Rebuilding a 2016 Beta 300RR

After not riding regularly for many years, Kurt finally talked me into getting a dirt bike again. Last year I picked up a 23 Husky 501 (which has been a blast!) but started looking for a 2 stroke to round out the stable for the time being for tighter single track. I ended up finding a deal on a 2016 Beta 300 RR last fall but it was pretty rough. I halfheartedly started rebuilding it until a recent push to get it up and going before I miss the summer singlet rack trails.

I'm horrible at taking pictures along the way and always think I have more. As I purchased it:


I knew it was in rough shape and it was pretty obvious rough around the edges and the custom bends on the radiators, but it seemed to run strong so I figured I was up for the challenge.



It had a fresh top end and as usual when buying used, the workmanship and quality wasn't where it needed. As I was chasing the water pump seals, I had to open it up a bit to change bearings so I decided to pull the engine out onto the stand and check it all a bit more thoroughly. As suspected, there were more issues, the piston was ok, but the PV was totally gummed up, the cylinder was scarred up and past the nikasil in a few spots and most unfortunately the conrod was out of spec and I ended up splitting the cases.




It was somewhere around here that I went into overdrive and had a bit of unreasonable escalation of commitment. Mostly from a time investment, but I also ordered up some nicer parts and decided to do it right. I stripped the frame down to powder coat it and I also blasted the case, swing arm, and various parts and sprayed and cured with Cerakote.

Here is the engine with a new bottom and top end rebuild. It helps to work in industrial repair because I was able to source bearings pretty economically and use all our sand blasters, paint booth, and ovens. It had a Rekluse Autoclutch when I bought it, but I want a manual clutch in this one so I swapped it out for a Rekluse Torq Drive Manual clutch. I finished it off with a larger water pump and RK Tek head.


Here is it is all going back together:
Suspension was rebuilt by Josh at Alpine XC to fix leaky seal and stanchions, and added some lucky cartridges as well. I rebuilt the all the swing arm and linkage bearings so it will all be in good shape.


Now fully up to date on where it sits today. Most the big stuff is done now but plenty of small stuff left. Need to rebuild the calipers, finish all the electrical, rebuild the carb, and make sure everything is in good order. Jonesing to get smokin soon!

Love Betas!

My brother had his 2018 300rr street legalized, not as an off-road vehicle, but as a legit street motorcycle. DMV seemed to miss the little part about it being two stroke 😂

Very nice!!

I have that problem on projects……I am in here so I might as well…..

That will be a good single track bike

Very nice! I’ve been eying down Betas lately.. let me know how you like it 😎

The_Lobbster said:

Love Betas!

My brother had his 2018 300rr street legalized, not as an off-road vehicle, but as a legit street motorcycle. DMV seemed to miss the little part about it being two stroke 😂

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I don't think there is any state code against street legal 2-stroke? We had one (KE100) plated for many years before selling it to @jeeper

No issue plating a 2 stroke. My last KTM 300 was steel legal.

cruiseroutfit said:

I don't think there is any state code against street legal 2-stroke? We had one (KE100) plated for many years before selling it to @jeeper

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You're probably right. I was under the impression they were not legal on a federal level since the 90's.

Nice bike build. You'll like those Lucky inserts.
If you all ever need a cylinder redone in the future, I've got an account with Millennium Plating.
I've had good luck fixing radiators myself but when they're that bad: Myler's Radiator (near SLC airport #2) has done a fantastic job of making them look brand new.

FYI, don't tell Josh at Alpine that you Cerakoted bike parts. He is pretty mild mannered and avoids sharing opinions until you talk about Cerakote or Tubliss

Rot Box said:

Very nice! I’ve been eying down Betas lately.. let me know how you like it 😎

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You'll have to come take it for a rip when she's dialed in.

Gravy said:

Nice bike build. You'll like those Lucky inserts.
If you all ever need a cylinder redone in the future, I've got an account with Millennium Plating.
I've had good luck fixing radiators myself but when they're that bad: Myler's Radiator (near SLC airport #2) has done a fantastic job of making them look brand new.

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I have the old cylinder (I ended up buying new). What does it typically run to get replated? Might want to get it done just to have as a backup.
I ended up just buying new Myler radiators but I'll keep it in mind for the future.

glockman said:

FYI, don't tell Josh at Alpine that you Cerakoted bike parts. He is pretty mild mannered and avoids sharing opinions until you talk about Cerakote or Tubliss

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Ha! I have chatted with him a few times about Tubliss so I can only imagine Cerakote. Gonna have to drop that gem next time I see it. I have been powder coating random stuff for a few years with pretty good results. So I was curious about Cerakote. So far I have been impressed with the ease of use and durability. If I had to pay someone else to do it all, I'd probably feel different.

Maybe 350-400 (depending on the damage)
but that's wholesale including a vertex piston. They won't sell without a matched piston these days. Smart IMO

I have a similar bike! I got the Xtrainer version but gave it a makeover with a FmF gnarly pipe, Fox shock, 48mm Sachs CC forks, and other goodies. I absolutely love my Beta.

Things I learned the hard way:
- several of the electrical connectors can be plugged in backwards because they are symmetrical.
- many electrical connections are not color coded I an intuitive way. In fact I had one hell of a time trouble shooting and it ended up being a 2 way connector (plugged in backwards) the wires were supposed to go white to blue, and white to blue. I had them white to white and blue to blue which was wrong
- translating Italian electrical schematics requires 4 beers and a whisky. Much of the wiring diagram does not match the reality. Several wires were labeled (in Italian) as a different color, or there were more/less wires than shown

^Yeah diagnosing that oil pump diode was evil ^

Gravy said:

^Yeah diagnosing that oil pump diode was evil ^

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I took the injection pump out of this one. Just because I want to have a better feel for the ratios and dial it in. Overall, I've had to look up itallian for a few colors but it hasn't been terrible hopefully it will all work out.

Made a bit more progress. Still need to clean up the wiring behind the mask and fill with fluids but getting close.

I got a Smart Carb for a screaming deal off KSL and sent it through the ultrasonic cleaner and rebuilt it and swapped for the right metering rod for the Beta with the RK Tek Head. I need to get it adjusted properly before getting it fully going hence being in the plastic on the seat. Got the controls mostly sorted out. Added new rear master cylinder and cleaned up and rebuilt both calipers and stuffed with new pads and clips. Getting there slowly but surely.

Looking good.