Maintenance, adjustments, and modifications to our Betas

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My guess is you overfilled it by 200ml.
Does your crankcase breather tube run up into your air box?

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On 12/10/2016 at 8:34 AM, moto9 said:

Rainy day, bored out of my mind project.

Home built sub tank

I used a left over ktm shock rez that was collecting cobwebs in a parts box, so I decided to put it to use.

The rez has the stock floating piston in it, I can charge the other side of the piston with air pressure to give it resistance.

On the forks I'm using flow control valves, I can meter the air flow all the way down to zero when fully closed.

This will help with changing conditions between muddy / slower speeds and dry / faster speeds.

I've used sub tanks on a couple different bikes and it adds to plushing out the trail trash.












So what Moto9? You sell this bike and get something else? I saw this for sale a while back but haven't seen what's up since.. buy a sherco or husky or ktm or gasgas???or..hmm maybe a yammie? You did take off your estart. .. well the 18's have the estart and no kicker for weight loss.. maybe that works too.

Edited by hawaiidirtrider
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On the four stroke Beta's, has anyone enlarged the head stay bolts holes to make it easier to line up the bolts? I think on my next valve check, I am going to enlarge the holes a couple of thousands to make every thing line up easier when it is loose.

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HELP - beta needs new valves!



I've got a 2012 350 RR - in need of a new set of valves I fear. already been through a few shim jobs and the last one only lasted about 10 hrs before she wouldn't run again. 

I've spoken with Mongoose here in the lower mainland and they didn't seem to have any specific information about the beta motor (have worked on the ktm motor betas) but I was hoping someone could shed some light. they recommended stainless valves and bronze seats but couldn't tell me what parts were needed from beta.

what I really want to do is substitute the stainless valves for the stock titanium ones. in hopes of getting a bit more longevity out of them, however its been a real pita trying to figure out what parts to order. Mountain motorcycle, the beta dealer here, didn't have any insight either. I even tried emailing American beta and the Italians without any response. :(

the usual is to upgrade the springs to accommodate the heavier valves, but curiously, beta only seems to have one part number for the springs even on the stainless valved models. 

anyone with experience here? anyone have any tips on a valve job on the 350's at all? 


any info will help at this point, I am pulling the motor in the next few weeks and it would be great if someone could help me figure out what parts to order etc. 


even if you've simple done a stock replacement with the titanium valves , I'd been keen on knowing how the process went, who did the machining etc. 


thanks for your help everyone. 



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