You need a engine mounted spring tensioner .the rear tentioner is junk , they come apart at high speed and chain locks the back tire up and then you are hurt.also try any chainsaw plug and you will really be impressed at the speed and power difference
I had trouble with the BT overheating and had to oil holes to the piston. If you plan on running that at higher rpm it may keep you from soft seizing. I said all that to tell you I think it is still my favorite engine. I’ve run Minarelli conversions, 80,yd100,110cc and the BT was definitely the fastest and most powerful as well as little maintenance
I've been worrying about that myself, I've read seizing is an issue with these. I'm running 25:1 oil mix and so far, a 20min ride at wide open throttle doesn't lead to overheating, the paint on the cylinder isn't even discolored yet. It is still fairly cool over here right now though. What mix were you running on yours?
@@rogerstafford-wakeinc.2088 What was your oil ratio? I've read a lot of nonsense saying you can run 50:1 in these, shortly followed by a pic of a destroyed engine.
I was getting what i thought was vapor lock which was starving it of fuel making the lean situation worse. Turned out the carburator was getting so hot the fuel was boiling back up the fuel line starving the motor of fuel. I modified a longer 40mm intake to fit the bolt pattern and it fixed the issue.
Cool vid bud, Oh I believe you guys just listening to the powerband kick in something fierce!!! Great job on getting that much power from modifying stock parts! Yeah, the VM18 will definitely put you to 8 or 9 HP with a larger diameter intake. But hey I'm just another dude pushing the limits on cHINA DOLLS...😅
I'll borrow a go-pro and record some top speed video. It's tricky over here in Aus as you can't legally ride them on the road, and its way too bumpy on the dirt roads here on the farm to do 45mph
Credit goes to Jayraye39 over on the motored bikes forum for coming up with this idea. The carb is still flowing way more air than it was designed for and it'll run rich up top because of that and ultimately limit the max RPM and HP. I had to jet down to lean up the top end, which also lost torque down low. It really needs a larger carb for this combo. I'm told by Jayraye39 that a velocity stack will increase power too so I'd say that is worth a try
Does your venturi opening go all the way through? Or did you only open it up till it meets the slide? This is definitely a hot roder’s secret to making the most power in the “nt spec” & non reed setup class. Love the videos. Great work mate! Keep em coming *edit* - read through the 100+ page thread on the forums. Another thank you for sharing all your data & info. Just modded my carb and excited to see what improvements I see
Hello, I really like the video. I have some questions tho. First: what plug are you running. Second: what is your experience so far with durability and third do plan on installing a jackshaft kit( that would be a suecide, a cool one tho) thanks in advance. Have a great day/night
Hey! Plugs: I've tested NGK/Bosch/China Z plug. Zero change in HP between them. Durability - These engines so far have lived their entire life at full throttle on the road or the dyno, and there's no wear visible on any of the parts so far. Jackshaft! Yes!!! I'm told the gearing won't hold up to this kind of power but I'll test it out anyway
@@SafetyUggs btw just a quick question. A site in my country says it sells the same motor, but the carb has a red filter. Do you think I should risk it
@@SGmotorsport9590 I'm told they ship with red or black air box so it's probably fine. If it's the same cylinder and crankcase, i'm sure it'll run great!
Hey, they're not really something we build to sell, I could build one to your engines specs but I'd imaging shipping from Australia to the US for something this bulky could get expensive
@@keeganhache6667 Apologies! If you want to pm me, follow the link in my bio to the motored bikes forum and we'll work out if it'll be at all cost effective to get you one.
What exactly does porting the stock carb do? I never really thought about doing that to it like that but I’m very curious now to experiment and would love to know the reasons you did it and how it makes changes to the power delivery.
It'll allow more air flow, and more HP before the carb goes extremely rich and bogs down. This is all based on the work of RayJaye39 on the motored bike forum, definitely drop by and take a read of his work
@jeremyhopkins6965 it was running rich to begin with. Porting the venturi was meant to fix that. Even if he ruins the carb that’s like what, $40 max? You’d be surprised, there’s all sorts of cracked hacks to squeeze more power out of these little engines.
with all due respect from Texas, USA I have to agree with the others, no stock china anything 66/80, 79.5/100cc will get over 3-4 hp, maybe 5 with a pipe and jetting, but that's pushing it without internal porting, windowed pistons, reeds and the rest. The Minarellis prebuilt by the pros with all the bells and whistles on them still don't even get 10hp. Your talking watercooled KTM 65cc and they still do not get that much power, especially unopened.
I hear ya! and you're probably right. I've tried to make all this as accurate as possible, not sure if you saw the video but we dyno'd our small 125cc 4t pitbike (lifan engine), reported to be 9hp at the motor, dyno'd at 7.4HP. I'll run my ttr250 and kx85 up on the same dyno this week for more numbers. A factory kx85 makes 29hp so my logic is, an 80cc china doll, ported, custom pipe, VM18 carb, 9hp isn't out of the question.
@@SafetyUggs I think the Smoliks are there and past it, but nothing is stock. I am thinking of putting one of those on a mountain bike and wondered how fast they are with having forward gears is. Yet if they got power I'd go the $250 for one of them, what do you think of them? Any snags mounting them?Thanks!
@@refuge33If you mean using your normal cassette/gears, you'll need a jackshaft kit and there's a limit to how much torque the stock chain and cassette pawl can handle. max speed is purely down to gearing and HP. If you've got the gearing sorted, you'll need ~4HP to hit 50mph. 5HP for 55mph and I think around 8-9hp for 60mph. Wind resistance vs speed is exponential so its harder and harder to gain MPH the faster you go. Out of the box, a $200 kit will get you maybe 30-35mph. Add a pipe and jetting and 40-45 shouldn't be a problem.
@@SafetyUggsyour hp/speed is accurate. I built a few motors years ago and 55mph was the best i could get. I estimate it at 5hp and compared to stock it felt very fast!
If it's all factory stock, "Never even opened" as you put it, there's 0% chance it is anywhere near 7hp. Any readings that would indicate that are so far off as to be worthless!
No expansion chamber, no reed valve and your dyno chart shows that you havent touched the cylinder porting.
Bro. Drop the wrenches and go home.😊
Man this is extremely good content. Please don't stop making these videos! You've got a new subscriber.
Thanks mate, appreciate the kind words!
You need a engine mounted spring tensioner .the rear tentioner is junk , they come apart at high speed and chain locks the back tire up and then you are hurt.also try any chainsaw plug and you will really be impressed at the speed and power difference
A spark plug will add power? tell me more!
Lol @@SafetyUggs
New subscriber. It's amazing what a good pipe can do to a 2 stroke. Those calling it bogus #'s are showing how little knowledge they have
I had trouble with the BT overheating and had to oil holes to the piston. If you plan on running that at higher rpm it may keep you from soft seizing. I said all that to tell you I think it is still my favorite engine. I’ve run Minarelli conversions, 80,yd100,110cc and the BT was definitely the fastest and most powerful as well as little maintenance
I've been worrying about that myself, I've read seizing is an issue with these. I'm running 25:1 oil mix and so far, a 20min ride at wide open throttle doesn't lead to overheating, the paint on the cylinder isn't even discolored yet. It is still fairly cool over here right now though. What mix were you running on yours?
@@SafetyUggs 35 roughly wide open would bind at times. Usually after 20miles
@@SafetyUggs I also found letting it cool off at times before modifying that it also was beneficial
@@rogerstafford-wakeinc.2088 What was your oil ratio? I've read a lot of nonsense saying you can run 50:1 in these, shortly followed by a pic of a destroyed engine.
@@SafetyUggs 35:1
Just awesome
I was getting what i thought was vapor lock which was starving it of fuel making the lean situation worse. Turned out the carburator was getting so hot the fuel was boiling back up the fuel line starving the motor of fuel. I modified a longer 40mm intake to fit the bolt pattern and it fixed the issue.
Interesting! I've never had a carb run that hot! Nice fix
Great channel. Definitely impressed. What's the stinger exit I.D.
12.1mm ID is what the pipe calculator called for. Once the VM18 is fitted I'll start shortening the stinger inch by inch and see how that affects HP
@@SafetyUggs youtube.com/@2strokecarbtuningportingin187?si=jNkaGgIO6uaV9Glc
@@SafetyUggs thanks
Cool vid bud, Oh I believe you guys just listening to the powerband kick in something fierce!!! Great job on getting that much power from modifying stock parts! Yeah, the VM18 will definitely put you to 8 or 9 HP with a larger diameter intake. But hey I'm just another dude pushing the limits on cHINA DOLLS...😅
Good stuff man! Subbed!
Cool.....oh what does subbed mean? I think I've been drinkin for too long.@@SafetyUggs
Is this built just for dyno? will we maybe see a top speed video
I'll borrow a go-pro and record some top speed video. It's tricky over here in Aus as you can't legally ride them on the road, and its way too bumpy on the dirt roads here on the farm to do 45mph
@@SafetyUggs sometimes its worth breaking the law brother 😉
Never heard of modding the carb like that. I might have to try it. Would a velocity stack+ richer jet be a good idea to pair with it?
Credit goes to Jayraye39 over on the motored bikes forum for coming up with this idea. The carb is still flowing way more air than it was designed for and it'll run rich up top because of that and ultimately limit the max RPM and HP. I had to jet down to lean up the top end, which also lost torque down low. It really needs a larger carb for this combo. I'm told by Jayraye39 that a velocity stack will increase power too so I'd say that is worth a try
Does your venturi opening go all the way through? Or did you only open it up till it meets the slide? This is definitely a hot roder’s secret to making the most power in the “nt spec” & non reed setup class. Love the videos. Great work mate! Keep em coming
*edit* - read through the 100+ page thread on the forums. Another thank you for sharing all your data & info. Just modded my carb and excited to see what improvements I see
How did it go!?!? We saw a pretty big improvement with RPM and power, hopefully you see the same!
@@MrJustalilcrazyso... what improvements did u see?
Hello, I really like the video. I have some questions tho. First: what plug are you running. Second: what is your experience so far with durability and third do plan on installing a jackshaft kit( that would be a suecide, a cool one tho) thanks in advance. Have a great day/night
Hey! Plugs: I've tested NGK/Bosch/China Z plug. Zero change in HP between them.
Durability - These engines so far have lived their entire life at full throttle on the road or the dyno, and there's no wear visible on any of the parts so far.
Jackshaft! Yes!!! I'm told the gearing won't hold up to this kind of power but I'll test it out anyway
@@SafetyUggs man, I thought building jet engines in your bedroom was crazy but here I am reading this. Be safe bro
@@SafetyUggs btw just a quick question. A site in my country says it sells the same motor, but the carb has a red filter. Do you think I should risk it
@@SGmotorsport9590 I'm told they ship with red or black air box so it's probably fine. If it's the same cylinder and crankcase, i'm sure it'll run great!
@SafetyUggs-fu4kw btw I found a video on smolik performance channel where they pushed an 80cc hybrid I think to 14hp. I can't find the 16hp one tho
How do you prevent the clutch cable from opening the drain valve on your bofeng?
I haven't had that problem. It might be related to the intake manifold you're using?
TURBO CHARGE IT
It’s a 2 stroke
Where my comment go, oh well Ill leave a new 1 🚴💥☁☁☁
There's nothing under 'held for review' so I'm not too sure what's going on! I know posts with link just won't appear, could be that?
Hey man I really like how you hydro formed that exhaust do you sell them? Could to some testing on the channel
Hey, they're not really something we build to sell, I could build one to your engines specs but I'd imaging shipping from Australia to the US for something this bulky could get expensive
@@SafetyUggs that’s true I’m in Canada lol
@@keeganhache6667 Apologies! If you want to pm me, follow the link in my bio to the motored bikes forum and we'll work out if it'll be at all cost effective to get you one.
👍
Is there a file for the tunnel ram intake? Would you be able to share?
There is! you can find it on the motoredbikes dot com forum, there should be a link in my profile.
@SafetyUggs legend bro, love ya work. ❤️ from Palmerston North, New Zealand 🇳🇿
Sussed it bro. Thank you
What exactly does porting the stock carb do? I never really thought about doing that to it like that but I’m very curious now to experiment and would love to know the reasons you did it and how it makes changes to the power delivery.
It'll allow more air flow, and more HP before the carb goes extremely rich and bogs down. This is all based on the work of RayJaye39 on the motored bike forum, definitely drop by and take a read of his work
Porting stock carb without reed valve will lower your torque and lower your hp. This dude is a joke if he thinks otherwise.
Zeta motors has one that makes 16hp
Got a link?
@@SafetyUggs just ride: zeda motor 16hp
@@SGmotorsport9590I've googled ^^ and no matches on google. Do you have a link?
That was a frank
Lol they definitely do not.
Same bike n motor but not turning chain to turn motor
Adjust the clutch?
Your chain is loose man.
It sure was! It's now on a 32t and tight tight tight!
im sorry but you must be joking modding your carb might as well be an air leak hope you run a heavy mix smh
@jeremyhopkins6965 it was running rich to begin with. Porting the venturi was meant to fix that. Even if he ruins the carb that’s like what, $40 max? You’d be surprised, there’s all sorts of cracked hacks to squeeze more power out of these little engines.
with all due respect from Texas, USA I have to agree with the others, no stock china anything 66/80, 79.5/100cc will get over 3-4 hp, maybe 5 with a pipe and jetting, but that's pushing it without internal porting, windowed pistons, reeds and the rest. The Minarellis prebuilt by the pros with all the bells and whistles on them still don't even get 10hp. Your talking watercooled KTM 65cc and they still do not get that much power, especially unopened.
I hear ya! and you're probably right. I've tried to make all this as accurate as possible, not sure if you saw the video but we dyno'd our small 125cc 4t pitbike (lifan engine), reported to be 9hp at the motor, dyno'd at 7.4HP. I'll run my ttr250 and kx85 up on the same dyno this week for more numbers. A factory kx85 makes 29hp so my logic is, an 80cc china doll, ported, custom pipe, VM18 carb, 9hp isn't out of the question.
@@SafetyUggs I think the Smoliks are there and past it, but nothing is stock. I am thinking of putting one of those on a mountain bike and wondered how fast they are with having forward gears is. Yet if they got power I'd go the $250 for one of them, what do you think of them? Any snags mounting them?Thanks!
@@refuge33If you mean using your normal cassette/gears, you'll need a jackshaft kit and there's a limit to how much torque the stock chain and cassette pawl can handle.
max speed is purely down to gearing and HP. If you've got the gearing sorted, you'll need ~4HP to hit 50mph. 5HP for 55mph and I think around 8-9hp for 60mph. Wind resistance vs speed is exponential so its harder and harder to gain MPH the faster you go.
Out of the box, a $200 kit will get you maybe 30-35mph. Add a pipe and jetting and 40-45 shouldn't be a problem.
@@SafetyUggsyour hp/speed is accurate. I built a few motors years ago and 55mph was the best i could get. I estimate it at 5hp and compared to stock it felt very fast!
get a better bike. a huffy cranbrook.
No need, we can't ride these over here in Australia :-( it's only for the dyno
Not sure where your Dyno issues are but there is literally no way that engine is putting out that kind of HP!
Did you watch the whole video?
If it's all factory stock, "Never even opened" as you put it, there's 0% chance it is anywhere near 7hp. Any readings that would indicate that are so far off as to be worthless!
Did you watch the whole video?