When should I change my piston?

[thx1138]

My Beta accumulated running time is now 70 hours.

Manual says change piston at 60 hours.

But, I doubt very much like I ride my Beta anything like the people that wrote the manual had in mind, I green lane it, and sometimes I tip-toe round pay and play courses, refuse obstacles, occasionally pull a feeble wheelie or do an ickle "jump"
and ride it on the road a lot more than most I should imagine.

It sounds and rides the same as it ever did.

[P.addy]

Double it if you aren't giving it beans.

[stevo as b4]

A 300cc two stroke won't eat pistons very quickly even a tuned snarling enduro lump. The X-trainer is closer to a trials bike engines state of tune isn't it?

As a guide the Italian kids who ride KTM 125 supermoto's on the street which are competition spec MX/enduro motors, they usually change the piston at 3000-5000miles. I don't know how many hours that equates to but it'll be more I expect than the manufacturers service interval.

Id be looking at maybe 150hours or 8-10'000miles as an approximate safe guess I would say.

[Kickstart]

Hi

How much is a piston and rings? I might be tempted to strip it down to have a look. Although I would very much doubt it is necessary yet.

All the best

Katy

PS - think for the 300cc KTM 2 strokes the top end kit with new piston, rings and gaskets is about £125
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Bloggsy]

If the bike is running ok, then leave well alone

Remember If It Aint Broke Don't Fix It.
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If It Aint broke Don't Fix It

[stinkwheel]

You could periodically log the compression and change it when compression starts to drop.

I'd be more concerned about the small ends than the piston. Worn rings/bore are just going to lead to a loss of compression and gradual loss in performance. When a small end lets go, chaos can ensue.
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

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[Old Git Racing]

It's a comp bike built to closer tolerances than a road bike. You might not notice a drop off in performance but you will notice the difference if you rebuild it. Its the other bits that wear too. Do nothing at your peril.
My TZ needed new pistons every 300 miles by 250 you could feel the difference. Only ran it over mileage once and it ate a ring.

OGR
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2022 Tiger Sport 660 2019 Street Twin 2003 K3 gixxer 1000 1998 Srad 600 track hack

[Kickstart]

[stevo as b4]

I did exactly this at 18600miles on a KMX 200 once. Fairly certain the engine had been apart before though, but can't say if it was the original piston? I'm guessing it was though as the old head gasket had been re-fitted with a plastering of silicone sealant.

No matter what the stroker is I'd never personally go more than 10'000miles on a top end, probably 7-8000miles max on a performance engine like an RGV, if the crap power valves don't take the motor out first that is?