So the salami sizzler is not performing on par with what it should. A few weeks ago it was popping pretty bad under any engine braking and not pulling as much as it should.
Recently done:
-CO adjustment at Southern Cal Motorcycles and they said that it was running alittle rich still and they couldnt adjust it out. (recommended loose closing valves, exhaust side. Or loose valve guide.)
-I did valve adjustment to .000" or .002" on closing for all valves and left opening at high end of spec (assumption that gap closes as valve stretches with time/use).
Now it still pops and feels sluggish.
I checked compression on a cold engine:
-60psi Horizontal
-90psi Vertical
Anyone know what else I should check?
Whats the average price for a head rebuild? If I take the heads off myself? If I buy the valves myself?
ME thinks $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
Are those numbers with the throttle held open?
If so, it's definitely low compression.
A leak down test would pinpoint whether it was valves or rings.
Do you have a way to put compressed air into the cylinder?
Even if the throttle was shut , and lets hope it was , the readings should have been closer to each other to be within spec
Quote from: ducpainter on April 04, 2013, 03:52:47 PM
Are those numbers with the throttle held open?
If so, it's definitely low compression.
A leak down test would pinpoint whether it was valves or rings.
Do you have a way to put compressed air into the cylinder?
+1
Also, was the engine warm?
Throttle closed (untouched)
No oil added to cylinder
Cold (Thanks for noticing [thumbsup])
I can pressurize the cylinder yes. How would I read if it leaks from the valves or the cylinder by doing so? I agree i will be able to see leakage but to pin-point the source?????
Quote from: DesmoTillDeath on April 04, 2013, 09:18:34 PM
Throttle closed (untouched)
No oil added to cylinder
Cold (Thanks for noticing [thumbsup])
I can pressurize the cylinder yes. How would I read if it leaks from the valves or the cylinder by doing so? I agree i will be able to see leakage but to pin-point the source?????
Re-test compression holding the throttle wide open. Results would ideally be within 10% of each other.
Listen for air leakage in the exhaust, the carbs, or the crankcase vent/oil filler.
First two would be valves...last would be rings.
There is a standard for leakdown ...I don't know the value.
Ideally the engine should be warm too. Piston fit is off on a cold engine.
ok tested it within 5 min after a 15 minute ride.
Vert: 105 psi
Horiz: 90-95 psi
I guess the leak-down test is next. Although those numbers arnt terrible.
Quote from: DesmoTillDeath on April 09, 2013, 01:06:40 AM
ok tested it within 5 min after a 15 minute ride.
Vert: 105 psi
Horiz: 90-95 psi
I guess the leak-down test is next. Although those numbers arnt terrible.
They're kinda low IMO.
Did the leak-down on a cold engine at TDC compression stroke.
At 90 psi air bellowed out of the exhaust and the airbox.
I ride her everyday and despite the intermittent poor running/good running, it is on average decreasing in "get up" and performance.
Are new guides the only possible solution?
How difficult is it to do this in the garage?
How many miles on the engine?
29,000 :o
Nick will correct me if I'm wrong, but if air is blowing out the exhaust and the airbox then the valves are not seating resulting in low compression.
Did you pull the oil filler, or the hose from the breather, and see if any was coming from there? That would indicate bad rings.
It needs a valve job at the least, and possibly guides in conjunction. Without some expensive equipment it isn't a DIY job.
I took off the oil filler cap and listened the best I could over the roar from the pipes but I couldn't make anything out.
Now by "valve job" you mean merely replacing the valves and lapping them?
Now valve guide replacement is not complicated in concept but I'm guessing the expensive tools you are referring to is that which cuts the valve guide cup and a cutter for the seats. I can use the arbor press at work but I agree cutting those components would be much more tricky.
From another thread I was told a valve job including guide replacement cost around $350. If this was for both heads or just one I not sure.
Tomorrow I will call Southern California motorcycles to get a quote.
By valve job I mean replacing/refacing valves, cutting seats as necessary, and lapping.
New guides doesn't change it all that much. You just do that first. The guides in the Duc heads are driven in and out. It takes a fair amount of heat to accomplish it.
Before taking anything apart check your valve clearance. You might get lucky.
Quote from: howie on April 30, 2013, 05:18:34 AM
Before taking anything apart check your valve clearance. You might get lucky.
+1
Quote from: howie on April 30, 2013, 05:18:34 AM
Before taking anything apart check your valve clearance. You might get lucky.
You'll see, as per the first post, the problem persisted following a valve adjustment. I'm not that lucky haha.
Some times Mechanics mess up. It's worth making sure.
Quote from: LowThudd on April 30, 2013, 01:44:16 PM
Some times Mechanics mess up. It's worth making sure.
From re-reading his first post, it sounds like he adjusted his own valves. But I'm with you and I was about to suggest the same thing, even though they've just been adjusted, I'd double check the valve adjustment before tearing anything apart.
Also, I don't know anything about Southern Cal Motorcycles, they may be just fine, but if I lived in Southern California I'd check with Speeddog about work that I couldn't do myself.