ring end gap

All Engine, Clutch, Chains, and Sprockets Stuff Here.
Post Reply
User avatar
other
Posts: 338
Joined: January 25th, 2010, 5:11 am
Location: Perth Hills, Western Australia

ring end gap

Post by other »

Dumb question time . . . . Brand new stock jug 89.0 bore, brand new stock cast piston, brand new standard rings . . . . wash the Honda honey off the bore, slip the rings in with the slug so they sit square, end gaps measure 19 and 20 thou. . . . . is this about right ? I know there was a formula that stipulated the end gap as a percentage of bore circumference, but I'm buggered if I can find it ! Just want to make sure this engine is as safe as possible. Any opinions ?
o.t.h.e.r . . . . .Over The Hill Enduro Rider
User avatar
Roostius_Maximus
Site Admin
Posts: 4641
Joined: November 16th, 2007, 3:24 pm
Location: Mt Nebo, Manitoba, Canada
Contact:

Post by Roostius_Maximus »

I'd have looked for .018", go with the .019"

have you measured that cylinder to see that its skirt is proper size?
User avatar
other
Posts: 338
Joined: January 25th, 2010, 5:11 am
Location: Perth Hills, Western Australia

Post by other »

ring end gaps measure the same top and bottom, so yeah, it seems pretty parallel. exhaust bridge is relieved too, so it seems ok to bolt up ?
o.t.h.e.r . . . . .Over The Hill Enduro Rider
User avatar
iggys-amsoil
Posts: 3602
Joined: June 1st, 2007, 6:09 pm
Location: Just North of March Airfield CA

Post by iggys-amsoil »

This is one thing that piss' me off sometimes.

The end gap in the manuel says .018-.020 max. I think there is a minium of .014?

I have yet to see an end gap of less than .018 with a fresh bore and rings.
Trinity Racing mild porting FMF
62 pilot, EGH needle, 172 main
03 Gen III CR250 frame

2013 Dodger Charger 5.7 Hemi

http://www.prisonplanet.com

Your Amsoil Customer # 350882
abrracing
Posts: 25
Joined: August 18th, 2013, 5:19 am

Re: ring end gap

Post by abrracing »

other wrote:Dumb question time . . . . Brand new stock jug 89.0 bore, brand new stock cast piston, brand new standard rings . . . . wash the Honda honey off the bore, slip the rings in with the slug so they sit square, end gaps measure 19 and 20 thou. . . . . is this about right ? I know there was a formula that stipulated the end gap as a percentage of bore circumference, but I'm buggered if I can find it ! Just want to make sure this engine is as safe as possible. Any opinions ?
I know the formula for a forged piston is usually .004" for every inch of bore.. for cast i'd just use the same... can't hurt... i've took a kx125 engine apart for a customer that had a ring end gap of .020" and it ran fine.. lol thats no joke.
User avatar
AlisoBob
"Hoon-father"
Posts: 15404
Joined: May 31st, 2007, 6:39 pm
Location: Aliso Viejo Ca

Post by AlisoBob »

If the rings ever butt, its all over. Go with ther bigger gap.
scooter5002
Posts: 425
Joined: July 31st, 2010, 5:22 am
Location: Tillsonburg On

Post by scooter5002 »

Roosty measured my end gap last summer at his shop when we were changing a couple of gears out in the trans. .050. That's right. 50 thou. Slammed it back together in June and rode it out to the end of the season. Fuck it, it's a Honda. It's bulletproof. Lol
User avatar
other
Posts: 338
Joined: January 25th, 2010, 5:11 am
Location: Perth Hills, Western Australia

Post by other »

Agreed Scooter (and Bob ). Gap can be big, no drama, they just blow-by a bit. Gap's too small, they blow-UP a bit. That's was the one I was tryin' to avoid !
o.t.h.e.r . . . . .Over The Hill Enduro Rider
Post Reply