Slowing down a Maxi that's too fast for my son.

Jonathan Bennett /

I'm working on my son's Maxi to get it to a super quick but not too much top speed bike. At the moment it has a TCCD 50cc, 14mm Bing, Metal Mesh Filter, a Estoril Side Bleed and 15/36 gearing on it. Got it close on the tuning the other day and it clocked 43mph on a relatively flat road.

I rebuilt the engine but used the original crank, only 1000 miles on it, probably should have changed it out while I was in there, oh well...

The gear chart says that 43mph is 8000rpms. I'd really like to keep him around 35mph, which would mean changing out one of the gears to match the chart, say a 13/36 which would give 37mph at 8000rpms.

So my question is, does changing the gearing out run the risk of over revving the engine? Would my top rmp of 8000 go up because of the new gearing? Or is the top rpm regulated more by the cylinder/carb/intake/exhaust combo?

Re: Slowing down a Maxi that's too fast for my son.

Jack Rutherford /

why not just slightly over jet it?

Re: Slowing down a Maxi that's too fast for my son.

Put a stack of washers on the throttle cable between the slide and top of carb so that you only get 3/4 throttle. You can put more or less to adjust it where you want.

Re: Slowing down a Maxi that's too fast for my son.

put the stock air box back on it ¯\_(ツ)_/¯

it will be slower and a bunch quieter

Re: Slowing down a Maxi that's too fast for my son.

treat it like a pw50 and limit the throttle cable.

Re: Slowing down a Maxi that's too fast for my son.

Overpriced Parts /

Adjust throttle cable and or run 16x45 gears, that pipe will hold rpms back some, it’s not a real hi rpm pipe,

Or You can put your magnum XK set up on son’s bike with the stock magnum pipe, and you could put that TCCD set up with estoril pipe on your magnum so your bike is faster

Re: Slowing down a Maxi that's too fast for my son.

Megasaurass wRexckses /

Keep it how it is, it’s unsafe to be under powered, ya know. Tell him traffic situations and sometimes u gotta have a little extra.

It’s 35mph uphill tuning to keep up. Plus u don’t wanna have to wait to ride side by side, that puts u both at risk. Make it faster not slower.(edited)

Re: Slowing down a Maxi that's too fast for my son.

You should get a faster son

Re: Slowing down a Maxi that's too fast for my son.

Gearing is the best way to keep it from going too fast and it's something you would notice if he changed it back. just hide the old gears.

Re: Slowing down a Maxi that's too fast for my son.

Megasaurass wRexckses /

Hay Guise whinot titan tha BREAKS ? duhhhh

Re: Slowing down a Maxi that's too fast for my son.

Just run even lower gearing, lower gearing you can hit higher revs. I'd put an 11t on that shit and it should do 32.

Re: Slowing down a Maxi that's too fast for my son.

> Daniel '' Wrote:

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

> Just run even lower gearing, lower gearing you can hit higher revs. I'd

> put an 11t on that shit and it should do 32.

i doubt his stock crank would last long like that

Re: Slowing down a Maxi that's too fast for my son.

Jonathan Bennett /

Yeah, I guess the question is two fold.

How do you have a super quick bike with a low top speed?

What does changing the gearing do to the life of the engine/crank?

Ken, I might just be doing that and putting that stuff on my Magnum. I did just order a circuit pipe to put on this Maxi. You can't spin the Maxi's pedals with this pipe without bending/extending/changing to a magnum pedal setup and spacer.

We will see what the circuit pipe does. If it's still too high a top speed, then I might change the front sprocket.

Re: Slowing down a Maxi that's too fast for my son.

I've got almost same set up but with a proma GP on it and rito crank jammer clutch hitting 38 on stock 16x45 gearing

Re: Slowing down a Maxi that's too fast for my son.

Jonathan Bennett /

> Erik Thalman Wrote:

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

> I've got almost same set up but with a proma GP on it and rito crank

> jammer clutch hitting 38 on stock 16x45 gearing

Looks like about 8200 rpms. What's a safe number for a stock crank?

Re: Slowing down a Maxi that's too fast for my son.

***VANILLA BLUNDER*** /

> Dave & Bummerzz Wrote:

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

> put the stock air box back on it ¯\_(ツ)_/¯

>

> it will be slower and a bunch quieter

Stock pipe, boyeeeee

Re: Slowing down a Maxi that's too fast for my son.

Overpriced Parts /

> Jonathan Bennett Wrote:

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

> > Erik Thalman Wrote:

>

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

>

> > I've got almost same set up but with a proma GP on it and rito crank

>

> > jammer clutch hitting 38 on stock 16x45 gearing

>

> Looks like about 8200 rpms. What's a safe number for a stock crank?

Don’t really know what’s safe, many puch cranks don’t even have a needle bearings in the bottom big end of the crank con rod just a bushing and there is only two tiny little slots for oil/gas mix to get in there,

The only real safe rpm and horsepower is stock configuration,

Re: Slowing down a Maxi that's too fast for my son.

Richard Eberline /

Ken is correct, I have a few OEM cranks with brass on both ends. They are mean't for a stock set up or with a smaller pipe.

Re: Slowing down a Maxi that's too fast for my son.

Jonathan Bennett /

What’s the best crank? Rito? Super Stuffy? Unstuffed?

Re: Slowing down a Maxi that's too fast for my son.

> Buttcheeks BUZZARD Wrote:

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

> Put a stack of washers on the throttle cable between the slide and top

> of carb so that you only get 3/4 throttle. You can put more or less to

> adjust it where you want.

This is the best idea I have heard I. A while for restriction.

Re: Slowing down a Maxi that's too fast for my son.

Overpriced Parts /

> Jonathan Bennett Wrote:

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

> What’s the best crank? Rito? Super Stuffy? Unstuffed?

Rito because most times you can use your stock clutch bell shims, basically a true bolt on,

Re: Slowing down a Maxi that's too fast for my son.

Megasaurass wRexckses /

The most logical thing to do is ride on back and yell in his ear SLOW DOOWwNn!!!

Re: Slowing down a Maxi that's too fast for my son.

> Ana L. of the Aurora Roras Wrote:

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

> The most logical thing to do is ride on back and yell in his ear SLOW

> DOOWwNn!!!

As you're screaming with fear for your life . LOL

Re: Slowing down a Maxi that's too fast for my son.

> JBOT Admin Wrote:

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

> You should get a faster son

i mean, really, a lot of the people posting on here with 10's of 1000's of miles under our belts riding mopeds will all tell you that having more speed and power available is safer in almost all driving situations. If he isn't responsible enough to control the moped at 43, he isn't ready for a moped period.

he problem with not giving it full throttle pull is that you don't get the power and accel at low rpms. I've dealt with that on the kiddie dirtbikes.

i think you could keep the stock crank in it, yeah the RPMs are bad for them but most of the damage is from increased load and heat from a kit. The 50cc puch kits are barely more power than stock so a clean stock crank should last just about forever.

Re: Slowing down a Maxi that's too fast for my son.

How can I speed up my son?

Re: Slowing down a Maxi that's too fast for my son.

Wolf Wizard /

It’s only 8 mph. Make sure he wears a helmet and let him make mistakes. If you’re really nervous upgrade the brakes to give him better capability to be able to slow down and avoid obstacles.

Re: Slowing down a Maxi that's too fast for my son.

Overpriced Parts /

> Graham Motzing Wrote:

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>

>

> i mean, really, a lot of the people posting on here with 10's of 1000's

>

> i think you could keep the stock crank in it, yeah the RPMs are bad for

> them but most of the damage is from increased load and heat from a kit.

> The 50cc puch kits are barely more power than stock so a clean stock

> crank should last just about forever.

No that’s a fallacy, It is the rpm that’s mostly the problem,

Cranks do not last forever just because you’re running a 50cc kit not a 70cc kit unless you run stock rpm for some puch cranks don’t even have needle bearings at the bottom big end bearing and have only teeny tiny little oil grooves in con rod at big end so very little lube gets in to big end or to the sides of the big end of the Conrod unlike the small end of the rod because it has a oil hole,

This crank (which was low mi and in great shape to begin with) got the big end of con rod side friction welded to the crank lobes when upped the RPM to around 9,000 rpm but still running the stock 50cc cylinder, It ran good full synthetic motor oil and a heavy 50 to 1 mix more like a 45 to 1 mix,

I’ve had several puch stock crank lock ups when I upped the rpm and for me it was always the big end of the rod and always same thing: Rod was friction welded to the side of the lobes something like this:

Reed type kits/cylinders take a bigger jet and have a more gas oil in air mixture into the crankcase and you may be able to get a bit more RPM out of them if you want to try before they lock up but regular piston port kits run a smaller/leaner jet so there’s less gas in the air mix and less getting to the sides of the crank so rpms need to be kept down

Re: Slowing down a Maxi that's too fast for my son.

♣Slew Foot♣ /

> JBOT Admin Wrote:

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

> You should get a faster son

This has to go in the highlight reel...

Re: Slowing down a Maxi that's too fast for my son.

welp(edited)

Re: Slowing down a Maxi that's too fast for my son.

> Becca C. Wrote:

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> welp

So , you're disappointed ?

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