Honda-SOHC

When I was in the market for a bigger piston kit for my CB750F2 I rode down to Dixon Racing in Godalming and spoke to the man himself. He didn't have any 812cc (64mm) piston kits in stock at the time so I bought the 823cc (64.5mm) kit instead. This was just a straight overbore from the 61mm standard bore that gives that engine the 736mm size. It is my understanding that 836mm (65mm) is the maximum that the sleeves will take before needing punching out & replacing with thicker ones.

I had the barrels bored to size then honed to clearance by a colleague that had a boring bar and a stone hone. As far as I can recollect (this was back in 1981) the hone to clearance was standard Honda specs as the pistons are cast, not forged, which have a different spec.

I have some spare piston rings that are surplus to requirements that I am willing to sell. I knew I kept them for a reason.

PM me if you are interested.

A few years ago I bought a nice condition CB550K3 from someone relatively local and it had a lean running problem. I made the point that I didn't know much about bikes & that it would have to be put in to a bike shop to be fixed.

In reality, I had a good idea where the problem was from the start & once home I pulled the carbs & replaced all four of the inlet manifold 'O' rings (part #14 on the fiche) as one was snapped & the other 3 didn't look in good enough condition. For what they cost it wasn't worth looking for cheap alternatives & having resolved the lean running it pulled in a similar way to the wife's CB550F2.

https://www.cmsnl.com/honda-cb550k3-four-england_model14671/partslist/E02.html#.Yhp5PrunzIU

I might have one in my box of CB750 parts. I'll have a look & see if I can find it.

Dave Silver have them

https://www.davidsilverspares.co.uk/CB550F2-SUPER-SPORT-1977/part_356530/

My Mrs and I attended the free Biker Down course at the Kent Fire & Rescue HQ at Rochester (Kent) the other year and there was a bod there preaching about how yellow & blue hi-viz jackets are not as easily seen as a pink one. I saw his fifteen minutes only as a way of pushing his book. The rest of the course was top notch and my Mrs learnt a bit more than she already knew but specifically about how to safely remove a smack hat (as my Dad used to call them) from a casualty.

https://www.london-fire.gov.uk/safety/road-safety/motorbike-safety-course-biker-down/

Dot 4 & 5 are compatible so won't give you any realistic problems as seal compatibility exists between them.

Apart from being less corrosive for 5 I understand it as Bryan put,  that it doesn't effectively absorb water.

It's a odd situation though as Dot 4 holds water in suspension,  and so reduces boiling point as %i ncreases. The same water ingress to Dot 5 effectively drops to the lowest point of the system IF it were to get into the system in the same fashion.  This would also reduce effectiveness in a similar fashion.

DoT 4 and 5 are not compatible. It is DoT 5.1 which is.

I used DoT 5 back in the early '80s for my Honda CB750F2 Special & never had any problems. It did need very careful bleeding as tiny air bubbles would compress under braking if not bled successfully.

Before adjusting the carbs i'd suggest doing the cam chain tension first, according to the Haynes manual.
The procedure in the owners handbook is incorrect.

I had nearly 40k on my F2 before its unfortunate demise & it always ran quietly

I've had my XR for quite a few years now & it's seen some very rough & some smooth surfaces. But since buying a newer race bike I decided to install some 17" wheels so that I could still have some fun on tarmac