2 Stroke Engine Durability

Wippenshox

Wippenshox

New Member
Said I have an engine parts supplier, and whenever my engine has problems I just buy and replace the part and get the engine running again. How many miles/kilometers will my engine last until I have to buy a new one (getting to a point where I can't fix it anymore)? I just want an approximate value.

I ask this because I'm going to buy a motorized bicycle to go to college and work and I will do approximately 40km/24mi a day.
If it lasts less than 13.000km/8.000mi I don't think it will worth it, because the engine would last just a few months.

I hope to get some posts from experienced owners.
Also, this is what I'm going to buy:

1297182965_1.jpg


It's from a brazilian factory/assembler.

Thanks in advance.
 
Well, starting with a running bike is a good start. Big problem is dependability. They can go bad right off or last thousands of miles, you just can't tell.

Use good air-cooled 2 stroke oil at 24:1 to start then after the first gallon switch to 32:1. 16:1 is just too much oil.

Get a 1/4 drive torque wrench. You need to torque the cylinder head 2-3 times after you get the bike. Keep a lookout for black oily stuff coming out from around the head. You can find torque values with a search here.

After you get the bike watch for loose nuts and bolts. The vibration can cause them to loosen and disappear. This means motor and bike.

Looks like a well made bike. Take proper care of it and it should last a long time :)

Oh, don't be suprised if that light dyno burns out in a hurry. They are not made to run at the speeds these bikes go. I'm going to be useing one also because I don't think the Morini motor I'll be useing has a generator circuit. What I'm thinking of doing is putting a larger diameter wheel on the dynamo to slow it down. I'm going to try twice the diameter to start.
 
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DaveC said:
Well, starting with a running bike is a good start. Big problem is dependability. They can go bad right off or last thousands of miles, you just can't tell.

Use good air-cooled 2 stroke oil at 24:1 to start then after the first gallon switch to 32:1. 16:1 is just too much oil.

Get a 1/4 drive torque wrench. You need to torque the cylinder head 2-3 times after you get the bike. Keep a lookout for black oily stuff coming out from around the head. You can find torque values with a search here.

After you get the bike watch for loose nuts and bolts. The vibration can cause them to loosen and disappear. This means motor and bike.

Looks like a well made bike. Take proper care of it and it should last a long time :)

Oh, don't be suprised if that light dyno burns out in a hurry. They are not made to run at the speeds these bikes go. I'm going to be useing one also because I don't think the Morini motor I'll be useing has a generator circuit. What I'm thinking of doing is putting a larger diameter wheel on the dynamo to slow it down. I'm going to try twice the diameter to start.
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Thanks for the tips. I have already done a lot of research on 2 stroke engine care. Also, Bicimoto, which sells the bike I shown above, sends all the instructions regarding everyday use, including engine break in and oil-gas ratio.

About the torque wrench, I was looking for it but I can't seem to find the right translation to my language, therefore I can't look for models. I know what it is, what it does and why it is important, but I just can't find it in my country. I'll try calling some big tool shops I know and see if they have something with a gauge that measures the torque of a bolt.

The dynamo light will be discarded when they burn. I'll try to not even get them with the bicycle when I buy it. I think the dynamo system is ugly, with inferior and weak lights. When you stop on a traffic light nobody will be able to see you, since the lights are off. I will install quality and very bright LED lights (from Cateye) and use them along with rechargeable batteries. For me, it's the best way to go, and those lights blink, which is way better than a static light.

What I'm really worried about is the time I have to buy a new engine, as I mentioned in my original post. I posted this same question on another forum and the admin said a well conserved engine will last over 6000km/3728mi easily. Another guy said most of them don't last more than 5000km/3100mi, which would be really bad for someone who is looking for heavy daily use. The admin said that even if the engines last little more than 6000km/3728mi it will worth it, because I won't have to pay taxes, registration, insurance and there is also the fuel economy, which easily pays a new engine. So I think this is the best deal I can think of.

Does Morini engines last much longer than the Chinese engines? I'm thinkin of importing one in the future, after I get my Chinese.
 
This one will work..As little as I use one I have one just like it.
VINTAGE INDESTRO SUPER TORQUE WRENCH INCH POUNDS 1/4 DR | eBay

For a better type...
NAPA 1/4" MICROMETER TORQUE WRENCH WITH CASE VERY NICE! | eBay

Brazil Govt Intervenes on $6.82 Per Gallon Gasoline Prices - Kenneth Rapoza - BRIC Breaker - Forbes
Americans might think they have it bad with gasoline approaching $4 per gallon nationwide. Last week, Brazilians paid an average of R$10.99 per gallon ($6.82) for gasoline, or R$2.91 per liter, according to the National Petroleum Agency.

1,000 miles at 40mpg x $6.82 = $170.50 . A car at 30mpg for those 1,000 miles=$227.. now add whatever paperwork is required.
 
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Thanks for the examples. I already had the idea what it looked like, but there is no way I would buy a small tool from another country. I was very busy today, so I didn't have the opportunity to call some shops and see if they had this tool. I'll do it tomorrow.

About the gas, yup, it's pretty expensive, but we don't seem to care too much. I mean, we complain and feel the price heavily on our pockets, but we are so accustomed to see everything so expensive that it becomes part of the culture. We then have to pay much more for everything than North America, Europe and Asia.

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I have a Volkswagen Saveiro Cross G5 1.6L (pictures above). It's a brazilian car. The fuel tank stores 55L/14,5 gallons, and it costs R$ 130.00/U$ 81.40 to make a complete fill, which lasts for 630km/391mi. I don't complain too much because my car is very economical, specially on highways. Very modern small 1.6L engine and very light car body, which makes the car fly when you need the power—believe me or not, I breaked even with a Hilux in a race. Now, back to the prices. What can be very irritating are taxes and other anual bills that every car has to pay in Brazil, and these are very, very expensive, mainly because our roads can't deal any more cars, so they make a lot harder to financially maintain a car and buy it (now you have to have half of the money in hands to buy a car, the other half you can parcel). How about that? Haha.
 
Ok. I discovered how the Torque Wrench is called here. With a literal translation to english, it's a "Torquimeter". Not that expensive, actually. But I checked some more professional models that are very salty on the price.

I gotta buy one anyway, so I'm doing it soon.
If anyone could add more about engine durability to this topic, I would be very pleased. What I would love to see here is some people saying they had over 20.000mi on a well cared 2T engine. If this is possible, I'm so gonna buy one 2T bike.
 
Save your money.
Only buy tools when you will need them.
You have backup transportation in the truck.
The reliability is a crap shoot.

Some fixes for common problems are here.
Classic Instructions for Building and Repairing Motorized Bicycle Engine Kits - Motorized Bicycle: Engine Kit Forum

Use blue threadlocker on everything you thread on. Or even superglue if nothing else is available.
Grease the front and rear wheel bearings as soon as you start to assemble your motorized bicycle.
Put tire liners in the tires.
Remove any front fender.

Double check the assembly.
Every day check the wheel nuts and the spokes, tire pressure before you ride.

You will save alot of money if everything works.
I go grocery shopping shopping with say $45.00 US Dollars.
The stores are about 15miles away I spend about 50 cents on fuel the rest buys goodies.

I prefer to heat cycle a new air cooled engine when I first start it up.
Start it.
Let it warm up without excessively racing the engine.
Shut it off and let it cool for about an hour.
Do this several times.
Now take it for the maiden voyage.
Varying the throttle and not going full speed.
Adjust as necessary.
Now go for it.
As the rings seat the engine power will rise.
Do not let it idle for longer than two minutes when stopped.
Do not close the throttle when going down hill. Pull in the clutch and coast down the hill.
It should last a long time.


Aey you buying a completed motorized bicycle, or building one?
 
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I've only had one HT fail and I feel it was my fault-overrevving it- which caused the cage on the wrist pin roller bearing fall apart. Replace this part with a quality bearing and use 1 oz of castor oil to 3 oz of synthetic oil (total is 32:1) and your engine should last a long time....don't forget to use an aftermarket airfitler...the stock ones are a joke.
 
Thank you so much for the tips, spad4me. I think I'm going to print your post, haha.

Yeah, the truck is very handy for a lot of things. Even better, if my engine fails 30km away from home I just call someone in my family and they come to pick me up (and the bike) with the GPS assistance. That way I would feel much safer when riding one of those for long distances.

About the front fender, I don't understand why I would have to remove it, since I'm definitely going to ride the bike in all weathers and the front fender avoids a littler water exposition on the engine.

The daily check on nuts and spokes will be done for sure, as on my regular bike I already check the tire pressure before every ride, always maintaining 45 PSI for little ground resistance.

I liked your tips about engine behaviour too, but you say we cannot leave the engine idle for more than 2 minutes. This is another thing I don't understand. Could it be because of overheating? Since the engine is air cooled and you aren't venting the engine when the bike is stopped. I ask that because Bicimoto, the factory that makes the bike I showed you in the beginning of this thread, says clearly in the manual to let the engine drink a whole thank on idle before riding it for the first time. If heat is problem, solving it is easy: domestic fan on the idling engine :D

About the buy, I'm probably going to buy the pre-assembled bike I shown above, the Bicimoto 80cc. It's the best in the country.

Skyliner70, what is an "HT fail"? I have never seen this HT anywhere except on forums. I'm sure it is not an engine suffix.
 
First why wouldn't buy a product from a foreign country...we do it all the time here. I have very good luck, with two exceptions. Both minor. Heck ...where do you think these engines come from?

Second "HT" is a name we refer to the Chinese 2 cycle in frame engine. "Happy Times"
 
Al.Fisherman said:
First why wouldn't buy a product from a foreign country...we do it all the time here. I have very good luck, with two exceptions. Both minor. Heck ...where do you think these engines come from?

Second "HT" is a name we refer to the Chinese 2 cycle in frame engine. "Happy Times"
Click to expand...

Thanks for the solve on the HT.

The difference here, in Brazil, is that you have to pay over 60% of taxes over the original price of the product, plus the expensive shipping price. It also takes months to get in our house and all this gives you a feel of low reliability of whether the product will get to your home or not.

So, we first do everything we can to find the product in the country, then we start to think about importing.
 
Wippenshox said:
Thanks for the solve on the HT.

The difference here, in Brazil, is that you have to pay over 60% of taxes over the original price of the product, plus the expensive shipping price. It also takes months to get in our house and all this gives you a feel of low reliability of whether the product will get to your home or not.

So, we first do everything we can to find the product in the country, then we start to think about importing.
Click to expand...

I wish we had a 60% import tax here in the United States. You think that the companies that took our jobs overseas would move back..it's not like we need the jobs..flg.

 
Wippenshox said:
About the front fender, I don't understand why I would have to remove it, since I'm definitely going to ride the bike in all weathers and the front fender avoids a littler water exposition on the engine.
Click to expand...

The reason a lot of members here say to remove it is because it poses a danger of being rattled loose and wrapping up in your front wheel, causing a wreck. If you take precautions and beef up the mount and upgrade the struts, they can be used with no problem. If the assembler takes this into account, and modifies it to withstand vibrations, then you're golden. If it is stock to the bicycle, and with only one strut and one mount holding it, I would modify it to be on the safe side.

There are some ideas on beefing up mounts on this forum, too, if you do a search you should find some good stuff...
 
Poopyboogin420 said:
Here's a good post on fenders...

http://motorbicycling.com/f11/fender-fixes-tip-bairdco-industries-14032.html

The guy that builds these bikes runs them at speeds of 50+ MPH. With fenders. Don't lose the fenders, just beef them up. They look great, and I am currently doing the mods that bairdco has suggested based on his rides...
Click to expand...
That's interesting. Thanks for sharing.


Poopyboogin420 said:
The reason a lot of members here say to remove it is because it poses a danger of being rattled loose and wrapping up in your front wheel, causing a wreck. If you take precautions and beef up the mount and upgrade the struts, they can be used with no problem. If the assembler takes this into account, and modifies it to withstand vibrations, then you're golden. If it is stock to the bicycle, and with only one strut and one mount holding it, I would modify it to be on the safe side.

There are some ideas on beefing up mounts on this forum, too, if you do a search you should find some good stuff...
Click to expand...
Thanks for clarifying. I'll be careful on this.

Diver said:
You don't need a torque wrench, just use a regular wrench. It's impossible to over-tighten the nuts 'cause they have CAPS. And the Lbs is like 10-12. Just tighten them and be done.
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I'm sorry, but I don't know what a cap is, mechanically speaking. But if you are talking about washers, sure, they could absorb some of the pressure by deforming, but still it is possible to damage the spiral pattern of a screw by applying too much pressure (if they are cheap), and specially the spiral pattern of the part being firmed (applies when there is no nut), which is aluminum on the engine body.

Also, could someone recommend me some really experienced forum members? You know, those guys that ride motorized bicycles for over 10 years. I would really like to ask them how much their engines usually last in terms of mileage.
If I PM them and get nice answers I'll come back here and share the info with all, speacially newbies like me.
 
Wippenshox said:
I'm sorry, but I don't know what a cap is, mechanically speaking. But if you are talking about washers, sure, they could absorb some of the pressure by deforming, but still it is possible to damage the spiral pattern of a screw by applying too much pressure (if they are cheap), and specially the spiral pattern of the part being firmed (applies when there is no nut), which is aluminum on the engine body
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DSCN3590.jpg


I'm just trying to be nice and imform you of the obvious, see these nuts have caps. You couldn't over-tighten them unless you were a gorilla on meth.

Buying a $60 tool you don't need-priceless.
 
I know it's sticking my neck out, on the global scene, but I agree with the Diver... A newbie doesn't need a $60 torque wrench for an HT maintenance kit.

Just a little hands on mentoring would be far more valuable in getting a suitable feel for how tight these nut's and bolts should be for most circumstances.

Chances are, they could strip out or pull threads even at proper torque settings.
Consistent metalurgy is just not one of the strong points here!

Good luck
rc
 
Diver said:
You don't need a torque wrench, just use a regular wrench. It's impossible to over-tighten the nuts 'cause they have CAPS. And the Lbs is like 10-12. Just tighten them and be done.
Click to expand...

This might be the worse advice ever given in one of these threads. Many times in what I'm sure is a cost cutting move the Chinese do not tap the holes all the way to the bottom. This leaves the threads sticking out further than designed. When you run those chump cap nuts down they can falsely bottom out. Keep reefing on them you will pull the threads right out of the block then you get to deal with that. One of the very first pieces of advice I read was to get rid of the cap screws and buy real hi-grade nuts. I bought the sick bike parts head stud kit, two sets to be exact. One in 6mm and one in M8 1.00 for 66 cc motors.

Telling someone not to use a torque wrench on a cylinder head flys in the face of over 200 YEARS of torquing heads down starting with steam engines and continues on to today. To the point of major motor manufactures use a torque device that torques ALL the nuts at the same time. Talk about an even pressure. Do it without a torque wrench and you have no idea in **** what torque you have at all.

$60? I said nothing about an S&K torque wrench. I bought my 1/4" beam type 25 years ago at a used tool shop for $7. They don't have to be exact, just have to read the same every time.

For a proper head gasket seal you don't just torque to the specified torque from the start, you go up in stages. I start the M8 nuts at 2.5 ft lbs and go up 2.5 lbs at a time until I reach 12.5 lbs. You also don't go in a circle around the head tightening the nuts. I use a "Z" pattern or you can also use a "X" pattern. Failure to do this can cause the gasket to leak. You will know it's leaking when black oily crud is coming out from under the head. Ignoring this will cause what is called "torching". The hot exhaust gasses will burn a groove or tunnel out of the cylinder, ruining the head or jug. The head can be saved by doing the glass & sandpaper routine. Torched cylinders are toast, you then need a new one.

After a motor has been run a bit you need to check the torques on the head. Do this when the motor is cold. Hot torques can vary wildly when rechecked cold.
 
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