Dyno testing 'performance mods'

[WillitBoost]

Hey guys! First post!

About 15yrs ago my girlfriend and I bolted on two of the cheapest 80cc kits we could find on eBay to two of the cheapest MTB's we could find at Kmart and decided to take them on a lap around Tasmania (Australia). A little over 1200km over 5 days, camping where we could. Surprisingly zero mechanical issues on our adventure though we really should have invested in some more comfortable seats....

We also had the opportunity to bring our bikes with us to work and rode them around a bunch of other countries, mostly Islands in the south pacific.

Fast forward 15yrs and we no longer have our bikes and laws in our state prohibit the riding of these bikes on public roads (pretty happy we went on our adventure when we did!) - But I do have a Chassis dyno in the shed, CNC milling machines, mig/tig welders and a background in electronics & engine tuning/modification/fabrication.

So! If you'd like to see real world dyno graphs of some of the most popular mods (I'm confident some of them will have absolutely no impact other than to your bank balance), I'd be happy to give them a test. I'll ask in the relevant forum sections what you'd like dyno tested and what engine kit I should invest in to do the testing. My IG channel is @WillitBoost but its mostly car stuff, until we get a kit to run on the dyno.

-Ben

 

[GW's Motorized]

You have got to Dino test a phantom for the people

 

[WillitBoost]

Just had a quick google on the phantom, looks to be a stock 80/100cc china motor with a very nice looking cylinder & reed block?

 

[GW's Motorized]

Just had a quick google on the phantom, looks to be a stock 80/100cc china motor with a very nice looking cylinder & reed block?

No. It's an engine based off the yd100 bottom end and a MS460 Stihl chainsaw clone jug. It is a true 85cc and is estimated a minimum of 5hp outta the box

 

[WillitBoost]

I just finished watching the review by LA Hover bikes. Looks like an interesting kit. His Wide Open Throttle pulls at the end were a bit of a disappointment after he spent 20min talking how it's so powerful it'll lift the front wheel off the ground. It didn't sound all that different from our old 80cc kit performance wise (just going off memory from way back when)

I'm really more interested in the potential gains from off the shelf and custom mods, rather than just buying the 'best' kit out there. I'd rather get the cheapest kit (or most popular) and put money into aftermarket CDI, carbs, reeds, cylinders, heads, porting, tuned exhaust etc. Once we know what is possible out of a bottom dollar china kit, then it might be worth comparing a phantom.

 

[DAMIEN1307]

This is the link to the Phantom 85 from where we buy it here in the states that also gives you its stats, along with a picture of one I took before putting it on my bike, as well as a pic of my bike with the motor on it...It also has an OZ type reed valve on the intake.

ZTMoto Phantom 85 V3 - Complete 52mm Bore 2 Stroke Motorized Bicycle Engine Kit - True 85cc Bike Motor

Your source for 2-Stroke and 4-Stroke Bicycle Engine Kits, Performance Parts, and Accessories!

www.bicycle-engines.com

 

[DAMIEN1307]

Once we know what is possible out of a bottom dollar china kit, then it might be worth comparing a phantom.

My Phantom went up to 51 MPH right out of the box using a 36 tooth rear sprocket without even trying before I chickened out...It still had left over throttle to go yet...I get that performance at a 4500 foot elevation in the high deserts of New Mexico USA.

You will pay much more with the bottom dollar China Girls when you add all the things it will need to even began to approach the torque and speed of one of these things using that modified chainsaw cloned one piece cylinders.

 

[WillitBoost]

Very nice build! A quick google shows no Aus distributors for that kit and with them being more or less illegal to ride in Australia, there aren't a lot of options beyond eBay/aliexpress.

It's probably been asked and answered, but why do they run the cylinder head in that orientation? Wouldn't 90deg rotated give better cooling?

and 51MPH / 80kph is pretty impressive. We'd cruise around at 65kph on the flat full throttle (40MPH) fully loaded up with camping gear, clothes and food. Using wind resistance calcs suggests you do infact need twice the wheel HP at 50MPH compared to 40.

 

[DAMIEN1307]

It's probably been asked and answered, but why do they run the cylinder head in that orientation? Wouldn't 90deg rotated give better cooling?

It's just how it's made I guess and you can't put it on the bottom end any other way than what it is because of intake and exhaust ports...lol.

 

[WillitBoost]

Fair enough. Wonder how hard it would be to mill the top off and fit an aftermarket head to it...