Does it have a iron sleeve? I looked at some F3 pics at ebay and they do have iron sleeve. I wouldn't nicasil iron sleeve. You can run little tighter piston to cylinder wall clearence which could be worth few hp but i think boring and honing the oem sleeve will be more cost effective. Ask for pricing on some machine shop that does borings. Is there anything wrong whit your pistons or cylinders? If they are fine it is not worth it. Cams, porting and a good exhaust will give you probably better gains.

What is the compression ratio oem and what it will be whit the 2mm oversize pistons and what will the displacement be whit the oversize pistons? What is the rev-limiter on f4i and what is it on the f3?

 

youre right, they are sleeved actually, Nothing wrong with the pistons or cylinders though, doing all this for Sh**s and giggles...and to have an even sweeter f3 But stock f3 comp. is 12:1, with the f4i pistons it would take it to 12.5 or 12.6:1.
not sure about the rev limits, but on the f3 redline is 13,5 and 14,5 for the f4i.
But since it is sleeved would i still need the nicasil? thats where the real cost is for the overbore.

 

Because it is sleeved you don't need nicasil. Just bore and honing. The displacement would be 637cc whit the 2 mm oversize pistons and compression ratio 13.1:1-13.5:1 depending on do you choose Wiseco or Je. I wouldn't expect huge gains from little compression raise and extra 37cc. Whit F4i cam on the intake and f3 intake cam on the exhaust you will probably need to get the limiter close to 14.5k to get the full use of the cams.

 

What are the specs of the cams F4i cams and what are the specs of the F3 cams and do they fit straight to the head?

 

not sure of the specs on the cams, cant seem to find them anywhere, and dont have anything to accurately measure them with at the moment. But the lobes on the f4i cam are 2.5 mm wider apart than the f3's. it still fits, but it looks like ill have to grind off some burs/ridges left from the casting process.

 

Do you have stiffer valve springs? The oem woun't probably do the job whit added lift and duration. One option would be to get another f3 intake cam and get it grinded and use the stock intake cam at the exhaust. It would probably be smarter then grinding of the cam towers. Is your bike cali model? On the f4 model the cams are different on cali models. Not sure about the f3. Is there anyway the extend the rev limiter on the f3? Whit added compression, more agressive cams and ported head that flows better the hp will probably come after the stock rev limiter.

 

i do plan on getting stiffer springs, and i wouldnt be grinding off the cam towers, it would be the area around where the springs sit. shes not a cali model. Not sure if i would be able to increase the rev limit or not. researched it a bit and havent found anything.

 

Whit dyno 2000 ignition you should be abble to increase the rev-lmit to what you need. What springs are you planning on using? You should take few photos of the cams and were you need to grind the head.

 

Ill look into the ignition. Not sure what springs ill use, really just getting into all this.
heres the head.
theres the little ridge from casting, and the spot where it dips down so the lobe clears, since the lobs are wider apart it may cause an issue, But im just setting it in there and spinning it, ill have to actually bolt on the cover that holds the cam in to know for sure

 

Are the lobes wider to bouth directions or is the spacing different. If the spacing if different you will probably run in lot of trouble whit the F4i cams. They wount hit the lifter/bucket properly if the spacing is wrong and it will wear the lifters and lobes. Is the spacing of the journal surfaces same on the F4i as the F3? Has it been done before?

There is lot to think whit these kind engine modifications. I ran in to lot of things to consider when i started building the 954 motor. I think i got them sorted pretty well but the engine hasn't run yet so will see how is the drivebility of the engine be. I'm personally little worried about that.

Whit your 2 mm overbore, added compression, cams etc. you can run in to lot problems whit the engine head. Is the stock valve sizes enough, does the valve angles work whit the bigger bore, how much do you need more air through the head etc.