School me on Finger Ports

[DoktorC]

I know what they are but I'd like to know if they are worth while on a lake motor (no drag racing at all). I'm in the planning stages of my build and don't want to put it together and find that I should have done this porting to start lol.

Who's got them? Did you see gains? where?
Are they only effective if you're spinning the engine above a certain RPM?
Do you loose anywhere?

Thanks all.

[Jason Johnson]

I wish you well on finding info on this subject. I put them in my 90 block. I could never really get anyone to offer rock solid info. Just a few to say put them in there. Mine are 1/2 inch wide and 1/4 inch deep

[brussrude]

I wish you well on finding info on this subject. I put them in my 90 block. I could never really get anyone to offer rock solid info. Just a few to say put them in there. Mine are 1/2 inch wide and 1/4 inch deep

Jason- how did they worked out for you? Have you felt an huge increase in power? How did you cut them with a mill or with use of the porting tools & hand pieces?

Brussrude

[Dingie 2]

I would also be real interested in the know what kind of performance gains that you found after finger porting a 90HP. Joe R

[DoktorC]

I would also be real interested in the know what kind of performance gains that you found after finger porting a 90HP. Joe R

Focus here people...we need 2.6L info first!!! :)

Then we'll deal with the 90 (and my 70 lol).

[Markus]

Finger porting (like most intake side porting) gives more power all the way from the bottom.

Contact Soren on this board. He has built several finger ported Yamahas with different finger port styles.

[Jason Johnson]

Yes I agree, keep the post on track, sorry I started that stuff. I too want to see the instructions for the big motors.

[1bad67]

i have a finger ported 2.6 but have not got to run it for very long (due to cold seizure on #5 hole :eek:) but for the time i did get to run it there is a very big difference from it to a stock ported motor:D. very stong from idle to around 8800 rpm. it also has tube ports and the rod slot have been cut. i hope to have it back up and running by this next spring. if anyone is interested i have 6 brand new promarine coated .040 over pistons that are drilled for the fingerports and a real nice set of 36mm carbs that i would sell

[whatsamerc??]

bill, if you still have the motor apart i would like to see the pics o those tube ports again. i lost the ones you sent me before. are those pistons the hydrotech f1 or regular style?...............thanks benji

[1bad67]

benji the promarine pistons are the domed factory style piston. i got rid of all the f1 pistons already to costly to replace when you mess up one. i will try and get some photos up on here in a day or two i will put some photos of the promarine pistons and carbs up to

[1bad67]

photos of port work

[1bad67]

photos of carbs and pistons

[mackeral5]

thanks for sharing the pics, it's not often that we get to see pics of a fingerported AND tube ported yamaha. did those tube ports require any work outside on the side of the block?? can you share any pics if there is work on the outside of the block? thanks again.

[1bad67]

while cutting the tubes you make a small hole(1/4" by about 1/4") in the block takes very little expoxy to cover this after painting the block it is almost impossible to see

[whatsamerc??]

thanks for the pics. is the rod slot open all the way into the transfer? will you have to cut the skirt on the non f1 pistons simular to merc pistons?

[whatsamerc??]

Focus here people...we need 2.6L info first!!! :)

Then we'll deal with the 90 (and my 70 lol).

the principals are the same, it doesent matter what size the motor is. learn what you can no matter what the source.................benji

[1bad67]

the rod slots are angle cut towards the ports but not cut into the ports. i would not reccommend cutting them this much on a lake motor it requires the front half to be milled to get crankcase compression back up. you can get good power with smaller index finger size angle cuts on the slots and will not require the milling of the front half. i'm going back with wiseco pistons and i'm cutting the skirts to open up the port window a little more this motor does not have the merc porting like the other f1 motors that was built

[lwbrainard]

1bad67,

Please send me a pm regarding your carbs for sale.
I would be very interested.

Thanks,
Lance

[berg969]

i like the z port.
are you going to mill the aluminum in the fingerports?

photos of port work

[1bad67]

i have been talking to some poeple about doing that some say to remove a little bit other say not to that it would compromise the cly by makeing it to thin but sense i have had the clys bored .040 over i don't think it will flow as much unless i do remove a little aluminum so i'm not sure at this time

[DoktorC]

the principals are the same, it doesent matter what size the motor is. learn what you can no matter what the source.................benji

I agree the principles are the same but I'm more worried about the actual application. I want to make sure regular lake boats will still get on plane...and function reasonablely well.

I do want to learn...especially about the small motors ('cause I have a 70 on a delta) but I really wanted to hear from the V6 guys to make sure I'm not getting into something that is only useful on a drag boat.

Benji...you should sell me a mid :).

[Dingie 2]

One of the most knowledgeable Yamaha Gurus around told me a couple months ago that finger porting woud help overall performance from holeshot to top end. Joe R

[mackeral5]

best yamaha thread I've seen in a while..... Benji---you got any updates on the tube port experimenting you were doing a good while back? I'll be tearing into my tired ole 175 soon, and while I'm in there I might as well do whatever I can, even if it ends up getting put back together with a vertical front half.......that can always be changed to horizontal whenever I find a way to trade my way into a horizontal front....

[soren]

the f.port i like best is whit 2 inlet ,one in bottom,one in top off the piston.
port maks size is 15mm wid,9mm deep,more volume is more hp.
hope this will help
soren

[aguywithabucket]

only thing i got to say on this is i sent out my 09 hpdi 300 for i light port and lightend flywheel and some outer stuff done like rev lim out and WOW went from 86 to 95 wach out thers a crazzy man goin out to his fishin hole with the rigger and rods out!!!!!!! i love what it did to the motor