Great info! My 2009 49cc Grubbee Skyhawk build is still going strong and I feel VERY lucky that the ONLY major problem I had, other than the chain tension, was the leaking intake tube. I replaced the stock tube with a cast one and used Hondabond to stop the leak. I then added one of the spring loaded tensioners that mounts on the bike frame after replacing the stock chain with a 410 chain. These kits have really come a long way since 2010!-John in Texas

The $99 ebay kits are good for spare parts. The engines are Stage One engines, mounting bolts are 6mm and they break. The Stage Two engines come with 8mm mounting bolts. Intake port bolt spacing is 40mm, and the crankshaft and clutch bearings seem to be a bit better. and the casting around the bearings are bigger and heftier,too.

I brought mine from the USA from eBay and everything is top quality!!

Yd100 is a great starting kit I’ve had mine for a year now and it’s lasting so good that I’m just building it again with reeds and oko carb with nasty jack pipe they are good power stick and modded are even better I would recommend it for ur first kit I got 2 and they both start up out of the box

Top tip. Play at 1.5x speed

Very good instructional video. When I started to install the sprocket, I immediately realized that there might be a problem with the sprocket not being true (symmetrical) to the wheel. So I measure the distance from the axle to the valleys between the teeth at 4 equal angles. I moved the sprocket around so the distances equaled. After tightening the sprocket I check the distances again. Then I measured the distance at 4 equal angles from the bike sprocket to the motor sprocket. I tightened the nuts to make the distances equal, making the distancing equal will make the motor sprocket some what parallel to the wheel. Also when I pulled the tire back to tighten the nuts I checked the distance from bike tubing on each side of the wheel, not the tire. So the wheel won’t be tilted one way more to one side than the other. Obviously none of this is going to be perfect, but it’s better than haphazardly slapping things together. Even if you had a CNC machined sprocket I would suggest doing the same

Thank you very much for the video Paul. Great sound advice for these two upgrades. I would do it like you say. I want to get a kit sometime for the hobby aspect. and these two modifications I feel also are a must.

Thanks man, Good Video it helped me out I am thinking buiding my Second bike, with better parts and I have a much more knowledge and experience now.

Gosh,, I just ordered my kit from China. Wish I'd watch this channel before I got a ride from China.

They’re not 80cc in America, but they are in China/japan. They measure their sizes differently, and the majority of the engines that say 80cc are being sold from either of those countries. Doesn’t matter if it is American made or Chinese made. They’re both built to work. Main difference is that American made is SAE nuts and bolts, and Chinese is metric. You pay for what you get, so keep that in mind. And you can never trust eBay, but you can always trust the ratings, trust the buyer, and the reviews of that specific product you’re looking at.

Regular motorcycles are usually rounded off to next highest size ie: a 500 might be only 490 491 cc

Also on the chain tensioner- go to the hardware store and get new bolts -also get new bolts for the rag joint of that rear sprocket! because they have to be tight as hell and the hardware that comes with them is so soft. When you search for a chain replacement, search "415H" the chains that are out there are garbage and I've broken so many before I found the "H" ones- it's tough to get links out of it to fit but they last so much longer and they're about 20 bucks.

as a former owner of one of these two stroke kits i agree with everything he is say. the chain tensioner with spring that is on the frame is crap don't get it i had both stiff and spring (stiff worked better) the starting of the motor caused the stiff and springed tensioner to go into the spokes and lock up the back tire. also make sure you have your front tire on properly or else you might flip and break your collar bone as i did. if you need questions answered feel free.

Great information....stock tensioner is crap and rear sprocket set up is also crap Hub mount is the best

the chinese "potato chip" rear sprockets are stampings, NOT castings. the stamping process uses basically giant toilet paper rolls of sheet metal which feed into first a flattening press, then a blanking press and profiling press, or a double draw press that completes both operations. all operations are performed cold, on sheet metal of "chineseum alloy", which is where the problem lies. the coiling operation that makes the rolls is performed hot, the cold working at multiple stations induces stress. here in the states, folks in the biz use alloys like "1140 stress-pruf" for such operations (like building car body panels), formulated to resist those induced stresses causing deformation, because quality and consistency of the finished part placed in multi part assemblies ends up costing less at the end of the run (time spent wrestling sheet metal using lower grade steel is a bigger bite than the additional cost of the stress resistant alloy). chinese labor is cheap, chinese manufacturing bosses are cheap skates, and NOBODY sends back kits over skewed pie plate sprockets (mostly because they see opportunity to "up sell" you, the final customer, one of those "CNC hub cinch and sprocket" sets at a higher profit than they make on the kit itself), so there exists NO inducement for the manufacturer to clean up his act. welcome to modern manufacturing run by "bean counters"

The steel sprocket plates are stamped, not cast. Even on most CNC sprocket adapters, sprocket itself is still stamped steel. The problem with the engine mounted tensioners is that the moving parts are right there at your leg. Also, you have a hard time getting Engine mounted tensioners in line with your chain because there is no real adjustment you can make side to side, unlike a frame mounted which can be adjusted my moving the mount on the frame. If you let your bolts and nuts loosen and allow it to get dragged into the spokes, you might not be mindful enough on your daily checks to even ride a machine like this safely. Still, a good call on upgrading from a non-spring to a spring tensioner. Also good call on upgrading from the sandwich-on-the-spokes sprocket to a sprocket adapter that mounts on the hub itself; they are my first 2 upgrades also. I hear that the difference in cc's is that in China, they count the top part of the combustion chamber that we don't count in the west. Whether its totally a marketing ploy, I couldn't say.

Are you telling me there's no difference between 80cc and 66cc I couldn't tell after the 5 times you said it lol.

Also a 100cc version avail here in Australia too

Never trust anyone that bought their motor from kingsmotorbikes

I remove or never install every chain tensioner off and Chuck it. Never had a problem. I call bullshit on those who say there needed. Get killed when it slams into the spokes.

The 80cc are named as such because in Japan they use a different system to determine size. Most marketers calling their engine 80cc aren't really trying to confuse anyone, it's more of a traditional term. People were used to seeing 80cc on these motors for so long that calling them 66cc makes them seem like something smaller. It's not really misleading people. Actually NOT calling them 80cc would be more misleading.

That was hard work to get to the end......all common sense,

A lot of people think that these engine kits are a joke but they dnt know the 1st motorcycle was with a Harley engine in a bike frame

jesus, you dont have to repeat yourself 3 times

in china they go by compression and combustion chamber area added together in america its just bore n stroke...so the 80cc has more compression.

Has anyone noticed that the link to the USA dealer is ALSO a dealer on eBay? imagine that.........

He Says dont buy from ebay but 90% of this video is me looking at Ebay... But isnt there a single kit you could point us to without buying the upgrades like chain tensioner?

I don't care for those spring loaded tensioners. The one I had installed wouldn't clear my pedals. Had to abandon my bike and it ended up getting stolen. I like a version of the arch tensioner that I make myself.

I noticed that the cut sprocket did not have a pineapple spacer to keep the chain from hitting against the bike that ever a problem

id up grade the 115 chain to a better made one and a new plug cap helps .also spark plug gap changes a lot how your motor runs.i adjust plug gap till i feel it runs best for me.

i play this to get to sleep at night ...thanks

Dude love the video, but there are 49 cc fore stroke kits, like the one i bought from bikeberry. There hasn't been a part that i haven't had to modify including the crank. These are not toys, but if you have the tools and build something solid you can have a lot of fun.I had no problems with the rear sprocket but had problems with the aftermarket crank.

*So you say dont buy from ebay? Next viable seller comes to mind is Amazon without spending $400+? OR A KIT WITH A CNC SPROCKET???*

The sprockets are stamped, not cast.

good man Paul for very sound advice. Eric Cuthbert. Rep of Ireland.

you can just connect the chain tensioner to the down tube below the seat.

The first part about chain tensioners is bogus, You want a sturdy chain tensioner, but not spring loaded. There are newer double clamp ones are better. But you should always drill a 9/64" hole in the main clamp and tap and thread it and the chains stay it's clamped to, for a hardened 10-24 coarse thread bolt, to make sure the tensioner arm doesn't turn into the spokes under the pull of the chain while coasting with throttle closed. Better yet make it a habit of pulling your clutch in and coasting on downhills. You won't be relying upon the engine for braking, ( note 2 cycles don't engine brake well, and they need lubrication while being spun by the wheel, possible seizing potential...) Secondly the spring loaded tensioner will allow the top run of chain to slacken under engine braking enough that it could bunch up and destroy your sprocket and or engine cases . The videographer's chain tensioner suggestion is a really bad idea.

Thanks,super helpful 👍

Keep this video near your bed. Puts you to sleep in no time at all.

thanks for the video...question ..Is the spring tensioner you mention universal? I 'm getting ready to do a 29" so far I see bikeberry as the best...if I'm wrong tell me...I CAN HANDLE THE TRUTH!

Thanks for the 66/80 lie. Thanks for all the important info

You know I'm building my third project after 3 years I sold the first one the second one I ditched it it's sitting in my garage I'm about to start a third project I waited a while to see what they come up with a lot of the issues you're talking about I've experienced I already know what to get and as for the chain tensioner yes I found a gun on eBay as well before I saw this video this time I just got myself a frame from eBay because unfortunately gasbike nor bikeberry have any in stock but come to find out later I found a bunch of other companies that do have it hopefully this one won't be a piece of junk but it has a built-in tank which is what I like I had a lot of issues with the tank leaking this time I know what to look for and I highly recommend and nobody buys the kit by the motor and buy all the parts separate it's not worth it

Gas bikenet is way better than BBerry CR machine is the best and very expensive then y0u have Zeda motorsports very cool designer two stroke engines high performance fast

There are a few 58cc engines. Ive got one 50cc is 48,49 or 50cc. 80cc is 66cc 58cc is an uncommon displacement in these

Will a 100 cc bicycle engine fit on a old school 26- 27 inch Schwinn 10 speed ?.

My neighbor got a basket instead of a top part of the motor. I couldn't believe it was a wicker basket. I am thinking about getting a 4 stroke motor for my cruiser bike. I want to get a kit from a good place and the best motor I can for the money. I am going to get a CNC sprocket and a mount to the hub instead of the spokes. Videos like these are helping me learn what I want. I am kinda thinking about just putting it on the rear rack. I seen some tensioners that connects to both the bottom and top bars that go down to the rear wheel. It keeps it away from the spokes. Thanks for video.

Right off the bat you know he don't know what he's talking about. These engines come in the following sizes. 48cc=40mm piston 38mm stroke, 50cc=40mm p 40mm s, 60cc= 45mm p 38mm s, 66cc=47mm p 38mm s, 69cc= 47mm p 40mm s. Stick to what you know, and leave what you don't know out.

There are also 48cc and 50cc engines

If u dnt have a welder drill a hole in center of chain tensioner and put a bolt through it problems solved

Thanks Paul , some VERY good points and recommdations ?! ;)

The Zeda 100cc to the yd100 is right at 80cc not quite tho but almost there

The chain tensioner I got from the company I went through I had to buy an extra bearing and extra bolts cuz I had to extend them

I think hes smoking pot, keeps repeating himself. Dude we arent def, move on!

Definitely no eBay! Amzon right now (july18) has Zeda80 "triple 40" Pk style engine kits for $150 and its absolutely the best twostroke deal out there right now. The engine is balanced much better than others and lets face it, they all come from China, and any US selller is basically just a middle-man. Many sellers claim to do work on them or upgrade (port and polish etc) and this justifies the exhorbitant price but you cannot trust these people!

Any recommendations on which brand name is best on your site? There's like 8-10 different engines with the same capacity

Dude your wrong about a lot lol but it’s nice that your trying to help people. Not all companies are the same.

Let me school you on something it is listed as 66-80 cc because depending on the cylinder head that is on the motor some have a larger hemispherical dome than others and this makes them 80cc . But yes there are 80cc engines out there the bt-100 is a true 80cc .

Every one of these engine's are made in China by 4 company's who distribute them to around 150 company's to sell, so weather you buy it from a USA company or from China it's the exact engine.

instructions are very god but REPEATING them over and overs is quite annoying. Thanks

Thank you very much. Good work.

how come it was 80cc When I Dynode the engine

Things have changed since your video post... 🤔🤔🤔

I don't know why the seller and the Chinese people are claiming and getting away of advertising a bicycle engine 80cc, No clue. Do you know the song on your video, I would like to know. Thanks

Mr, what the regular spocket to put on the hub am planning to use the CNC spocket

What ones on eBay do u recommend if I have $200

Kings is a great company. Stay away from gas bike.net. great advise. I put both sprocket and engine mounted chain tensioner. Never have thrown a chain. I think having a chain tensioner mounted to your frame also causes more vibration. The chain running thru that plastic wheel, mounted to your frame. Just saying. Peace friend

Quite long winded, but informative. Thnx - Just shorten things up a bit.

I’ve seen some stock sprockets that look like pot metal, then others that were chrome plated and looked quite heavy duty.

Do you have a link for cnc sprocket?

So there are three types of engine , 2 stroke , 4 stroke and a gas engine , I can seem to find any vids on the gas engine.

who makes these spring chain tensioner?

How do you open the boot on a Ebike?

This was such a boring video but i muscled through it

I bought my engine kit from Walmart on line $99.99.

thank you

4:20 how do you keep the CNC sprocket from bending the spooks?I had one on two bikes but they kept bending the spooks so I had to go back to the stock sprocket.

Sorry I live in the UK and I can not fine a company that sells them can any 1 help me

you saved me from being a dumbass! thanx

anybody have any experiences buying from bicyclemotorworks?? thinking of buying from them but i am not sure if its just another resale site. any help??

Whut about 92cc and pk100?

The 80cc thing started in china ... i got mine from gasbikes.net ... a jet black stallion ... even the words on the carb are chines

Replace the Chinese chain with a quality chain you won't have to stretch so much

66 and 80cc are the same thing...

i just bought a 18 dollard motor kit do you think its gonna be real or a scam

sold out

So how big are the 80cc engines? I want to buy one because my 66cc needs more power.

I hate the pineapple joints, they are pain in the butt

hello I like to buy American but all engine is made in China is that is true

whatsthe name of the song?

Nice helpfull vid bro

I bought 80cc

What I want to know is, are there are any engines for bicycles using a kickstart lever? I hate that pull cord design. (It ain't a lawnmower!)

Does anybody know this music

Unfortunately Kings doesn't have 49cc bikes. In my state, 49cc is street legal. No license or insurance needed. Any recommendations? I'm looking for a kit with the bike included, so I know everything will fit.

no mine is 80cc really

i shut this video down after you said there are no 80cc engines lol, its all about the mods to get it to a certain point thats why they sell the upgrades with the motor!

diff ..specks in asain country

What do you think about the kits on Amazon.com?

Does anybody know this song

How can i order this engine