Topic: F2 piston kit

[Madseacow]

Having a hard time finding a +2 piston kit for the '78 f. All the ones I'm finding are for k models, will that work? Also need a matching hg

[Madseacow]

Sorry, I meant +.05 or a step 2.

[CB750F2]

You will have a tough time finding oversize pistons for your F2. However there are 836 kits available from Dynoman and I think CycleX. Bear in mind that it is a lot more expensive to bore to 65mm then say 62mm - it is in Australia anyway. Browse Ebay you may get lucky. Another option would be to find another set of unworn barrels to fit your pistons. The K pistons will work but you will need to machine at least 1mm off the F2 head to get compression back to near standard. I was in the same situation recently and I decided to use one of the cheap 836 piston kits from ebay and used a K head. It has turned out OK but the rebore was expensive. Pat

[filipo]

I'm in the same boat. It seems it's either

- find a different set of jugs on eBay (unlikely to find a set that won't need an overbore anyway)

- get the "cheap" 836 kit with the flat tops, and mill the head (not great to me, since you can't go back, and you'll have to start over with an eBay head [see above])

- get the "real" $$ 836 kit, with the domed heads--but then you have to also get the new cam etc for $$$

Hondaman said in this thread that CycleX was the only place that (at one point) had the F2 .5mm pistons. Maybe worth checking with them?

[PeWe]

836 pistons with CR 12.5 for K will fit F2?  Maybe same pistons that give 10 something in F2?

Dynoman has for F2 both 836 and 915
http://www.dynoman.net/engine/pistons/custom.html#F2

Better to buy correct pistons instead of milling the head that cannot be undone.

CB900 con rods will lift the pistons 1,5mm otherwise. Used by some when tuning when CB900 con rods are stronger than CB750 std. I have just bought a set

[CB750F2]

If you do score a set of jugs on ebay make sure that they are F2 jugs - the oil drain back arrangement is different to the K jugs. Another option would be to replace the liners in your jugs and fit your old pistons - if they are in good shape.. I do not know how expensive this would be but contact Cyclex  or others to discuss. Pat

[Madseacow]

Thanks for the responses, I found A piston in the Netherlands, looks like I will go with dynoman's setup and a cam. Nothing easy is worth doing I guess.

[filipo]

Just got a response from Dynoman that "The .25, .50. 75 and 1.0 pistons have been discontinued from Honda for a long time."

But does that mean aftermarket oversize pistons as well? Anyone?

[Wobbly]

I found a .25mm kit on EBay. http://www.ebay.com/itm/Honda-CB750F-piston-SET-OF-FOUR-4-13102-410-003-O-S-0-25mm-new-NOS-/111149662253?pt=Motorcycles_Parts_Accessories&hash=item19e109402d&vxp=mtr
This set and a used head would do too.
I had the same problem with my K7, but finally found one (last) set on German EBay. Too bad you are already at 0.50mm. I keep looking for you, but getting a used cylinder with this set seems a reasonable alternative.

[Wobbly]

Not cheap, but this would work:
http://www.scheuerlein-motorentechnik.de/motorenersatzteile/motorrad/Honda/700-799-ccm-h7/CB750-F2--OHC-/kolbenkit-cb750f2-1-uem.html

Shipping to the U.S., you can deduct 19% VAT.
It's O.E.M., made in Japan.