Piston replacement.

[dirtbird]

Yes that's ok but you should be more concerned about cranckshaft bearings which is considerably more work.
In my 2014 I run always expensive synth oil at 2% and with 100hrs I replaced together with the new owner piston rings. Just for peace of mind.

On the OI 2017, I keep using the same expensive oil BUT I plan to put some oil in the tank periodically.

Not for the piston.
Just for the lower end.

Understood. Bottom end is still tight. I have run 1.6% in all my 2 strokes for 10 years and have never lost a bottom end. That is both racing and trail riding. I see no reason to change.

My intention as well is not to start an oil debate but only to ad my opinion for discussion.
If you are satisfied and feel confident with the ratio you run, certainly its ok with me.
However I do agree that the proposed oil ratios from euro manufacturers have more to do with political correctness than engine life.
Its interesting also to ad that the designer of the Beta engine is the designer of the previous KTM engine as well (he jumped ships few years before 2010 maybe around 2007). You can see the similarities in design.

[Cactus Jack]

I am astonished by the hours that you are getting out of top ends. Having spent the last 10 years working in the motorcycle industry I have seen so many pistons that have skirt fatigue at around 80 hours or 2500-3000 k's. My experience comes from time in a Husqvarna dealership spent mostly on the older HVA Red WR series 2 strokes. We have always recommended running at 40:1 or 50:1.

When I pick up my 250RR this week, I will be running it on the OI system and will happily allow for it to do 50-60 hrs on the first top end. I honestly sit here in amazement that some guys are taking it out to 200+ hours on a top end. Personally, and this is my opinion only, but I wouldn't take the risk on leaving it for that amount of time. If a skirt does fail, the damage is devastating.

Further to the discussion of mixture ratios, it is also interesting that people are premixing as low as 32:1. I am a fan of 50:1 or 60:1 for modern 2 stroke enduro bikes. It just gives a nice clean burn and seems to offer ample lubrication. On my trials bike I have always ran it at 100:1 without issue.
Again this is all just personal opinion based on my experience.

[mlstevens]

My UK RR300 2016 Oil injection when new had a Compression of 130psi then at 49Hours it was 140Psi now after a year and 111 Hours it is still at 140Psi. The other day I was out on it and felt it whent as well as it ever had. I hope to get in excess of 200 hours before i consider a piston replacement. Do you think this to be fair.

[Johnno]

I bought an IT 175F brand new just after the Civil War.

I roared laughing when i read in the owners manual ( that I still have ) that the rings needed to be replaced at 1600 klm.

Which'd be 60 or 80 hours I suppose.

Once the odometer showed 1601 klm you could not kick start the bike, you needed to sprint like a lion was chasing you and clutch start it.

At 1700 klm an XR 80 with a grown man on it would show you a clean pair of heels..

I can't see my 300 being that bad but I reckon I'll change the piston and rings at 100 hrs but only because I wanna add one of those aftermarket heads.

[Enmerdeur]

. If a skirt does fail, the damage is devastating.

Depends on your definition of devastating. On a 2 stroke there is never anything devastating when compared to when a 4 stroke lets go.

Piston skirt letting go on a 2-stroke at worst may require splitting the cases to clean things up but with how soft piston material is it rarely causes any major damage.

[Cactus Jack]

. If a skirt does fail, the damage is devastating.

Depends on your definition of devastating. On a 2 stroke there is never anything devastating when compared to when a 4 stroke lets go.

Piston skirt letting go on a 2-stroke at worst may require splitting the cases to clean things up but with how soft piston material is it rarely causes any major damage.

If you would happily run a bottom end without replacing any of the bearings that have had ground up metal go through them, then go for it. But in my experience once a skirt has gone through an engine, a complete rebuild is required which usually entails a new barrel too.

[Enmerdeur]

If you would happily run a bottom end without replacing any of the bearings that have had ground up metal go through them, then go for it. But in my experience once a skirt has gone through an engine, a complete rebuild is required which usually entails a new barrel too.

Yes worse case scenario but still not devastating

[dibbs]

does anyone have any videos on changing a piston? as I cant find any Beta specific vids on you tube! or is the process pretty much the same for all 2t's I love teaching myself stuff from watching videos and find its much better than reading instructions from a book or manual. And over here in the UK the dealer network is very few and far between at the moment, so for info on jetting, suspension etc you tube is my friend!!!

[Enmerdeur]

does anyone have any videos on changing a piston? as I cant find any Beta specific vids on you tube! or is the process pretty much the same for all 2t's I love teaching myself stuff from watching videos and find its much better than reading instructions from a book or manual. And over here in the UK the dealer network is very few and far between at the moment, so for info on jetting, suspension etc you tube is my friend!!!

Pretty much the same as a KTM

https://www.youtube.com/watch?v=dYdpyNdDE9w

[dibbs]

That works for me! thank you sir..