yamaha excel suggestions please

[bully]

I have an '89 excel that is stock. I am turning a laser 21" 5700rpms and getting 60 gps on my custom bay boat. I would like to do some head shaving and reeds. Any suggestions and real world results would be much appreciated.

I want to keep it as reliable as possible, but I am willing to take some risks.

Bully

[yamaha]

you can cut heads, reed valves etc.
but if you want extra power you can finger port the motor and pistons and lighten flywheel ,relieve exhaust
in other words you can sink some money into it
but if your looking for little gains
modify heads, install reed valves and lighten flywheel
this will give you good excelleration and midrange
depending on your setup you will gain some mph

[bully]

Yamaha
I have the 6K701 heads that came on the motor. I also have a set of 6g501 heads that I could shave which would leave me the option of returning to stock. A buddy of mine has his excel torn down. His heads are 6k700. They look identical to the 6g501 heads except the 6k700 look like they were shaved more from the factory. The squish measures the same. What is the difference between the 700 and 701?

I have read that the 220 special heads are the best to use, but nobody has stated why. What is the reason?

I really don't want to get into porting, I just want to do some bolt on enhancements.

[Boz]

I run a 200 Pro-V 93'. I put on 220 heads, did some MILD exhaust porting(1.575), snipped my rev limiter, and have a reliable turn key deal.
Randy Pierson at GPI did my work and I am very happy with it and with him. He's a long way from you though.
We figure I'm sitting close to 250-255 hp.
Oh ya, I also took my stock tuner off, put a tuner on and removed my liner.

[yamaha]

id suggest calling bob kottman in mo
636-338-4080

[Jeff "Yammer"]

Well it all depends on the weight of your boat and what you want to do with it. You have to be realistic. It seems that you want to get a bit more torque than anything.

Hydro-Tec makes a hight torque tuner that did work very well for me. The reeds will also make a difference. Remove the can from the exhaust. The porting of coarse will get you the most. The 220 as mentioned will get you a great "bolt on" gain. Hopefully Ray Neudecker will show up in this thread for ya.

Jeff

[Jeff "Yammer"]

I have a real nice mildy ported 2.6 block with finger ports in you could buy for a real good price.
Let me know

Jeff
289-314-2626

[Jeff "Yammer"]

........... but they do come apart like all the rest.

[bully]

Thanks for the replies.


I would feel better if someone could tell me why 220 heads are better.

[Jeff "Yammer"]

They give the most compression out of any "Stock" Yamaha head produced.

Jeff

[bully]

Thanks Jeff

So I guess the squish area is smaller than the other heads?

Hey Boz

Is your 93 pro v 200 much louder than stock?

I like the idea of porting the exhaust since I wouldn't have to pull the power head.

I feel like I am trying to get my cake and eat it too, but I am trying to find out the most practical ways to get more power.

I think I will start with the reeds and move to the heads. What will I need to rejet to when I do each mod respectively?

Thanks Guys

You all seem very helpful!!!!!!

[ghost28]

while we are on the subject of modifying yammies.. can i ask a few questions.. i have been toying around with the idea of trying to get a little more out orf my rig.. it is a big and heavy offshore rig with twin 96 pro v 200,s.. ialways wondered if the hydro tech high torque tuner would work in my application.. also how would the boat sound if i removed the liner do they get alot louder ?? also when you remove the liner you have to cut it off of the exhaust plate right?? how about jetting what are your experiences.. thanks in advance..

[Boz]

Mine a louder than stock by a long shot. It's not crazy but sure sounds nice. Really crisp. That stock tuner on that Pro-V takes both sides and funnels them into one. This is done to choke the 225 powerhead down to 200 hp. There are differing opinions on liner removal though.
I didn't change my jetting and everything is ok.

[J Lamb]

I'm running the hydrotec tuner on my ProV 150. It is somewhat louder than stock but I pulled the liner too. You get use to it. It does sound good. I have been told the tuner and liner mods don't help the top end. I don't know because all my mods were done at one time, heads , carbs etc. .

[Boz]

When I yanked my stock tuner off and put on my current tuner (which I ran on my 88' Yamama), hole shot improved immensley. Some say taking the liner out is worse than leaving it in. Depends on who you talk to; talk to 5 people, you'll likely get 5 different answers. Find someone you trust and go with them.

[bully]

A buddy of mine has an 86 special 220 and his cyl heads are 6g700's. Does this sound right?


Where is the exhaust liner? Is it under the water jacket between the heads?

Hey Boz

did you port the exhaust ports or the main dump at the bottom of the block?

[J Lamb]

The liner is in the midsection. With it in the exhaust goes thru the LU mostly. With the Hydrotec tuner all the exhaust is dumped in the midsection. Sounds pretty good when its up on plane. Can't tell you much about the heads.

[Boz]

Exhaust ports

[Ray Neudecker]

In order to see real gains on the Excell, you will need to go to porting. Pro V 200's can gain from the use of the changing of the exhaust divider plate if it is the 64d version to the old 220 version. This was in most V-6's prior to 1990. The 64d was used to choke horsepower.

[bully]

Will someone explain finger porting. I understand that opening up the intake and exhaust ports on the cylinder wall helps, but what about the opening in the back of the cylinder itself that feeds the intake ports and other imperfections in the intake manifold.

It looks nearly impossible to get at the intake ports. If it was easy to get at them, I dont see much that can be done because of the small channel/ dish area that the air flows through.

[Markus]

You make a channel in the sleeve that looks like (half) a finger. It is fed through a hole drilled in the piston.

You can do a lot of intake porting on Yamahas. If you need someone to modify your engine, talk to Ray. Another choice is Wayne Taylor.

Btw, even though the 220 special heads are the best Yamaha heads, the 225 Excel are the second best, so you would not get as big a boost from those heads as someone with, say, 150 heads would.

[bully]

Well I picked up some top end rpm today. I cut out the screens on the air silencer and drilled 2 2 inch holes in the air intake on the cowling.

I picked up a solid 100 rpm. I can now turn 5800 rpm and do 61 mph. Not bad for free, huh!! She feels stronger over 5000 rpm as well. This motor has never hit 5800 rpm!!!

As for the finger porting, do you cut new fingers into the sleave. Or do you just cut into the existing ports?? Sounds to me that you better be qualified to try cutting new ones.

[Ray Neudecker]

You cut new ports into the sleeve and grind the portsinto the block.

[bully]

Ray

That sounds like too much sugar for a dime in my case. I like the idea of what Boz has done with his exhaust ports. Is it necessary to slightly bevel the port in the sleave to keep the ring from binding?

I have ported 4 stroke heads before. Do you think that with a decent die grinder I could do it at home? I have an old 200 block I could practice on. I just don't know any one around here that is into 2 stroke performance.

When opening up the ports, do you open towards the head or open up and down (vertically)? How much is necessary?

thanks
billy

[Yamaha 225]

Hi everyone!

I am sure the Yammies has a lot of potensial because of their high quality construction.

Porting requires a lot of knowledge am I told. It is easy to do things wrong and get less horsepower. I have also heared that the curve of the upper edge in the intake ports are more important than the height. If the edge is very curved it will cause more turbulens and therefor better mixture of the fuel and air. I know of a guy who has ported 10 different 90 hp YAmahas for 1,3 litre racing. He has done everyone different, and all engines behaved differently. After the tenth engine, the upper story was told.

I guess Ray Neudecer and Hydro Tec is the best men to talk with when it comes to mods on Yam 2,6 l. V6!

Why don't you guys run more rpms.? :confused: I run about 7000 rpm. and the engine has now run 1000 houres on 14 years without overhaul. The compression is 130 PSI, and the engine goes like hell. More top end rpms. gain alot better accelleration.

[bully]

Yamaha 225

What type of modifications have you done to run 7000 rpm?

Billy

[Markus]

Talk to Wayne Taylor, Ray Neudecker or Bob Kottman if you can take his attitude.

Hydrotec's reputation for mods is a bit mixed. Their parts department is fantastic, though.