A Newbie Mistake, help appreciated.

I recently cleaned the carbs on my 82 Seca 750 because the bike started running like crap. The bike was chugging with no power and eventually pittering out, the fact that the number 3 carb had a makeshift filter on it may have contributed to it's ultimate demise. I figured the #3 carb was gunked up and a crab clean was needed.

I am an amature at cleaning carbs but never the less took the challange on and sure enough the #3 carb was filthy and the main needle jet holes were severly clogged. I cleaned the carbs till they were spotless but took no note of the position of the main or slow jet orientation positions...

Now that the carbs are back on the bike it runs like crap (because they are very out of sync now?) the bike starts with some throttle and only stays running while there is open throttle, it dies otherwise. The choke also has to be open to get the bike started and stay semi running. It's also very weak and has little response to open throttle, when the trottle is opened all the way is has low rpms and a slow response.

If the orientation of the jets is causing this issue, how do I fix it? Is a vacume carb sync needed?

Thanks in advance.

 

The orientation is probably wrong (unless you nailed the 1:16 chance of getting them all in the right position). Are you talking about the jets on the top of the carbs, under the diaphrams? If so, the one that goes toward the rear of the carbs should have the small hole (the position that would be in the more "centered" position in the carb), and the one with the larger hole would go in the other. If these are reversed you'd have the symptoms you're describing.

 

I am talking about the Needle jet (main nozzle) under the diaphragm. There are several sets of holes on the jet, three on two sides and four on the other. Is that what you are referencing?

What is the correct position for the jets?

 

The orientation of the needle jet doesn't matter on the carburetor on your 750. Where the orientation matters there is a keyway to align it.

 

Keyway meaning the the orientation of the main jet on the bottom of the carb when the float bowl is removed?

How do I correctly adjust these to the correct orientation? Trial and error?

 

THERE IS NO INCORRECT ORIENTATION OF YOUR JET. ON CARBURETORS WHERE ORIENTATION MATTERS THERE IS A KEYWAY (A SLOT AND A PIN) TO ALIGN THEM. YOU DO NOT HAVE A KEYWAY. LOOK ELSEWHERE FOR YOUR PROBLEM

 

Apologies for being a newb but I think you left your caps lock on.

 

I think what you may be asking is the location of the pilot and main jets..??
And you think that you may have put the mains in the pilot holes and vice-versa???

 

I think what you may be asking is the location of the pilot and main jets..??
And you think that you may have put the mains in the pilot holes and vice-versa???

 

the main jet, the one with the larger hole, goes up on the "tower"that is what hold in the needle jet or emulsion tube in it should have 120 stamped on it
the other low speed jet with the tiny hole goes in the other hole it should have 40 on it
have a look at this
http://xjbikes.com/Forums/viewtopic/t=2908.html
it's written by a real pro and even a rookie can understand it

 

Awesome Polock, thanks for the link. I ran across that article when searching the forums but didn't give it the attnetion it needed.

I have the jets in the correct position (99.9% sure) but I'm going to review the Enrichment circuit.

Any other thoughts on why the bike would be chugging and not getting enough fuel? Would a leak in the carb boots produce similar symptoms?

 

a leak in the carb boots usually will be a runaway idle
did you have the floats out and the needle valve and it's seat there's a micro fine screen in there that may be blocked, unless someone took it out
read that carb cleaning thread the answer is in there someplace
take your time, be careful, don't break anything, don't hesitate to ask questions

 

Carbs are torn to shreds. Almost eveything dismantled without tearing each individual carb apart.

+1 to RickOmatic's guide as well as his use of the muffin tin!

 

Ok, carbs are back on the bike. Hit the start switch and she started right up and throttled exceptionally well. I couldn't remove the drain plugs on the float bowls to check the float levels but no sign of leakage on the carbs. She's running a bit rich and will need some minor adjustments (the pilot screws are the ones for air/fuel ration correct? and the best way to monitor this is by the sprak plugs?)

I'm waiting on some new pod filters because I'm missing one, which lead to the crab rebuild in the first place and I have a slight air leak in the carb boots. Any suggestions on where to buy these items? Any recommended Vendors on this forum? I know Old Bike Barn has the pods but I wouldn't mind throwing some buisness elsewere if they deserve it.

Thanks for the help!

 

hold on there scout, before you go any farther i think the best thing you can do at this point is find a stock air box and filter and install them
it may be running better after the good cleaning but with stock jets and pod filters, i seriously doubt it's running rich
start with a new set of plugs and keep a eye on them and adjust accordingly
unless you enjoy carb work the fastest way to happiness is the stock setup
please say you have stock exhaust

 

I was wondering about that when I pulled the carbs off, as they had stock jets. I'm going to be looking for a stock airbox, I do agree that's the best thing for a smooth running bike (for me, a newb).

It does have the stock exhaust.

Still working on the bike, I recently had an issue with the starter motor and after a good cleaning starts right up. Do you have any suggestions as far as where to get a stock box? I haven't done any research on it yet and plan on doing some tomorrow. How about the carb boots?

Thanks,

Scout.

 

Carb boots can be purchased from Chacal in the XJ4ever section. Great prices great service and has a lot of parts you can't get anywhere else.

He does not carry air-boxes though. No one does. It is going pretty tough to find one. Start patrolling e-bay see if anyone here has a spare one.

Good luck.

 

what kind of bike? I know there are parts on ebay for a lot of different years
please update your signature with your bike info!

 

i don't know if you can put a airbox in with the engine still in the frame
somebody here does !
try the buy sell trade thread, someone has one
think long and hard before getting new manifold boots, lots of bolts get snapped off changing them, you might be lucky, might not
if yours aren't leaking just smear some black rtv on them

 

Thanks for the updates. I'll read a bit more into re-installing the stock airbox. There is a slight run away idle, as you put it, that's what made me think the carb boots might be leaking. That and I sprayed some ether on them and got a slight change is rpms, nothing extreme, could just be pulling some of the spray into the pods.

I'm sure I'll be back with more questions, thanks a ton for all the help.

She's getting close to being ridable and reliable.