Help! Carb/overfuel issue???

So my "new" 82 xj650 (seca) has some carb issues.

Its had the carbs cleaned by previous owner as well as a carb kit put through it 1-2 years ago.
When it runs, its rough and wont idle.

Ive had it to a classic bike mechanic and hes looked at carbs, says theyre spotless, it has new floats and weve put in new diaphragms and done a carb sync.

Still rough.

Aparently runs at higher rpm but at idle and low its overfuling apparently?

Any ideas where to start?
Mechanic suggested new carbs but then back at square one with oldies as you can't but em new obviously...


Please help as i need to get her running in 2 weeks (roadworthy cert for registration etc)

 

You need to go to Church.

The Church of Clean

The overflowing is down to the float needles not sealing when the float bowls are full.
Ignore whatever the PO said he did, and ignore what seems to be a cursory examination by the mechanic.
Did he bother to tell you why he replaced the diaphrams? Did he show you that there were holes in the old ones? Did he say why he replaced foam floats that almost never fail?

Strip your carbs, clean them, and rebuild them (including throttle shaft seals). Replace any jets that you can't get spotless. Replace the float needles and seats. Replace the idle air screw o-rings. Replace the fuel rail o-rings.

 

And verify that the jets weren't installed in backward order,!too....

 

I saw the carbs. They looked spotless to me.
Diaphragms had holes. Yes i saw them too.
Not sure why floats were replaced.
Ive never worked on this stuff so am struggling. Especially since im under pressure time wise.
This was aupposed to be a first bike.

It aldo has a dicky neutral switch and the rear wheel locks up when tightened correctly.

Pulling my hair out guys...

It runs. It idles but overfuels and starts fouling the plugs on 3 cylinders (i think)
If you work it, at higher rpm it runs ok.

Any other ideas apart from back to scratch with a fine tooth comb and a couple hundred dollars of carb rekits that ill hsve to wait weeks to get ftom the us? (Am in australia)

 

The previous owner also has:
frame powdercoated professionally
Body and tank parts painted professionally
New bearings front rear and head
Engine stripped and checked (can see all the new seals etc)
New rear break shoes

 

did you check the fuel height after replacing the floats?

 

That was from previous owner so can only assume so.
Dont think that would cause overfueling tho, would it?

 

Mechanic says it looked ok.

I may have to sit down and strip them when i get it back and check everything

 

while your here you might as well learn how to do it your self thats what this site is all about.
What i mean is how it working for you paying a classic bike mechanic and not getting the job done right.

 

Jamie,
We hear what you are saying. . . . But now hear this, the advice given above is all good - but you are in a pinch with two weeks until road test.

Find a way to delay your road test is my advice. Remove that portion of pressure from your plate. Your bike is pretty, but pretty does not mean safe and reliable. You need to go to Church, and you need to understand this:
http://www.xjbikes.com/forums/threads/the-information-overload-hour.27544/
These bikes require meticulous attention to detail and having a time crunch hanging over you can create overlooked / half arsed errors.

Some folks work well under pressure, manic mania doesn't equate success for me.

Keep asking questions here and we (they) will get you through this.

 

Or borrow another bike.

NEVER. Assume

What is THAT supposed to mean though?

 

Thanks all for your thoughts and advice.

Turns out my 14 days is actually 7 days. So let's be honest, by the time i get the bike back there wont be time. Ill have to sit down and learn/rectify this myself and just cop the reassess fee for roadworthy inspection down the track.

The rear wheel also locks up when tightened according to mechanic, and the neutral switch is dicky and stays on in gear.

So looks like ive got my work cut out for me, even though you guys will prob find it a walk in the park.

Ill check back and bother you all as i get into it and see where this leads.

Mabey this wasnt the best choice for my first bike. Havent even been able to ride it. My permit will expire before i get the darn thing on the road :-S

 

The rear wheel locking may be an incorrect procedure, pinch bolt, axle bolt tightening? Someone here can get you through this,
Overfueling , like someone else already said could be a jet installed incorrectly..
You are starting with an incredibly reliable and durable engineered platform.
I love the look of you bike , that's almost the same color I plan to paint my 650 seca.
Alan

 

Play the long game. By the time you have it roadworthy you will be able to fix any forseeable problem before it happens.
Read The Information Overload Hour (link in my signature) and and get a notebook so you can form a plan of attack and keep records of what you've done.

 

Hey just while i think about it, and i could be wrong (will have to check) the float valve needles. I could have sworn the ones i saw in my carbs were all steel or brass or whstever. whereas a lot of pics im seeing the tips are a black material?

Which is correct -all metal or black tipped, and could this be the source of the issues perhaps?

 

K-moe, im already recording everything in a notebook so am on the right track.

Alan63 thanks, the colour of the bike is actually what "suckered me into buying"
Thst plus it was only aud $1600 haha

 

A good investment for sure.
New float valve needles come in both conditions either rubber tipped or solid brass. I believe the solid brass are prefered.

There was a recent thread about rear axle castle bolt proper torquing technique . . . here it is:
http://www.xjbikes.com/forums/threa...id-rear-wheel-installation.73506/#post-480638

No bother asking questions here, been said before:
You are the best person to work on YOUR bike, ask the questions here as you move through it and be amazed at how the people here can assist you from a computer screen.

 

all metal are best brass, make sure the tips are springey they are spring loaded. the rubber tipped ones the rubber can come loose

 

Ok so bike back.
It actually starts under its own steam now (just) so i guess those diaphrams made a difference.

Silly question, but mechanic said hed been thinking about it and it could be an electrical issue instead of carbs.
Thoughts/opinions/checks i can do?

Am taking what the mech said with much scheptisism as he also managed to crack the rear plastic and scratch the paint on right front of the fuel tank.

 

So did he replace his own damage?

What does he means by" rear wheel locks up when adjusted"? Cuz when I set mine up, I like to adjust the rear to where there is just a slight drag when turning the rim, then I back off til it juuuust disappears.... Then I fine tune to where the rear brakes will lock up with onlyabout 1/4" play with fingertips on the brake pedal. When it's back on the ground, that gives me about 1/2" or so for brakes to start grabbing under load, and very clean toe/brake pedal control with no slop

 

Never assume that a mechanic knows what to do with your bike, either. These Xj's are too old. That makes them:

-Simple enough for YOU to work on

-Simple enough for YOU to learn on

-Simple enough to not need to be hooked up to a computer for diagnosis

Since it can't be hooked up to a computer, a lot of mechanics LITERALLY do not know how to diagnose/repair your bike without a computer telling them what to do. That's where YOU become your own expert. We're here to help YOU.

 

Hogfiddles, nooe gunna talk to him on monday bout the dammage but tbink its just a bame and shamer. Im now assuming everyone i encounter thats not on here is an a**hole and wants nothing more than the money in my wallet.

Rear wheel lockup is prob him not reinstalling correctly.
Will investigste when time allows.

As for the mechanic hes got 45 years experience and deals in classics. My bikes 1) too new for him
2) seems s**t at his job. Will never go back to CENTERAL MOTOTCYCLES in melbourne australia

 

A lot of mechanics also assume that since you have an old bike that you don't have a lot of money, so they spend as little time as possible so as to not get stuck if the customer doesn't pay.

 

True k-moe.
I specified what i wanted done, that i was on a budget and was paying cash.
In this case i just think hes not good at his job tho and wanted the money.

 

Then there are also those that charge really high rates so that:

-Hopefully you won't come back

- if you are dumb enough to come back, they can charge you even more

-they're paid more to " make it worth the hassle"

 

Also true. Happy to just leave it as is. Dwelling will achive zero.

Thoughts re carb overfuling/possible electrical fault

 

Overflowing carbs will be because of :

1: a petcock that is allowing fuel to continue to flow

2: at least 1 needle valve is not sealing because either a float is hanging up or there's dirt in the valve body or the needle is worn/hardened/damaged etc......
3: incorrect float heights

Electrical..... Lets work on just carbs first. Be methodical. Solve a problem. Then the next. As problems are eliminated, others will be exposed and the causes are automatically being selectively and methodically being addressed and/or eliminated.

If you just try a myriad of things, with no sequence, you'll "spin your wheels" and not get anywhere

 

Hey again all. So ive completed my first xj650 "fix"
While removing the old number plate and rego sticker i have relocated the reflector from a slip in alloy plate to its stock location!

A small victory i know but have to start somewhere

Ive also found a couple of things on the bike id like help with. See next post

 

+1. In addition you'll start to understand how the bike was built and why particular components are necessary. You're not just fixing it, you're learning it.The courses being offered here are the basic principles and concepts used across the board for classic bike restoration. The Mod Forum is a advanced course.

Gary H.

 

Ok so number 1, the petcock has two lines. I read a little about them but will ask the silly question, one line for vacuum and one for fuel, yes? (See photo)

Second and more importantly there is an earth lead on the right rear of the motor. Its about 10-15cm long. Photo shows location.
Is this important and where does it attach as on my bike its just sitting loose! Somewhere on the frame i presume?

Is this earth important and could it be causing my bike any problems (read is this part of my carb/overfueling problem)

And info/advice appreciated

 

Petcock....

Small is vacuum line to petcock, big is fuel line from petcock.

Ground strap.... Engine to frame, or to battery neg terminal if long enough

 

A silly question is one that is not asked. Yes, the smaller hose is the vacuum hose (looks like the vac hose on your bike has collapsed). The fuel line also looks like vac hose. Are you certain it's for fuel (it's important that it is). Both lines should have clamp connections at the petcock. The earth ground is also important and should connect to the frame at a screw that holds the air box in place under the left side cover. You may need to remove paint from the frame to make it a solid connection. Hope this helps.

Gary H.

 

Thanks rocs!
No idea re fuel and vac lines. Am 100% new to this. Dont think they had clamps. Will check tomorrow.

Will attach the earth as you mentioned at the same time.

Will the earth being disconnected be causing any issues, or not really?

 

Mine was not making a good connection (frame paint) a couple years back and my new battery wouldn't re-charge. Scratched the paint and haven't had any issues since. Idk what other problems may occur. I wouldn't eliminate it...it's there for a reason. Cheers.

Gary H.

 

All good. It will be reconnected correctly.
My brothers a mechanic for toyota so am familiar with earths and their importance.

I only asked incase it could have been causing poor spark or other issues that may be manufesting as overfueling or similar.

Will correct it and continue ftom there...

Thanks for all the help this far, and all that i will be needing in the future. I cant say how inspiring it is. Especislly with a task that feels at least for now, so daunting.

 

These issues are not earth ground related. Follow the related advice to solve them. Be encouraged...you've got this.

Gary H.

 

Good ground connections on these bikes is paramount as well as any other connection. 30 plus years of previous owners and weather can be problems with any or all of the connectors on these bikes. My suggestion is to check and secure all connections including ground connections.

 

It can cause problems if other grounds are not good..... Better safe than sorry. Ground the engine, ground the frame, etc....

 

If the frame was painted then likely the ground attachment points were not masked and do need to be sanded to bare metal. Some bikes have the engine to frame ground instead of relying on the motor to frame. There is also a ground at the ignition coil mounting hardware where 1 or 2 eyelet terminals from the main harness are grounded via the coil mounting hardware.

Is the fuel filter installed backwards? Should have an arrow on it indicating direction of fuel flow, and I am not sure if backwards would cause an issue but may slow flow enough to cause fuel starvation with spirited riding - pic #3.

 

Fuel filter IS actually backwards.

 

The fuel line is just the original Yamaha line (which is why it looks like vac line). The fuel filter is backwards, but that won't effect flow until the strainer begins to fill up with crud. I'd flip it around anyway.

 

Didja say frame was powdercoated? That'll prevent it from grounding properly.

 

So the earth wire is too short to reach the point you mentioned. Must go somewhere else?
Will addlso correct the inline fuel filter when i remove the carbs. Mabey at the weekend.
Will also take a look at the air filter and see what it looks like too i think.

So much to do, oh my...

 

I have mine located here under the r/r.



Gary H.

 

Tup loojs like my seca must be different. Will start playing properly on thursday and the weekend, weather and wife permitting!

Stay tuned fore more soon guys

 

That's where the ground cable goes on the frame; at the lower airbox bolt. It may be that it's not on the correct case bolt. It mounts to the bolt that is just to the right of the output shaft.
Long story short....electrically it doesn't matter. Just bolt it somewhere convenient and out of the way of the swingarm and driveline.

 

Will relocate the earth later k-moe.
Ive popped the tank iff and had a propper look around now.
Standard issue old fusebox in average condition, air filter looks good.
I corrected the inline fuel filter orientation, checked the vac line. looks ok, just some plier marks from removal where it looks crushed (its not)
Found the choke was staying on a bit due to a goofy lil kink in the cable from where PO ran it. Relocated and checked ok now.


So now rather than tail chase ill put a video of the bike up and you guys can see/hear this thing. Still overfueling i recon but its a dash better now.

Thoughts/opinions needed.
Video link to follow

 

Watch "Xj650" on YouTube

 

it says this video is private ???