BD125-2 "Boomcat"

[oincman]

VM22 carb is too big. The PZ20 is adjustable, just remove the cap over the air/fuel screw right to the left of the idle screw (pry it out). I turned mine out about 1/4 turn and it's running much better and not having the hesitation issue. Ordered jets for it as well. The stock is a 75 or 78 (can't remember).

Got the little thing running pretty good and Belmont Bikes/Venom Motorsports have been extremely responsive about broken parts and are sending replacements.

Drain the forks and replace with 4oz of ATF (in each) and it smoothed out the bouncy front end.

[cheapermoto]

Still wringing out the BD125-2. Stock carb 17T front and 35T rear.
Seems to be working out pretty good so far. Will hopefully do a run up to this place called Sugarloaf in the coming weeks. It's a 2000' climb and about a 20 mile round trip. We'll see how the Boom does. For now this was the most recent outing.

Cheers!

[Big Bird]

Originally Posted by cheapermoto

Still wringing out the BD125-2. Stock carb 17T front and 35T rear.
Seems to be working out pretty good so far. Will hopefully do a run up to this place called Sugarloaf in the coming weeks. It's a 2000' climb and about a 20 mile round trip. We'll see how the Boom does. For now this was the most recent outing.

Cheers!

Funny, I grew up in Bennett Valley, and my mom worked at that state hospital for a bit. So I know the area pretty well. I would be interested how the bike does in Bennett Valley RD, I think it would be a fun ride if it could manage the hills. The boomcat is what got me interested in china bikes again I was excited to know that china bikes were CARB legal and ended up going with a Grom clone due to more parts support. I think the boomcat is a cool little bike and enjoy riding along with you.

[cheapermoto]

Originally Posted by Big Bird

Funny, I grew up in Bennett Valley, and my mom worked at that state hospital for a bit. So I know the area pretty well. I would be interested how the bike does in Bennett Valley RD, I think it would be a fun ride if it could manage the hills. The boomcat is what got me interested in china bikes again I was excited to know that china bikes were CARB legal and ended up going with a Grom clone due to more parts support. I think the boomcat is a cool little bike and enjoy riding along with you.

That's awesome! Maybe I can get her out to Bennett Valley rd.. It would be a nice little ride. Of course you know hwy 12 is a bit of a stretch with people routinely going over 60mph, but I'll bet I could hit most of the back roads to negotiate my way over to Bennett Valley. I will try to put that on the to do list and have a little video of it.

Sounds like you've done a lot to your Grom clone. How do you like it? The better parts support is certainly a worthy point. Does it have enough Gusto to get on Hwy 12 and run at 60mph? Seems like running at 60mph for any 125cc is maybe asking a lot. I've had the Boomcat to 55mph and it seems okay, but for me, its sweet spot is 45-50mph with a little top end reserve at those speeds. Maybe see you out on the road one of these days. Thanks for checking out my vid. Cheers!

[Big Bird]

Originally Posted by cheapermoto

That's awesome! Maybe I can get her out to Bennett Valley rd.. It would be a nice little ride. Of course you know hwy 12 is a bit of a stretch with people routinely going over 60mph, but I'll bet I could hit most of the back roads to negotiate my way over to Bennett Valley. I will try to put that on the to do list and have a little video of it.

Sounds like you've done a lot to your Grom clone. How do you like it? The better parts support is certainly a worthy point. Does it have enough Gusto to get on Hwy 12 and run at 60mph? Seems like running at 60mph for any 125cc is maybe asking a lot. I've had the Boomcat to 55mph and it seems okay, but for me, its sweet spot is 45-50mph with a little top end reserve at those speeds. Maybe see you out on the road one of these days. Thanks for checking out my vid. Cheers!

In order to hit 60mph (gps verified) on mine I had to upgrade the carb, front sprocket and exhaust and be in a full tuck. And that's if I wasn't hitting a head wind. The engine didn't seem to have any trouble handling it for a good amount of time. I have kept it full throttle 8.5k rpm for a few miles at a time. When I tore it apart to do the big bore I couldn't find any scouring or anything. Everything still looked good.

I am still breaking in the new cylinder and cam so I haven't done any new top speed runs with the 141 but I really like it so far. Has more low end grunt(even sounds like a bigger bike) and I have had it up to about 55 mph without even trying no tucking with a lot of throttle left. From what I hear the powerband should pull till the valves float with the z40 cam.

Our engines are the same so everything could be done on your bike if you are mechanically inclined. Pretty sure it would have no trouble on hwy 12 then. Not sure what the gearing is like on the boomcat but on mine upping the front sprocket a couple teeth did a world of difference for rideablity and cruising at higher speeds.

I actually live out in the central valley now north of Sacramento. Although I plan on transporting my bike out to Sonoma county one of these days to do a run down hwy 1 and mess around in Santa Rosa.

Have you contacted Kronikracing for oem parts for the boomcat? He is a Boom dealer so he should have access to parts.

[rlich8]

Also, I am curious, the second I turn the keyed ignition on, the headlight comes on. I seemingly cannot turn it off and the high beam low beam doesn't really seem to do a lot (it's hard to tell in broad daylight I guess I could test it at night). The passing light works fine but the headlight is giving me grief. Is the switch bad, or is this just the way it works?

[oincman]

To continue the ongoing saga.... The rear swingarm is bent. I can't for the life of me get the wheel centered (and I did true it). Got it as close as I can, but the chain is slack on one revolution and extremely tight on another. Belmont is having another swingarm shipped, but that's gonna take a bit. Gonna add a 14t front sprocket (13 is stock) to try and smooth out the gearing. 1st is practically worthless and will pop the front wheels pretty easily (wife doesn't like it). However, with the 13t, this thing will climb hills pretty easily in 4th and still top out around 50. And I need to find some different rear shocks. No matter the adjustment, this thing is pretty bouncy.

[Shmerlin]

Updated review, only 157mi on the bike and I've had several issues with it. Going through the Moto-pro seller, they have advised the factory discontinued the model and that they can not supply parts for it anymore.

[cheapermoto]

[cheapermoto]

Have changed both front and rear sprockets. Front 17T and rear 35T.

The 35T is the smallest you can go without shortening the chain. Nice improvement and better cruising RPM's. Rear sprocket needed center hole to be machined out by 1/8" or so to fit properly.

I did notice a little lean of the rear wheel to one side after this mod. Not really sure what the cause is. Wheel is on properly with spacers in place etc. Seems like swingarm and or frame might of been tweaked a little from the factory and never noticed before.

Anyone else have any issue with their rear wheel leaning to one side? I'm thinking maybe they are just not that accurate from the factory. Does not seem to be an issue when riding, but may take some measurements to see if I can verify whether or not the swingarm or frame has a bit of twist.

Anyhow, hope this helps others who might be trying to squeeze a little more top end out of this little 125cc. Been having fun with it. These little bikes really take you back to your early days of motorcycle riding. Truly tons of fun.

[Michiganboomcatter]

did you ever find an upgraded shock?

[oincman]

It is what it is. I expected no less and got exactly that. Am I bummed. Nope. Nobody else made one and it's a cool looking retro bike. And it's a wheelie monster for a 125cc with stock gearing.

I'll take it for what it is and try my best to make it better. Worst case, I'm out $1k and change. Still better than a $5k+ Honda that I'd be disillusioned with and pissed at myself for wasting hard earned money on. Who(IMO) doesn't make anything cool, even the Chinese grom clones are better than the Grom.

[oincman]

Let me add to this. I'm not a Honda hater. I have two CT90's (which are a hoot). And I think Honda's are a terrific motorcycle. But they are over priced for what your getting and they (Honda) have built a reputation for quality (not innovation, hence the new CRF300L not even having LED lighting) and get away with overpricing.

And I just bought a new Suzuki VanVan (cause I love the styling). And it is in no way shape or form better than the Lifan KPM200 I have (which is actually faster than the VanVan and cost $2K less). Though it can go off road and the KPM can't (which new tires will fix that issue).

I love the Ducati Scramblers, but not the price nor the fat ass weight. I like the Huskvarna Svartilan too, but I'm on the fence about the styling (but I don't mind the $4999 price for a 400cc Dual Sport that'll do 100mph and has Pirelli Scorpian tires).

[felixaj]

Yes, my garage is a disaster.

I've been tinkering a bit this winter, but it's too cold to ride in Michigan, so I can't get it tuned in for a few more months.

Upgrades so far:

Removed EGR/Charcoal stuff (not sure what it's called)
-made a block-off plate for the cylinder head port

Knockoff Mikuni VM22 card
-used the stock jets that came with it
-got a thumb screw extension for the fuel/air mix screw
-used the included cone air filter with an angled hose

Semi-knobby tires - links in earlier posts in this thread

Painted the wheels black

Honda CL70 fork boots from eBay

Wire harness for a Battery Tender

Lower handle bars

LED lights - Headlight and rear only
-all lights flashed when LEDs were in the front

Upgraded chain

17 Tooth sprocket in the front

33 Tooth sprocket in the rear

Custom license place bracket

Phone holder

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I see in one of the photos that I need to adjust the throttle cable at the carb, which I can do by adjusting the nuts at the handle lever. Also, I need to reconnect the carb vent hose and carb bowl drain hose - these both just dangle and should exit below the engine cylinder. The tank vent hose is also just dangling, so I need to secure that down somehow. With this knockoff Mikuni, it starts right up and idles perfectly. With the old one, I could not get it tuned right and would not idle fine until it warmed up, so I would have to constantly give it throttle up and down until it was warm. I'm hoping the carb will give me a little more pickup power to offset the sprockets and I'm not too concerned with going higher than 55mph. I just want it to go 55 at lower RPM's.

If you don't mind tinkering, I think this is a great bike for the money, especially a great first bike. It's not perfect, but I have learned a ton, which I think is worth more than the difference I would spend on a more expensive bike.

Let me know if you want links to anything I used.

[China Rider 27]

Looks cool, cafe racer style. Is that intake stock or did you buy it somewhere? Is the exhaust stock or aftermarket?