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2 stroke guys, how many hours on your top ends?

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3 hours ago, 200woodsrider said:

Hey just wondering what your guys are getting on your top ends. Research research research. 

Might wanna let your fingers do the asking, there has been a bunch of reports for this question on this Beta forum :ride:

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On a 300 I go for every 200ish hrs. Have heard of 3hundos going for lots more hrs.

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I am on 120 hrs - 5000 kms. Grabbed a top end rebuild kit a few days ago - Beta AU. Pulling the barrel sometime this week to rebuild.

Will post pics when I do.

I am gonna grab a compression test tool for future, takes a bit of guess work out.

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Hitting 2 hundy just now on a 2014 RR300. will go for a top end in the next 20 or so. Still pulls and sounds puuurfect. Looked through the exhaust port about 30 ago and all looked as it should be. Its my play bike, and doesn't get raced. But still leaves the young guys behind when we hit the gnarly stuff:)

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It truly depends on how & what kind of riding you & or the bike has done. For constant high output such as racing & starting from a fresh rebuild. I go back & replace my coolant (engine ice only), top end gaskets, ring(s), clean my power valve & cleaned the carb every 20hr's/5 race day's or so & I always did the whole top end every 40hr's/10 race day's or so. Thats running it hard (obviously) with a 44:1 & 50:1 ratio in a 250cc or bigger bike. In 144cc & smaller bikes, I always did the same but I did the ring(s) & ex ever 3 race day's/15hr's or so & every 6 race day's/30hr's or so for the complete top end at a 36:1 & 40:1 ratio. If you mainly trail ride or just ride for fun such as a weekend worrier or what not on a 250cc or bigger. I'd recommend doing the ring(s) & ex every 100hr's or so & the complete top end every 200hr's or so & thats running it at a consistent 40:1 ratio. If on a 144cc or smaller, I'd replace the ring(s) & ex every 75hr's & a complete top end every 150-175hr's on a consistent mix ratio of 32:1. Of course this is assuming ALL regular maintenance is well kept up with. Then I always go ahead & rebuild the bottom end (crank or rod kit, all bearings & seals, clutch steels, fibers, springs & any other found worn or damaged parts, ex) & re-nickle/re-surface, bore & sleeve or just bore over the cylinder/jug/barrel after every 4 sets of ring(s) & 2 pistons depending on what you want or the condition it was found in. The reason I recommend doing it sooner on a 144cc or lower engine is because they have less of a stroke & produce more RPM's so a already higher RPM output on top of they are usually (with most rider's) kept at that higher RPM range consistently to keep the power at the ready therefore causing the entire power plant (engine) to wear out a little faster in my experience.

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For a 300RR both raced in HS mostly at B level, and ridden off weekends, 180 - 200 hr top ends came out almost new in spec.  36:1 mix, good jetting, clean filters, bike always warmed up.   From previous 250 GGs running Vertex I'd guess the Beta 250 is good for 100 hrs easy, same conditions, but I'll find out.  Don't even worry about just rings.  If you run adequate oil, <= 40:1, you will find ring end gap barely increases and the PV stays clean over this interval.  I service more for potential fatigue than wear and performance loss. 

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Did my top end yesterday @120 Hours. Bore and Piston like new, slight ridge on the powervalve side of the piston.

Since the day it was new I have ran Lucas Semi Synthetic Oil 40:1 , after looking at how clean everything was I am sticking with it.

Gonna run it in this morning.

The Beta 2 Stroke Top End rebuild kit is excellent value. Vertex Piston.

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Did my top end yesterday @120 Hours. Bore and Piston like new, slight ridge on the powervalve side of the piston.
Since the day it was new I have ran Lucas Semi Synthetic Oil 40:1 , after looking at how clean everything was I am sticking with it.
Gonna run it in this morning.
The Beta 2 Stroke Top End rebuild kit is excellent value. Vertex Piston.
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IMG_5039.JPG.277a662e4529396a0e0a6ddfd27ef212.JPG
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IMG_5047.JPG.1de0c13914080e5d744629f29687784b.JPG

Holy blow by!

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Mine (300) was close to new spec @ 180+ hrs. Second one removed @ 120 for 250 conversion could easily go back in.

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