50cc 2stroke Lifespan

[macocoy]

How long does our two stroke last?(engine,pistons etc.)Is it true that 4 strokes last longer.?
I wonder what's the highest mileage/km a 2stroke has ever reach without changing pistons ,engine etc.

[scootermaven]

I know there are a lot of variables that would determine the longevity of either engine configuration.  I wonder if anyone has ever done a controlled test where the most important variables were the same to determine the results.  Surely someone has somewhere along the line.  I would like to hear my scooter mechanic Josh (a.k.a. "areomyst" on here) chime-in on this topic.

[axy]

How long does our two stroke last?(engine,pistons etc.)Is it true that 4 strokes last longer.?
I wonder what's the highest mileage/km a 2stroke has ever reach without changing pistons ,engine etc.

There is a large difference between "piston" (not "pistonS") and "engine".

Piston, rings and cylinder for air cooled 50 cc usually costs around 60-70 EUR. For water cooled, 110-120 EUR.
So, this cost is pretty much low, compared to everything else that may go wrong on the scoot, from suspension to crankshaft and many other things. Change of front disc and pads might easily cost roughly the same.

I consider piston+cylinder to be in a "mature" state after 20-25.000 kms, but they usually run well until the very last day when something goes very wrong and the little piston gets "bricked".

There are three things that every user can do to prolong their trouble free life:

- avoid overloading them and overheating during summer
- avoid going flat out for the first few minutes until little engine warms up (it is impossible to drive small 2 strokers below 5-6.000 rpms, but you do not have to rev it to 10.000 immediately...)
- use good quality semi synthetic oil and make sure that little oil pump is not clogged or that the belt is not snapped, if it is belt powered

[macocoy]

Thanks for replies,and being very specific(Axy),
So which 2stroke last longer(piston,crankshaft,cylinder etc.)?Modified or stock?I know what most people are thinking(stock r boring).I'm in the beginning of modifying my Sting/yup50.Just a curious question....

[axy]

Thanks for replies,and being very specific(Axy),
So which 2stroke last longer(piston,crankshaft,cylinder etc.)?Modified or stock?I know what most people are thinking(stock r boring).I'm in the beginning of modifying my Sting/yup50.Just a curious question....

All info I provided refers to STOCK engines.
If by "modified" you mean aftermarket cyl/piston kits, I have experience with Italian scooters and 72 cc kits.

The longest it worked properly was 10.000 kms, the shortest around 6.000 kms.

If you have stock kit for 20.000 kms, then install aftermarket 72 cc kit and it lasts 10.000 kms, the crankshaft is usually the next to go after 5.000 kms or so. OTOH, 2 stroke scoots rarely overall last for 30.000+ kms, they are either scrapped, used for parts, discarded or something like that...

Aftermarket 72 cc kits are usually of very poor quality and it is a guesswork trying to find a reputable source and long-lasting kit.

The real deal would be new kit + new performance crankshaft... however, performance crankshaft alone costs 250-300 EUR!
Performance exhaust that is a must is 250-300 EUR.

So it is really a game of numbers. If you take original value of new 50 cc 2 stroke scoot and add cost of new filter, carb, crankshaft, piston, rings, 72 cc cylinder and maybe pay for the work to be done, you have already exceeded the price of a good Taiwanese or Italian 125-150 cc 4stroke scoot.

[macocoy]

I didn't mean to say modify my engine ,I don't think I'll go that far,but basically thinking of expansion exhaust,aftermarket variators/clutch,maybe open airbox and bigger cylinder.most of the scooter here in the Philippines are 2stroke and they seem to last forever.

[grantourismo]

they re very reliable
my one been fitted 72 cc kit runs so well , just make sure everytime before fill up gas tank. put like two caps of 2 stroke oil
in side tank , it will be sweet. my last 14000 km before stolen today

[blue]

If you care for your scoot and dont do to many up grades to theam they well last a long time.If your the typ of person that has to do a lot of up grades and need the speed then you well shorten the life of the scoot. I have seen more scoots right out of the box last longer staying with all stock parts then the ones we all like to up grade.

[juice]

It seems to be generally accepted that ANY part that is not a stock replacement part is an upgrade on any powersport equipment . I like to think that the engineers and designers might have gotten it right occasonally . I suspect that a lot of money is wasted on "upgrades" that might actually be inferior to stock . JMO .

[Peters]

Granturismo, that sucks man. Sorry to hear your scoot was stolen. You gonna get another one?



I absolutely agree. A lot of research and development goes into automobiles, scooters/motorcycles, atvs, and watercraft.

We tend to ruin these things with all the aftermarket parts. Sure they may perform better in certain situations but not all around.

I love the people trying to sell a car or truck and think it's worth more $ because of all the aftermarket parts. It's stupid . If anything I think it's worth less money. I know the type of person that adds a lot of aftermarket parts. And I know not everybody that does tears them up but most do. Don't wanna piss anybody off on here . It's your ride you can do whatever you want with it.

I chose to put a few aftermarket parts on my scooter because I am a big dude and I like to keep up with traffic. Im not into racing or doing wheelies.

I think I pissed some people off when I bought my 4 wheeler and joined the Yamaha Blaster forum. I told them I wanted to keep it mostly stock and it was like I said something so horrible .

[macocoy]

Thanks for all replies,I just received the tecnigas next r for my kymco sting50,this question may not be related to topic but I'm just wondering do I have to upjet ?I'm leaving my stock airbox as is.my main jet right now is #75 .Would it be lean?

So Gran,was your bike oil injected?and adding capful of 2stroke oil in gas tank would be more protection?
I add 1oz of seafoam every tank hoping it will help more in lubrication and cleaning.I learned it here.

[Peters]

Yes you will have to upjet. You never never want to run it lean. Running lean will do a lot of damage. As I understand the fuel/oil mix actually cools and lubricates the cylinder and piston. Especially in a 2 stroke air cooled small engine. You can burn holes in the piston running it lean.

A 75 main jet is very small. You should be at least at an 85 main or higher. You'll probably need a 90 main or higher with the Tecnigas pipe. Do a search on this forum on doing a "plug chop" it will help you to find the right main jet size. Good luck

[macocoy]

Thanks Peters,as I remember you're running with stock air box right?I read one if your post liking stock airbox than aftermarket ,.
Some people here told me I should be fine with stock main jet if I don't change my stock airbox,and you're saying go atleast #85(confusing)But I guess plugchop will answer that for me?
Is it hard to upjet?can a regular guy do this?
When I upjet ,do I have to adjust idle mix?where is the screw for adjustment.

[Peters]

First off what scooter do you have? Is it 2 stroke?

Anytime you change to a less restrictive exhaust then you have to rejet. Doesn't have anything to do with the intake. Believe me or not.

Yes I run the stock air box. The aftermarket filter I bought was very cheap so I don't know if a name brand one would work better. Also it was very loud.

Changing out the jet is very simple. I didn't take the carb all the way out of my scooter. All I had to do is disconnect the air box duct, take off the throttle cable(screws off the top of the carb), pull off two small fuel lines, and remove the nuts holding the carb to the intake manifold. All you need is to be able to twist the carb sideways to remove the bowl from the bottom and there it is. Main jet is in the very center.

[macocoy]

Another helpful info peters,thanks.As I'm trying to build up courage to work on my own carb.I know a few people making mistakes on their carbs and didn't run the same again.when I change my main jet ,do I have to adjust any screws(idle,pilot/slow)?I see two screws on the side of my carb but not quite sure which is which,and how..my bike is sting50 2009 2stroke.Still didn't install my tecnigas next r(don't wanna run lean like u said.......