Topic: 350F or 400F Topend.

[peterlm844]

Hi Forum
I might be short of a TopEnd for my 350F.
Does anyone know if a 400F head is similar to the one on the CB 350F? I have not seen many 350F spareparts, so if the 400 is similar that might be the reason.

Ive heard that it will fit, but Ive also heard that it can be problematic to do so.

Does anyone here know for sure?

Peter

[Danno]

no it wont fit I dont believe I have one that is complete and I am sure rebuildable if not usable now I don't know for sure because I have not pulled it off yet if there are any other parts you need let me know It still has a few also let me know if you want me to pull it if you interested I got the bike for Mark(hondaman) and pulled the parts off that he wanted there is still some left like an engine fork tubes handle bars air box just let me know

[fmctm1sw]

A while back I considered (actually still doing but other projects are ahead of it) putting a 350F top end on a 400f bottom end (simply because of parts I have laying around).  IIRC, the crankshaft and con rods are the same part number.  My plan was to use a 350F jug and head and bolt it right onto the 400F cases.  I read the valves were different in the 400F head.

[Triffecpa]

the cb350f and the 400f share the same bolt pattern on the heads.  There is a minor casting difference around the front center two head studs though.  The 350 uses longer studs.  I have put a 400F head on a 350F bottom end by putting some washers in as spacers.

The 400F cylinder will fit on the 350F bottom end if you open up the holes in the upper engine cases as the liners on the 400F cylinders are larger diameter than those on the 350.

The cams are indentical as are the cam covers and rocker arms.

I think that the 350 valves are a half mm or something smaller than the 400 valves, but honestly that difference would be pretty hard to notice.

TR

[Sparked]

What part exactly are you looking for? I do have some extra 350f parts from a couple of seized engines.