1982 XJ550 Maxim rebuild

Shims on the way. I stoned the cylinders before the first re-assembly. At this point two different piston and ring sets (used) have been in the bores. The set in there right now are used. #3 held almost 100psi all night and only leaked out about 3psi over 8 hours. It has to be shims and incorrect clearance measuring. I'll remeasure it when I redo the rest of them with the incoming shims. If it's around 100 I'm gonna let it fly because #2 is really good. I'll just have to make sure it's tuned accordingly.

 

Thanks for clearing that up for us. There could be come carbon on the valve seals too, so once it is running that could burn away and help you out a little. Checking shims should be a breeze for you after changing those pistons and rings out.

 

Intake on #4 had 260 needed 255 but I ordered a 255 in 25mm not 29mm. GAH.. It's close enough from clearance measurement so I'm gonna let it go for now. If I have a hard time with #4 I'll swap that shim out later. All are around 120psi based on battery crank test with no plugs in.

 

Well it popped a few times on start. When I filled the carbs #3 decided to overflow. I wet set these on level so WTF. Guess the carbs come back off again.. and again. Is it possible, in the TCI, to have ignition timing 180° out? I don't see how that's possible since it runs wasted spark but I have to ask because I could not get it to fire on all 4 at all. It ran on spray before I removed it from the frame and I see spark, albeit low, on both coils. Once I find the 2 missing oil pan screws (or substitutes) I'm going to fill the case up and get it all primed.

 

BEfore you pull the carbs tap on teh float bowl with a screwdriver handle. It's not uncommon for a float to stick during the initial fill.

Spark timing will only be 180 out if the coils are not hooked up to the correct feeds, the plug wires connected to the wrong cylinder pairs.

 

It is possible I could have the coil feeds backwards. The coils by cylinder are correct, though.

 

I have never had such a pita timing coordination to deal with.
Every time I got it all "right" on the top and put the tensioner in, it would end up off by 1 F'n tooth after a single cycle.




"And there was much rejoicing..."

 

Ya. Getting the cam timing off by just one tooth is pretty easy.
Did you notice the flats that are cast into the cams? Those are for a wrench so you can hold the cams in time as you set the chain on them. One of those things that the service manual glosses over (might not even be in there).
If I pulled cams more often it would be worthwhile to make a special tool for that job so the cam timing is fixed in place without needing to lay hands on wrenches.

 

This baffles me? If the ring gaps are correct how can it hold pressure for any length of time?

 

Yup, a 7/8 fits in there OK. Adjustable won't fit. The issue is the slack from the crank sprocket the intake sprocket. The intake always rocked backwards a couple degrees when the tensioner is put in. There are better ways of setting timing on an OHC like an indexing plate for the sprocket with more than 1 cam alignment position.

 

My guess is oil from the cylinder blocking the space. I put a couple tbsp of 30W in the plug holes. It held the pressure, which is all I care about. The next time the engine comes back apart the bike will be parted out.

 

Both of the ignition coils are 2.5ohms and 2/3 spark looks barely active. The book says primary(no idea which one it is) should be 2.5 but secondary should be 11k. Secondary? I do not understand that. Help? Pickup coils are 650ohms, at spec. Something is up with the ignition, unburned vapor is puffing out exhaust ports but it will not run.

 

Primary coil is the low voltage side (the connections to the TCI). Secondary coil is the spark plug leads. The secondary spec does not include the spark plug caps, so add 10K for those if you're testing with them on.

 

Well it must be the timing or the TCI. I do not know what else it could be. The cam dots were lined up to the cap dot on the long I mark for T on the crank. Carbs are primed and fuel is getting sucked in if I manually choke the carb inlet. 120-140psi avg max compression. Plug gaps are .028 and I see spark on the plugs.

 

Both secondary coils read nothing on the dmm between the plug caps and also the plug wires. Primary coils are fine at 2.5ohms. I can not even get a continuity beep on 200ohm ranging for secondary. Guess I need to replace them. Maybe the super weak spark was just not enough.

 

Did you check for corrosion on the plug wires? How did the insulation look and feel?

 

The wires feel fine and rubbery. One plug cap is broken but for most part the boots and contacts are clean and the contacts are silver-looking. I stabbed the DMM probes into the wire where the donut fits over and still got nothing. Do you unscrew the contacts out of the boots? I can nip off a little bit of wire if needed. What's odd is I was seeing spark physically on the plugs but one coil is much brighter than the other.

 

Is this a typo - you would need to be on the 200K scale to check the secondaries with the plug caps installed. You certainly are not going to get a continuity beep with that high of a resistance, even with the plug caps off your still looking at 11K +/- 20%.

 

I tried the whole scale. Nada.

 

The coils measure fine with the plug caps off. I cleaned them up and snipped back some wire. There is a spring and what looks like a graphite pin under the screw terminal. I clean up what I could and put it all back together. Same spark result, not running. I have pulled the carbs again and will be tearing them back apart. If I spray into the open boots I get fire but not on all 4. I am about to put it in storage at this point.

 

That carbon pin is the resistor. They can fail. Measure the cap separately, spec is 5 K ohms.

 

I don't get anything through the caps with the DMM. Only across the bare coil wires. I am going to order some new caps. Still, there looks to be enough spark on the plugs to fire it over.

Does anyone know what the air mix needles should be set to on the carbs? They are typically blocked off and I've not seen a spec in the book. I'm going to tear the carbs apart again and check all of the jets. I'm going to remove the intake boots and seal them with some rtv to make sure no leaks there. Anything else to check apart from the diaphrams and slides?

 

Baseline is 2 1/2 turns out from a soft seat, then tune from there. Generally you'll end up around 2 3/4 to 3 turns out.
If your idle mixture screws are still factory capped you'll want to replace the o-rings for them.

 

I did that already during the rebuild. I set them to 2-1/2 so I dunno what's going on unless there's a major air leak on the boots or the carbs just aren't feeding properly. I have the YICS eliminator pushed all the way in and both capping bolts in so that should not be an issue.

 

Try turning them out a bit more. The YICS being blocked will eliminate the supplemental fuel that comes from the three non-firing carbs. That has the potential to make it lean enough that they won't fire at the baseline setting.

 

you can get a crude running sync with just the starter, be quick and don't abuse the starter. and with that silly yics tool in you should see a major vacuum leak

 

OK, I'll try that tonight. The YICS eliminator was out initially and it still would not start up on all 4. I'm going to check all 4 diaphragms and put the carb set back on with 3 turns on the idle mix screws. #3 stopped peeing out after the fuel unstock the float.

 

It will run full tilt if I manually choke the carbs. I got fuel flowing through but I suspect the idle circuits are clogged. Not what I wanted as a result of the rebuild.

 

30 mins with the bowls off, carbs back on.

 

She sounds goooood.
Do a running synch to dial her in (after you have the exhaust back on) and you're golden.

 

Oh yeah, I couldn't hear well for a bit after that. 9:30pm with the garage door closed. I prolly woke the neighbors up.

I am surprised at the throttle response and idle settle with it being a cold start. The mix is a bit rich as well so it should tighten up a little more and smooth out idle. It was sucking fuel fast and spewing blue flames. The exhaust ports were wet so it would have been back firing like mad with headers on. I turned the idle mix back a tad and will be putting new plug caps on before the next run video. The resistors are shot and the spark is weak so I think I can tone the fuel down quite a bit with new NGK resistor caps on. Next, rear wheel balance, chain install and re-torqueing all of the frame components.

 

per·se·ver·ance
/ˌpərsəˈvirəns/

1. persistence in doing something despite difficulty or delay in achieving success.

Hopefully the future is mostly successes

 

Gas leaks and runs have ruined the clutch cover paint. I just can't win!

 

It runs. You won. Cosmetics are just details that you can't see while riding.

 

Well, I spent a lot of time refreshing the bits and pieces. I would have thought "Engine Enamel" would not dissolve with gasoline once cured. I'm not pulling the clutch cover off again, it's full of oil now. I may just leave it.

What's the typical vacuum draw on the intake nipples during idle? Trying to decide how I want to do the sync.

 

No spec was given. Just get them even. match 1 to 2, then 3 to 4, then the 1/2 pair to 3/4.

 

Right. I'll just measure it. Debating about playing with some MAP sensors on it.

 

i put the tires on 5/4 deck board and used the side stand, pulled the clutch cover and didn't loose any oil. it was close though

 

So it runs. Until you put it in gear, regardless of clutch position. Hmm... I hear a relay clicking when I put it in gear, engine off. I also have no headlight so I'm wondering if the diode pack is fried. Lights work fine.

 

Is the kickstand down?

If not, you'll get that sorted pretty quickly I'm sure. You seem good with electrical and I believe you have the FSM, it covers the test procedures pretty well for that circuit.

 

lift the seat and remove the relay that you see marked with blue on connector. if it stops stalling when put in gear it is your sidestand switch

spray contact cleaner in the switch then some dry silicon spray

also sidestand must be up or bike stalls when put in gear. i use my sidestand to kill motor when I stop to park bike.

 

The sidestand switch is disconnected. It's sitting on the center stand with the side stand up. I'll check it again, though.

 

The headlight relay and the sidestand relay are cross-swappable. The symptoms you have indicate that the relays are not in their correct positions.

 

switch being disconnected does not bypass it relay needs to be pulled

 

That's probably the case. I'll check it after dinner, thanks.

 

Side stand switch was the issue. Looks like the clutch cover is coming off anyway. Pack won't disengage. All gears run and sound smooth though. Shifting is fairly clean. As others have noted finding neutral can be a pain.

 

It's normal for the rear wheel to spin when on the center stand if that is what you are seeing - there is enough friction from the oil between the plates to cause this.

 

I put my foot on the drive gear to stop it and it proceeded to eat the sole up and nearly rip my foot off. I don't think a small amount of friction on the plates would do that? I dunno.

 

The clutch is essentially a poorly designed torque converter when in neutral. There's a lot of force being transmitted to the output gear even then.

 

Try the rear brake, it should easily stop the wheel without stalling the motor.