Polini 65 kitted e50, burnt piston?

Johnny Brapp /

So I slapped a kit on my maxi about 2 weeks ago and it’s been running alright. Still trying to dial the 19mm Delerto PHBG Race carb in. Upon inspection, looks like it really need some pointers before it seizes. Here’s the rundown on the bike:

64cc Polini Kit - Gasket Matched & Ported

Polini 2 petal reeds

Stuffed 44mm Treats Stroker Crank

Treats Race Clutch

HPI Inner Rotor

Homoet p6 race pipe

Delorto 19mm Race Carb - Clone

Choke: 60

Pilot/Idle: 45

Main: 99

Needle: W7 (2nd clip from top)

Atomizer: 262AU

Bike is decent, but getting on the pipe the bike is breaking up. If it does get on the pipe it runs awesome, 48mph 15x42 gearing. Idk if it’s fourstroking or what the breaking up is, mid throttle. But these pics aren’t to inviting... I don’t want to hurt the bike, any ideas?

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Re: Polini 65 kitted e50, burnt piston?

Wolf Wizard /

Looks like regular carbon buildup to me.

If it’s breaking up like it’s completely missing don’t rule out electrical.

If it’s more a rich 4 stroke noise where it goes Brbrbrbrbrbrbrbr like it’s missing every other stroke then try to move the needle clip up.

This will then position the needle further down into the atomizer, which means it takes more throttle pull till you get all of the gas from your main jet.

Needle controls not just how much, but also when you get your gas. If you want to lean out your mid range you have the get a needle with a thinner diameter. They are separate into class by tip diameter. Moving the needle down does not really make it any richer, you just get the gas sooner relative to throttle position.

This photo helped me a bunch. I wish it was complete and had every needle but these are common ones. Dellorto has a chart that lists the dimensions of all of em, but I like pictures

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(edited)

Re: Polini 65 kitted e50, burnt piston?

Johnny Brapp /

Yeah, I wasn’t sure if that was normal. But I guess so, to a degree. Thanks for sharing that needle chart. I cleaned my piston off, 95% of that came off with a PB Blaster & a rag/plastic scraper.

Also, I blocked the decompression hole, which I wasn’t aware was there until today. That along with installing the treats o ringed hi compression polini head, and it’s running even closer to 100%

I should’ve tried to video what is going on with it. I’m thinking it’s that needle, low end is great until about 1/2-3/4 throttle. If I let it kinda rev out while only about 1/3 throttle and then WOT it will get into the powerband and pull hard all the way to, right around 50mph which is up there in RPM.

But, if I just roll into the throttle, or crack it wide up under load it breaks up. Again, thanks for that diagram with needle info!

Re: Polini 65 kitted e50, burnt piston?

Overpriced Parts /

I run 264 atomizer 100 main jet and neutral needle position with k&n filter and estroil pipe but I run true rubberized 4 pedal insert in polini cage not crappy 2 pedal

I have ran 262 atomizer, 100 main but then I had to go one rich on the needle

You didn’t say if you we’re case matched, What air filter You’re running, what oil, what your head temps are,

The more info the better, and really if you’re only going 48mph with a expensive kit, head, pipe and carb really you could do that with a 69$ kit and a 14 mm Bing

Re: Polini 65 kitted e50, burnt piston?

Johnny Brapp /

First off, thank you for the input homie. I am cased matched, I’ll attach a pic of my porting. It’s my first kit so bare with me. Temps are under 390, with this horrible flashing trail tech I wasted money on. I am running the polini PHBG velocity stack as opposed to a filter. Plug is B6HS (can’t find BR6HS locally.) Fuel is 88 octane with Ams oil Saber at 70:1 for break in.

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Re: Polini 65 kitted e50, burnt piston?

Overpriced Parts /

That is the worst dremeling/porting of the intake I’ve ever seen in my life and you shouldn’t do any of that until the kit Well is broken in

70to1 is for a Weedwhacker, saber sucks over 50 to 1on a real engine, you should go with a 8 range plug,

I can’t believe counting the HPI you probably spent near 700$ plus to get 48mph !

I almost wish all these people Like you that were spending way too much money to make their bikes go marginally faster lived close to me,

Polini kit, intake that compression with stock un rebuilt bottom end, polini kit, free maxi head, 14$ metal mesh filter 15mm bing mm carb, estroil pipe, Tomos reed plate, thick kickstart springs, 17×38 gearing,

Video was many years ago and I rode the bike yesterday and it even went faster after all these years, it stills hit Ps near 60 mph withgreattake off and still has the 40 year old original clutch!

Man so many people are wasting so much money! I don’t understand why people go with HPI, high rpm pipes, Big carburetors, polini cage, race cranks and all that crap to go 48mph, I don’t have none of that, Come over and you’ll see I’m telling the truth

Re: Polini 65 kitted e50, burnt piston?

Johnny Brapp /

You do understand my limitation besides minor tuning is brakes, gearing and suspension at this point, right?

It’s a 70mph bike all day.

Run 15x42 then let’s see you blast me (edited)

Re: Polini 65 kitted e50, burnt piston?

> Johnny Brapp Wrote:

> -------------------------------------------------------

> It’s a 70mph bike all day.

>

lol

Re: Polini 65 kitted e50, burnt piston?

Johnny Brapp /

Honestly, I built the bike this far without a single question asked. I’m not sure why I’m being mocked for trying to sort out tuning. Sure maybe 70 is the high end of the spectrum, but why not aim high? Money isnt the issue here, so save that shit. I just bought a 4 bearing e50, straight cut gears, stroker crank and a gila kit for another bike I have sitting here.

Oh well, guess I’ll figure it out myself. Thanks for the tips, I’ll run with the little bit of info I’ve received. Thanks, I guess

Re: Polini 65 kitted e50, burnt piston?

Aiming for a "70mph all day" bike is not the same as actually having one (unless it's a Tomos in NJ.) The gulf between a 50mph moped and a 70mph moped is vast. A reliable daily 70mph bike? Ok prove it.

Don't worry about Ken tho. He's set in his ways. He has a good point but it's pretty much the only point and he tends to make it on every thread so don't take it personally.

Also... fast parts don't always mean fast bikes, as decades of forum posts here can attest to. (edited)

Re: Polini 65 kitted e50, burnt piston?

Johnny Brapp /

Yeah I completely understand that, 70mph honestly was never my goal. I am already tickled pink with my 40mph bar hopper. Im at the point where if I want to I can gear down. I’m just looking for real advice on how to perfect this build so it’s happy. Happy bike = happy me. Sorry for snapping out, but this thread was never about why did I spend x$ and only go xMPH

Next round on me, cheers!

Ps; where’s that e50 on 15x42 gears that’s gonna blast me at? (edited)

Re: Polini 65 kitted e50, burnt piston?

Based on that carbon buildup I'd stop running such a rich premix and maybe go one hotter on the plug? After checking the needle adjustment mentioned above of course. Once change at a time :)

Re: Polini 65 kitted e50, burnt piston?

Johnny Brapp /

Gracias amigo! I have dominator out in the shop. Would you recommend that over the saber? I was going to run the saber at 90:1 per some stuff I read through the forum/wiki about polinis and how synthetic oils burn hotter than gas, which makes running less oil favorable

Re: Polini 65 kitted e50, burnt piston?

Johnny Brapp /

Double post, delete

Re: Polini 65 kitted e50, burnt piston?

Johnny Brapp /

> Overpriced Parts Wrote:

> -------------------------------------------------------

>

> Polini kit, intake that compression with stock un rebuilt bottom end,

> polini kit, free maxi head, 14$ metal mesh filter 15mm bing mm carb,

> estroil pipe, Tomos reed plate, thick kickstart springs, 17×38 gearing,

>

>

> Video was many years ago and I rode the bike yesterday and it even went

> faster after all these years, it stills hit Ps near 60 mph withgreattake

> off and still has the 40 year old original clutch!

>

Lol, sorry chief. But my bike is a 100% different animal than that. If I was running your gearing you would see my nothing but blue smoke and my tail light.that bike has no hit... NOTHING... talk about snoozefest. Stock brakes yet? Fuck that, have fun but that isn’t what I’m after, at all. Lol also, that video is old as all get out.... can’t u build anything faster? (edited)

Re: Polini 65 kitted e50, burnt piston?

The carbon on the piston like that is no bueno, it's not running right. It's good you stopped before blowing it up. Either your timing is too advanced, too rich, your case seal is sucking in oil, or your squish isn't setup right

I like to run my polinis hot hot so they'll will build up some black carbon on the piston face but it's thin and dry, when you are seeing that thick wet oily deposit it's either because you are running too much oil or the tune is off.

Do you have a head temp gauge? Probably a good idea.

Re: Polini 65 kitted e50, burnt piston?

Wesley Ambrosini /

Your temp gauge flickers because you aren't using a resistor plug.

Re: Polini 65 kitted e50, burnt piston?

Johnny Brapp /

Again, where’s that 15x42 bike that’s going to blast me?

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Re: Polini 65 kitted e50, burnt piston?

Johnny Brapp /

> Wesley Ambrosini Wrote:

> -------------------------------------------------------

> Your temp gauge flickers because you aren't using a resistor plug.

Yeah, I gotta get around to ordering one. No parts stores around me seem to stock them. Half the knuckle heads behind the counter at the parts stores look at me like I’m crazy when I start asking for iridium NGKs or even the resistor “bR” plugs

Re: Polini 65 kitted e50, burnt piston?

> Johnny Brapp Wrote:

> -------------------------------------------------------

> > Wesley Ambrosini Wrote:

>

> > -------------------------------------------------------

>

> > Your temp gauge flickers because you aren't using a resistor plug.

>

> Yeah, I gotta get around to ordering one. No parts stores around me seem

> to stock them. Half the knuckle heads behind the counter at the parts

> stores look at me like I’m crazy when I start asking for iridium NGKs or

> even the resistor “bR” plugs

If you want to see some dumbfounded looks , ask them to order some Ruthenium HX plugs from NGK . ;)

Re: Polini 65 kitted e50, burnt piston?

Brandon Weiss (Detective brandon to you) /

> Johnny Brapp Wrote:

> -------------------------------------------------------

> Again, where’s that 15x42 bike that’s going to blast me?

57mph? Didn't you say it was 48mph? That'd mean you're turning almost 13,000rpms, pretty bold claim for someone in your position, and is unheard of with "slapped on" un-ported cylinders, even polini. Post some video!

Re: Polini 65 kitted e50, burnt piston?

Johnny Brapp /

> Brandon Weiss (Detective brandon to you) Wrote:

> -------------------------------------------------------

> > Johnny Brapp Wrote:

>

> > -------------------------------------------------------

>

> > Again, where’s that 15x42 bike that’s going to blast me?

>

> 57mph? Didn't you say it was 48mph? That'd mean you're turning almost

> 13,000rpms, pretty bold claim for someone in your position, and is

> unheard of with "slapped on" un-ported cylinders, even polini. Post some

> video!

I was still braking it in, hadn’t really pushed it much into the big end. Tomorrow is supposed to be decent. Let’s see if I seize it.

Re: Polini 65 kitted e50, burnt piston?

Johnny Brapp /

This was a more flat of a grade, not as long as either. 15x42 gearing.

Who was the one who said I had the worst porting ever seen? Lol

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Re: Polini 65 kitted e50, burnt piston?

All your screenshots prove is that you have gps on your phone.

Re: Polini 65 kitted e50, burnt piston?

Johnny Brapp /

> Bas Autowas Wrote:

> -------------------------------------------------------

> All your screenshots prove is that you have gps on your phone.

Well, that’s news to me! I wasn’t aware I had anything to prove in the first place.

Re: Polini 65 kitted e50, burnt piston?

It sure seems like you have something to prove, but you mainly look very butthurt.

Re: Polini 65 kitted e50, burnt piston?

You don't have to prove anything. But if you claim you have a fast ass moped we'd all like to see it. Nobody is actively hating on you or your build, just we're a sceptical crowd here at Moped Army.

If in fact your bike does rip, we wanna know how you did it. Think of it as tough love.

Re: Polini 65 kitted e50, burnt piston?

It's entertaining , at least . ;)

Re: Polini 65 kitted e50, burnt piston?

Maybe he's from NJ where all mopeds go 60+ mph

Re: Polini 65 kitted e50, burnt piston?

Matt Mahloch -- MBM Customs /

That’s some weird goo looking stuff on the piston. The wash looks good but the substance we weird.

I run saber at 80:1 and swear by it despite what anyone says. I’ve seized countless kits on other oils but that saber is a magical snake oil.

If you’re gently rolling of the throttle I’d speculate you’re hearing a lean condition as you get in the pipe. Very common with a single speed kitted bike with a pipe. Try moving the needle so it’s richer. It’s trial and error. It’s progressive tuning. Once you get that better and the kit broke in and start going wide open to adjust your main you’ll have to come back and adjust your needle more.

Trial and error, just try stuff and watch the temp.

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