I would look for a f2 cylinder, then it will all be a bolt in. If you go 836 you will still need to get the F2 specific kit so you dont lose compression ratio.
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Engine VIN restamped, BUT DOESNT MATCH my F2?!?
- Thread starter CR92
- Start date
CR92
CB750 Member
I take it that there's no way on earth the k version of the cylinder went on the F2?
Why did it have to change haha, I'm guessing it would cause all sorts of leaks?!
Was it a hard job doing it to yours dirtdigger?
Why did it have to change haha, I'm guessing it would cause all sorts of leaks?!
Was it a hard job doing it to yours dirtdigger?
CR92
CB750 Member
Also, do you know anyone selling cylinders that will fit? Haha
Cheers
Cheers
You have to send the head to a machine shop because the sleeves have to be a slight press fit. The holes need to be bored and fine honed then the sleeves pressed in. Then you will need to have the head surfaced to make sure everything is still flat after the pressing. I have either APE or Cycle X do my machine work but that probably wont work for you beings you are not in this contry, Im sure shipping prices would not make it worth it. I would watch ebay, seems to be the best source for used parts. I have an F2 cylinder but I dont sell.
CR92
CB750 Member
If I'm honest, I can't see why having an F2 head with K cylinders is an issue.
The drain holes in question are return oil galleries under low pressure, then the oil runs down it will just meet with an extra gallerie
Where as a K head on F2 cylinder I can see where there might be leaks due to oil build up and block of flow.
Correct me if I'm wrong but I don't see how it's a major issues
Plus boring and skimming the head should raise the ratio so that it's virtually unrecognisable if it's F2 or k block?
Cheers
The drain holes in question are return oil galleries under low pressure, then the oil runs down it will just meet with an extra gallerie
Where as a K head on F2 cylinder I can see where there might be leaks due to oil build up and block of flow.
Correct me if I'm wrong but I don't see how it's a major issues
Plus boring and skimming the head should raise the ratio so that it's virtually unrecognisable if it's F2 or k block?
Cheers
The k uses 8 oil returns, the f uses 4. The f block deletes 4 passages the k stil has 8. If you use the k crankcase pressure will blow oil back up the passages in the head. The issues is that 4 of passages in the cyinder block match up with the 4 in the cylinder head that is open to air in the cylinder head. If you put a f2 head on k block you WILL have oil all over because of crankcase pressure. On the reverse...dirt and water can make is way down into the crankcase through these same 4 holes.
When the head is machined they only take the very minimum needed to get it true, it will not affect compression enough to notice unless it is extremely warped and a large amount needs to be taken. The compression has nothing to do with the cylinder block it has to do with the head and the piston design. The piston is higher compression in the f as apposed to the k because the chamber is much larger in the f2 head. Put k pistons in a f2 head and you will have a dog of a motor because of low compression ratio.
Its up to you its your motor, I have done this conversion several times I know what I am talking about and trying to save you headaches down the line. You have to do it right or you will have leaks.
When the head is machined they only take the very minimum needed to get it true, it will not affect compression enough to notice unless it is extremely warped and a large amount needs to be taken. The compression has nothing to do with the cylinder block it has to do with the head and the piston design. The piston is higher compression in the f as apposed to the k because the chamber is much larger in the f2 head. Put k pistons in a f2 head and you will have a dog of a motor because of low compression ratio.
Its up to you its your motor, I have done this conversion several times I know what I am talking about and trying to save you headaches down the line. You have to do it right or you will have leaks.
amc49
CB750 Guru
X2 to all of that, I'd listen to the man....................many have been down this same route and all who were firmly convinced 'it would work' then found it was not so lacking the specialty work to make it happen. When dealing with proper compression most look at the 'slight' difference in head and piston and shrug it off, what they miss is that the volume there is a function of the compression ratio, in short an 8 or 9X error bigger than you think because the top volume does not now match the bottom overall volume to be efficient. Even a slight difference there low and the engine won't pull a far girl off a tricycle. Or, too much even slightly and the engine pings to no end with the fuel now available.
For instance, on the DOHCs there is a combo that people tend to flock to because it's 'easy' that puts the available piston a measly .060" (1/16 inch) down lower in the hole, the engines built like that then run like crap. The people doing it think it'll run better because the piston has a higher dome, therefore it must add compression..........WRONG!
For instance, on the DOHCs there is a combo that people tend to flock to because it's 'easy' that puts the available piston a measly .060" (1/16 inch) down lower in the hole, the engines built like that then run like crap. The people doing it think it'll run better because the piston has a higher dome, therefore it must add compression..........WRONG!
