BannedCR500Riders.com

How noisy is a cr500 motor supposed to be? the crank is tight, I just has the top end off. It DOES need bored (the bore has a few issues), but the piston is new and fits snugly in the bore. it has awesome compression, so I didnt see the point in rebuilding it yet, maybe next winter. But the more I ride it, the more I wonder.

My 250 engine is really noisy. Always has been, even with 100% fresh everything. From what people have said, they are knows to be a bit noisy.

So, my question is, how noisy should the 500 be? it isnt louder than the 250, but it isnt quieter either. The noises they make are just different.

check with the clutch IN, when the clutch is out it will rattle quite a bit

if everything is close to spec run the crap out of it

Most CR500's sound like cement mixers....

Vibration, and not sound, let you know if its healthy.....

The bike runs really smooth, vibes definitely arent any worse than my 250.

The spots in the bore I had mentioned are two goofy looking, but perfectly matched gouges about as wide as my finger, about a centimeter long. they are right above the exhaust ports, on either side of the bridge. They are causing blow-by streaks on the piston. Not to mention the stud streaks....

Almost seems like grinder marks, but other than the boost ports being touched up a little, the cylinder looks pretty virgin.

I guess I'll run it this year and see how she looks this winter. If it starts vibrating, I'll shut her down and get it done sooner.

I have those marks in my cylinder as well. Roosty will tell you what they are. He just did my top end and they are still there.

I believe those are OEM decompression divots. In every 500 cylinder Honda makes. They go away as you bore it. When they aren't there any more, you probably know that cylinder is getting closed to used up. They appear to be causing blow by because that's the earliest opening to the exhaust port with a concentrated flow point. Then it's full on exhaust port function. It's maybe also a de-tuning thing. No worries. BEAT ON IT!

Is the blow-by below the rings or right at them? Maybe your seal is going on your rings. I think you will have a heavier concentration right AT the rings, if memory serves.

NightBiker07 wrote:They are causing blow-by streaks on the piston.

They should pretty faint....

it is all the way down the side of the piston where those two divots are, nothing like what you have pictured there, Bob.

Yeah That's a good picture of the factory compression release slots/reliefs and how the blow by discolors the piston. They don't make much sense to me but I suppose to a smaller light weight rider it helps with starting the beast!

NightBiker07 wrote:it is all the way down the side of the piston where those two divots are, nothing like what you have pictured there, Bob.

Then you gots issues....

AlisoBob wrote:

NightBiker07 wrote:it is all the way down the side of the piston where those two divots are, nothing like what you have pictured there, Bob.

Then you gots issues....

I know the bore has issues. It DOES need a top end job. The stud-streaks told me that instantly. Everything fits tight, and it has wicked compression. The whole point of this thread was to see if I was safe to run it, and I believe I have my answer. Since the crank is tight, I am not too worried about it grenading. I was just unsure how much noise is normal for these.

Not sure how much of a hurry you are in, but get ahold of Adam. Send it up to his N. Dakota address, have him bore it with the torque plate on, and mail it back. Voila. A job you can count on with a Vertex piston. Live happily ever after. Fairy princess not included.

scooter5002 wrote:Not sure how much of a hurry you are in, but get ahold of Adam. Send it up to his N. Dakota address, have him bore it with the torque plate on, and mail it back. Voila. A job you can count on with a Vertex piston. Live happily ever after. Fairy princess not included.

I just got the thing back together, not gonna waste the gasket kit Plus, I have to practically pull the motor to get the jug off :/