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125 RRS big bore-hop up

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I don't believe I ever followed up on my buddy's 125 that we put the 183cc big bore kit and Scalvini pipe on. 

Installation is no problem if your used to 4t motors. Even if your not the single cam motor makes a good first time 4t motor to do a top end on. Also removed all the smog equipment. 

I went ahead upped the pilot and main jet a few sizes to begin with. Upon starting the bike it started up right away and revved nice and clean with no bogs. However it seemed to have a slight miss at 1/4 to half throttle. After trying a bunch of different combos without much luck I finally threw the stock jets in there and to my surprise it runs great! 

As expected the bike has a lot more power now. I would say a little under a stock choked up CRF 250L. On a steep road uphill the bike will pull a solid 10 mph fast than before. 

The Scalvini exhaust makes it sound like a real bike, but not  obnoxiously loud. It's also much lighter. I think a foam air filter would also help a lot, but we haven't done that yet. 

 

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1 hour ago, ccullins said:

I don't believe I ever followed up on my buddy's 125 that we put the 183cc big bore kit and Scalvini pipe on. 

Installation is no problem if your used to 4t motors. Even if your not the single cam motor makes a good first time 4t motor to do a top end on. Also removed all the smog equipment. 

I went ahead upped the pilot and main jet a few sizes to begin with. Upon starting the bike it started up right away and revved nice and clean with no bogs. However it seemed to have a slight miss at 1/4 to half throttle. After trying a bunch of different combos without much luck I finally threw the stock jets in there and to my surprise it runs great! 

As expected the bike has a lot more power now. I would say a little under a stock choked up CRF 250L. On a steep road uphill the bike will pull a solid 10 mph fast than before. 

The Scalvini exhaust makes it sound like a real bike, but not  obnoxiously loud. It's also much lighter. I think a foam air filter would also help a lot, but we haven't done that yet. 

Thanks Chris. This is very helpful. Would you say the bike is now likely to overwhelm the stock suspension when flogged on whooped out trails?

Edited by Old Plonker
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Bigger bore creates more vacume and often takes a smaller jet to compensate. Glad you got it dialed in.

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3 hours ago, Old Plonker said:

Thanks Chris. This is very helpful. Would you say the bike is now likely to overwhelm the stock suspension when flogged on whooped out trails?

Oh yeah, but I would say the same about the bike stock. Or any other low cost dual sport bike for that matter. The difference is the Beta is a lot lighter and can get away with more. 

I have to  amend my first post. Power is close to a 230 Honda. I haven't ridden the 250. 

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Air filter and filter frame of the RR300 fits. Then main jet 140 is just a bit lean.

Motor is the same as for ex:

Fantic CABALLERO 125 REGOLARITA´ - 2005/2010 - Off-road (mx)
    Honda CRE F 125 X - 2008/2011 - Off-road (mx)
    Honda CRM F 125 X - 2008/2011 - Off-road (mx)
    Husqvarna SMS4-TE 125 - 2011/ - Off-road (mx)
    Rieju MARATHON 125 PRO/SM - 2009/ - Off-road (mx)

 

and many more.

Its a great small bike!

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On 7/8/2017 at 0:39 PM, Old Plonker said:

Thanks Chris. This is very helpful. Would you say the bike is now likely to overwhelm the stock suspension when flogged on whooped out trails?

 

On 7/8/2017 at 4:05 PM, ccullins said:

Oh yeah, but I would say the same about the bike stock. Or any other low cost dual sport bike for that matter. The difference is the Beta is a lot lighter and can get away with more. 

I have to  amend my first post. Power is close to a 230 Honda. I haven't ridden the 250. 

My wifes 2017 beta 125 rr-s, has the stock engine. But I've done the db killer delete to the stock muffler, and also added the twinair air cleaner that comes with the bike as a replacement off road filter to the paper road filter. It's also the same aircleaner thats on my 2017 beta 500 rr-s. This really woke the little beastie up into a solid little bike.

Any ways I took it out on the practice track at hungry valley and it handled the it really good. The track has some whoops and lots of chop from hardly ever being groomed, so you could say it was a little rough. Well, I felt the need to slow down not because the performance of the bike couldnt handle it, because it did OK. But I slowed down for fear of breaking the frame or some other main support component. I'm sure that it could be beefed up, and modded just like any other pit bike. But I dont think it was meant for a dude like me to be ripping around a mx track on. It really is more of a play/pit bike than a mx bike. and although it can handle trails and small hills, dont think that it can pound whoops and tackle really rough stuff. It will do OK, but there is definitely a point of exceding its limits even with a stock engine. This bike is a really fun bike. It's perfect as a campbike or a ladies bike, or a pit bike with a plate. It could always use more power though. and I'm pretty sure that my ladies is gonna end up with a bigbore kit and the same scalvini pipe at some point in the near future, but not till its out of the 1 year warrantee period. I think the power will be most welcomed when the bike is ridden on the street as it is in need of a bit more power to stay out of the way of all the prius's and other nonsense out there.

I like the bike and its a great bike but its no replacement for a full size bike. 

@ ccullins, Thanks for write up on these components, Lots of us out here are interested want to know about it.

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5 hours ago, danketchpel said:

How much was vibration affected?

Didn't notice any increase in vibration. IMO the motor is way overbuilt for only 125cc. When I pulled the cylinder off the little 125 piston looked silly sitting in the big motor. Seems it was built for more cc's. 

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13 minutes ago, ccullins said:

Didn't notice any increase in vibration. IMO the motor is way overbuilt for only 125cc. When I pulled the cylinder off the little 125 piston looked silly sitting in the big motor. Seems it was built for more cc's. 

That wouldn't be surprising. It may very well be the basis for an eventual 250 also. That would make huge sense in the big picture.

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How do you get the dB killer out of the exhaust?  I have removed the circlip, and pulled at the insert.  Ended up having the end of the insert come out, but there appears to have another type of snap ring, and the rest of the insert won’t budge.  Do you need to remove the end cap?

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On 10/23/2017 at 8:08 AM, Gflo said:

How do you get the dB killer out of the exhaust?  I have removed the circlip, and pulled at the insert.  Ended up having the end of the insert come out, but there appears to have another type of snap ring, and the rest of the insert won’t budge.  Do you need to remove the end cap?

No, I did not remove the end cap. I used some long skinny needlenoses and twisted it so that it would partialy stick out of the hole. One side of the end of the db killer plug is flared out so you gotta get it lined up just right and then give it a really big yank and it will pop out. It's kind of a pain but it's worth it. I also twisted the end crumpling it, and making it smaller than the muff hole. it was easier to pull it out this way. I will not be sticking it back in so no worries.

It did fall all the way down the exhaust pipe and I thought I might have to pull the muffler off but I just used one of those spring loaded grabbers and twisted and pulled it up enough to grab with needle nose pliers. then I crumpled the end and yanked it out.

It's totally worth the hassle.

 

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11 minutes ago, surfer-dude said:

No, I did not remove the end cap. I used some long skinny needlenoses and twisted it so that it would partialy stick out of the hole. One side of the end of the db killer plug is flared out so you gotta get it lined up just right and then give it a really big yank and it will pop out. It's kind of a pain but it's worth it. I also twisted the end crumpling it, and making it smaller than the muff hole. it was easier to pull it out this way. I will not be sticking it back in so no worries.

It did fall all the way down the exhaust pipe and I thought I might have to pull the muffler off but I just used one of those spring loaded grabbers and twisted and pulled it up enough to grab with needle nose pliers. then I crumpled the end and yanked it out.

It's totally worth the hassle.

 

Is the part you took out just the little screen that looks like the top of a salt shaker.  That fell out as I was unloading the bike.  The parts fiche shows the dB reduction device as a tube about 8” long with holes in the side.  That is the part I can’t get out.  

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2 minutes ago, Gflo said:

Is the part you took out just the little screen that looks like the top of a salt shaker.  That fell out as I was unloading the bike.  The parts fiche shows the dB reduction device as a tube about 8” long with holes in the side.  That is the part I can’t get out.  

it's about 4" long. 

The pieces I removed were:

the circlip

a retaining washer 

and the plug itself

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just use 2 sets of needle nose pliers, one long for grabbing and manipulating, and one short with good crushing strength. and have a grabber on standby just in case.

hold it with the long ones and get it as close to the end as you can, I could get it partially sticking out, and then while still holding it with the long ones, take the shorter ones and crush the end to get it to clear the hole, and yank that sucker out.

if the plug starts falling down the muffler towards the header, just use one of those cheap spring loaded grabbers and pull it back up and finagle it as best as you can.

Don't worry about damging the db killer. Because once you pull it out and ride it, Your not gonna want to put it back in.

oh yeah, I also remember that the plug was welded to the retaining washer, but the weld broke when I was removing mine. So don't be afraid to use a little persuasion. 

 

Edited by surfer-dude

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Okay, thanks.  That is the part I want to remove.  I removed the circlip, then got off a piece that looks like a thick stepped washer.  Removed another snap ring.  Just looking into a thin tube.

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Thanks engl, I found an aftermarket xr50 shiftee from a blown up xr50 that matches up on the splines, but I still gotta bend it up to clear the case. I gonna look into the ones that you mentioned especially the aftermarket.

I contacted hammerhead as they have one listed that fits both my 500 and the 125, but when I tried to fit the 500 shifter on it, the spline hole is way to big to fit on the 125's shaft, so I contacted them and they said they would correct their website.

I've also shaved down my wifey's seat so that she can touch the ground better, I just used 1/4" staples to put the cover back on.

all is well

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My gf bought one of these. Removed the smog stuff and she is still wanting a little more power. I ordered one of those big bore kits from the uk. How’s it holding up? And it the stock jetting still sufficient? 

These little things are awesome single track killers though. 

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