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.
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.
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.
Volume is volume. A 750 ml bottle of booze is 750 ml (or cc) no matter where it is measured - in China or in the USA.. Same with a 49 cc engine volume. 49 cc is always 49cc. Same thing with 66 cc. If a displacement is really 66 cc then saying it is 80 cc somewhere else is quite "fake news" - in other words a lie. The USA also makes metric nuts and bolts, not just China. Caveat Emptor.
Are you kidding me? volume is volume. It may be metric or in cubic inches, but there is a precise conversion factor. Please tell me of a reputable American made engine. There are very little to no American who can design and manufacture a small engine better than the asians. As an example there are no cell phones, TV's, DVD players, cameras that an American can reliably manufacture. Go to Asia and they can make it much better and at a cheaper price. Imagine what an iPhone would cost if we made it here....plus it would not be the same quality. It is hard to find dedicated workers in the US. Stick to Asian engines if possible. Honda makes great 4 strokes. The Chinese make the best 2 strokes.
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
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.
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.
Mine too. They said they sourced the parts and assembled it themselves. Course the cast parts came from China. But they claimed the bearings where Japanese. So far so good. I also replace the Chinese assassin chain tensioner.
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"
@@crismarino8958 There is 78.5 cc excatly. Look for the Zeda 100 or YD100 Engine-Kit. It is the biggest and strongest (low-end torque) engine out there
The king's website he has in the description has every 2 stroke listed as 66cc or 80cc lol discredited everything he stated on cc size I gotta 50 cc kit I'm staring at unopened box trying to find out any information on what I'm gonna have to do an what I should get to improve the low quality of a 140$ 50cc engine kit from walmart
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
Bernie Olivera the cnc sprocket doesnt need to be trued like the stock sprocket does because the cnc sprocket mounts to the wheel hub, not to the spokes like the stock one.
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.
@Bike Life_93 I dunno but it's sooo much better than 50/80/66 whatever they are. Bt100 was what I ordered and they were only available here for a short time.
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.
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!
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.
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.
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.
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.
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
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.
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?
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.
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
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 .
A "dome" in the cylinder head does not increase the cc capacity , it affects the compression ratio, the only thing that increases/decreases an engines cc capacity (size) is bore and stroke
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!
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.
Lion Silver easy, you didn't have the mount tight enough. The cnc sprocket as you should know mounts to the hub of the wheel. If its bending the spokes, the mount is moving because its not tight enough on the hub.
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.
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
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
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.
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??
I bought a ported motor from them. Good motor. But don't buy parts from them. They'll substitute parts without letting you know and I've also had items missing from a parts order that I placed. They wouldn't even respond to any of my 4 emails that I sent them about the missing parts. They screwed me for about $30 worth of parts. Would never order parts from them again.
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!
Im going to order a kit today I've been looking around and was leaning toward amazon because of customer service , additional warranty and next day free shipping with my prime account. Please let me know what you think. I'll be using it to go back and forth between my 2 jobs and home. Buses are always running late making me late to work. So I need a good kit at a good price as soon as possible. Also I don't know if it makes a difference but there will be no up hill travel on my route. Thank you
