This bike is the bane of my existence!! Free canadian beer to anybody coming to help!

[rich_mcd]

Hello again,

I don't know where to exactly start so I will start with what I found and the issues im having. The left hand (while sitting on the bike) cylinder seems to be missfiring. It gets warm but not hot, and the plug ends up oil fouled and damp.

I have a 1980 xs650, stock carbs, stock ignition, stock 2-1 exhaust with an emgo shorty muffler, brand new EVO2 8 cell ballistic battery.

I took the carbs apart recently and cleaned every orifice and piece of varnish I could see. Put in new o-rings, checked the jets (all stock) replaced the gaskets, checked the floats for holes or leaks and adjusted the float heights as per the manual.

I changed the oil to rotella 15w40, and in order checked the cam chain tensioner, then set valve clearances. The bike will kick over pretty easily (starter seems to bog though, which is weird, another topic all together) It will run ok but the left side gets warm, never hot.

I switched plug wires to the other side and it didn't follow the wires, still the left cylinder fouling the plugs. Checked the compression and it was about 140-150 (took both plugs out, disconnected power and kicked it about 5 times)

Does this sound like an ignition problem, carb problem or piston issue? I was planning on doing the PMA next season and changing the ignition at the same time with either points/pamco or boyer but maybe I need to do the ignition first?

Sorry for the novel, but I am so baffled by this bike!!!!

 

[Tron]

Carbs synced?

I had this issue at one point with a barn find and it just needed a carb sync. While your at it, check cam tension, timing, and valve clearance.

 

[retiredgentleman]

Even though you have a new battery, I'm wondering if your charging system is charging properly. The starter motor bogging down can indicate low battery voltage/capacity. What voltage does the battery measure with the engine idling at 1200 rpm (wait a few minutes after starting)? What voltage does the battery measure with the engine at 3000 rpm? These bikes need good voltage.

When you had the carbs opened up, did they both have the rubber plug covering the pilot jet?

It may be worthwhile to view the spark on each cylinder. You would want to see a nice fat blue spark. You do not want to see a wimpy yellow spark. Here's a pic of the spark I get on my bike.

If you make up a "spark tester" as seen in my pic, you can clip it to an engine fin to view the spark. Use a stiff copper wire such as a #12 soild wire, which will hold the plug in a position to easily see the spark. I used a hose clamp to clamp the copper wire to the plug body. Use a good clean plug as the test plug. Do this in a darkened garage.

The reward of free beer has me motivated to get your engine running right

 

[brendo22]

This sounds dumb, but did you set the valve clearances with the engine being warm right after checking cam tension? The way you worded it was a little unclear, thought I'd ask...

 

[Curtis P]

The wet plug indicates an over fueling. Check.your float height and vacume test your needle and seat at 5psi and make sure it holds that pressure for a min. of 1 minute.

 

[rich_mcd]

Thanks for all the suggestions so far guys,
carbs are synced, I will check the battery at 1200 and 3000 rpm, am I looking for a minimum number here? 12.5v or higher? Can the plug tester be attached to a cooling fin? The engine was warm-ish, its a little brisk here today and was running for a couple of minutes before checking.
Hey Curtis, can you explain a little more about checking the floats at vacuum?
Thanks again

 

[Curtis P]

http://www.princessauto.com/pal/product/8050832/


remove carbs. Hold up side down and attach hose to the pump. Pump ot until the gauge reads 5psi that is the standard holding.pressure for.a needle and seat

 

[rich_mcd]

So the tests done so far didn't help me. The meter I have is reading 16.2-16.6volts while the bike is off. When the bike is running it goes up to 18 or 19V. Maybe I need a new meter? There is a blue spark but they are kind of whispy....if that makes sense. A bunch of thin blue sparks. The bike would run on the right cylinder ok, when I had the left plug out for testing, but when I had the right side plug out testing it, it was a chore to keep it running and it kept popping and puffing smoke out the uni filter. Will try the test for needle and seats.

Just to clarify, 1980 brass floats are set to 27.3mm from the carb body with no gasket to the top of the float body? Correct?

Gonna try and video everything together and put it up on youtube, maybe it will make more sense.

 

[TwoManyXS1Bs]

Hey rich_mcd,
Do you have any idea of how many 'hits' this post has received since posting?

Anyway, this sounds VERY familiar, especially after carb overhaul.
Quick test: Remove left mixture screw, blast compressed air and/or carb cleaner into the mixture screw opening, reinstall mixture screw.
Start bike. If it runs different, you've identified a blocked air bleed (those little holes alongside the carb inlet bell)
Good luck.

 

[MechNewb]

Hopefully someone else can confirm but those voltages sound high. You might need a new regulator.

 

[Take Warning15]

I have the same question about vacuum testing floats and needles. How?

At 3000 rpm the charging system should put out about 14v I believe, maybe a bit better. yes, you can ground the plug to an unpainted cooling fin.

I also want to add a question, which may help both of us. If the battery is charged and charging, what else, short of replacing coils, could help remedy a weak spark? Would the next step be to replace/ tests individual parts in the ignition system?

 

[TwoManyXS1Bs]

rich_mcd,
I also think your meter is sc**wed. But, if it's showing about 2v difference `tween off/not-running and running/charging, then the charging system is probably ok.

 

[rich_mcd]

Just for the record......you guys are awesome! I assume the hits are due to the free beer offer......i mean, its canadian beer!! (having said that, rolling rock and sam adams are 2 of the best beers going, I digress)

I have been trying each of these diagnostics as they come up. On a positive note, I blasted out the hole with the mixing screw and I THINK there was a positive sign. The right pipe was getting hot.......then I ran out of gas. (the tank and fenders are out for paint) It is still sputtering, farting and backfiring a little bit but if the other cylinder is firing that is a good sign. I am going to get a new meter tomorrow and see if that makes a difference with my diagnostics.

And yes, I would like to know how to remedy a weak spark aside from replacing the whole thing. Here it is as of this afternoon.


Rich

 

[TwoManyXS1Bs]

I can't have beer. Who wants mine?

 

[MacMcMacmac]

Make sure your petcock diaphragm isn't leaking into the vacuum port either.

Funny, my left cylinder seems to be a bit soft too when the volts are down. I pulled the plug wire to confirm. Once there was a bit of temperature in it, it caught fine. I wonder if it's the whole positive/negative polarity plug thing.

If you throw a hotter coil on there it should smarten up the sparks. Try cleaning all your electrical connections first though.

 

[Tomterrific]

The most common problem with old bikes is a plugged idle jet. Did you poke a thin wire through the idle jet when you cleaned the carbs? Even if the jet was clean when you put the carbs back on, a small particle of dirt could block the idle jet. Dirt so fine it can get through a screen filter can be larger than the tiny idle jet drilling and block it. My quick fix is to blast the dirt back into the float bowl by sticking the tube from a can of carb cleaner in the mixture screw hole. The screw must be removed before blasting.

The TCI ignition is a good igniton so there is no need to replace it. You do have a TCI? I ask because maybe Canada used points in 1980.

Macmacmac's idea that the vacuum diaphragm of the petcock may be leaking is something to check. I have heard this happen on the SR500 forum.

Tom

 

[rich_mcd]

If idle jet is the pilot jet, then yes I cleaned it. Took a long while too. Used a bunch of carb cleaner and a guitar string. I took the carbs off again and blew compressed air through the mixture screw port on both sides and adjusted the idle and sync screws again using the guitar wire to get them close. I am going to re-sync them shortly.

I dont have a vacuum petcock, sportster tank and currently I am using a funnel as a temporary tank.

I got a new meter today and my old one was in fact, pooched. New readings were 13.25V not running and about 14.5-14.75V running. The left side was running better today, the left side was screaming hot though. Maybe due to not being synced properly. For some reason I cant attach the pic I took of the 2 plugs. The left is king of dark but the right is pitch black and covered in soot.

Here is a video of it running. Sounds a bit like a lawnmore, lol.

Since I know that the battery is good, there is spark on both sides and my carbs are cleaned I am thinking I maybe start at the cam tensioner, valves and then carb sync? In that order.

 

[rich_mcd]

and after reading the carb guide, things that stuck out in my mind from the vid were exhaust hanging or slow to return to idle, after rolling off throttle, popping from exhaust, and possibly a lean misfire. So with stock jetting would an increase by 1 size on my pilot make sense?

 

[TwoManyXS1Bs]

Rich, the compressed air trick isn't a fix, it's a diagnostic.
What you've described means goin thru those carbs again, really clean inner carb passages good.

 

[rich_mcd]

Getting the bike a lot closer . I opened it all up. Cleaned everything I had doubts about and installed a 45 pilot jet. Kept adjusting and got the sync pretty close I think. Now, for some reason the starter doesn't lag which is AWESOME. When it is set up where it should be, the starter fires it right away.

I think I need a longer hose for the sync tool it was getting awful close to pulling all the oil from the manometer into the barb.(a little did get in and I assume it burned of by the burst of smoke)

This might be a dumb question to ask but for the carbs. Do I set the idle on each carb individually via the dead cylinder method and then adjust the sync by only touching the sync screw? I was messing with both of them and had to take the carbs off the bike and start from scratch a couple of times.

New video for comparison sake.