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I've had several people ask me why I didn't get a "safer" cruiser style bike. I explained I just don't feel in control sitting on my tailbone with my feet way out in front. Inevitably, they say I must be wrong, because so many more people are killed on sport bikes. They just won't factor in age and stupidity. I'm sure there are lots of folks who do just fine on cruisers, but I learned to ride in the dirt>In other words, ride the front wheel. At 59, I don't think I want to re- learn everything...
Off topic to this thread, but I'd have to agree... aside from the fact that typical off road riding involves a fair amount of "weight on the foot pegs and butt off the seat", the seated off road riding position is pretty close to that of riding a sport bike. The cruiser riding position is very different, more like that of driving a car, or sitting back in a Lazy-Boy recliner. After all these years of riding Off Road & Dual Sport bikes, I don't think I could ever get comfortable with the ergonomics of a cruiser... it just looks uncomfortable and a little scary to me.
 

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I'd say that 99% of the owners on cbr250.net wont even wear out the stock tyres before dropping it, saying its a lemon, and then selling at a huge loss and moving on to their first big boy bike.....

all on finance of course lol.
I own my cbr250r bought new in May last year, tyres are almost worn, never been dropped and still looks like it just came off the showroom floor due to maintenance and cleaning. ;-)

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Yeah, it's really not that important.
I sense some sarcasm there. When I get the time I may attempt it, if the valves are out of spec, do you notice when riding (rough idle or other factors)? Bike is still running smooth like when I first bought it.

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Some guys, on a CBR indian FB page, are well over 50/60 000. the road conditions there are let say, hard for a small bike, very hot, dusty.... and they seem to go on and on and on... At the end it is a Honda NO?

Diffrerent bike, but a friend of mine has a Vmax 1988 with 220 000kil, so.... take care of her she will take care of you
 

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I have run every bike i have owned to redline,
and have not had a engine failure since 1977,
When every comp. changed to 4 stroke.
I ran a 77 gs550/4 to redline for 20yrs!
 

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Some guys, on a CBR indian FB page, are well over 50/60 000. the road conditions there are let say, hard for a small bike, very hot, dusty.... and they seem to go on and on and on... At the end it is a Honda NO?

Diffrerent bike, but a friend of mine has a Vmax 1988 with 220 000kil, so.... take care of her she will take care of you
I had an 86 V-max, bought it brand new, sold it with 105,000 miles ( touring miles mostly ) on the clock, never had to fix anything, never had a servicing done on it, did all my own oil changes. The guy that bought it took it straight to a shop to have the valves checked, all still within factory specs.
 

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I've had several people ask me why I didn't get a "safer" cruiser style bike. I explained I just don't feel in control sitting on my tailbone with my feet way out in front. Inevitably, they say I must be wrong, because so many more people are killed on sport bikes. They just won't factor in age and stupidity. I'm sure there are lots of folks who do just fine on cruisers, but I learned to ride in the dirt>In other words, ride the front wheel. At 59, I don't think I want to re- learn everything...
Agree with Phil 100%. I've had cruisers before and never got used to the tailbone thing along with arms stretched way out to the bars. I started with dirt bikes and dual purpose bikes and prefer the upright riding position. The 2nd brand new bike I bought was a Honda 750 Nighthawk, now I see the CB1000 has been out and very much the same. Even the Harley Sportsters are upright. Whatever floats your boat...
 

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Ino it's an old thread, but I figured this is the most relevant place to post my questions.

I have replaced the top end twice due to piston knocking, at ~15k miles and ~30kmiles (at a shop), and I am preparing to do another top end rebuild myself (first time) with about ~50k miles on her. I've taken everything apart and the piston has a thick deposit of carbon on it, the cylinder has wear from knocking, the combustion side of the head is pretty toast, and the camshaft lobes are worn.

I purchased over $750 in tools and parts for this job a few days ago, which should ship out today. The day after I purchased these, I was talking to my uncle about my progress with the rebuild and he asked me how many miles I had on her now, to which I replied about 50,000. In his normal, confident manner, he says to me that it's time to replace the transmission. This hit me deep in the stomach, especially for what I just dropped on the top end. However, I have not yet taken what he said as truth, partly because I am a skeptic but also because he doesn't work with motorcycles (although he is mechanically proficient). The transmission is a big piece of the engine and has many working components.

I did some research on the internet and came up with a few crumbs regarding roller bearing failure in the transmission. I will keep searching, but I am looking for something more concrete. My questions: is there long-interval maintenance that should be done on a transmission? Are there symptoms that I should look out for that can prevent total failure? Or should I just break her open and follow my trusty Service Manual through the inspection process?

My bike's history: on it's third top end, oil&filter changed b/t 4k and 8k miles every time, followed proper chain maintenance, dropped a few times but all impact occurred on frame sliders, popped maybe 15 wheelies with probably same number of clutchless shifts over time...hehe. I follow the maintenance intervals very well. I am hoping for some educated advice, preferably from those who have worked on motorcycle transmissions before. Thanks in advance!

I am also open to discussions about the top end diagnosis as well. The honda service tech I frequent mentioned that it IS one piston going at 7k-8k rpms for thousands of miles. It makes sense that the rings lose their seal over constant, high friction. Another possibility could be the gasoline: either the different suppliers or the percentage ethanol. I was initially a dedicated chevron buyer, then with the first top end work, I switched to Shell. With the second top end work, the carbon deposit and the damage seemed much worse, so I switched back. My riding didn't change much between these intervals, but it's still pretty inconclusive.

Okay, that's all.
 

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I have replaced the top end twice due to piston knocking, at ~15k miles and ~30kmiles (at a shop), and I am preparing to do another top end rebuild myself (first time) with about ~50k miles on her. I've taken everything apart and the piston has a thick deposit of carbon on it, the cylinder has wear from knocking, the combustion side of the head is pretty toast, and the camshaft lobes are worn.
I'm no expert but all of this doesn't sound right. I believe that the knocking is from the carbon build up. The carbon is increasing the height of the piston giving it a higher compression ratio. But there shouldn't be that much build up. What I want to know is what kind of riding do you do? A lot of city riding at low RPM's can contribute to carbon building up. Also lugging the engine can do the same. I noticed that you also have an after market pipe. Do you have it tuned at all or stock map? If it running rich carbon with definitely start to form. Also how often do get up near red line and ring her out?

It just doesn't seem right to me. When I did my valve adjustment at 12,000 I looked in through the spark plug hole and my piston looked basically spotless.
 

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Thanks for the reply. That must have felt nice to peek at your piston and see that.

The carbon is increasing the height of the piston giving it a higher compression ratio
Interesting point. But wouldn't the CR be lower with carbon build up? A deposit layer would add to the top of the piston and decrease the stroke from bottom dead center to top dead center? ...also not an expert haha


What kind of riding do you do? A lot of city riding at low RPM's can contribute to carbon building up
How does low RPM contribute to carbon build up? My riding style has been very dynamic throughout my ownership...I've done a lot of city riding where I shift a lot, but I also have done a lot of weekend riding in the hills, but in all cases I usually ride her +75%. I redline fairly frequently. I also got back from and 8000 mile trip about 3000 miles ago (last September) where I cruised at avg 8500 rpm.

Hahaha, I need to update my mod list; I got rid of that sucker a while ago. It was annoyingly loud to me. I reset the ECU after I put it on and after I re-replaced it with the stock pipe
 

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Interesting point. But wouldn't the CR be lower with carbon build up? A deposit layer would add to the top of the piston and decrease the stroke from bottom dead center to top dead center? ...also not an expert haha
No; the stroke doesn't change due to carbon build up. The stroke will remain the same as the carbon is simply lengthening the "rod" (consisting of the piston and connecting rod), not changing the distance it travels. But, since the combustion chamber is sealed, adding material to the top of the piston reduces the volume inside the combustion chamber, generating more pressure when the piston comes up to compress the fuel and air mixture. Too much pressure, predetonation/pinging happens.


How does low RPM contribute to carbon build up? My riding style has been very dynamic throughout my ownership...I've done a lot of city riding where I shift a lot, but I also have done a lot of weekend riding in the hills, but in all cases I usually ride her +75%. I redline fairly frequently. I also got back from and 8000 mile trip about 3000 miles ago (last September) where I cruised at avg 8500 rpm.

Hahaha, I need to update my mod list; I got rid of that sucker a while ago. It was annoyingly loud to me. I reset the ECU after I put it on and after I re-replaced it with the stock pipe
Low RPM exclusive riding doesn't allow the combustion chamber to experience full pressures and stresses, full operating temperature, and also the engine turns at a slower speed. Therefore, it's more difficult for the combustion chamber to "self-clean" if it's not rung out occasionally.
 

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Schroeder, have you taken a look at your piston?
No, I'm not much of a mechanic. I had my bike serviced at a Honda dealer and they said everything was ok (they changed the spark plug though at 16.000 miles even though I think that wasn't necessary). The bike runs great like on day one.
 

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No; the stroke doesn't change due to carbon build up. The stroke will remain the same as the carbon is simply lengthening the "rod" (consisting of the piston and connecting rod), not changing the distance it travels. But, since the combustion chamber is sealed, adding material to the top of the piston reduces the volume inside the combustion chamber, generating more pressure when the piston comes up to compress the fuel and air mixture. Too much pressure, predetonation/pinging happens.
Ahh, I get it; the intake of fuel/air is mapped for a certain volume, therefore decreasing that volume increases pressure, predetonation, etc.


Low RPM exclusive riding doesn't allow the combustion chamber to experience full pressures and stresses, full operating temperature, and also the engine turns at a slower speed. Therefore, it's more difficult for the combustion chamber to "self-clean" if it's not rung out occasionally.
So high heat and high presure help "clean out" the combustion chamber by utilizing intake as efficiently as possible, which would in turn maximize exhaust volume?

Thanks for your insight. Do you have any thoughts on transmission maintenance for this bike, like inspection intervals?
 

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No, I'm not much of a mechanic. I had my bike serviced at a Honda dealer and they said everything was ok (they changed the spark plug though at 16.000 miles even though I think that wasn't necessary). The bike runs great like on day one.
That's great. How many miles do you have on it now?
 

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I just noticed that I had a calculation error on my side. The plug was changed at the 24,000km service which is just ~14,900 miles, not 16,000. I have now ~26,700 km which is ~ 16,590 miles.
Okay cool. I think your next valve check is around 50km, probably 48000km. Have them take a peek next time if its easy. Although by the sound of it, that won't be for another 24000km. Hahaha the imperial system is such ********************. I just spent a month in Northern Europe and was loving all the kilometers and liters. It's sad to be back in that regard
 
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