2019 EC300 parts compatibility
 

Hi;

So I just bought a 2018(19 model year with the different powervalve adjustment) EC300 with about 130 hours on it (the trip computer shows 105, but the seller claims it was changed out about 30 hours in).

It supposedly also has a new-ish piston - but you all know how that goes.

The bike as a rattling noise at iddle, that I hopped was the common power valve preload issue, since the bike didn't like to get into the pipe consistently.

However, the powervalve is the newer system that you can set the preload from outside the clutch cover. After cleaning out the powervalve, which was absolutely caked in hard carbon that not even the ultrasonic cleaner could touch, the noise was still there.


There's a bit of a ring ridge in the cylinder and I can fit a 0.25mm feeler gauge between the top of the piston and the cylinder itself. I'm waiting on a dial bore gauge to get a proper measurement, but I'm guessing the cylinder is pretty much done :(

Now to the actual question. Does anyone know if the 2017 cylinder will fit the 2019 bike? I can get the whole cylinder/piston/lid kit for about 500?.

Well, the plot thickens.

Turns out that the new-ish piston is actually a piece of trash. Front to back it measured about 71.4mm, so there's the noise - piston slap.


https://i.imgur.com/X6byz2Y.jpg

https://i.imgur.com/VHdiAOR.jpg

https://i.imgur.com/pcIRqTg.jpg

https://i.imgur.com/sOTRfRD.jpg

The cylinder has some marks on it, but nothing that I can feel with a finger nail.

So, what do you guys think? Run one more piston and swap the jug out next time?

Give it a hone and see how it measures and cleans up. There are specific ball hones made for nikasil plating. I don?t like the look of those light coloured rings. It looks like the plating has worn through to the bare aluminium.
I would get a replate as opposed to a new cylinder. The 2017 will fit though FYI.

As above. Send it to a replate that offers hone as they have the right gear to measure and evaluate it, or replate if required then tell you what size piston to buy.

Something has happened. These top ends just don't usually wear out. 3 I've had apart were mint. I'd say 100:1 lunnie or water and grit air filter.

Check your bottom end for smooth running and no sign of blueing.

From what I can tell in the cylinder/piston, I think the piston probably seized and then came loose.

Maybe high rpms for too long? Maybe forgot to mix oil in the gas?

I don't know how long the piston was slapping around (I certainly didn't do it any favors with the sunday ride), so anything is just a guess.

Can't feel any up/down play in the crank or the flywheel, so after some more fettling I think the cylinder is salvageable - at least for one more piston. The ring ridge I was worried about was just some carbon and the bore is pretty round and mostly in spec.

I ended up ordering a vertex piston, so we'll see how it goes when that arrives. Even if it's "good" - I think I'll probably replace it soon-ish.

Aight, just a follow up.

The piston and gasket kit showed up last friday, so as soon as I could get off work, I threw those on.

Vertex b piston (a bit looser than it should be, but oh well) and a gasket kit for about 200?. Not great, not terrible.

The bike now has a LOT more compression and the rattle is gone. I mean, I hear something buzzing at off idle frequencies, but I'm suspecting a loose bolt or something.

There's now enough compression to make it hard to kick and the starter also struggles while it's in gear. Sometimes it will crank and crank, but it ends up not starting or backfiring a bit. Plop it in neutral and off it goes.

The previous owner gave me a 10w40 motul jug, but I think I'm going to try some 5w30 instead.