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Piston and Cyl pics...
Posted: November 12th, 2011, 8:20 pm
by maddog1927
helping a friend with his 500. Top end has about 2 hrs on it. Reason for tear down is a shifting issue, but noted some marks on the piston and cylinder. Ring end gap is .016".
Any ideas on what caused this and how to correct. Some of the scratches in the piston are .005" or so. with eyes closed marks in cyl cannot be felt.

Posted: November 12th, 2011, 8:48 pm
by Gmbond
Intake side only??
Dirt ingestion past air filter or airboot seal??
Posted: November 12th, 2011, 8:49 pm
by AlisoBob
Throttle was hammered on without the engine being brought up to temp.
Who gasported the piston?
Posted: November 13th, 2011, 5:28 am
by maddog1927
AlisoBob wrote:
Who gasported the piston?
Jay Boren, a friend of mine in the phoenix east valley that does mostly banshee stuff.
Posted: November 13th, 2011, 7:02 pm
by 100hp honda
mine did same thing but got exh side also. main 1 step small was my final conclusion. not sure what happened on yours. chamfers look fine so i dont know
Posted: November 13th, 2011, 7:26 pm
by 100hp honda
dont try and be a hero at the dunes

. still aint got around to taking it fully apart yet. popped the head just to see what damage was done

Posted: November 13th, 2011, 7:35 pm
by britincali
Whats all the red shit?
Posted: November 13th, 2011, 7:39 pm
by 100hp honda
just grease. put it around the top and bolt the head on then put oil in the plug hole to get your compression ratio
Posted: November 13th, 2011, 8:43 pm
by AlisoBob
100hp honda wrote:I put oil in the plug hole to get your compression ratio
They just got this new fangled shit called MATH all figgered out.
You should check out that shit.....
Posted: November 13th, 2011, 8:53 pm
by 100hp honda
its always easy for people that never done it

.
ALOT faster to pour oil.... about 2 hours faster but thanks for your concearn on my math skills
Posted: November 13th, 2011, 9:02 pm
by 100hp honda
no point in making a 10min deal a 7hr head scratcher. alot of bullshit to figure it on paper. im not even sure how to do it. wouldnt you still have to pour something in the dome then subtract the amount the piston protrudes into it then figure was volume in in the headgasket bore and blah blah blah. ill stick with oil in the plug hole

Posted: November 13th, 2011, 9:04 pm
by AlisoBob
100hp honda wrote:....but thanks for your concearn on my math skills
[youtube]
http://www.youtube.com/watch?v=Pj3SIXtL ... e=youtu.be[/youtube]
Posted: November 13th, 2011, 9:06 pm
by 100hp honda
from start to finish i doubt the oil thing takes 10min. piston at tdc, smear grease, bolt on head, measure amount of oil poured in hole. divide that by your total cc. shazam dont get no easier than that

. watch and learn grasshopper

Posted: November 13th, 2011, 9:11 pm
by AlisoBob
I told you to buy the bore gauge.... so you have that right?
So measure the bore.
With that measurement, the distance from the roof of the exhaust port to the deck, the head gasket thickness, and the head volume you can compute the true compression ratio.
THEN, if you change ( or just want to run the numbers) on a new setup like a different head or exhaust port timing... you just punch the numbers into your calculations...
Its 2011 Clyde.
Posted: November 13th, 2011, 9:16 pm
by AlisoBob
100hp honda wrote:watch and learn grasshopper

The REAL FUCKING compression ratio starts when the exhaust port closes ..... grasshopper.
500cc of displacement, crammed into a 50cc chamber ISNT a 10:1 motor.
Ahhhhhhhhh.................. no.
If you think that, it explains ALLOT as to why your shit doesnt run...
Posted: November 13th, 2011, 10:00 pm
by 2strokeforever
With that measurement, the distance from the roof of the exhaust port to the deck, the head gasket thickness, and the head volume you can compute the true compression ratio.
and the dome shape on the top of the piston dosent matter?
500cc of displacement, crammed into a 50cc chamber ISNT a 10:1 motor.
that could depend on the pipe and rpm if you want to get technical, to figure out what exactly is going on in there is gonna be tough
Posted: November 13th, 2011, 10:08 pm
by AlisoBob
2strokeforever wrote:...and the dome shape on the top of the piston dosent matter?
No..... its a constant.
The displacement of the dome when the exhaust port closes is the same displacement at TDC
Posted: November 13th, 2011, 10:21 pm
by 2strokeforever
good point, i never even thought about that
Reason for tear down is a shifting issue
if it was put together and it didnt shift i would wonder if whoever put it together knew what they were doing
maybe he assembled it dry, without oil and the first time it ran it scored a little?
maybe crooked bore and/or tight piston
Posted: November 13th, 2011, 10:26 pm
by 100hp honda
if you want to spend your life doing shit the hard way then go ahead.

Posted: November 13th, 2011, 10:26 pm
by 100hp honda
Posted: November 13th, 2011, 10:31 pm
by AlisoBob
100hp honda wrote:if you want to spend your life doing shit the hard way then go ahead.

You and your buddy GSSlen are closer than you will ever admit.
Math is easier than smearing grease on everything .... but your too stupid to see that.
Thread hijack over.....
Posted: November 13th, 2011, 10:43 pm
by 100hp honda
by your method how do you propose to figure the head volume ? on paper ??????

at this point your kinda looking really dumb
Posted: November 14th, 2011, 1:04 am
by britincali
I just bolt my shit together and kick it.....
Posted: November 14th, 2011, 5:52 am
by Roostius_Maximus
Posted: November 14th, 2011, 7:17 am
by AlisoBob
100hp honda wrote: at this point your kinda looking really dumb
Can you even read?
AlisoBob wrote:...With that measurement, the distance from the roof of the exhaust port to the deck, the head gasket thickness, and the head volume you can compute the true compression ratio.
I'm starting to think Gsslen IS your Dad... Why dont you go on Springer, and have a "Baby-Daddy" test done?