Author Topic: Top End--when to do it??,  (Read 2051 times)

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Offline billygoat500

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Top End--when to do it??,
« on: June 06, 2006, 06:15:30 PM »
My Hunny is a 2000
I got'er two years ago. She was minty, mint, mint except for some road rash on the rad shroud (some chump bit the dirt and sold her, wuss)
I think it most likley sat in the showroom for the first couple years of its life.
I still keep her mint (shes my hunny)

Anyway, She's never had new rings.
I don't ride wide open, like the sand and ice guys,all the time.
I used to mix at 40:1, now 50:1. Bel-Ray synthetic oil.
Up untill a week ago she has always been jetted stock (very fat at 3900 feet)
Now she's jetted: 165 main,2 turns, stock slow jet, needle at #2 pos.(still needs leaner pilot)

When should I do a top end re-build? The engine seems to be in minty shape.
Has gobs of compresion still. Had a look at the piston through intake and exhaust and not a mark on it. I looked through the spark plug hole with my boroscope and it looks mint in there.

Should a guy ho likes low end power increase compression when he does the re-build.

This site rocks, thanks for all the help.
Do to the fact that the hunny is not in production. It is my job to keep this piece of history in mint shape.SO HELP ME GOD

Offline hughes

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Re: Top End--when to do it??,
« Reply #1 on: June 07, 2006, 07:14:18 AM »
Even with good compression it's always a good idea to teardown to fully inspect the bore and piston. The top ends on these things are tuff. Clean air filters and good oil and the top end will last for many years. Gasket are cheap. I would teardown once a year for inspection. Look for any polished marks on the piston and cylinder walls. might want to check ring end gap or just replace them. Most pistons will show wear on the intake and exhaust sides. The piston is being forced into this side of the bore.(with rotation of the crank with rod the piston is loaded into the intake side on the compression stroke and then it is loaded into the exhaust side on exhaust stroke.)
Open Class 2-Stroke Kawasaki KX500
Yamaha 2005 YZ250
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Offline Timbowe

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Re: Top End--when to do it??,
« Reply #2 on: June 07, 2006, 08:26:22 PM »
Good call there Hughes. Peace of mind is a wonderfull thing.
KX500
Weapon in the hands of the Master

Offline 5dracing

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Re: Top End--when to do it??,
« Reply #3 on: June 09, 2006, 12:55:53 AM »
Compression tests help in knowing when to do a top. Get a baseline and check it every ten or so hours. I got my bike with 175psi compression and as of January of this year it was still very close to the same number. The bike only got about 15 hours on it last year. I am pretty sure mine has the cometic thin gasket for more compression. I've done 2 different tests, one cold with oil to help sealing and one at normal running temp. The 2 are very different. When cold using the oil to help seal compression is very good, mine came in over 200 psi. Warm the compression was 175psi.

Just my 2 cents worth!
The torch has been passed; Father to Son. He is faster!!!