Mini Crotch Rocket Build Part 6 

Hyosung bikes were meant to to have the feel and look of much bigger bikes yet sit in smaller displacement classes for licensing. Most other countries use tiered motorbike licensing.

When you're in the mood to watch a lil bit of rather B welding and it pops up on the Home page . . . Nice! Hahaha

A lot of times, if you can get it started, as long as its not truly rusted or corroded, those things will clear up, compression willl come back, and valves will reseal. But that said, a tear down is never wasted, if you care about the project, becuase you'll know the exact shape of the engine.

a trick i've used in the past for automotive engines i've stored, put a light coat of atf in the cylinders and soak the engine completely with WD40 and wrap with pallet cling wrap, the WD40 will protect against moisture, and the cling wrap will keep dirt/debris out/off of the engine as well as adding an extra layer of protection against moisture ingress, you can substitue the atf in the cylinder bore with some deep creep from seafoam, or you can also spray WD40 right into the cylinders as well, just anything to displace any moisture that might get into the cylinders, great build man, she should be a real ripper once the engine woes are sorted and the grimlins are evicted from the premises

id be more concerned with your brake rotor hitting the ground than your footpegs haha, that thing is super close!

It looks sick, but it woulda been Even better with a little bigger wheels.

Just a thought... You build them and have 2vintage do the engine work. Both have great channels. You are amazing with the builds and his detail getting engines running like new is amazing. I think a collaboration would be phenomenal! Either way love it, keep going!!

Really like how easy it is to drop out the engine. Good design feature. Keep up the great work!

The amount of work you get done for each video is outstanding!

A good way to check valve sealing. With a head upside down with the combustion chamber up, spray some soapy water in the combustion chamber, blow into the ports with air, and check for bubbles around the valves

Love the way that frame popped off.

Your attention to detail is just amazing. I could not do what you do.

What a roller coaster! Chris: " we can either do a rebuild or just send it" Me: "rebuild. Rebuild. REBUILD!" Chris: " we're just gonna send it" Me: "awwww" Chris: "we need to rebuild" Yaaaayyyyy!!!!!

Cool thing is you could easily put a longer swingarm and taller forks and larger wheels on it and make it a bigger bike.

It looks amazing but it just needs one thing, bigger wheels, bigger wheels, bigger wheels 🙂

I agree with the chorus of "bigger wheels" but I say get it running and riding first. Loving it, this thing looks sick.

Coming together nicely. Glad you are rebuilding that engine.

Definitely has to be one of my fav builds so hype for updates!

They sell 4'×8' plastic sheets online, you should buy some and make styrofoam molds and heat form some plastic body panels, that would be sick. Great job on this build 👍 can't wait to see you ripping it

Love your enthusiasm for just the perfect design 👌

Good call to rebuild the heads. It will save you work down the road.

Loving this build !! Great job bub! Keep up the good work!

Dude your skills are getting better and better with every passing month!!!! Super good work dude!!!!

Things going to run like a top now 😁👍 I'm kinda glad you had to rebuild it. I feel like you will get more performance out of it and thus have more fun with it! I love your builds ☺️

Such a tinkerer's mind to not even check to make sure the engine is good before starting the project! But one that can build like this can rebuild a small engine so no love lost, lol. made me laugh though when you said you weren't sure if it was a good engine. I am glad I am not alone on priorities when I make.

handle bars an foot pegs? you don't need that crap bro just crank it up an ride it all in front of the grumpy neighbors house we haven't seen him ina while we miss him

You are a amazing welder and machinist!

Knowing what I know about bicycle frames, I guessed 22 pounds. Nailed it!

I think 12 inch rear and 14 inch front rim and tire would make it sit a lot better for you on clearance

Love this build!

Fantastic as usual

Your bike is looking really good bro keep up the good work from cruzermans inventions 😁👍🎉 I better get back to my dark night trike build part 8 coming up 👌 cool cool

You can pour some kind of liquid in the intake and exhaust ports to make sure the valve to check for leaks

Yeah I’m here, definitely here!

Great build 👏

Could you do a video touring your collection of homemade vehicles, some history over them and tour your garage?

Personally, I love the small tires. feels more true to form as a crotch rocket barely clearing the ground. You can always add larger tires later.

Brilliant stuff

Sweet frane. Looks like it came from Borgo Panigale.

Seems to me this project really needs wheels and tires about 2"-4" taller. Other than that its a homerun!

Hi. Iv been watching some of your builds for a couple of years now. I like the ideas you have. I have a project on myself. It's an electric buggy. When it's working I have plenty of fun with it off-road with my dogs. Just wished I knew someone like you to help with some of the mods. lol

Pro tip: Chop a lapping suction cup thingy axle in half and then turn it down to fit a drill. Minimize the lapping time turning it with the drill.

You could shim the valves and re-assemble the cams back into the heads waiting for headgaskets too dude!

I mentioned this in an earlier video, you NEED larger wheels and tires! That front tire is going to understeer horribly and cause you to high side right off that thing. Good luck

Love the bike makes me want to get back into tryi g to build cool stuff to that will be useful to me or others

I'm really digging the bare metal look of it

If you actually did a valve seat cut on the head it might need shims, but I don't think lapping them will remove that much material

Next time you want to put some oil down the spark plug hole to see if the compression comes up if it doesn’t it’s you valves that need doing if the compression comes up your rings need doing just so you know what needs doing before you take it apart nice vid mate

Shine a light on one side of the valves to see any gap

Those bsr clamps u made came out sick

i love your videos, love form malaysia ❤️

The engine is big and heavy because not only is it air cooled, but it's also a 2 cylinder 250cc instead of just one cylinder. The 650cc engine is bigger but not buy a massive amount because it's probably also a 2 cylinder engine. Its like having two 125cc motors strapped together instead of just a bigger piston.

Why didn't you do the compression test first? Than you would have known if anything is leaking... 👍😁 Good video again Chris! Thank you. 👍😁👍😁

You can set the heads upside down on bench and fill the combustion chambers with gasoline . Any leaks will show up .

This bike is so odd it’s awesome. Kinda like an extra small person with a full size handgun. 😎

The carb boot on the front cylinder looks cracked. If it is cracked enough to cause a vacuum leak you may have a lean cylinder and cause a miss. Probably not but if it runs rough measure the temp of each cylinder to verify an even burn. Love the look so far!

I must say your machine skills are impressive....

Looks awesome Man! I'd agree with some of the others that you could scale up the wheels a bit but whatever. Still looks sick. Look into doing a lithium battery, you could get plenty enough CCA for that engine in a really small format compared to a regular lead acid. That would give you way more options for mounting.

Get some specialist paint and paint certain parts of the engine. It'd help protect it and look really cool. Man do the rebuild the bike is sooooo worth the extra mile, please.

Good idea to check the valves, now you know they are good.

It's heavy because they made it bigger then it needs to be and they made bigger then it needs to be so it would look like a bigger engine to fill the frame more, (in other words they wanted it to look like a bigger bike)...

A lot of people who build café bikes swap to lithium batteries or build lithium packs. They are very small and pack a lot of power.

When you're riding "aggressively" you should have the balls of your foot up on the pegs anyway, so you really should have plenty of clearance for your feet when leaning. We do that even on full sized bikes, and it's even more necessary with those tiny wheels you have.

i guess that engine is so big because it shares parts with the 650 version in the hyosung comet and some other models. FIY the 650 is somewhat derived from the suzuki SV650 engine, think of it like a chinese copy

Good work👍🏻

What are you listening to when the video goes into high speed? Surly not what you play for us? It's looking so goooood!

Gotta put vinager in the valves and let it sit over night. It will clean the rust right out

Really like this bike build! Glad you decided to do the engine work. You said you thought the compression was possibly low, Could some of that be the piston rings too? Anyway good work!

great stuff thanks

You should try using a lithium/tool battery. There is a guy who built a racecar whose entire ignition runs off of Milwaukee battery. Goofy built/PFI Speed. It's a mount with wiring that you can purchase online. Don't ask me where. Lol it's tiny AF though.

Man I've been watching for a while and you're a great machinist slash fabricator!! You Really should think about starting a small business!!

Looks sick!!! Just needs a bigger front wheel, proportions are off a little just with the small front wheel.

22lb for the frame seems pretty good to me

next time you have to leave anything metal outside, try using dry silicone spray (shoe waterproofing spray is cheapest) and get it in everywhere! internals as well. 6 dollar insurance and will last up to a year. works great on the snow shovels too.....snow just falls off.

Rather B Welding you should the making fairings for it

I always thoughts you hear that air sound when rolling over motor slow. I always check valves by pouring a lil fuel down from top of head like where the valve springs are and check bottom side of head to see if fuel is leaking around valve. Got that from a Suzuki service manual it sure beats hoping the valves are sealing and wasting time and possibly gaskets

U ever hear of compressor test or leak down test that will take all the guess work plus u can pour some gas or some kind of liquid in the intake or exhaust ports to make sure they are seal tight

aluminium oxidize, not corrode! Love it, keep going ;-)

To put it in perspective, the frame weighs like a 2.6gal of water, or 10kg, which is like, not a lot.

This is going to be an interesting little bike and I'd like to test it out some day.... I just wish he would try and build something w/ a high powered electric motor. 😁

Option C pull the valve covers and slather marvel mystery oil over everything and run it

I do like the low handlebars, but think it would look a lot better if they were designed in a 'clipon style'

I've seen on RU-vid, the Hyosung GT250R, wich has the same engine as the GV250, going 160kph, and I think that's about 110mph??? On my 70's style enduro build that I used that same engine on, I was able to get it up to around 80mph, but that was only because I didn't quite get around to fine tuning the carbs, and it starts running a little rich after about 3/4 throttle. The carbs didn't come with that exact engine that I bought for it.

I would have started with the engine to make sure it was good to go before building an entire bike around it. I'm not sure why you always do the build first and then try to get the engine running, but I hope it works out. I've been looking forward to seeing this thing run and drive.

Finally back to this

Yayyy a long video

I don't normally have a comment on your builds because I think you do a great job but I do think slightly bigger wheels would look much better.keep up the good work man

I would sure like to know what that second song is called I really like that earily sound. I was close I guessed twenty five pounds on the frame weight. the engine is over four times as heavy as the frame. on aluminum that white corosion is called sulfating. it's quite common on aluminum that has been sitting around for a while. if there is any amount of pitting and or corosion on the valve seats or the faces of the valves you will have a problem. a sure fire way to tell if you have an issue with the rings is to use a compression guadge. and add a small amount of oil to the combustion chambers. if the compression rises significantly you have an issue with the rings, if not it's the valves. but sometimes the rings will get stuck in the the ring lands of the pistons if the engine has been sitting for quite a while. and will free up once the engine is running. I suggest using a compression guadge in the future.

That motor is heavy because it’s DOHC and 4 valve, so the heads and timing chains, etc. are all beefier than usual.

looks like a full sized bike with tiny wheels & tires.

Cool

Ps I'm.FTFM Garage. Love learning and watching I'm 65 but some kids never grow up.

15:10 the reason the ninja engine is so much lighter in comparison, is that it has a bigger internal volume (650cc) and thus less metal inside /j ;)

Look ing good bro

hey man when you get the time, can we please see some videos of your 2/3 speed karts shifting? I'm really interested to see how they perform, keep up the good work bro!

I had a cixi kingring motorcycle a few years back. Pretty sure it had the same brand engine

I made a little bike like this. I started with big tube coleman mini bike frame.

you know, most engines like this have a decompression lobe that helps the engine turn over easier. once the engine fires the decompressor is out of the equation and full compression is restored.

Good you decided to do valves.

Woo!