Yamaha 130 V4 Project Build.

[Mr. Demeanor]

Thought I would start a thread for my upcoming Yamaha V4 build.
First off I want to thank Mackeral for helping me with parts and posting a lot of info when he was tinkering with his V4. Most of the info on this site before I came around about Yamaha V4's was his and I have read all of it. I also want to than Ray Neudecker for a lot of solid info and answering my questions over the last couple years. Ray and I spoke on the phone as well and he seems to be a genuinely good guy.
I have been running my stock 130 and beating the crap out of it. Could not be happier with the motor. It is 19 years old and has never been apart other than the intake to install reeds and I pulled the heads last year to have a look. What I saw was disturbing but she still had 130psi on all four holes.
Last weekend while at the keys run, a comedy of errors has finally injured the little motor. An inoperative overheat alarm combined with my new lower unit that doesnt prime at idle without some throttle blipping and my distraction by bikini clad babes at the sandbar has apparently resulted in a slightly scuffed cylinder...or two. Compression is down to 110 on one and 120 on another hole.
So....now is the time and I just happen to have a block on the way to start with. I am planning a very mild build. Basical light port works, heads, etc.

One of my concerns is my limitations due to the 2:1 gear ration. Right now I am turning a 30 pitch ET to 6800rpm and 84.5mph on a hot summer day. If I port the motor for more high rpm HP, I could easily be into the mid to high 7K rpm range. I am not sure the rotating assembly will last. I also have concerns about losing low end power. If I cant break the 30 pitch prop loose to get on plane, all that top end HP is useless. Basically I am already near where I am comfortable turning the motor so going crazy on port work probably isnt wise. I do want this motor to remain reliable.
Plugging the numbers into the prop slip calculation puts me near 100mph with a 32ET at 7700rpm. The question is will the boat get on plane with the motor ported for that? The other question is do I want to go that fast in a 13' boat....eh...it would be cool to do it once but I know myself better

My gut is telling me to clean up the ports but not enlarge them or at least leave the height alone and maybe make them a little wider. The only Yamaha V4 block I have seen stripped down left a lot to be desired. The port window in the sleeves was smaller than the port behind with a pretty good "lip" at the window in the sleeve. Just cleaning matching that up should help a lot.

I will update this post as things move along. This isnt happening quickly unless the motor I have now lets loose. There is very little Yamaha V4 info out there so I want to document what I do and the results.

[1FASTLASER]

10-4!!!!!! I will be watching this thread very closely

[mrcrsr]

get the compression up, that will help bring back some torque if you do modify the port timing. you can still get away w/ pump fuel mixed w/ some aces chris.

[Mr. Demeanor]

Compression is at the top of the list.
Just no need to go crazy on port work and build a race motor that I cant find props big big enough to take advantage of due to the gear ration I am stuck with. I think compression and a mild port cleanup will be the ticket.

On the topic of compression, I know there are some model year heads that are better than other but I dont recall which. And of course, whats the max compression I can shoot for with premium fuel I know most say 145psi but this motor has 135psi stock and I have been running 87 octane in it for years. Another 10psi just doesnt seem like much.

[1FASTLASER]

Speaking of gear ratio's doesn't anyone make a gearset other than the 2.00 for the V4 hammers?

[baja200merk]

Y are we always working on out chit at the same time?!?

My bone stock 2011 300 got water in #3 thanks to a cracked glue line in the block behind the sleeve. It still had good compression but rust took out the rod bearing . Salt water injection is not good. Its apart on the bench, crank is going to CA and the sleeve is coming out on monday.

Port it to the moon use this to get on plane

[mrcrsr]

on the merc's i've run 160 psi and higher w/ premium fuel and aces. as far the heads you could get yours flatmilled to get the compression up

[prosken300]

I run 170 psi on europe 98 fuel.
you need to calculate the compression ratio and match your heads and exhaust port height to your desired ratio.
Milled my head this winter, 2,5cc less then before. Still need to start the porting job, but curious how much psi it will have.

like said before, more compression gives you better bottom end that can compensate for mild porting.
But i would do like you said, its not a race engine and needs to be reliable.
Clean up the ports, maybe widen them a bit. And bump that compression up.

[Mr. Demeanor]

Here are some pics of a port job on a V4 Yamaha an overseas (Europe if I remeber correctly) member here sent me. THIS IS NOT MY MOTOR.

[Mr. Demeanor]

Y are we always working on out chit at the same time?!?

My bone stock 2011 300 got water in #3 thanks to a cracked glue line in the block behind the sleeve. It still had good compression but rust took out the rod bearing . Salt water injection is not good. Its apart on the bench, crank is going to CA and the sleeve is coming out on monday.

Port it to the moon use this to get on plane

I actually thought about spraying the stock motor until it died but it died early. I thought it would give me an idea of where to go with the build.

[ultrafast]

listen to Ray But I wouldnt waste my time with a mild port job I have seen Rays v6 motors spin up I guarantee your v4 can do the same. Use good fuel and good oil and let it eat.

[baja200merk]

How far down from the deck is your exhaust port now? How wide is it?

According to advanced sleeve's site the widest and tallest V6 port was 1.665" Width 2.360 on a late 80s 200. The site doesnt list the dimensions of the V4. Surely you could go at least that wide.

[Markus]

as far the heads you could get yours flatmilled to get the compression up

Can't mill the heads flat, because the piston tops are not flat.

[mrcrsr]

how much piston to head clearance is there? there's got be some room to remove the some material from the head gasket surface, maybe before pulling the old motor apart use some clay and check piston to head clearance

[whatsamerc??]

what about finger porting it? if you pull the sleeves you can work on the transfer ports in the block too. that way you arent messing with the height too much, but you may have to do some stuffing to get the crankcase pressure back................benji