Boom Vader engine rebuild
 

I tried to wheelie my Boom Vader a while back, dropped it, and ended up snapping some gear dogs in the transmission. The pieces of these got into the timing chain and caused it to snap.

I took the engine off the frame and rebuilt it.

I replaced the following:

Speedo cluster
Transmission
Clutch pack
Timing chain
141 bbk from TBoltUSA.com - includes piston, piston pin, big jug, jug and metal head gaskets
140yx head from Amazon- includes head, z40 camshaft,
upgraded springs, 32T sprocket (now the only reason I bought this head is because the large 42mm bearing bore on my stock head was out of round)

I debated upgrading to the ZS190 but I heard it had its own issues, and I was not going back to 125cc, so the 141 bbk was the perfect in between.

I took this thing all the way apart. I wanted to learn from this, whether it worked or failed. It's was worth it!

I learned a ton from this forum about tuning my carb, and I am able to retain the same jetting in my vm22-133, which is the perfect size for a 140. Thank you China Riders!!

I learned a ton from Minibike Action on YouTube. I reached out to him and he was willing to help me along the way and it was great having someone who knows what's going on helping me on my first go round. So thank you John!

I started with Chinese bikes because I know the quality is on the rise and I wanted to go bike school. This is it. They have so much to offer.

Thank you for reading, I'll be posting updates. I've completed 4 heat cycles and once it stops raining I'll go for a drive.

Love to see some video of the bike with the new engine in action (no stunts, just cruising).

Here is a video. Hope you have a look!

https://youtu.be/t5fMgCR8wow

Got a link to the head you used?

I have a spare 125 I need that head for...

Great rebuild, engine sounds good and strong. I also have the 141bbk on my original Vader engine.

I did end up with a ZS190 (the issues you hear about are only a problem if you abuse the engine or do things wrong). But that 141 with a cam and slightly ported head sure did rip!

https://www.amazon.com/YX-valves-Eng...2-63e904010ad0

Thank you. I'm enjoying it so far.

The main reason I skipped on the 190 was the price. If this engine fails I'll look into the 190 for sure.

I hear ya there... when I got my 190, price was $100 higher than when I started thinking about, about $850. Now I think it's closer to $1k. And that doesn't even count the $200 exhaust you need to really make full power.

I was happy with my 141 while I ran it though. Imagine if that is how they came stock?!

It s 900 shipped and then yeah the exhaust on top, plus it's wise to upgrade everything to handle the power, like the brakes and suspension so the price goes up.

I wish they were stock 140cc.

Agreed. I installed better forks, an OE Grom rear shock, and added stainless braided brake lines. Not to mention every critical bolt and axle replaced with OE Honda parts.

Total spent on it is still less than even a slightly used Grom. Still no regrets, but definitely not a "budget build".

Nice! I may need to steal your formula for the extra 125cc I took off my Tao Tao supermoto. Might as well build it up for a go-kart. lol.

1. Hell yeah!
2. It took me a long time because there was much to be done to finalize the shed interior to receive the engine. I store the bike in there and do minor service in there but the storage was all wrong and unorganized. Once the bench was clear I had the engine on it pretty quick. I think the rebuild itself took shy of a month due to having to acquire tools, and having to buy a new yx140 head, that set me back some. I took the engine and the head apart. Lots going on in there. Good bosses are rare these days amen

3 every frankenshed needs a frankenbike. Lol once the fairings are back on it'll look less gnarly

4. Got a picture? I got this muffler for free

Thanks man! I will gladly answer what I can if you should seek advice later on

Great video!! The bike sounds really throaty; much better and more deep than a riding lawnmower :lmao:

I believe the engine to be broken in, it is an absolute rippa!

I just bought this and will be upgrading to the 141bbk. It'll be my first time as well in getting into these bikes. Would like to see what steps I need to do in order to get this on. I searched youtube and watched what I can find but I think there are steps missing. Any insight is appreciated. The Tbolt kit should be arriving next week.

Thanks