Hi guys,

I have a problem with the oneway bearing thats on the Sirio 12. The oneway refuses to grab the pullstart shaft after a full tank of fuel has been digested. I'm on the third tank and each emptied tank I've had to dismantle the pullstart to get to the bearing. The bearing will grab once the excess oil has been cleaned off. The motor sounds great. It starts and idles perfectly. Am I experiencing this problem do to the fact that its still being broken in and running rich? A buddy suggested that I switch over to 30%. I'm thinking of just changing the oneway with a stock or after market bearing. Is anyone having problems with their sirio 12s oneway. Are you guys using 20% or 30% for this motor? The bike is almost complete. I am just waiting for the fail safe and batteries to arrive.

Steve

Hey Steve,

EVERYONE has experienced the same problem with the oneway bearing on the sirio, it's put simple a crap bearing. You need to replace it with a branded bearing. What you're looking for is a 10mm OD x 6mm ID x 12mm one way bearing. Be carefully when ordering, some have a HEX outer shell, these ones wont fit, you need the one with a round outer shell.

Part # 6392K22 from www.mcmaster.com

As for fuel, I ran the sirio in on 5%, then after a few tanks 16% nitro:11% oil.
You'll want to change the glow plug to an OS A3. Personally I feel the motor is fine for learning the limits of the bike and getting used to controlling it, and worth the $15 to replace the one-way. Before long though you'll be itching for a little more torque and top end, that just wont be there. By then the engine will probably be nearing the end of it's life anyway, and it'll be time to get something higher end, like an OS, REX or NR

HTH

Pat

That helps Pat!! What are you running now? I'm thinking of putting in the Force .12 I've got since I can't use it on the TTN.
Tom

Hi Tom,

I've still got the sirio sitting in the bike, I haven't had a chance to run it over the past few weeks so I haven't been too worried about it. It still runs, but has absolutely no top end, it splutters and gurgles away. I'm sure the piston/liner is shot, the motor is really loose once it warms up.

I've got a couple of force 12's here, and as soon as I get around to making a set of mounts one will be going in, if I can't find a reasonably priced REX between now and then.

Pat

Ah, thats right, the Sirio mounts to the chassis through the starter. I forgot about that, I'll probably have to order a set myself at some point, but its about to get pretty cold here so I think I have some time to spare!
Tom

Hey Pat,

Very helpful indeed. I appreciate you giving the part# aswell. I've gone and ordered the part and should arrive next week. For now, break-in procedure will just have to be monotonous. As soon I get this to move about I will need to order you disk breaks. Do you sell them only in sets? I only need the rears.

BTW: Can I just hammer out the old needle bearing when installing the new one?

steve

Originally Posted by pat1967

Hey Steve,

EVERYONE has experienced the same problem with the oneway bearing on the sirio, it's put simple a crap bearing. You need to replace it with a branded bearing. What you're looking for is a 10mm OD x 6mm ID x 12mm one way bearing. Be carefully when ordering, some have a HEX outer shell, these ones wont fit, you need the one with a round outer shell.

Part # 6392K22 from www.mcmaster.com

As for fuel, I ran the sirio in on 5%, then after a few tanks 16% nitro:11% oil.
You'll want to change the glow plug to an OS A3. Personally I feel the motor is fine for learning the limits of the bike and getting used to controlling it, and worth the $15 to replace the one-way. Before long though you'll be itching for a little more torque and top end, that just wont be there. By then the engine will probably be nearing the end of it's life anyway, and it'll be time to get something higher end, like an OS, REX or NR

HTH

Pat

I just wanted to add that the TT OWB seems to be the same as the one Pat mentioned for the Sirio. I'm gonna order one and I will let you know. BTW, anybody know how to remove the bearing from the TT unit? It seems like its pressed in there pretty good, I was thinking of putting it in the oven for a little while but someone here mentioned that I should try and freeze it. I thought the oven would make the metal expand and the bearing would come out easier but this guys says the bearing will expand too? Whats the consensus here?
Tom

Tom, I haven't had much luck removing bearing by freezing, but I have gotten various bearings out, including a press fitted OWB from one of my crappy rotostarters, by boiling them.

just my experience. HTH

Don't know how easy it is with the TTN but with the sirio I was able to gently tap it out. If you plan on ordering the part from MCMASTER-CARR the part # is
6392 K22. Let the rep know that you need the rounded outer shell one.

Just eyeballing my TTn is the part that's getting broken the bearing itself, or a retainer for the bearing? If it's a retainer, why would the McMaster bearing help?

STeve B (ain't broke it yet) in NC

The part that breaks is the retainer for the bearing.

can you post a picture of what is breaking? I thought it was the bearing itself.

Here is the broken TTN thingee that goes around the bearing. Sorry about the quality; camara phone.

Just an update, the bearings from McMaster that Pat mentioned are exactly the same as what comes with the TTN. We still need to see a pic of that homemade ring from an axle spacer.
Tom

just bought 3 of the OWB from my LHS yesterday, they got the parts from Ace, i paid 8.99 each. have'nt had bearing problem, just breaking the ring.