More power mods/motors

noah9988

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Oh... and I wonder. If I use the solid piston... and it breaks... will Bicycle Engines cover the warranty or am I forced to use the inferior windowed piston to get said warranty? I probably should have inquired about that PRIOR to purchasing that chainsaw piston... but holy crap... if I can PREVENT issues by using it ...

...so tore.
1000% would not use the stock piston. The warranty states:
  • Damage resulting from the addition of parts or accessories not included with the original motorized bicycle kit or the use of non-OEM parts.
It says damage RESULTING FROM, so presumingly if you use an aftermarket part but it's not the cause of the failure, you can get the warranty. But this is going on some wordplay, and it might not be their intention.
 

Chainlube

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What motor should I get for my next build? I've been getting pk80s, they're pretty good, but how would a phantom 85 compare?
This is what I was thinking, the Zeda 80 is a fair engine in the balance department, so one of those with the wrist pin clips changed to inside circlips would make a sturdy engine.
 

Zac

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If you want speed, just get a minarelli.

I don't know what their reputation is and I don't want to get in trouble with damien, but southerncustomcc has a prebuilt minarelli with a preadapted mz65 pipe for $450. After what I've been through and wasting so much time on this junk I'd much rather spend the extra money on that minarelli.

(Venting ends)
What is a minarelli, and why are they getting popular? I have no clue what they are or how they make more power, would you mind explaining?
 

noah9988

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What is a minarelli, and why are they getting popular? I have no clue what they are or how they make more power, would you mind explaining?
Minarelli is an Italian motorcycle company. You can adapt a scooter cylinder, piston, and reed assembly from them and put it on a chinese bottom end. I don't know the exact differences but the cylinder design and porting is far superior compared to a stock cylinder. Unlike the phantom which has very good low and mid range power, minarellis are top end screamers that turn a lot of rpms, which is best suited for top speed.
 

Zac

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Minarelli is an Italian motorcycle company. You can adapt a scooter cylinder, piston, and reed assembly from them and put it on a chinese bottom end. I don't know the exact differences but the cylinder design and porting is far superior compared to a stock cylinder. Unlike the phantom which has very good low and mid range power, minarellis are top end screamers that turn a lot of rpms, which is best suited for top speed.
Where can I get a minarelli
 

ImpulseRocket89

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Minarelli builds are great for top end power but they don't compare well to a saw-cylinder based engine like the Phantom in regards to low end and mid range power. The transfer designs on saw cylinders and their port timing figures contribute to it. Don't be fooled into thinking a Phantom has no top end power though. My Phantom pulls all the way to 9000rpm without breaking a sweat. I haven't gone beyond that because I don't trust the bottom end to last even with my crank being balanced.

As far as your setup - you have a bunch of bolt on parts but nothing about that setup is optimized either. Port matching the transfers at the case and jug, roughing up the intake, carb setup, squish gap, and in my opinion getting rid of the cheap clone pipe - or at the very least correcting the flaws, The clone pipe headers are actually a decent length for the RPM range these engines run in but are generally too small in diameter for anything bigger than a 49cc engine all while the stinger tends to be too large for proper back pressure.

After that proper port timing and crank balancing would be the next step.
 

ImpulseRocket89

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Oh... and I wonder. If I use the solid piston... and it breaks... will Bicycle Engines cover the warranty or am I forced to use the inferior windowed piston to get said warranty? I probably should have inquired about that PRIOR to purchasing that chainsaw piston... but holy crap... if I can PREVENT issues by using it ...

...so tore.

1000% would not use the stock piston. The warranty states:
  • Damage resulting from the addition of parts or accessories not included with the original motorized bicycle kit or the use of non-OEM parts.
It says damage RESULTING FROM, so presumingly if you use an aftermarket part but it's not the cause of the failure, you can get the warranty. But this is going on some wordplay, and it might not be their intention.
The simple truth of the Phantom 85 is that you basically have to sacrifice the warranty in order to make it reliable enough to potentially not need to use the warranty. Kind of a catch 22. Or be one of the lucky people that gets one and it doesn't have problems... they do exist. All of it's other quality control issues aside the biggest flaw of the engine is the piston. I can't and won't trust one. Ever.
 

Sidewinder Jerry

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Minarelli builds are great for top end power but they don't compare well to a saw-cylinder based engine like the Phantom in regards to low end and mid range power. The transfer designs on saw cylinders and their port timing figures contribute to it. Don't be fooled into thinking a Phantom has no top end power though. My Phantom pulls all the way to 9000rpm without breaking a sweat. I haven't gone beyond that because I don't trust the bottom end to last even with my crank being balanced.

As far as your setup - you have a bunch of bolt on parts but nothing about that setup is optimized either. Port matching the transfers at the case and jug, roughing up the intake, carb setup, squish gap, and in my opinion getting rid of the cheap clone pipe - or at the very least correcting the flaws, The clone pipe headers are actually a decent length for the RPM range these engines run in but are generally too small in diameter for anything bigger than a 49cc engine all while the stinger tends to be too large for proper back pressure.

After that proper port timing and crank balancing would be the next step.
(9,000×26×π)÷(1,056×4.1×(32
÷10))=53.0600893371

(9,000×27.5×π)÷(1,056×4.1×(34
÷10))=52.8199984351

(9,000×29×π)÷(1,056×4.1×(36
÷10))=52.6065843

You'd need at least a 10/32 on 26" tires to break 50 mph

You'd need at least a 10/34 on 27.5 tires to break 50 mph

You need at least a 10/36 on 29" tires to break 50 mph

If you ran something like this using a fixed gear IGH transmission 10/20; 20/44 on 26" wheels you'd break 50 mph in the top gear. The big advantage is it wouldn't take several miles and a lot of pedal assist like it would with a single ratio of 10/32, to break 50 mph.

Speeds

First Gear
(9,000×26×π)÷(1,056×4.1×(4
÷3)×(20÷10)×(44÷20.))=28.9418669111

Second Gear
(9,000×26×π)÷(1,056×4.1×(20÷10)×(44÷20.))=
38.5891558815

Third Gear
(9,000×26×π)÷(1,056×4.1×(3
÷4)×(20÷10)×(44÷20.))=51.452207842

IGH Reductions

First Gear
24.05:1

Second Gear
18.04:1

Third Gear
13.53:1

Single Drive Ratio (10/32)
Reduction
13.12:1
 
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