starting rebuild on vf750f just a couple of questions....

ok so im buying a good used crank ,rod and pistons to put in my vf because my old one spun a rod bearing but what im wondering is should i or can i use the pistons im getting with my new crank or should i reuse my old ones (that are fine)on the new rods??? i read in the service manual not to interchange pistons rod and pins but i have to replace one rod anyways becasue its beat outa shape from the bearing going, so what would be the best thing to do ????
thanks for any advise

 

It shouldn't really matter that much. All the parts are stock and the same. They should all weigh the same so you shouldn't have to balance the crank. You have to mic all your parts to see where they are as far as tolerance is concerned. That could be the reason for Honda saying not to swap pins and rods. They have to be matched up. Even Honda has a margin to machine in. So a pin machined on the small side and the rod pin bore is on the big side you may have to much/little clearance for the correct tolerance they spec. Find out what specs they have for pin to rod bore, pin to piston, piston to cylinder etc and take measurements of your parts to see what will and will not work. You may have to take your parts to a good machinist to have them mic'd properly if you don't know how or have the mics.

Other wise it's a crap shoot on just throwing parts in that are suppose to work in the engine. How luck do you feel??

 

not lucky enough to throw parts in haha
i want that thing to work right the first try,,thanks for the advise ill check out my parts

 

if they all mic out the same, consider weighing each set piston, rod and pin and shaving metal of (you will see where it was done at the factory do it in the same place) this will help to balance and remove exes vibration. have you considered the 929 piston swap out and over bore?

 

Hey I'm just curious....does your VF750F have the top end oil mod done?

 

i really dont have the funds for boring or buy more parts so this was going to be a quick rebuild for now

and i have never done the top end oil mod and everythign looked stock on the bike when i got it but i do plan on drilliung out the banjo bolts and using the bigger tubing going to the heads and also buying the best oil i can find

would a postage scale that weighs in grams be accurate enough to ballance my rod-pistons? i have on that tells grams but not fractions of grams
thank god for this site,without it im sure my rebuild wouldnt make it to the end of the street haha