about to give up on my 650

...ok, the bike will run on choke, but will eventually die, i dont know if it's from flooding or what, and without choke when i blip the throttle it sputters and dies. The carbs are clean as a whistle, and i guarantee it's not them, i dont have them set perfect but i'm pretty sure i have them set good enough to run:

All carbs set between 3-3 1/4, the butterflys open and close perfectly to the naked eye.

When i put a little propane through the airbox, the bike picks up but the throttle still isn't responsive below 1500-2000 rpm's without the choke. I have noticed that it does have some spontaneous idle, it will set in one spot for awhile but somewhere around the engine it lets off little coughes once in awhile, i looked at the plugs and they aren't fouled or oily and each cylinder is firing.
The cylinders do make some noise when they move, kind of a little wheeze or whine, the bike has 27,000 miles and has never had a rebuild or anything like that, it has sat in a garage for the past 8-10 years. Could this all be caused by low compression for some reason unknown. I looked inside the cylinders and there is some oily nasty material sitting on top of all the pistons themselves.
I've put some good dough into the bike over the past year, it looks great, and don't want to have that all go to waste but my patience is about gone.....

 

Have you tried the seafoam trick. Run some seafoam through the fuel tank. Have about a gallon of fuel in the tank to start then pour about a half can of seafoam in the tank and let it run. Wait until some while smoke starts to come out of the exhaust and shut the bike off. Let it sit for a day and then add more gas to fill up the tank and run the bike again. This may dislodge some hidden crap from the carbs. It does sound like a carb issue. This helps mine in the spring when it gets ridden again. Generally I put seafoam in it throught the winter. Unless I am riding it. I have to draw the line at about 20 degrees though. Wind chill bites.

 

Your question of low compreesion needs to be verified... Check it.
If it's low or not the same across each cylinder (<=14psi) then you might want to pull the cam cover and check the valve clearance.

I picked up an '80 xj650 that sat for around 12 years with 11k mi on it. Unfortunately it sat outside the last 3 and had water in the cylinders. Even after I replaced them, I had low compression due to incorrect valve clearance. Once corrected I had 150psi across them all.

You said the carbs are clean. Did you make sure that the orfice in the downtube of the float bowl is open on all of them ? I had a hell of a time getting all of them clear as there was a bunch of hard varnish in them and you can't get in there real good. I cleaned them from the bottom first, then from the top with a small stainless steel wire off of my wire brush. Lotta work to get them clear even after soaking them in Seafoam and a few other products for 2 days. This is part of the Idle circuit in that carb which could cause the problems your having.

Your weeze could be from an intake carb boot. If you can get it running check it with that propane around the head area where the carb boots are. I had one that was loose and I was hearing a high pitch weeze as well.

 

That's most likely what it is.

You need to:
Check that the small fuel WELL at the rear of the Float Bowl is filling when the Float Bowl is filled with gas.

Probe the holes at the bottom of the Float Bowl with a Carb Cleaner Red Tube you whittle to a needle point.

Send a Probe UP into the Brass Tube that extends into that WELL. One member said a Guitar String will do the trick.

Remove the Pilot Jet Screw from up top.
Remove the Pilot Jet from the Fuel Bowl.
Plug the Air Jets on the sides of the Carb Intake.
Blow Carb Cleaner into the Pilot Jet Port in the Lower Body and check that it exits from the Pilot Mixture Screw Port -- topside.
Blow it the opposite way; too.
Un-plug the air Jet and Blow-out that passage ... you should get Carb cleaner exiting topside and through the lower Pilot Jet Port.

Once you are confident that the Jets and Top-Side Passages are free and clear ...
Put the Pilot Jets back in.
Put the Pilot Mixture Screws back-in.
Set the Pilot Mixture Screws to 3-Turns Out.

Run it.

The only thing it should need is fine-tune tweaking.

 

yep, i've taken care of every single one of those points, a couple 4 times now. I have taken the carbs off my bike 4 times altogether, each time there has been riding in between and every time i take them off, there is really no build-up. I cleaned the mixture screws and little tubes at the rear of the bowls a time ago and when i just took them off they were clean as a whistle.
I really can't see how this can be carb related anymore, as many times as i've taken them off and cleaned them, and i have run seafoam through multiple tanks, does piston and low compression problems cause it to cut out at low idle???

 

You say you have run seafoam through it. I had a problem with my bike that was caused by too much seafoam..Too much will foul the plugs. Have you installed plugs in it recently. Plugs like to foul out way up inside them. You may get spark at the electrode but it may not be enough of a spark at low Idle. Have you thought about the charging system brushes. Any thing below 11mm and they sould be replaced. ric-o-matic has quite a few write ups on this situation. I checked mine last year and it did make a difference. Other than that, check all the electrical plugs for any corrosion and clean them up. unfortunately some more work on it may be in order. I am sure you can get it right though. We have faith in you. Goto keep another xj'r on the road.

 

Yes.

The SPARK from the Spark Plug ... only provides the Mixture with a point for Ignition. There has to be adequate COMPRESSION of the Mixture to make it volatile enough to be Ignited by the spark.

Insufficient Compression will cause misfire, plug fouling and all the related "Won't run right or Not at All" situation.

 

My XJ700N sat for 10 yrs, I think yours setting from 8-10 yrs is the key here.
2 things here.

1) Like Rick said check the passage from the float bowl to the pickup tube.
Mike was so clogged I had to use a wire guage drill bit to open it back up again (even after letting them soak foe a couple days.

2) The jet that your metering rod goes thru, did you take that apart?
If you dont remove it from the body of the carb, I guarantee it to be full of crap.

Those two items can make all the difference in the world.

Just curious.... all the air and fuel jets are in the right places right?

 

Is this problem:

a) Fuel Starvation
b) Ignition Breakdown
c) Compression Related

a. Shoot a quick shot of Starting Fluid in the airbox when the bike is running.

Revs increase: Yes/No
Yes? Fuel Related -- Carb are insufficiently cleaned.
No? Ignition related. Trouble shoot ignition system.

b. Run bike with a TCI Known to be good.

c. Corrective measures. Valve job, piston rings, install used engine.

Determine what the problem IS.

Compression test results.
Fuel Starvation test.
(Ign test ... somehow ... somebody close to you MUST have a box you can try ... huh???

 

i dont no anyone with a TCI box, one that will work with my bike anywayz, i didn't actually take the tube that goes into the port in the rear of the fuel bowls off, but i did stick a small cleaning rod up into it and it ran very smoothly through it, i wasn't sure if the siphons were removable or not and i wasn't going to snap them off.
The plugs are all the correct size and were brand spankin new last summer, i bought a gap adjuster and set them all perfectly. There is spark at idle but i am not mechanically inclined enough to test if it's sufficient, i am having a guy in town take it for a few days if we can work out a time.....hopefully sooner than later, just got my full fledged bike License on thursday and am really looking forward to riding.............legally

 

Ok, once again.
When you remove the float bowls and look in the bottom, there is a chamber where the pickup tube takes suction and hangs into.
Check to be sure the little tiny port or passage from the main float bowl is totally clear into the chamber that the pickup tube hangs or it will starve for fuel.

The other thing is the jet that is in the main body of the carb where your diaphran needle hangs in. well there is a jet in there and it has to come out and be cleaned and so does the inside of the carb body where that jet goes. and so does the passage that connects to it!

Good Luck

 

Here is a diagram( the correct carb, Lol) with some of the key items that have been mentioned to check and are highlighted.

The Emulsion Tube that Hvnbnd mentioned is probably full of crap as well.
If you pull the diaphram cover, pull the diaphram w/slide/metering rod, remove float bowl, loosen the main jet and tap it inward lightly, the Emulsion tube will dislodge, remove the main jet and pull the Emulsion tube from the top side and clean it. It has mulitple holes in it that all need to be clear.

The pickup tube well in the float bowl that we all talk about is not shown, but in the bottom of that well, if you look closely in it with a light you will see an orfice, this has to be clear. If you stick you carb cleaner tube in it and spray it should come out into the bottom of the float bowl, If not, it's clogged.

Congrats on getting your MC License !
Be Careful out there, make sure you check you equipment thoroughly before riding.

 

The Emulsion Tube is the #-1 Thing neglected by Carb Cleaners. The Emulsion Tube needs to be disconnected from the bottom ... by removing the Main Jet and Washer ... then, PRESSED-Out ... by removing the Top-End Diaphragm Assembly and pushing-out the Emulsion Tube from the bottom through the top.

There are as many as 24 Openings on some model tubes. The Ports are drilled straight through the Tube and you should be able to "See Light" through the holes when you examine them for being clean.

This one part ... the Emulsion Tube ... can be the MOST FOULED Part and mmost difficult to clean. Not only are its Metering Ports the smallest ... but, the part is Solid Brass. The holes will often times be filled and need a cleaning tool to clear them. The Brass will also tarnish -- [Green slime] -- and make removal difficult.

Ideally ... the Tube can be DRIVEN Out ... by using a Medium or Long Metric Cap Screw with matching thread ... screwing the Cap Screw into the bottom of the Tube, in the threaded end from where the Main Jet was removed, and tapping on the Cap Screw to drive-out the long, cylindrical-shaped, Emulsion Tube.

As important to having the Emulsion Tube clean ... is the cleanliness of the Air Passage connecting the Emulsion Tube to atmosphere.
The air passage surrounds the Emulsion Tube and has a air passage which connects directly to the Main Air Jet.

If the Main Air Passage is clogged ... or, the Main Air Jet clogged or not the correct value ... Fuel Supply Starvation will occur throughout the powerband.

The above diagram provides an example of how the AIR passages are connected to the Pilot Jet and Emulsion Tube ... although, the ACTUAL Passages are drilled and routed in a slightly different pattern on the HSC Model Hitachi found on most of the XJ-Bikes equipped with Hitachi Carbs.

 

ok,
I have cleaned the emulsion tube twice and the second time it wasn't dirty.
I cleaned out the little hole that sips fuel up through the pickup tube, it was dirty and i did clean it, but that didn't solve my problem.
I have thoroughly cleaned the pilot and main jets 3 times and they have been clean as clean can be the last 2.

I do have a couple questions now that i see that diagram.
1. The Blue highlighted passage, It must be slightly different than mine, but what would be the best way to clean that properly. From my remembrance, i squirted PB Blaster down through the mixture screw ports and that's about it, is there a better way?
2. The main air jet and pilot air jet ( red highlights ) are those the little jets you see when you take the cap off and remove the diaphrams, then there is a little cover to take off that exposes those jets?
Thank Guys

 

Rpgoerlich is right, the emulsion tube is a good idea to get clean. I just rebuilt my carbs and I took the jets and emulsion tubes from all 4 carbs to a buddy of mine who works at a yamaha dealer/service shop and he soaked them in something that ate all the crap off in a couple of hours. Safe riding.

Wesley

 

Hi,

these days I've got a similar problem. And that was caused by the carb, more or less by the filter not beeing there on the petrol cock. So all the garbage coming from the tank did flood the carb. Take a look at the pic. Maybe it's worth a check. I had this problems two times.

Ramon

 

#1. Pretty much the only way to make sure you got that passage clear is to spray a cleaner(non rubber destructive if you have any rubber parts still in carb) with pilot screw removed, alternate blocking openings to make sure you got flow all the way through the passage.

#2. Yes.

Pic may be a bit different as Rick pointed out on your carb.

Ramon, I had the same problem on all my carbs. Thats why the screen on top of the float needle seat is there. But after prolonged storage it seems to be the place where most of the crap is located.

 

i got a few days before i can rip into it again, i'll check back with progress.....

 

The PHOTO Above is the Bottom-End to a MIKUNI Carb. Note the recessed "Bullet-type" Pilot Jet.
<><><><><><><><><>

On the HSC Carbs we all know and love ...

The Air Jets and those passages begin right on the Carb Body.
Look at the Main Intake ... the big, round, opening that the Airbox Boot slips over.
The Air Jets are on the Left and Right. They're open enough to slide the Carb Cleaner Red Tube ... right in and blast away.
Give the flush somewhere to go.
Yank the Pilot Jet out of the Bottom-End ... and, take out the whole works Up-Top ... removing the Pilot Screw, Spring, Washer and O-ring.
Blast it 3 ways.
Shoot through the Air Jet and check for flow at the Pilot Jet Port and the Pilot Screw Port.
Then, do the other 2 connecting orifices; too.

Carefully study the ridges on the sides of the carbs and you see how the ports are drilled, connected and closed off.

 

In all you said you did, did you make sure the tiny hole were clear in the bottom of the float bowls that connects the pickup tube chamber to the rest of the float bowls?

I must have missed where you said that was ok too.

 

yep, that's the reason i took the carbs off again last time. I probed those holes, then stuck one of those little red tubes on a PB Blaster can and shot them clean.
I then took a pen light and shined it through the bottom to make sure they were clean. I was certain that would fix my problem, but i guess not...

 

Possibly not your problem at all.

Nobody has yet suggested float levels. Set too high and it will choke and die trying to get revs up. Set them on the low side of spec and see how it goes.

Mentioned earlier was valve clearances. Have you checked these yet?

You mentioned in your first post about wheezing. Was this while turning by hand? If it was, then definitely check the valve clearances as it sounds like compression is leaking past the valves.

 

the weezing is constant. It has been present since i started working on the bike.
The bike did run pretty decently about 3 weeks ago then all of the sudden it started the B.S. it's doin now.....could the float levels all of the sudden start acting this drastically, out of the blue?

 

No.

But, now ... to shake this thing down ... we got to start from scratch and do a tune-up "By The Numbers"

Compression
Valve clearances
Coil resistance check.

If your compression is good ... and your valves are all spec ... and we know that the coils are fine ...

We figure out a new plan.

 

well, about 11 o'clock tonight i got my bike put back together and she runs very well. It idles, doesn't die and has nice pick-up.
Earlier today i had troubles with it starting after it warmed up, so i took the carbs off again, cleaned the starter jets and adjusted the float levels the best i could and wow, that really helped. It runs and starts after i shut it off.
The wheezing in the engine is still present and i can hear the pistons going up and down but the performance, i don't feel, is affected. Sometime later this summer i suppose i'll take the head off and see if maybe i need some new seals, gaskets or a valve adjustment but i'm going to get a little riding in for now, FINALLY!!!!!

 

Well done! Such a great feeling when you solve a problem, way better than handing a mechanic great wads 'o-cash . Glad you did not give up?!

You might want to spend a couple hours and sync the carbs using one of the guides on the FAQ and Rick's string MMO YCIS tool one rainy day too.

I would not take the head off. If you have no oil leaks then your seals and gaskets are just fine. If you are worried about the state of the engine or head gasket check your valves and give her a compression or leakdown test. If you are not burning oil your rings should be fine too.

These motors go and go and go. Very hard to kill one.

Enjoy your ride .

 

so i can check the valves without ripping into it??

 

Yes you can check the valve clearances by taking the valve cover off and the left hand crankcase end cover off. Under the valve cover is a 19mm square end that you use to turn the motor by hand to line up each cam lobe. You can then check the clearance of that valve with feeler (or thickness) gauges. Any clearances that are not within spec need to have a new shim fitted.

There is a special tool to remove the shim or search zip tie method on this site. Others take the cams out to replace the shims but you don't have to.

There are tables to work out which shim is needed.

If you mean the valve seat condition, a compression test can give you an idea if all is ok. A leakdown test will tell you for sure.

No need to disassemble the whole motor.

 

EXCELLENT Pictures MiCarl! Sticky material for sure! Dang, we need a topic with the How-To pictures.

 

Thanks for the great pics MiCarl

Anybody know,
How tight are those shims in there?
If there is correct to too much clearance, would a magnet pull them out

 

i put a little bit of octane booster in my full fuel tank, i'll cycle that through and see if it helps with the noise, not very confident it will and if it doesn't ill go from there.

 

Shims aren't very tight, but probably iffy getting to them with a magnet.

There is a small slot in the shim cup that lets you get under them to pop them out. You can see it in the 2nd photo below the end of the camshaft, looks like oil is pooled over the cup but actually that is the gap.

When servicing the shims the opening needs to be aimed more or less toward the center of the engine. Then you can get in there and pop them out (I used a dental pick).

The valve needs to be held partially open to leave room to pull the shim. There is a special tool available to hold the cup down or you can insert something through the sparkplug hole to keep the valve from closing.

Beware, after pulling a shim oil will pool in the cup. When the shim is replaced the oil will be trapped. As you apply pressure with the cam the oil will spurt out of that gap - keep your face away.

 

If the shim clearance is over spec's ... you need to replace that shim with one that brings the clearance to within specs.

Under spec's:
Valve may leak and burn valve, seat or both.
Sudden compression change bad for engine.
Low compression could cause connecting rod failure.

Over spec's:
Noise.
Lift and duration affected.
Throw a shim; Wreck an Engine.