1976 Honda GL1000
- Thread starter john83
- Start date
john83
Over 1,000 Posts
So, I had borrowed Bens timing light and was trying to use that. The trouble is so much oil gets slung up on the fly wheel it's near impossible to see the marks when it's running. I got out my test light, read Randakks instructions for static timing and tried it that way.
The timing was so far off I'm surprised this thing would run at all. Took me a few tries but finally got it to where I was satisfied. Fired it up and it runs a LITTLE better. The idle is still pretty erratic, 950 RPM one minute and then revving up to 3,000 the next. I think part of this could be caused by my extremely leaky exhaust. I'm gonna fix that and verify timing again before I start messing with the carbs again. I'm sure they need to synchronized as well.
That's all, just a little progress today but one step at a time.
Sorry I haven't been posting pictures with this lately but there hasn't been much that was picture worthy. Aside from me throwing wrenches.
The timing was so far off I'm surprised this thing would run at all. Took me a few tries but finally got it to where I was satisfied. Fired it up and it runs a LITTLE better. The idle is still pretty erratic, 950 RPM one minute and then revving up to 3,000 the next. I think part of this could be caused by my extremely leaky exhaust. I'm gonna fix that and verify timing again before I start messing with the carbs again. I'm sure they need to synchronized as well.
That's all, just a little progress today but one step at a time.
Sorry I haven't been posting pictures with this lately but there hasn't been much that was picture worthy. Aside from me throwing wrenches.
Hoosier Daddy
Earache my eye...
john83 said:
So what was it?
This?
Also, I find it hard to believe an exhaust leak can cause such an erratic idle. I'd be more inclined to check the ignition or intake systems. A flaky spark on one cylinder that comes and goes... or sounds more like a vacuum leak or fuel delivery problem to me. A carb piston sticking on corrosion inside the vacuum cap can make these engines do all kids of crazy shit...
A carb sync won't cause that either, the synchronizing just balances the carbs throttle plates opening according to vacuum. Everything else has to be spot on before that will be effective and should be done last.
pidjones
Over 1,000 Posts
I'd like to second HD's comment on carb sync only AFTER everything else is sorted. Compression, timing, good plugs and ignition (including good connections), vacuum system tight, all have to be right or sync won't be right. I've made that mistake once, and it cost several weeks work and poor riding. Dyna systems eliminate the point arcing, but they still have to be timed right. Some folks will lower the oil level a quart or more to prevent the slinging if timing by light, but most now just do it static. Just remember to add the oil back!
Sent from my LePanII using Tapatalk 2
Sent from my LePanII using Tapatalk 2
john83
Over 1,000 Posts
Hoosier Daddy said:
I reckon. I mean it runs on all four now. I'm still gonna put a compression tester on it, check and recheck timing and verify all that other stuff before I try and synch the carbs. The plugs are brand new. I have been meaning to pull the carb pistons out and make sure they're still good.
john83
Over 1,000 Posts
Other than around the carb intake runners where else would it have a vacuum leak?
When I revved it up yesterday it would take about 30 seconds to return to idle so my first thought was vacuum leak. I sprayed a little DW40 around the intake runners to try and find it but no luck.
When I revved it up yesterday it would take about 30 seconds to return to idle so my first thought was vacuum leak. I sprayed a little DW40 around the intake runners to try and find it but no luck.
Hoosier Daddy
Earache my eye...
Not only where the rubber boots attach to the carbs but there are o-rings where the intake runners meet the head.
Not sure what WD-40 will do to detect a vacuum leak. I use short blast of carb spray as it is flamable and will richen the mixture if drawn in a vacuum leak.
Not sure what WD-40 will do to detect a vacuum leak. I use short blast of carb spray as it is flamable and will richen the mixture if drawn in a vacuum leak.
john83
Over 1,000 Posts
I was always told spraying WD40 would cause the engine to rev just like the ether. Anyways I went out and sprayed some ether at it, didn't notice the engine revving so no real obvious vacuum leaks. I checked the ignition timing again, it's perhaps a little off but VERY close to dead on. I pulled the pistons out of the #2 and #4 carburetors to make sure they were not sticking. Cleaned them up and rubbed them with a little aluminum foil to make sure there was no corrosion in there.
It'll run but it takes a while for the exhaust on the left side to start coming out hot. Left side of the engine doesn't feel very hot but the right side of the bike feels like an oven.
?
It'll run but it takes a while for the exhaust on the left side to start coming out hot. Left side of the engine doesn't feel very hot but the right side of the bike feels like an oven.
?
john83
Over 1,000 Posts
Bought a compression tester, it's in the mail right now. Bought a shift lever, also in the mail. Bled the front brakes and got all the nasty fluid out of them. Need to do the same to the rear brakes. Once the compression tester gets here I'll know more about how to proceed.
If the cylinders have low compression, how can I narrow down the culprit? I mean figure out if it's a valve, or rings or the head gasket? I've read one way utilizing an air compressor but I ain't got one of those.
If the cylinders have low compression, how can I narrow down the culprit? I mean figure out if it's a valve, or rings or the head gasket? I've read one way utilizing an air compressor but I ain't got one of those.
Bozz
Coast to Coast
You can do a sort of poor mans leak down test.
Pull the spark plug and kick it around until you are at the very beginning of the compression stroke for that cyl.
Have a friend slowly kick the motor through the compression stroke and listen very carefully at the intake, exhaust and oil fill.
(it may take one cycle per suspect)
You may well be able to hear your leak.
Intake or exhaust is valves, if you can hear it in the oil fill it's rings.
Not ideal, certainly, and with your compression tester you are halfway to having a leakdown tester anyway.
You can do a leak down with a portable air tank as well if you're in a bind.
Now if I was a betting man, I'd bet you will have some leaking around the valves if you do have low compression.
THe rings are certainly suspect as well, but statistically the valves are the more likely culprit with less than 50k miles on the motor, all other things being equal...
Pull the spark plug and kick it around until you are at the very beginning of the compression stroke for that cyl.
Have a friend slowly kick the motor through the compression stroke and listen very carefully at the intake, exhaust and oil fill.
(it may take one cycle per suspect)
You may well be able to hear your leak.
Intake or exhaust is valves, if you can hear it in the oil fill it's rings.
Not ideal, certainly, and with your compression tester you are halfway to having a leakdown tester anyway.
You can do a leak down with a portable air tank as well if you're in a bind.
Now if I was a betting man, I'd bet you will have some leaking around the valves if you do have low compression.
THe rings are certainly suspect as well, but statistically the valves are the more likely culprit with less than 50k miles on the motor, all other things being equal...
john83
Over 1,000 Posts
Bozz said:
I'm leaning in this direction as well. If the clocks are correct this thing only has 20,000 miles on it. I find it easier to believe that there is some junk on the valves causing some compression loss as opposed to worn rings.
Also of note. I took a good look in the gas tank today. Somehow before I never could see the very bottom, probably just poor lighting but today I had it outside the shed and used a very good flash light. There is some rust/sediment at the very bottom and the screen that is supposed to be over the pickup tubes is pretty much gone. Since I ran the engine a little without a fuel filter I wonder if I soaked up enough crap to clog the carbs a bit. Reckon it's time to give those another bit of cleaning and clean the gas tank.
pidjones
Over 1,000 Posts
I was able to pinpoint intake valve on #3 by removing the intake (well, the carbs were off for rebuild), spraying a little PB Blaster in the plug hole, putting the compression gauge on it (a plug would have done the same), and watching down the intake to see air blowing, foaming, and bubbling around the valve. Pretty definitive. The head has to come off to repair head gasket, valve, or piston/cylinder. You just want to pinpoint the problem first.
Yeah, any time with no filter could junk up the carbs, plus the fuel pump check valves. Flush well to avoid future problems, and consider double filters.
Sent from my LePanII using Tapatalk 2
Yeah, any time with no filter could junk up the carbs, plus the fuel pump check valves. Flush well to avoid future problems, and consider double filters.
Sent from my LePanII using Tapatalk 2
