J Pistons

[Jerry Wieland]

How far can a late 61" J cylinder be bored and where can pistons be found? Jerry

[exeric]

Great question Jerry. My front cylinder is rust pitted and I need pistons as well. I recall Matt Walksler stating on another forum that he used flathead Ford pistons in his 61". Does anyone know if Ford pistons are viable replacement?

[Jerry Wieland]

My rear is used at +.100" and the piston has no markings and I am not really familiar with J's. Front is used at standard.

[dlm32]

Think you can use UL Pistons or get higher compression pistons from Competition Distributing. Check the Yahoo harley j/jd group. There's a long post on using UL pistons. The J/JDs had a taper ground bore(tighter at the top than the bottom.). The cylinders need to be straight bored to use more modern pistons.

[Jerry Wieland]

David That stuff all works for JD but I do not think J. Competition has only 74" pistons on their website - no 61's. I am going to call them and see. Their pistons I think are made by Venolia.

Jerry

[Tommo]

I use 214 cu in Bedford truck pistons.
There is a Mitsubishi piston that a lot of guys use and it raises the com a bit.
If you want to know exactly which Mitsi piston I'll have to ask around for details.
Bedford pistons go straight in with no mods needed. Maybe there's a Chev equivilant as they are both GM products.
Don't get too carried away with your overbore size as you wouldn't be the first person to end up with a detachable head cylinder.

[bill campbell]

flathead piston

hey Jerry I may have a stash of n.o.s. flat head piston's at the old house, I will be stopping by later today and I will see whats left.

[MMasa]

Tommo
I'd be interested in the part numbers of the Bedford truck piston as well as the Mits.
Thanks
Mark

[Tommo]

Mark
The Hepolite number for the Bedford pistons is 10171
As soon as I find out the Mitsi details I'll let you know.

[Jerry Wieland]

Tommo Have you found out anything more on the pistons. I tried searching for your numbers but could not really come up with much.

Jerry