How many miles?

How many miles can one reasonably expect to get out of a small 4 stroke such as the ones in the gy-5? Assume that break-in is done properly and oil is changed regularly.

[katoranger]

Fatboy is over 10K. I think about 20K would be a reasonable life expectancy if maintained well.

I don't know if oversized pistons and rings are available yet for top end replacement.

My yamaha xt200 suffered a trans failure at 4600miles so my lifan with 4200 is about to pass it up.

Allen

[Q]

It would be nice to know how many miles these bikes are going in other countries where they have been around longer.

Some bikes last a long time. I put 170,000 miles on a Vespa and over 100,000 miles on a Honda CX500, which is still running great. I'm planning on putting over 10,000 miles on the Lifan next summer in addition to the 1600 I have on it already. As long as parts are available, they should last indefinitely.

Q

[katoranger]

I should be to about 10K by July.

Are you asking how long before rebuild? or How long until a new bike is needed?

Allen

I was just wondering because I'm fairly new to motorcycling (well its been 20 odd years since I've owned one) and am curious if the engines wear out quicker because they are higher revving. I know one thing, I'll be riding the wheels off mine this spring/summer, hopefully it is up to the task.

[Q]

High revving doesn't necessarily mean shorter engine life, and these engines turn pretty slow compared to many other motorcycle engines. Even though the tach shows a redline of something like 10,500, I doubt you could ever get it that high except in neutral. They run out of power at about 8000.

Q

Originally Posted by zapkin

I was just wondering because I'm fairly new to motorcycling (well its been 20 odd years since I've owned one) and am curious if the engines wear out quicker because they are higher revving. I know one thing, I'll be riding the wheels off mine this spring/summer, hopefully it is up to the task.

i guess my newbieness is showing. i had no idea motorcycle engines could last as long as they do. i just naturally assumed they wear out quickly, in fact I was just in a conversation the other day about this very thing and now it appears that I totally stuck my foot in my mouth. Oh well, I guess to live is to learn.

[fatboy250]

Originally Posted by zapkin

How many miles can one reasonably expect to get out of a small 4 stroke such as the ones in the gy-5? Assume that break-in is done properly and oil is changed regularly.

To be honest, I believe my engines (push rod and OHC) will outlast every other part of the the motorcycles. So, if you're only worried about the engine, you should be fine for at least 20k. Some here haven't been so lucky because of gaskets or trannys. I'm only speaking from my experience with about 12k on the OHC that I have. The push rod only has about 1k on it now. Both have exceeded my initial expectations. I would like to go 36k before I'm finally done with my first one.

Jason

I can understand why a gasket failure would be an issue, but what do trannys have to do with it? Are they like gremlins?

[fatboy250]

No but if you let one ride yours, your bike will probably come back later and try to tell you all these years that it's been a sport bike trapped inside a dirt bike's body and it's about time to let the outside match what's on the inside....

[HardlyDangerous]

The biggest causes of premature engine wear/failure are.

#1 mineral based engine oils and incorrect fuel octane levels.
#2 incorrect jetting spark plug heat range.
#3 piss poor air filters

Starting with #1. Head gaskets can leak over time because of carbon build up and increase uneven combustion pressures. Incorrect fuel octane levels can also cause problems. Too low and the engine suffers from detonation and pre-ignition, too high and the engine will build up carbon deposits that can increase combustion and uneven combustion pressures. Not to mention carbon deposits create hot spots in the combustion chamber that also promotes detonation. Run only the octane high enough to eliminate knocking usually around 89 octane for all conditions/loads. One other often-overlooked issue is proper torque specs. Over time with the stress of heat and combustion pressures fasteners will need to be re-torque. This should be done shortly after break in and during each valve inspection. Other seals and gaskets can leak over time because of gum and varnish deposits that prevent oil from lubricating these seals and gaskets, they dry out and start to leak or in cases like the counter shaft seals grit and sand wear they seals and cause premature wear. Keeping the engine clean will help eliminate some leaks and show signs of early leaks.
Valves, rings, cylinders and bearings all wear due to friction and heat. Using top quality synthetic oil will reduce friction and heat and greatly prolong engine performance. Non mineral based synthetic oils contain no by products that break down easily with heat to form sludge/gum/varnish deposits or carbon so it keeps the engine clean and super lubricated and running cooler. Most synthetics also have lower pour points and higher oil migration so cold start engine wear is also greatly reduced if not eliminated.
The best thing for your engine is to switch to a pure synthetic oil once the engine is broken in. Not only will it greatly reduce engine wear and friction but also help the engine run cooler and perform better MUCH longer then a conventional oil will. You can tell when you engine is fully broken in because the compression level with reach a max level and not go any higher.

#2 incorrect jetting and incorrect spark plug heat range... it's all about keeping the engine running cool and efficient. If the jetting is too lean the engine will run overly hot and possibly cause detonation and pre-ignition not to mention add stress and wear on vital engine components suck as the valves. Too rich and the cylinder are washed from excessive fuel and you increase premature ring wear not to mention build up carbon and causes the engine to run too cool. Jet it properly and the engine will run strong and problem free. As for the spark plug, make sure you are running the correct gap and heat range. A spark plug works like a heat exchanger and removes heat from the combustion chamber (spark plugs to not create heat) too cold of a spark plug and the spark plug will not be able to self clean quickly and will foul easily and cause the engine to misfire. Too hot of a spark plug heat range and not enough heat will be removed from the combustion chamber causing over heating and pre-ignition.
#3 crappy air filters, most of these Chinese bikes come with crappy K&N style air filters that are only good for filtering out small birds and animals. So much dirt and grit can get through these chap filter medias not to mention around the poor seal. All of this dust and grit is sucked right into the engine causing a lot of wear and damage. The first thing everyone should do is replace these filters with a decent foam filter and oil it well using a proper foam air filter oil. Uni and twin air make great filters that will filter out even the finest dust and prevent any premature wear.

Now all that said I have seen some very high mileage bikes in my days working as a mechanic and even have a few of my own with over 70,000km. Some of the older air cooled 4 stroke engines like the Honda XL/XR engines, Yamaha TT/TTR engines seem to go forever when properly maintain while others using cheap oils and scrimping on the maintenance barely get 10,000miles. Look after it as I have said and you should easily get 50,000+ miles as I have.

[Q]

You have 50,000 miles on your China bike? That's pretty darn good.

Q

Originally Posted by HardlyDangerous

Look after it as I have said and you should easily get 50,000+ miles as I have.

[HardlyDangerous]

No not on my own china bike,
Yamaha XT, Honda XL, CM/CMX all have had more then 50,000miles
Then again the engines in my China bikes are Japanese design/specs (Loncin)
My CM200 has 70,00km and still has nearly perfect compression and has never needed the valves adjusted. I ran this bike back and forth to Kenora, basically WOT for 3 days strait each time.
I sold my XL185 with over 60,00km.

The question was
"How many miles can one reasonably expect to get out of a small 4 stroke such as the ones in the gy-5"

It depends on the state of tune and how well you maintain it.
eliminate stress, friction and heat and the engine will last thousands more miles then the ones that have not.

I have a couple customers with small air cooled and water cooled single cylinder engines with over 80,00km
such as a DR250, NX250, KLR650 XL350
One person in my motor cycle club put nearly 20,000 km and 2 sets of tires on his CB125 this year alone. He sold his gas suckin' talon for the cheapest NEW street bike he could find to commute back and forth everyday from Fort Erie to Toronto. This little bike runs at 95-110kph all day everyday on the major highways (401-QEW) By this time next year he will have doubled that mileage+

I have personally seen MANY enduro bikes from the late 70's up to the 80's with more then 50,000 miles. It's rare to see these new china bikes with these kinds of miles because not to many people ride a small bike that often and they have not been out long enough. Give it a few years an people will start seing it more and more with gas prices the way they are and how affordable these bikes are and how much more reliable they are.

[jdnva]

well i don't know about miles but I am currently just under 28000km's on my gy-2 so thats like roughly 17 000 miles? still running fine and i ride it hard almost always, I do allot of maintenance though

Hey Hardly just wanted to thank you for the detailed response. I reckon I have a lot to learn, but it will be fun in the process.