MOPED ARMY

this is why my go to build is an estoril, 15 bing 44mm or 45mm airsal kit. fast, easy and reliable. you can send them out in the world and they MIGHT not blow up immediately in the hands of a rando (edited)

Nice breakdown, the only thing I can't agree with is the boss pipe! Circuit pipe would be my first choice but on bikes that I don't want to look like they have a grody nutsack, proma GP or even the bullet seems to have a better power band.

I've never bought a clone 15 (that specific one from treats?) Do they have good enough tuning parts in them to run out of the box or do you end up replacing everything? I usually stick to the OEM 14 for that reason.

Sha or nah? I've been meaning to try one on my airsal, you know, for science, but I just can't bring myself to tear apart a rock solid 'perfect loaner' build and I'm sure I'd end up having to jack up the throttle cable which I find distasteful.

Proma circuit pipe will keep you below 8,500

are you running a stock cylinder head on both of your setups?

and you’re using the stock 2 ring piston that the kit comes with, too?

Prices seem reasonable to me.

Would it be worth it to sell prebuilt, bolt and go setups with all new hardware?

I’m not in the moped fixing business, I only build race bikes once a year, but I’m curious if selling someone a prebuilt would be less time and more profit (and smaller chance of issues).

any established shop is probably sitting on 5-10 e50s at this very moment. i’d put money on it.

and if not, they are truly dime a dozen.

I have 4-5 bottom ends sitting on a shelf including one or two clamshells.

There's also a rumor that aftermarket e50 cases might be coming soon...

I could see not pre-building motors because most of the customers would be like: “can I get the number 7, but like… with the number 2 crank and a go-fast piston instead?”

I think the part missing from most reliable builds is the precision. I would love a shop to be tooled up for balancing and alignment and sell me that.

If I buy a crank and kit, they could weigh the reciprocating mass and balance the crank for my horizontal engine. Spin the flywheel, clutch, and bell up to 12,000 rpm on a balancing machine and fix them to be perfect. Key the cylinder to the case somehow so the crank is perfectly centered and no lateral stress is on the con rod bearing for the cylinder being .5mm off to one side.

If all is built to it’s best possible, the limiting factor should be piston rings. At least that’s what I remember from Jennings.

All that said, it’s still probably best to build around that 8.5-10k rpm just for practicality. That’s the target rpm that lets you run a reasonable pipe for a clutch that grabs at survivable rpms. If I had to sell a customer on the idea of “8,500 rpm” I would approach it from the clutch and pipe perspective.

Heard they may be extra special too…. 🙄

i hope they actually work for regular e50 stuff and aren't just for case inducted scooter kits.

oh super cool! what have you deemed acceptable for run out in all 3 directions?

nah, you didn't come off as arrogant. in fact that a pretty neat way to check for how true something might be.

but if we are being 100 percent serious, even an errant mailman can set a crankshaft out of true.

I agree. I never knew how soft they were until I tried to true my own after that conrod swap. I probably pressed it in weird or something. But, to the point, it took very little force to make changes to the play on the end of the shaft.

Made me think twice about using a piston stop to torque on flywheels and clutches. I try to hold the parts now while torquing.

And that’s probably all the more reasoning to keep rpms lower? Because people will be working on their own motors even if they buy something. It wouldn’t be a good thing to build a super precision blueprint motor that can run 12k rpm for days and then the owner pops an impact on the crank nut the wrong direction for .25 seconds and ruins everything.

So, I like to try to gear tall at like 18X45 to get the speed from gear rather than from RPM.

BUT with Option A you kind of risk creating a situation where you never get into the pipe to pull the gear. Especially with a larger rider, so the hihi head helps you get off the line a bit quicker and helps avoid a situation where the bike just never hits.

With Option B you don't really need it, but since the bike will be limited in RPM (and heat) by the small stock carb and pipe; so why not give it the extra low end power.

With Option C, I actually usually run a stock head because the bike will already have plenty of power and the low comp head will make it easier to start and it will run cooler (for longevity on the fully kitted bike). I just left it in the bid comparison for consistency between them / to not over-complicate the comparison.

.... wait, were you just asking why I run a 50cc head with a 65cc kit? If so, because it's cheaper, always available, seals well, and does not cause any issues.

With standard 50cc & 70cc piston port kits I always run the corresponding sized cheap heads. With reed kits and/or with the larger kits I always run the heads specifically cut for them. The 65cc kits just don't have a good option and 50cc head works fine. (edited)