Broken Piston Return Spring! - Ducati.ms

swingwing · Jan 24th, 2009, 6:24 pm

Hello all. Just wanted to put out some info on bad piston return springs. I rode my bike for the first time in a month yesterday, and my engine blew the piston return spring in the front cylinder again. I can't f!@#$king believe it! Both times it has happened was while riding a wheelie in third gear with the red shift light on the dash on. I don't know if it's the Desmo engine or if other bikes have had this problem. For the of you who are saying WTF is the piston return spring it is exactly that. It returns your piston to TDC to be fired down again with the next air fuel charge. It also increases compression depending on the spring rate. The last time it broke I replaced it with a lighter heavier titanium spring. This incresed the compression to 150psi. and let the bike rev quicker. The bike ran awesome until it broke again.

**Chuckracer** · Jan 24th, 2009, 6:44 pm

Wow! I gotta get me one of those piston return springs! Do they fit any bike with pistons, or is this just a Ducati thing?

Sorry yours broke. You should have stayed at Starbucks.

cassiopia · Jan 24th, 2009, 7:09 pm

Maybe the red shift light means just that, shift. I don't have a shift light on my bike but I know when I hit the rev limiter it would be a good idea to shift and sooner than that is better. I had valve springs on my older non Desmo Ducatis, these piston springs must be on the newer Desmos then?

swingwing · Jan 24th, 2009, 7:10 pm

That's funny I just left starbucks when it happened.

swingwing · Jan 24th, 2009, 7:11 pm

Quote:

Originally Posted by cassiopia

Maybe the red shift light means just that, shift. I don't have a shift light on my bike but I know when I hit the rev limiter it would be a good idea to shift and sooner than that is better. I had valve springs on my older non Desmo Ducatis, these piston springs must be on the newer Desmos then?

The red shift light stays on alot! I'm not sure if it's broke or not.

swingwing · Jan 24th, 2009, 7:15 pm

[QUOTE=Chuckracer;547580]Wow! I gotta get me one of those piston return springs! Do they fit any bike with pistons, or is this just a Ducati thing?

All Ducati desmo engines have piston return springs. They dont have valve springs. I'm gonna up the compression again with the new even lighter titanium springs.

Fast1 · Jan 25th, 2009, 7:19 pm

[QUOTE=swingwing;547603]

Quote:

Originally Posted by Chuckracer

Wow! I gotta get me one of those piston return springs! Do they fit any bike with pistons, or is this just a Ducati thing?

All Ducati desmo engines have piston return springs. They dont have valve springs. I'm gonna up the compression again with the new even lighter titanium springs.

how do the valves return to the closed position without valve springs?

Monstaman · Jan 25th, 2009, 7:46 pm

Check your muffler bearings as they may need re-greasing too.

Another point to note is don't use up too many of the red shift light flickers cos these is only so many they can fit into the ECU and of course most ECU's are getting smaller as technology progresses.

jpgibson · Jan 25th, 2009, 8:37 pm

Wow, I thought I knew a bit about bikes , but this is revolutionary! That means you never need to put fuel in your bike once running as the piston return spring returns it to TDC and the momentum forces it past this so the crank keeps turning.
Did you use a left or right handed ratchet to tighten up the spring?
Got to go , muffler grease awaits.

08hyper · Jan 25th, 2009, 9:01 pm

I found a kit that will fix the stupid desmo set-up, it will replace the cam that closes the valve with high tech valve springs, for higher revs like a Jap bike, also there is a new large diameter high-temp spring that fits in the combustion chamber, that will help "push the piston down faster" on the downstroke, also helping power & increased RPM! can't wait to try it!

Aloha Alex