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  Topic Review (Newest First)
06-22-2019 06:50 AM
CAM2
Re: New to little bikes.

Quote:
Originally Posted by MrKitty View Post
i think i got the closest to finding the right Balance Factor on my girlfriends mini quad engine that engine really raps out the RPM it is like magic.

unfortunately no 2 CAG engines are a like or have the same balance factor especially with the Chinese throwing filler metals into the vat...

i just keep learning more and more every day will see how the next one works out.

Nice.....It indeed takes the right balance...……….Once you know the numbers to make the magic happen you can replicate and be close but its more like playing the lottery when you try different things and get even more magic out of your build than expected...…......…LOL.

Theyre making advancements in automotive /motorcycle technology even myself has made a breakthrough that may be picked up through a highend raceteam to further develop for their brand then try out..

New best and newest advancements is the ability to 3D print high quality aluminum that doesn't expand half as much as a CNC or a cast piston so you can successfully run tighter piston to cylinder tolerances to build even more power...…

On a miniquad Id go with nothing less than a 4 port cylinder but I definitely recommend 5.....The extra torque really takes back some of the frictional losses of the locked rear axle and spongy tires...….
06-21-2019 06:06 PM
MrKitty i think i got the closest to finding the right Balance Factor on my girlfriends mini quad engine that engine really raps out the RPM it is like magic.

unfortunately no 2 CAG engines are a like or have the same balance factor especially with the Chinese throwing filler metals into the vat...

i just keep learning more and more every day will see how the next one works out.
06-21-2019 02:58 PM
CAM2
Re: New to little bikes.

Quote:
Originally Posted by MrKitty View Post
i do know about Subaru Robin engine and china CAG engine being a copy based off of it i saw a Makita rock saw with the same engine as CAGs i allso saw a mini china rototiller at ACE with it good news to me as long as china keeps useing this engins for stuff i can basicley keep them going forever LOL the bad news as we all know is these engines are internally flow-restricted to be a free revving engine that can be run for extended periods of time at wide open throttle.

A lot of it can be overcome by simply following the recipes on this site and not thinking about it too much and that a lot of the information you read from 2-stroke tuning and porting books wont apply.

then we do have our secrets 🙂 they are the things that have never been discussed or brought up here if you want to read between the lines...
If you had how come youve never mentioned it in your "crank problem thread" as its kinda a pertinent point to make when addressing parts for these engines and explain what theyre about...

Its easy to research and get furthermore info to add after you get the initial facts....LOL

Kinda like how Zuckerberg stole the idea for flakebook………...LOL

As far as secrets theres very little you've told us about yourself yet in 5 minutes or less I can divulge those secrets quite easily like a magician yet theres tons of things Ive told about myself but can you do the same.......?

If you can PM me my name and address and Ill reply with yours plus your mother and fathers and sisters name...….LOL..

Theres been jokers in this forum that have tried playing games but have just suddenly stopped when their telephone rings and its me on the other end wanting to discuss where their lives went wrong...….LOL

Everybody has secrets..Some tell them eventually and some vaguely tell but hardly nobody ever holds their secret forever

"Thats a given fact especially when its not pertinent to hold that secret anymore"..Even when a gag order was enforced..

Kinda like secret gov't documents and classified info...…….......LOL
06-21-2019 02:43 PM
MrKitty i do know about Subaru Robin engine and china CAG engine being a copy based off of it i saw a Makita rock saw with the same engine as CAGs i allso saw a mini china rototiller at ACE with it good news to me as long as china keeps useing this engins for stuff i can basicley keep them going forever LOL the bad news as we all know is these engines are internally flow-restricted to be a free revving engine that can be run for extended periods of time at wide open throttle.

A lot of it can be overcome by simply following the recipes on this site and not thinking about it too much and that a lot of the information you read from 2-stroke tuning and porting books wont apply.

then we do have our secrets 🙂 they are the things that have never been discussed or brought up here if you want to read between the lines...
06-21-2019 02:17 PM
CAM2
Re: New to little bikes.

Quote:
Originally Posted by pntrbl View Post
Just for old times sake I got a pair of Briggs flatheads sittin' on a shelf waiting for something. I dunno what, but they're still there.

BTW, is there any chance that a piston port and a reed valve CAG have the same motor mounts? Are they interchangeable?
Theres engines that they use for the Cateyes and the X7's with the grey colored fancases that have engine mounts similar to a cag to mount them as you can see from this picture it has 3 different ways to mount it...…..



With that engine plate that EPR explained about the mounting is pretty similar as a cag but youll also need to mount the transmission with it..


On my homemade scooter and my Homemade r/c buggy I used 1 1/2" x 2" L angle steel a drill welder and grinder and had a bulletproof mounting for both.....………

06-21-2019 11:44 AM
EPR
Re: New to little bikes.

No they are completely different. There is a U shaped bracket the engine bolts to with 4 mounting holes on the bottom, might be able to, mount it to the plate holding your Cag engine frame plate.
06-20-2019 10:57 PM
pntrbl
Re: New to little bikes.

Just for old times sake I got a pair of Briggs flatheads sittin' on a shelf waiting for something. I dunno what, but they're still there.

BTW, is there any chance that a piston port and a reed valve CAG have the same motor mounts? Are they interchangeable?
06-20-2019 08:16 PM
CAM2
Re: New to little bikes.

Quote:
Originally Posted by pntrbl View Post
Personally I'm having some serious doubts about my math CAM. While at the races I found out those China Girl bike motors have a 4.1 to 1 primary reduction ratio. 20T on the crank and 82 on the clutch gear. A typical final ratio is a 10T counter with 40 something rear gear which means they're turning a 26" bicycle wheel with overall ratio's of something like16-17 to 1. My math had me thinking I was gonna need somewhere near 32! You warned me about that and were right to do so. Math is theoretical while seeing is believing.


On the motor front there are 2 classes that are all piston port CAG's. One is the Go-Quad class, think go-karts with funny little wheels. The other is Go-Peds, which are motorized scooters, and man do those little motors RIP! You don't need no stinkin' tach to tell the difference. Ears are enough .....


All pumper carbs too which is a new trick this old dog is gonna have to learn. My only experience with pumpers goes back 50 years to 5 horse Briggs flatheads. I was unimpressed with them then and hadn't seen anything to change my mind until I started hanging around here. But I can still learn.


I will be sticking with my reed valve CAG vs the piston port tho. I've already got the motor and pipe mounts done and when you realize how fussy I can be that's quite an accomplishment. It's a 10-15 y/o motor that got left out in the rain so I expect all I'll be using over are the cases, the HCC, and maybe the flywheel. I've also come to the realization that I'm gonna need more that one motor! LOL! I haven't built one yet and already I need two. Racetrack refugees don't work well on the street. Definitely gonna need one of each, but the price of admission is so small .... who cares?
Seeing is believing but experience trumps all........

Ive been building motorized bicycles of all sorts from an early age..Chainsaw engine powered skateboard wheeled wooden gocarts that can cruise on railroad tracks too....LOL

July 4th 1983 I took an old Schwinn StingRay that I just got done installing an 80cc alky powered western bend brand racekart engine that propelled jr racekarts to 75-80mph and put that thing to the test....Everybody who witnessed the run which ended with the rearwheel literally blowing apart swore I was hitting a hundred miles per hour also said I was lucky to be alive...My mom aged 10 years that day..LOL

Torque is a bigger factor over rpm's in 2 stroke engines.....The more extra boost ports you grind into a cag cylinder plus the more fuel you feed it the more torque you build...Windowing a piston adds torque too.....

I know how to build two strokers to where max torque falls off within 1000-2000rpm's off of the built engines redline whereas most regular engines the torque dropsoff at around 4500-5000rpm's on an engine that spins 7500-8000rpm's Im talking max torque on a built 2 stroker ending at 8,000-9000 rpm's of an engine that redlines at 9500-10,000rpm's

Some people know how to pull the torque out their builds so they can gear their stuff so low it seems impossible on paper but really isn't when you change the factors at work and not tell anybody...Kinda like a magician …;-even myself...

Like I stated in an earlier thread...I don't divulge all my secrets...…...LOL

This 5 post cylinder with windowed piston propelled a cag geared 7:1 to 53mph with my 160lb brother on it....On the engines first 5 port build where the engine was built just like the average joe would build it maxxed out at 49.3mph.....



I also convert snowblower engines into engines that rival engines they put in Jr Dragsters

When I was growing up there were tons of others with minibikes and gocarts with Briggs/techumseh flattop engines.....It was pretty embarrassing to them when theyre steel framed 5hp Brigg engines got smoked by a wooden framed gocart shaped like a dragster with 3.5hp flattop briggs….LOL

I guarantee youll judge the book by its cover by its looks on the mini minibike below....If you rode it though and peg the throttle wide open youd literally crap your pants when the frontwheel leaves the ground just as the powerbands starting to wind up and takes all of my 200lbs to put it back down....The lil 5hp flattop got the power of an 7.5-8hp engine and the red Manco converted to a drag minibike has a wickedly modified 4hp 2 stroke snowblower engine pushing about 12hp.........…..



Heres my racing version 5hp flattop....80mph racekart alky powered..Its been around literally forever...….LOL.

06-20-2019 02:04 PM
pntrbl
Re: New to little bikes.

Quote:
Originally Posted by CAM2 View Post
..I know you'll understand the math....

Personally I'm having some serious doubts about my math CAM. While at the races I found out those China Girl bike motors have a 4.1 to 1 primary reduction ratio. 20T on the crank and 82 on the clutch gear. A typical final ratio is a 10T counter with 40 something rear gear which means they're turning a 26" bicycle wheel with overall ratio's of something like16-17 to 1. My math had me thinking I was gonna need somewhere near 32! You warned me about that and were right to do so. Math is theoretical while seeing is believing.


On the motor front there are 2 classes that are all piston port CAG's. One is the Go-Quad class, think go-karts with funny little wheels. The other is Go-Peds, which are motorized scooters, and man do those little motors RIP! You don't need no stinkin' tach to tell the difference. Ears are enough .....


All pumper carbs too which is a new trick this old dog is gonna have to learn. My only experience with pumpers goes back 50 years to 5 horse Briggs flatheads. I was unimpressed with them then and hadn't seen anything to change my mind until I started hanging around here. But I can still learn.


I will be sticking with my reed valve CAG vs the piston port tho. I've already got the motor and pipe mounts done and when you realize how fussy I can be that's quite an accomplishment. It's a 10-15 y/o motor that got left out in the rain so I expect all I'll be using over are the cases, the HCC, and maybe the flywheel. I've also come to the realization that I'm gonna need more that one motor! LOL! I haven't built one yet and already I need two. Racetrack refugees don't work well on the street. Definitely gonna need one of each, but the price of admission is so small .... who cares?
06-20-2019 10:55 AM
CAM2
Re: New to little bikes.

Quote:
Originally Posted by MrKitty View Post
i agree those engines are junk the guy up the street is into them when he has them dialed in and the clutch is working ok its kind of fun but then he says stuff like be ready for it to lock up at any moment befor i take off for a ride and i know he is not kidding with all of the broken ones he has

kind of the opposite thing you tell somebody when i let them ride the cag
the way you ride this is you give it gas and stay on it dont let off all the way and gas it again and again let it have it
When I opened one up the first thing that came to my mind was the guy who designed this cheesiness was a moneymaking genius.....Kinda the same difference buying your silverware you eat with in the dollar store or Walmart.LOL

Im sure if the cag engines were designed solely for pocketbikes and not repurposed tool engines they'd be the same crude quality as those bike engine kits...…..

The counterweights on those engine cranks are screwed onto the crank journals with fragile potmetal screws............LOL

On the build I did I glued the crankweights to the journal plates with anerobic sealer and used better quality screws...….

Even this small 18cc weedeater engine I modded for one of my 24" long 60mph straight shafted balsawood hydroplane I built has a way better quality crank that can handle spinning 16-20k rpm's easily and its only 1 sided and very very similar to a nitro powered r/c engine especially with the aluminum rod.........LOL...…..



As you can see from the untouched topside you gotta hog it out real wide to get the real power.....



Everything cleaned up pretty well this trash treasure was a low hour engine where the old owner obviously couldnt rebuild or even easier just replace the carb...

Luckily for me I happened on it before the trashman...…..LOL



Viola and in the end result after working the porting magic on the cylinder you have whats known as a Baller on a Budget powerhouse sleeper deluxe...



Even the internal flex shaft gets repurposed as the propshaft…...
06-19-2019 06:58 PM
MrKitty i agree those engines are junk the guy up the street is into them when he has them dialed in and the clutch is working ok its kind of fun but then he says stuff like be ready for it to lock up at any moment befor i take off for a ride and i know he is not kidding with all of the broken ones he has

kind of the opposite thing you tell somebody when i let them ride the cag
the way you ride this is you give it gas and stay on it dont let off all the way and gas it again and again let it have it
06-19-2019 02:09 PM
CAM2
Re: New to little bikes.

Quote:
Originally Posted by MrKitty View Post
just be carfull you dont spank them to bad or they wont let you run it anymore lol

Giving those bike guys an eye-opener as to show them how theyre wasting theyre time , money and thoughts is much more fun to me especially when the competition starts dropping off in futility and disgust when theyre being shown bigger isn't always better......LOL

Its like drilling a hole in your competitors gastank before a race or giving them the true meaning of the phrase "whizzing up a rope with gusto and hope".........LOL

A lil oldschool 60's model 48cc Marinelli engine is the same size and design as those cheapie bike kits yet packs a way more powerful punch than those bike kits at I believe 4 stock 66cc kits combined to 1 48cc Marinelli or Ducati 48...LOL



Even an engine like this will clean the house , the clocktower and the dungeon before they even start cleaning the garage......LOL

Look at the torque rating...……...The engine is nothing but brute force torque throughout the max rpm band.....LOL

https://www.morinifrancousa.com/engine2.htm

Ive built a bunch of those Grubee SkyHawk brand bicycle engines and have built them in the power realm of the most potent ones sold or built by people like us who dedicate their time into their type of hobby but to me is 100% the absolute worst hobby engine to waste your time and money on unless youre looking for cheap mediocre mode of transport and happy at going 20-25mph......….



The absolute worst part about them is the modular crankshaft..Its too weak and flexes way too much...……...

Luckily for me it wasn't my money I was playing with and actually was making pretty good cash doing it for the rubes but it made them happy with the extra power...Little did they realize I could've smoked them badly on my 40cc Evil wasp cag with ease....LOL
06-19-2019 01:53 PM
CAM2
Re: New to little bikes.

Quote:
Originally Posted by MrKitty View Post
cag engines are surprisingly built way better then any of those bike engines. Those bike engines are purely built out of junk with unbelievable sloppy tolerances...
Those el cheapo bike engine kits are meant to break easily....I call them 4:1 engines.....It takes 4 of them to surpass the longevity of 1 good better quality built engine....

Its a good proposition if you manufacturing them and selling them to make a real profit...……..LOL

Cag engines are built way better because they are built for Industrial tools........Im quite sure you know that by now so therefore it will be built a lot better...


Did you know that the engine they put in the Blata 2.5 is a tool based engine?

Did you know that it was made by Subaru Robin and is model # NB-411....



I was quite disgusted when I smoked the engine on the Blata 2.5 and a friend of mine who was a lawn equipment engine specialist started laughing saying my expensive toy had a crappy auger/brushcutter engine in it then proved it to me............

Did you know that the chinese copied the same brand engine for their low buck reed inducted 2 stroke cag engines but a later built EC or EO series model but still shares the same crankshaft as the NB-351/NB-411?

Google up NB-411 crankshaft and see what pops up......LOL
06-19-2019 01:46 PM
MrKitty just be carfull you dont spank them to bad or they wont let you run it anymore lol
06-19-2019 01:19 PM
CAM2
Re: New to little bikes.

Quote:
Originally Posted by pntrbl View Post
Hey CAM, I'm learning myself how to make hubs. Got the front done with a hydraulic brake ready to go ...



Workin' on a rear.

I've also gotten infatuated with the idea of racing a motorized bike. There's some local SoCal nut jobs who do this on go kart tracks and after spectating at a couple of events I seem to fit right in!

The biggest class is those 66cc bike motors they call China Girls, and I'd love to spank 'em down the straights with a lil' CAG. Do ya think that's possible?
Looks pretty sweet......Im liking it...….Nice job...…….


Ill answer your question like this....I know you'll understand the math....


Those bicycle engines can only belt out a max of 8000 rpm's and the cheesy pickup coils on the ignition systems start dropping off at around 7800rpm's........

Cag engines can belt out up to 14,000rpm's and spin even higher if tuned on alky........


If you really want an engine that will get the job done Id go with a piston ported engine with 2pc headmod tuned on alky........Even a 1pc build will suit you....Those engines have lots and lots of torque down low and they can scream pretty high especially the 43cc builds...….







Another engine to mount would be a 39cc aircooled euro style knockoff...

They wouldn't touch you with a 25ft pole and you'd be owning them hardcore with an engine with almost half the cc's....LOL
06-17-2019 09:52 PM
EPR
Re: New to little bikes.

Oh yeah, forsure, so many ways to mod a Cag engine.
06-17-2019 04:34 PM
MrKitty cag engines are surprisingly built way better then any of those bike engines. Those bike engines are purely built out of junk with unbelievable sloppy tolerances...
06-17-2019 07:12 AM
pntrbl Hey CAM, I'm learning myself how to make hubs. Got the front done with a hydraulic brake ready to go ...



Workin' on a rear.

I've also gotten infatuated with the idea of racing a motorized bike. There's some local SoCal nut jobs who do this on go kart tracks and after spectating at a couple of events I seem to fit right in!

The biggest class is those 66cc bike motors they call China Girls, and I'd love to spank 'em down the straights with a lil' CAG. Do ya think that's possible?
06-16-2019 11:10 PM
EPR
Re: New to little bikes.

Dave's, one of my favorite shops, that is for fast scooters and maybe RC cars and trucks. I will post photos I'm on my tablet right now, lol.
06-16-2019 02:33 PM
MrKitty I found this thing for the piston ported engine http://www.davesmotors.com/trevor-si...reed-case.html
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