BD125-2 "Boomcat"

[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.

[felixaj]

Anyone know what wheel bearings I need for front and rear? I'm seeing a ton of Grom bearings, but just want to be sure of the size before I buy them or if they are the same.

This is what I'm looking at:

https://www.amazon.com/All-Balls-25-...ZKF0NA53B23QB8

Although they look similar, I really want to know the actual sizes.

Thanks.

[felixaj]

OK, the stock wheel bearings are garbage. I was just going to do the rear bearings because the sprocket hub bearing was feeling sandy, but I pulled the front wheel off and those were seized and I didn't even realize it (not many miles on the bike). The inner race was just spinning on the axle, luckily I caught it early enough with minimal scoring on the shaft. I did notice the spacer inside the wheel that prevents the bearings from getting pinched when tightening the axle bolt/nut was about 1/16th too long. After reading a few Honda S90 forums, this is normal and is OK - just put the bearing in first with the shallower shoulder, then put in the spacer, then the other bearing just enough to where you can slightly move the spacer with a small screwdriver but not too loose. You should be able to move it but it should stay in place when you put the wheel upright - this will prevent the bearing from moving when you tighten the axle. I was able to use large sockets that fit perfectly and were just slightly smaller that the outer race of the bearing. I put the socket wrench side against the bearing so it pushed the outer and inner race equally.

I went with all-balls racing bearings and they fit perfectly!!

Front:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Rear:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I didn't have time to mess around with carb tuning because of the short whether window here in Michigan, so I threw on the original carb and it worked fine. My original goal was to just keep up with traffic at 55mph at lower RPM and it's really comfortable now with the 17T front and 33T rear sprockets. I used to go 25mph in the neighborhood in 4th gear and now I'm in 3rd gear at similar RPM. I bet I could easily hit 65mph, but I'm not going to push it.

[rlich8]

I am a new member here and I think this might be one of the only threads on the internet about the BD125-2. I just ordered one of these bikes from Kronikracing and really look forward to getting it and learning it. This bike appears to have gotten slightly harder to get during COVID, but the Boom Warehouse in California had one in stock and it is on my way to me as of today. On the topic of parts availability, the owner of Kronik Racing says that things are going slow and lots of stuff is scarce because of COVID. I thought this worth mentioning since there are only a few posts since February/March when the world began dealing with that. Hopefully, stuff is more available long term, because this bike is really cool and affordable. I am going to post pictures of my bike and the assembly when I get it. Please try to do business with Pete at Kronik Racing if you can. All my best fellow Boom owners. Kind regards.

[felixaj]

Welcome, rlich8. I think you will like this bike! Actual BD125-2 parts might be hard to come by, but interchangeable parts are quite easy to find, as most parts are compatible with Honda S90/CL70 bikes. I upgraded a ton of parts and it didn't cost much at all and most/all parts were right from Amazon. If you skim the past replies, you will see links to some of the essential parts I have so far. I've added a few more since my last post, but I'm just waiting on time to make an updated list with a video review.

[rlich8]

Hey guys, it's taken a while but I've finally gotten around to starting to set my bike up. She got a good going over and tightening so far. Starting off with basic stuff right now like better tires and wheel bearings, next is 17 and 35 sprockets, and shock boots.

I am wondering if anyone has a recommendation for an LED headlight and an LED tail light. The headlight is more important to me but the tail light would be nice too.

Here are my tires and new wheel bearings. I can't wait to get the bike on the road. It reminds me of growing up and having a 110cc dirt bike.

[4T_Goblin]

https://www.facebook.com/marketplace...2709237537615/

$900 I think this is the bike you're talking about?

Would you pay 900 for a used one with 2500 miles on it

[rlich8]

Originally Posted by 4T_Goblin

https://www.facebook.com/marketplace...2709237537615/

$900 I think this is the bike you're talking about?

Would you pay 900 for a used one with 2500 miles on it

Go take a look at it and see how it's held up or been sorted out over those miles. Sometimes a few more miles can be better. It's worth $900 either way in my opinion. You can't get this cool looking of a bike anywhere else for that kind of money. You just need to listen to the bike and let it tell you what it needs and then fix it.

[rlich8]

I got my bike fully set up. It runs well. I haven't needed to play with the carburetor much other than to set the idle. She doesn't really even need much choke to get going. I'll drive her a bit and pull the plug and see how it looks after 25 or 30 miles. The bike is very cool looking. It's quick and I have it geared at 17/35. The foot pegs are a bit far back and shifting and braking is a bit interesting. It's sort of like shifting a tractor. I am used to having foot pegs and just simply being able to operate the controls. It will take a bit of getting used to being that the pegs are where they are. Overall for a $1000 bike and another $175 or so in parts (tires, wheel bearings, sprockets, fork boots, a handful of fasteners) that I knew I wanted to upgrade on the front end I am pretty happy with my purchase. The bike is funky and unique and nobody else on the road has something like it. I never see small CC bikes in my city but it's fast enough to keep up with modern traffic and I can't wait to torque around more a bit in an urban environment.

EDIT: It's just occurred to me that my bike is missing the front peg set after comparing it to a few other bikes!! Looks like I need to get that.

[TyGuy]

Nice looking bike! I was just going to ask if those pegs that are set far back are intended for passengers. Seems like the rider set is missing.

[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?

[Coloradogoose]

Pretty standard for inexpensive bikes to have always-on headlights. Most don't have a way to turn the low beam off at all, but some will kill the light while starting the bike to save juice.

Definitely check the high beam at night, but lights are one place where manufacturers save money. Cheap bulbs and cheap reflectors. Neither will help the high beam be very effective.

[rlich8]

Thank you!

[krat]

As of 1981 all motorcycles sold in the U.S. are required to have the headlight on at all times. Price or brand has nothing to do with it.

You guys did not get he memo?