superfour rebore?

[fitzpaddy]

hi there, does anyone know if its possible to economically rebore my superfour? I have been told that honda dont do oversize pistons and rings.

thanks fitzpaddy

[Superjack44]

Good question , I have never heard of anyone having a honda engine rebored before .
Why do you want to rebore yours, have you stripped the engine and found the bores worn.

[fitzpaddy]

hi there
i had low compression on number 3 cylinder, only 25 psi, compared to about 115-120 on the others. stripped it down and number 3 cylinder was definitely worn. i contacted david silver spares and they said honda dont do oversize pistons and rings for the superfour. i think this may be due to it being a jap market bike only, and they dont tend to keep bikes long because of the stringent laws over there. i may be wrong though. the cylinders arent plated though, i am quite sure about that. standard pistons are so expensive though, with rings, wrist pins and circlips, they come to over £100 each. i was quoted £140 for a rebore for all 4 cylinders which makes a total of £550 in all.

[Superjack44]

Did you check the valve clearences before you stripped the motor.

[fitzpaddy]

hi there
i must admit i didnt check the valve clearances, but no3 cylinder is not like the other three in condition. its definitely worn, you can feel ridges with your fingertips never mind your fingernail.

cheers fitzpaddy

[Superjack44]

I would have thought all bores should have the same amount of wear, I would replace the camshafts in the head and check the clearences I suspect you will find that the clearences on the suspect cylinder are too tight.
Be careful of fitting the camshafts make sure they are sitting in the bearings the right way round there is a guide on the camshaft that sits in a guide in the head and camshaft bearing covers do not get this wrong otherwise the head is well and truly buggered .
The camshaft holders are made to fit that head and are not interchangeable or so I am led to believe.

[fitzpaddy]

cheers, thanks. i might have been a bit premature in taking it apart. i would warn other superfour owners that the cost of rebuilding one of these engines is ridiculously expensive. the head and base gaskets alone are about £60 each, the pistons, rings, wrist pins and circlips come to over £100 for each cylinder. if checking the valve clearances doesn't point to a closing of the gaps ill probably break the bike.

[Superjack44]

When you replace the cam bearing keeps make sure the camshafts are the right way round and definately tighten up the keeps gradually so as to pull the camshaft down evenly they are cast metal and crack very easily .

[fitzpaddy]

cheers thanks for the info.