Reply
 
Thread Tools Search this Thread
 
Old 16 February 2013, 11:15   #1
Member
 
ajstars's Avatar
 
Country: UK - England
Town: Horley
Boat name: Pending!
Make: Cobra
Length: 7m +
Engine: 225hp Outboard
Join Date: Jul 2012
Posts: 401
Yamaha 5hp 5BS Piston Rings

Hi, so I have purchased some new Yamaha genuine piston rings for my Yamaha 5hp 5BS air cooled engine but I don't know which is which. One of the rings is green on the outer edge - is this the top ring or the bottom ring? I guess one is specifically for oil wiping?
__________________
ajstars is offline   Reply With Quote
Old 18 February 2013, 12:56   #2
Member
 
Country: UK - England
Town: wolverhampton
Boat name: bluefin
Make: picton
Length: 4m +
Engine: outboard
Join Date: Nov 2011
Posts: 137
Hi are they the same thickness?
__________________
steve66 is offline   Reply With Quote
Old 18 February 2013, 13:00   #3
Member
 
ajstars's Avatar
 
Country: UK - England
Town: Horley
Boat name: Pending!
Make: Cobra
Length: 7m +
Engine: 225hp Outboard
Join Date: Jul 2012
Posts: 401
They do look to be. It was only the colour/coating that I could see was different.
__________________
ajstars is offline   Reply With Quote
Old 18 February 2013, 13:01   #4
Member
 
ajstars's Avatar
 
Country: UK - England
Town: Horley
Boat name: Pending!
Make: Cobra
Length: 7m +
Engine: 225hp Outboard
Join Date: Jul 2012
Posts: 401
Yes I think so it was only the colour/coating that seems to differ -
Apologies double posted!
__________________
ajstars is offline   Reply With Quote
Old 18 February 2013, 13:46   #5
Member
 
Country: UK - England
Town: wolverhampton
Boat name: bluefin
Make: picton
Length: 4m +
Engine: outboard
Join Date: Nov 2011
Posts: 137
I wouldnt have thought it matters, being a 2 stroke and 100/1 they wont have a lot of oil to scrape.
Steve
__________________
steve66 is offline   Reply With Quote
Old 18 February 2013, 13:51   #6
Member
 
ajstars's Avatar
 
Country: UK - England
Town: Horley
Boat name: Pending!
Make: Cobra
Length: 7m +
Engine: 225hp Outboard
Join Date: Jul 2012
Posts: 401
Ok thanks. Is it worth getting it honed too prior to fitting? I can't see any physical wear though! I'm just hoping the problem was the rings! Problem was similar to that of a failed reed valve but it doesn't have one as its a three port design! Apparently exhaust coming out of air intake!
The old rings seem really loose around the piston.
__________________
ajstars is offline   Reply With Quote
Old 18 February 2013, 14:03   #7
Member
 
Country: UK - England
Town: wolverhampton
Boat name: bluefin
Make: picton
Length: 4m +
Engine: outboard
Join Date: Nov 2011
Posts: 137
I personally wouldnt. Your technically removing a little more of the cylinder. I would put them in rebuild it and run in at a minimum of 50/1. I think its absolutely suicidal running motors at 100/1 even though the manufacturer says its ok. You wont see a difference much of a difference between running 50/1 and 100/1
__________________
steve66 is offline   Reply With Quote
Old 18 February 2013, 14:15   #8
Member
 
ajstars's Avatar
 
Country: UK - England
Town: Horley
Boat name: Pending!
Make: Cobra
Length: 7m +
Engine: 225hp Outboard
Join Date: Jul 2012
Posts: 401
Ok thanks, I shall give it a shot - fingers crossed. Thanks for the help.
__________________
ajstars is offline   Reply With Quote
Old 18 February 2013, 15:44   #9
Member
 
Country: UK - England
Town: southampton
Boat name: hydradrive
Make: yamaha
Length: no boat
Engine: sterndrives
Join Date: Sep 2012
Posts: 290
Some rings have t1 and t2 writing on them.

T1 = 1 and facing upwards
T2 = 2 and facing upwards
Hope this helps
__________________
yam man is offline   Reply With Quote
Old 19 February 2013, 08:49   #10
Member
 
ajstars's Avatar
 
Country: UK - England
Town: Horley
Boat name: Pending!
Make: Cobra
Length: 7m +
Engine: 225hp Outboard
Join Date: Jul 2012
Posts: 401
1N and 2N are printed on my rings (good spot, thanks). The 1N is green whilst the 2N is the black ring. Any ideas?
__________________
ajstars is offline   Reply With Quote
Old 19 February 2013, 08:56   #11
Member
 
Country: UK - England
Town: southampton
Boat name: hydradrive
Make: yamaha
Length: no boat
Engine: sterndrives
Join Date: Sep 2012
Posts: 290
1n top and 2 n bottom writing facing crown of piston. Locate rings in piston lactate pins this so the rings won't spin a catch a port forward facing arrow pston to exhaust
__________________
yam man is offline   Reply With Quote
Old 19 February 2013, 08:57   #12
Member
 
Country: UK - England
Town: southampton
Boat name: hydradrive
Make: yamaha
Length: no boat
Engine: sterndrives
Join Date: Sep 2012
Posts: 290
# port
__________________
yam man is offline   Reply With Quote
Old 19 February 2013, 09:07   #13
Member
 
ajstars's Avatar
 
Country: UK - England
Town: Horley
Boat name: Pending!
Make: Cobra
Length: 7m +
Engine: 225hp Outboard
Join Date: Jul 2012
Posts: 401
Thankyou
__________________
ajstars is offline   Reply With Quote
Old 19 February 2013, 09:34   #14
Member
 
Country: UK - England
Town: wolverhampton
Boat name: bluefin
Make: picton
Length: 4m +
Engine: outboard
Join Date: Nov 2011
Posts: 137
Good advice Yam man
__________________
steve66 is offline   Reply With Quote
Old 19 February 2013, 18:12   #15
Member
 
ajstars's Avatar
 
Country: UK - England
Town: Horley
Boat name: Pending!
Make: Cobra
Length: 7m +
Engine: 225hp Outboard
Join Date: Jul 2012
Posts: 401
All working except it won't go above idle without stalling!
__________________
ajstars is offline   Reply With Quote
Old 19 February 2013, 18:17   #16
Member
 
Country: UK - England
Town: wolverhampton
Boat name: bluefin
Make: picton
Length: 4m +
Engine: outboard
Join Date: Nov 2011
Posts: 137
Carburettor needs a good clean or check carb gasket or inlet for leakage.
__________________
steve66 is offline   Reply With Quote
Old 20 February 2013, 15:03   #17
Member
 
ajstars's Avatar
 
Country: UK - England
Town: Horley
Boat name: Pending!
Make: Cobra
Length: 7m +
Engine: 225hp Outboard
Join Date: Jul 2012
Posts: 401
Thanks for all the info, I will check for leaks! Just a thought as its air cooled should I be using a different premix oil or will standard quicksilver 2 stroke oil do the trick?
__________________
ajstars is offline   Reply With Quote
Old 23 February 2013, 16:54   #18
Member
 
ajstars's Avatar
 
Country: UK - England
Town: Horley
Boat name: Pending!
Make: Cobra
Length: 7m +
Engine: 225hp Outboard
Join Date: Jul 2012
Posts: 401
Yam man has helped out loads - so thanks to his advice the engine is now running. I have stripped down the carb and rebuilt it but it still won't accelerate. I can't find any air leaks - if I spray carb cleaner all around the carb it still idles on. Only when some gets into the air intake does it splutter.
I'm stuck for ideas now. If anyone fancies a go at fixing it I would be forever in their debt!
__________________
ajstars is offline   Reply With Quote
Old 23 April 2020, 11:53   #19
Member
 
Country: Other
Town: UK
Length: no boat
Join Date: Apr 2020
Posts: 1
Hi ! Recently i purchased an yamaha 5bs 661 5 hp 2 stroke air cooled and when i disasambly i found the engine was rebuild but he used an broken piston.Can somebody help me with a piston code ? Maybe something equivalent ? I will atached photos..I try to find a piston for about 2 month...
Attached Thumbnails
Click image for larger version

Name:	90226892_636509020416357_5944649584260153344_n (1).jpg
Views:	99
Size:	84.4 KB
ID:	132824   Click image for larger version

Name:	90454086_328656914760572_7270523928613748736_n.jpg
Views:	164
Size:	86.7 KB
ID:	132825   Click image for larger version

Name:	90563535_225046768900719_3993823520852279296_n (1).jpg
Views:	156
Size:	80.6 KB
ID:	132826   Click image for larger version

Name:	90702291_1054379991593777_5594983368841232384_n.jpg
Views:	93
Size:	48.8 KB
ID:	132827  
__________________
ionutfg is offline   Reply With Quote
Old 06 July 2020, 22:53   #20
Member
 
Country: UK - N Ireland
Town: Ballycastle
Boat name: Lady's soul
Make: Fantasy
Length: 10m +
Engine: 70hp
Join Date: Jul 2020
Posts: 1
Hi did you manage to locate the piston part number im look for rings and gaskets myself and can't seem to find a supplier who stocks there's . Kind regards
__________________
Chric007 is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




All times are GMT. The time now is 21:03.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.