| Author |
Message |
|
|
|
|
Post subject: Piston tang and transfer bottom porting ?
|
|
|
|
old59 Joined: 07 Nov 2007 Total posts: 26 |
Is it a good idea to remove the tang on the inlet end of a valve piston when fitting to a 4lo ?
and
Is there anything to be gained by removing some of the cylinder liner at the bottom of the transfer port channel next to the crank case, or is that old hat?
|
|
|
|
Posted: Fri Jul 04, 2008 5:51 pm
|
|
|
|
|
|
Post subject:
|
|
|
|
Bare All-gear Wheelie! Joined: 28 Jan 2006 Total posts: 1812 Location: Vancouver Canada |
Yes! Mandatory as that tang 'could' catch the port edge with unpleasant result.
Liner sides?
insert a piston and place it's crown edge halfway thru the transfer ports.. .. then look to see how much of the liner is above the piston skirt... you can remove that much (approx 6mm if memory serves) .. IF.. you feel the need.
But unless the porting has or is being seriously upgraded (with genuine skill .. that's the real issue) you are more than unlikely to notice any differences.
MUCH more result from deleting the head gasket and adjusting the Squish to 0.9mm.. Lotsa info on that... start searching
|
|
|
|
|
Posted: Fri Jul 04, 2008 7:55 pm
|
|
|
|
|
|
Post subject:
|
|
|
|
| old59 Joined: 07 Nov 2007 Total posts: 26 |
Yes Indeed, Bare, I have searched the archive and pushed the piston up and down the barrel and have seen that not a lot of barrel sleeve obscures the ports when compared with the piston as it approaches BDC, but I just wonder if some dynamic exists not evident with such manipulation.
The piston tang does not appear to be a good idea, fair enough tnx.
|
|
|
|
|
Posted: Fri Jul 04, 2008 9:10 pm
|
|
|
|
|
|
Post subject:
|
|
|
|
BillyAll-gear Wheelie! Joined: 12 Oct 2007 Total posts: 1916 Location: Sweden arise! |
| old59 wrote: |
Yes Indeed, Bare, I have searched the archive and pushed the piston up and down the barrel and have seen that not a lot of barrel sleeve obscures the ports when compared with the piston as it approaches BDC, but I just wonder if some dynamic exists not evident with such manipulation.
The piston tang does not appear to be a good idea, fair enough tnx. |
Take it off.  It won't hurt the engine. Just take away any obvious obsticles. And you don't have to have the edges sharp as a knife!
Don't forget to make the edges on the sleeve smooth where the piston goes rubbing. I usually do it with a file and then fine sandpaper.
I did this on my barrels but i don't know if it gave anything. I never rode the bike when it was stock so i can't compare.. 
|
|
|
|
|
Posted: Fri Jul 04, 2008 9:19 pm
|
|
|
|
|
|
Post subject:
|
|
|
|
PJ ENGINEERING (PROX) Daily Burner Joined: 03 Aug 2003 Total posts: 134 Location: WEST MIDLANDS |
Question has any one ever had the tage clip / chip / catch the port
I never in 19 years of doing rebores taken the so called tange off and not had 1 problem.
I think this all started on the net 
|
|
|
|
|
Posted: Fri Jul 04, 2008 11:14 pm
|
|
|
|
|
|
Post subject:
|
|
|
|
BillyAll-gear Wheelie! Joined: 12 Oct 2007 Total posts: 1916 Location: Sweden arise! |
| PJ ENGINEERING (PROX) wrote: |
Question has any one ever had the tage clip / chip / catch the port
I never in 19 years of doing rebores taken the so called tange off and not had 1 problem.
I think this all started on the net |
Maybe nobody have had it, but it's just safer to take it off. To be honest, the tab would - if it's in the way - most likely just wear down and not be in the way anymore. But you never know!
|
|
|
|
|
Posted: Sat Jul 05, 2008 4:55 am
|
|
|
|
|
|
Post subject:
|
|
|
|
TonyDDaily Burner Joined: 24 Aug 2006 Total posts: 207 Location: London N4 Ex East Midlands |
| PJ ENGINEERING (PROX) wrote: |
Question has any one ever had the tage clip / chip / catch the port
I never in 19 years of doing rebores taken the so called tange off and not had 1 problem.
I think this all started on the net |
Good Point
in the box of used piston I got with my 350lc racer non of these tangs had been removed, didn't find a mark on any of em. Having said that I may chamfer or remove tang the new ones (from your goodselves) I'm putting in soon.
Tony
|
|
|
|
|
Posted: Sat Jul 05, 2008 9:39 am
|
|
|
|
|
|
Post subject:
|
|
|
|
Trig One-handed Stoppie! Joined: 04 Aug 2003 Total posts: 2376 Location: On Cloud 9 |
| PJ ENGINEERING (PROX) wrote: |
Question has any one ever had the tage clip / chip / catch the port
I never in 19 years of doing rebores taken the so called tange off and not had 1 problem.
I think this all started on the net |
It does on an RD400, took 5 pistons to realise what it was 
|
|
|
|
|
Posted: Sat Jul 05, 2008 8:03 pm
|
|
|
|
|
|
Post subject:
|
|
|
|
mikejeff Mmm, Fully Synthetic! Joined: 11 Feb 2007 Total posts: 1100 Location: the glen of rothes. |
seen the backs broken off in 4l's before but ported motors with wider
inlets think the piston rocks slightly
a valvie has a bridged inlet so no probs for them
|
|
|
|
|
Posted: Sun Jul 06, 2008 9:18 am
|
|
|
|
|
|
Post subject:
|
|
|
|
| old59 Joined: 07 Nov 2007 Total posts: 26 |
Seems like a hung jury on the piston business.
Is there any down side to removing the tang ?
I'm still wondering about removing some piston liner at the transfer port inlet area, has anybody done this or had it done?
|
|
|
|
|
Posted: Sun Jul 06, 2008 6:04 pm
|
|
|
|
|
|
Post subject:
|
|
|
|
BillyAll-gear Wheelie! Joined: 12 Oct 2007 Total posts: 1916 Location: Sweden arise! |
| old59 wrote: |
Seems like a hung jury on the piston business.
Is there any down side to removing the tang ?
I'm still wondering about removing some piston liner at the transfer port inlet area, has anybody done this or had it done? |
There are no downside of doing it if you're gonna put it in a lc. It's safer and it won't happen anything with the power. Maybe a half % or so, i dunno. But you will most likely not notice any difference.
Yes, i have done the mod on the sleeves where the transfer ports begins. I don't know if it makes any difference in power but i would say that you get better flow through the engine. The sleeves are a big obsticle on a stock cylinder so..
Same with the intakes, you can see the sleeves going down (where the boost ports are located) and are in the way a bit. But i didn't do anything about that since i didn't have bigger reeds. No need to do it then.
jmw have good pics..
http://i224.photobucket.com/albums/dd50/Krafs/LC10.jpg
http://i224.photobucket.com/albums/dd50/Krafs/LC009.jpg
Edit: Rich's ypvs barrels. It's the same thing here, cutting down the sleeves to open the transfer inlets.
http://www.yamaha-rd.com/forum/viewtopic.php?t=52342&postdays=0&postorder=asc&start=0
Yamahafreak i think. Abbey ported anyway.
http://i224.photobucket.com/albums/dd50/Krafs/DSC00992.jpg
|
|
|
|
|
Posted: Mon Jul 07, 2008 9:05 am
|
|
|
|
|
|
Post subject:
|
|
|
|
| old59 Joined: 07 Nov 2007 Total posts: 26 |
Thats a lot of carving on those barrels,
you wouldnt be doing that with the wee dremel !
Thanks for the pics and other info.
|
|
|
|
|
Posted: Tue Jul 08, 2008 4:14 pm
|
|
|
|
Options and Permissions
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum
|
| Page 1 of 2 .:. Goto page 1, 2 Next |
|
Powered by phpBB. copyright © 2002 phpBB Group. Template design - Vereor.
