 

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I've worked on various early and late TWs with different combinations of air filters and exhausts and never needed to change the pilot. I'd be thinking something is messed up somewhere. Either fuel is not flowing properly or there is a vacuum leak.
 

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Discussion Starter · #9 ·
Tried a richer pilot--a 42. Set the idle to 2 1/2 and she started up first try. But she sounded different and was exhibiting a whole new set of symptoms, which was nice for a change, except she'd die soon thereafter. Even with idle dialed in to near closure of the passage.



Where could this vacuum leak be? All my gaskets are new and boots are tight, though the front one is old. Can an invisible crack wreak such havok? I've used the starter fluid method and got nothing. Used a piece of tube to search around for hissing, and nothing.



D
 

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OK, where to go from here. IF you have not done so, please do as qwerty & I suggested & completely & carefully go through your carb, use only factory parts, and use the stock jets for now, it's a starting place. Replace the 4 screws that hold the bowl to the carb with Allan / hex head screws, this will make it easier to remove bowl for future work. Order a new fuel tank petcock, (pt.# 23F-24500-11-00) & replace it, making sure your tank is clean. You could check the price of the petcock gasket, but for a few dollars more, it's hard to beat a new unit.



As for the carb to engine connection, (part #2JX-13586-00-00, & O-ring pt#93210-35537-00) , replace it! You said you had to RTV a small crack in it already, the thing is probably old & hard & cracked, take it off the list of suspects! Use only the factory clamps, they make a better seal than regular hose clamps. (In my opinion.)



For now I would recommend staying with the factory air filter / box combination, and a new clean oiled air filter element. This will keep the variables down.



If you have any reason to suspect that the stock jet(s) could have been tampered with, replace them with new stock. As qwerty said, you have a classic lean run condition here, and there can be many culprits. It’s frustrating, but you must treat this methodically, or you will never get the proper performance. m.
 
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