How often is "regular Maintenance" ?

[greenmonkey]

Ive asked this question before, but how often do you end up needing to put a topend on a 2-stroke, if your not racing it?

Ive never had to replace anything on my old 1980 2-stroke other than mabey tires, plugs, chains, sprockets.etc but thats common.
Now all i seem to hear is "replace, replace, replace, blah blah blah" but do the newer 2-stroke really run that much harder even if your easy with them?

 

[TRAIL]

depends on how much you ride and how hard you ride.

 

[JasonWho]

Different sized engines require different maintenance schedules. For example, an 80cc or 125cc MX bike can be revved higher than a KX500 for example. More revs = more wear.

When is the last time you checked your piston diameter, cylinder inner diameter and piston ring(s) end gaps?

 

[greenmonkey]

ive never checked them...
as long as it goes i dont feel the need
it runs fine for its age, although it acts almost like a 4-stroke but all the older 2-strokes ive rode are like that
by the way it is 80cc

 

[JasonWho]

"as long as it goes i dont feel the need"

That is not maintenance. That is just horrible. Why waste our time asking a question such as that when you won't do any maintenance anyway??

 

[uts]

You can look at it 2 ways. A lot of people are hell bent on replacing the top end all the time to prevent costly engine damage. But too many people do it way too often. If you are mechanically able you can strip it down and check it out, but if you are not it will cost a lot to pay a mechanic to do it for you. If you leave it and just ride it may go years and then blow up. Now you may have wrecked the bottom end as well and are up for a complete rebuild. But if you replaced the top end as often as others say you may have spent more money in the same time on top ends.(now I have confused myself)

Get a manual for your bike and strip it down. Take the piston assembly and cylinder to a shop and get them to do the specs. The instructions in the manuals are very easy to follow.

 

[greenmonkey]

I am mostly a four-stroke rider, as far as the trails go. I only ride my 2-stoke just around in the country and on what hills the tractor trails can bring me.
So maintenance on a four-stroke is all i know. With four-strokes you ride until somthing breaks or when you hear/feel a differnce and then fix it...
:think:
The reason i posted this message is because i want to buy a newer 2-stroke (80cc), but i dont want to have to spend $200 every other year just to put a new piston it.
And.. i was wondering if that was possible, so i am asking how often do most of you riders (not racers) have to do it?

i appriciate your replys everyone :worship:

 

[rickyd]

I do a top end on my bike once a year.. DOing a top end on a 80 should be much cheaper than $200 if you do it yourself.. A "rule of thumb" i use is, "if the bike takes a few kicks too start, the top end needs servicing"
RIck

 

[JasonWho]

"With four-strokes you ride until somthing breaks or when you hear/feel a differnce and then fix it..."

GD, get a clue.

 

[Someone]

"With four-strokes you ride until somthing breaks or when you hear/feel a differnce and then fix it..."

There's also another term relevant to your question, it's called "preventative maintenance".

 

[greenmonkey]

"GD, get a clue."


How often do you check your piston diameter in your chainsaw, or weedeater? Better yet your car.
Well if your normal you probably dont... you drive it until it makes noise, is slugish, or even worse dosent start, before you take a look.
I dont just wake up and go check out my alternator unless my car has trouble starting... I have a full time job and a family, so i dont just have all the time in the world to fix stuff, aside from rideing.
I am capable of checking the pistons and even replaceing them, but i never have to on my stuff... I have had the same chainsaw for 15 years and used it, at times, all day long (12hrs+). It still starts on the first or second pull...
i am asking how often do most of you riders (not racers) have to replace top end.etc on your bike

 

[JasonWho]

Can you please tell us what 1980 80cc 2 stroke you own so that we may gear our answer toward your bike? Is this a bike you ride or a child rides? It sounds like you have a family, but ride an 80cc bike. How tall are you?? How much do you weigh?? Most folks don't ride an 80cc bike is why I ask.

The point of taking the measurements on the ring end gaps, cylinder diameter and piston diameter is to know where they are at compared to the factory specification. For example: You buy a new trail bike and ride it for one year. At the end of the year, you take the top end apart and measure the parts. If the ring end gaps are close to half way worn out, then you know that at the end of the following year, it will be time for new rings. A common practice is to replace the rings, then next time replace the piston, piston pin, small end bearing, piston pin circlips and rings the next time. Different bikes have different maintenance time frames. I elieve the new four stroke 250cc MX bikes generally have a maintenance time frame of ring replacement after 15 hours at race pace. They are designed for high performance. Top fuel dragsters usually need to be rebuilt after every run down the track. Someone feel free to correct me on that, but I am close.

Like TRAIL said, it depends on how often you ride and how hard. You say you have a 1980 80cc bike. If it is on its original rings and piston, then we already know it isn't a MX bike seeing frequent action over 25 years. The piston, crankshaft, etc. would have broken by now, destroying the cylinder, maybe head and/or crnkcases, etc. All these are expensive parts. Some people want the best performance from their engines, some try to keep them from blowing up. I hope you are not about to try a big jump on your bike, because it WILL blow up with your non-maintenance style.

 

[greenmonkey]

I think it might be a CR...
all the labels are peeled off, hell it is probably older than 1980 and im too damn lazy to walk to out to my shed right now.
i know im not the 1st owner so im sure the top end has been changed at some point in time. I have no papers or even registration... it was just an old hillbilly trade i made.
And im 5'8 around 165 or 170. The whole reason i like 80cc it because they are light as hell and i can just pick it up and put it in my truck, or whatever. I do not want a 125cc...
Ive rode a new RM 125 and i have no need for such power or size other than to send myself to the hospital...
when you said "seeing frequent action over 25 years" I do not jump my bike or even ride it hard, i use my atv's for that. I am easy on it.
I am still debating if i should get new 80cc 2-stroke due to the "prevenative maintenance" required.
Please give me an idea on what it cost to replace the piston, piston pin, small end bearing, piston pin circlips and rings on a new 80cc, considering i do it myself?

 

[JasonWho]

After you decide which model you want, go to a place like www.denniskirk.com and see what is available for it. A piston kit is around $100 and a gasket sert is around $30. Just rings are around $30, so you would be looking at $60 to change rings, then next time $130 to change it all. If you hardly ever ride it and don't ride it hard, then it will probably be a once a year task on rings, then every other year for piston and all. As always, it depends on how often you ride and how hard.

 

[greenmonkey]

Okay

Can you or anyone tell me why you never have to do such maintenance on other small 2-strokes?
Mopeds go twenty+ years without needing a new topend... same with chainsaws.etc
Why is it now a requirement to aviod costly repair?
When i was young no one hardly ever changed topends on the old 2-strokes bikes?

 

[uts]

I totally agree with your points green monkey. If all these other 2 strokes like mowers and chainsaws go for years without any maintenence then why do motorbikes need so much. I am starting to believe it's all a money making scheme. I have done 100 hours on a 250 2 stroke, pulled it down and there was hardly any wear. Yet some guys will have an 02 model 2 strke and say that after 50 hours the piston fell apart. Maybe they didn't clean the air filter enough. This is the only real difference I can see. With dirt bikes you are always riding in dust so air filters need much more attention than mowers etc. Maybe it is because of the light weight alloys and stuff they use to make the pistons now. Maybe they wear quicker. One thing is for sure, anyone who replaces the top end as often as manufacturers say is being ripped off.

 

[JasonWho]

Hi, uts, which 250cc two stroke do you have?

A dirt bike runs at different loads than a weed trimmer or lawn mower, plus a lawn mower is not designed with performance in mind. If you want to talk chainsaws, ask the lumberjack competition people on ESPN how often they do maintenance on their chainsaws.

Also, what RPM does a lawn mower or weed trimmer run at? A modern 125cc motocrosser or 250 4 stroke runs at 11,000 I believe. I don't have a teach on my weed trimmer, but I don't think it is revving out that far.

 

[uts]

Hi Jasonwho,

you are right about the loads and rpm. I doubt a mower revs any where near as hard as a bike. I guess since these bikes are made for racing they are actually built to be rebuilt. Like say in the moto gp I am certain they would rebuild week in week out. Since most moto bikes are used for recreation and less for racing there is a clashing of worlds. I have a friend who races and does his top end every four hours or so. He says this is probably not necessary but even if he loses 5% power because of a small amount of wear this could lose him a race. Fair point. For rec riders who don't have that much cash, it's a trade off between regular top ends = $$$ and leave it until it breaks =$$$ but which = more $$$. Obviosly if performance drops then it's time.
I've always been unsure about this topic.
All that said, I replace the top end on my CR250 about every 75 hrs of use. Well I did it once after about 100 and next after about 75. Second time I didn't measure the specs(except the bore) I just replaced the lot. First time there was little wear. Maybe I just ride like a weener.

 

[greenmonkey]

i used chainsaw motor to build a go cart a few years back, so i tached it.
it idled at around 2,500 rpm and the clutch didnt fully lock until almost 3,500.
I estimate it probably ran, during use, at about 4,500+ rpm
now it may not run as fast but as far as loads go, household 2-strokes "other than mowers" often carry more load than your dirtbike, in comparesion to size. How often have you got in a situation where your wheel just didnt have the power to spin? Never, unless you try to take off in 6th gear right? It happens all the time with weedeaters, chainsaws and most of all, mopeds ...
I dont want to go overboard or off subject with the "chainsaw-weedeater" discussion it just a way of demonstrating how durable 2-stroke motors can be...
I belive it is the rpm not the load that wears the motors down so fast, bringing in the "built for performance topic"
I cant find any charts.etc on the rpm/power ratio of these newer 2-stroke motors. when does the powerband kick in?
Any way a better question is do they still make 2-strokes for the trails, like all the older 2-strokes? This is probably why they last much longer. I doubt they rev much higer than 6,500-7,000 tops unless you dont now how to shift....

 

[JasonWho]

If you want a two stroke trail bike, check into the Kawasaki KDX200 or 220R. Other trail bikes will be four stroke. If you get a bike with a mild engine, it should last longer because it won't rev as high, plus other factors. For those wanting maximum performance, they get to do maximum maintenance.

I assume your Honda CR80 will hit 10,000 RPM. A KDX200 trail bike will hit 9,000 and I think makes its most power around 8,000. You'll have to dig up some charts to check for sure. That is just as best I can remember.

 

[Someone]

I have a 2001 YZ 250. I ran the stock top-end until last winter, so I rode it 3 years on the stock top end. When I had the top end replaced and everything checked, the mechanic said it was still within specs, but was getting close to needing replaced. When I got the new top-end, I really didn't notice any more power or performance. But peace of mind is priceless.

I do my brakes pads and brake fluid 2-3 times a year. I let the air out of the forks, check, lube, adjust the chain, check tire pressure before each ride. I change oil, clean out airbox, and clean air filter after every other ride. About once a month I go over critical bolts/nuts and make sure they're still tight.

 

[greenmonkey]

That sounds more like it somone.
And the whole reason i want a 2-stroke, like i said before, is because they come in 80cc with alot of power. So the ONLY 2-stroke bike ill ever get will be an 80cc unless i get really good on it and decide to move on... Personally i favor 4-strokes, but then again im an ATV rider right now...
I guess ill learn as i go, huh...
one more question...
when jasonwho said that CR 80s will rev up to about 10,000 rpm , thats only if you make it.... I could probably get my old 2-stroke up that high for about 10 seconds steady before it would blow... Anyway i guess what im asking is im not going to have make one of these new 2-stroke wind-up that high to get a decent amount of power am I? Im not talking motocross but enough power to play with would be nice without goin past 8krpm on average. I know some high rpms are unavoidable when climbing and such but for the most part do you/anyone think this is possible?

 

[GREENBEAN]

How often have you got in a situation where your wheel just didnt have the power to spin? Never, unless you try to take off in 6th gear right? It happens all the time with weedeaters, chainsaws and most of all, mopeds ...

All those devices have a clutch which as you said doesnt let go till 3500... if the engine is running and the wheel is stopped then guess what the clutch is slipping.... In the sand it is a very great load to keep that tire spinning actually...

 

[greenmonkey]

the 3500 is for the chainsaw...
mopeds and weedeaters are very different...
mopeds clutchs are set low so you can take off without having to give it 1/4 the throttle...
and the MAJORITY of riders use dirt to ride on...
anyway i just wanted answers and reply to my Questions, not jackasses like you wanting to correct me.

 

[bpositive]

well i see it like this :
it's all how hard u work it --- and all about what you want out of it ----and for how long...
so figure that out then it will be easier for people to answer you

if you want low maintenence get a big bike so it doesn't work as hard..
i don't know how big you r but an 80cc 2 stroke is for a 75lb kid ....