Fuel, Compression, Ignition

[LewieBike]

I wonder how many of the "youngsters" here even know what a set of points is, what is cam lube, and how to gap them...lol...DAMIEN

The annoying thing about Ducatis of this vintage is they have no tappet adjusters, you have to fish out a cup shaped shim on top of the end of the valvestems and have a proper motorcycle shop grind them down to get valve clearance. Points and condensors on these are easy.

 

[Cisco]

I did some compression testing of my two engines. The PK80 is fairly well broken in and running on a 32:1 mix. The Zeda80 is barely broken in and running on a 16:1 mix. I did cold and hot tests, with the petcock on and throttle open, at an estimated 10 mph for approx. 30 feet. Reporting the highest readings of three trials. The PK80 pumped up to 125psi cold and 110psi hot. The Zeda80 pumped up to 89psi cold and 80psi hot. I was surprised that the hot compression was lower than the cold compression (cylinder expansion?).

 

[Frogslayer]

I did some compression testing of my two engines. The PK80 is fairly well broken in and running on a 32:1 mix. The Zeda80 is barely broken in and running on a 16:1 mix. I did cold and hot tests, with the petcock on and throttle open, at an estimated 10 mph for approx. 30 feet. Reporting the highest readings of three trials. The PK80 pumped up to 125psi cold and 110psi hot. The Zeda80 pumped up to 89psi cold and 80psi hot. I was surprised that the hot compression was lower than the cold compression (cylinder expansion?).

And the oil is thinner when warmer.

 

[Street Ryderz]

I did some compression testing of my two engines. The PK80 is fairly well broken in and running on a 32:1 mix. The Zeda80 is barely broken in and running on a 16:1 mix. I did cold and hot tests, with the petcock on and throttle open, at an estimated 10 mph for approx. 30 feet. Reporting the highest readings of three trials. The PK80 pumped up to 125psi cold and 110psi hot. The Zeda80 pumped up to 89psi cold and 80psi hot. I was surprised that the hot compression was lower than the cold compression (cylinder expansion?).

That's pretty low I would have expected 140-160 for the pk and higher for the Zeda being new.

 

[Cisco]

That's pretty low

Perhaps my gage isn't accurate or the test conditions aren't right. I have another compression gage to compare readings. I just figured the Zeda engine isn't broken in yet. I didn't know what compression to expect from the 38mm stroke PK engine, but I would expect the 40mm stroke Zeda to pump up higher after the rings have seated.

 

[DAMIEN1307]

Perhaps my gage isn't accurate or the test conditions aren't right. I have another compression gage to compare readings. I just figured the Zeda engine isn't broken in yet. I didn't know what compression to expect from the 38mm stroke PK engine, but I would expect the 40mm stroke Zeda to pump up higher after the rings have seated.

I hope your using conventional 2 stroke oil rather than synthetic during breakin on the Zeda...Their instruction manual is pretty specific about that......DAMIEN

Ps...They are so specific, that they even specify to use Valvoline Multi-Purpose 2 stroke oil for the breakin period.

 

[Cisco]

I hope your using conventional 2 stroke oil

Yes, I am using non-synthetic, petroleum 2 stroke oil. That was a tip from the instructions that you posted. I haven't even run a full tank through the Zeda engine yet. There are a lot of miles in a tank, and I am still only accelerating up to half throttle.

 

[Cisco]

@Street Ryderz I have been using the heat cycle break in method you suggested. From my house it is about one mile down hill to the bottom of the road (coasting all the way). On the return, I accelerate, then disengage the clutch letting the engine idle down, and accelerate again. After getting home and letting the engine cool down completely, I check the head torque, then do it again. The engine has gained compression over time, but it is still low as you indicated. I haven't run through a tank yet, and I haven't accelerated above half throttle. Am I babying it too much?

 

[DAMIEN1307]

I haven't accelerated above half throttle. Am I babying it too much?

I didnt baby my Zeda 80 at all during break in...It is still running beautifully over 900 miles and a year and 3 months later...lol...I was also doing some uphill full throttle during breakin as well...DAMIEN

 

[Street Ryderz]

@Street Ryderz I have been using the heat cycle break in method you suggested. From my house it is about one mile down hill to the bottom of the road (coasting all the way). On the return, I accelerate, then disengage the clutch letting the engine idle down, and accelerate again. After getting home and letting the engine cool down completely, I check the head torque, then do it again. The engine has gained compression over time, but it is still low as you indicated. I haven't run through a tank yet, and I haven't accelerated above half throttle. Am I babying it too much?

Sounds like you are doing good.