Yamaha 130 V4 Project Build.

[200valeroyt]

Agree, closer to what your motor had when it was stock. I remember a pic you posted of it 2 or 3 yrs back, which looked even leaner than above pics.

[Dave Strong]

Looked at some flat top pistons and it was about he size of the tip of my pinky finger.

Thumb nail is about right on domed case reed pistons, finger tip on flat tops is good. If you go to cly reeds it gets way different. Nice to see wash on 4 corners but will never be the same, all motors are a bit different and the only way you know exatly have lean you can go is to squeek one.

Dave

[Euroski]

Are the clean spots on the pistons from the intake ports?

[Mr. Demeanor]

Are the clean spots on the pistons from the intake ports?

Yes, relatively cool fuel cleans the carbon off at the intake/transfer ports. More fuel (richer) equal bigger clean spot.

[Mr. Demeanor]

Just posting a pic. I think this came out pretty cool. I have a lot of water coming out these hoses and have always had a problem with water coming up the back of the motor. When I was out the other day Dago pointed out you couldnt even see my midsection. I "think" it was water from the blue hose attached to the poppet on the port side. Lots of low pressure behind the transom and the air coming through the tunnel seems to get sucked upward.

Anyway, I ran the hoses through the cav plate. Even if its not water from the hoses I think it looks good.

Maybe Ill get some extra speed from pushing the water from the hoses with the prop

My pics keep getting turned sideways??//

[Mr. Demeanor]

Great news. I beat the crap out of it yesterday running 45 miles most of it in white capped chop. I tried to break it. The only thing hurt is me. Im pretty sore today.
The thing sounded like a hydroplane in choppy water. I should have taken some video because the way it was eating up pretty snotty water yesterday was really impressive. It extra setback is allowing my to run a little more negative trim without it bow steering and helped the rough water handling a lot. Too rough to throw the big prop on but soon....

[CharlieN]

It is neat to watch your development with each step making your boat one step better. And that is better from pretty damn good from the beginning. Fun to watch and fun to learn.

[Mr. Demeanor]

Thanks Charlie. Its been as fun, well most of the time, sharing it. When I drag raced motorcycles I honestly like test and tune days more than actual competition. I just enjoy trying new things and besting my previous performance.
I worry about this thread sometimes that I dont come off as "look at me" which isnt my goal. I just enjoy sharing what Im doing and the feedback with like minded people. I wish more members would do build and project threads.

[CharlieN]

I can see that some would look at this thinking "look at me" but I bet they are the ones that will never gamble with trying new things to find if they work.
I also see most of here recognize the effort and the risk taken with each step of development. Not everything works as desired but that is development.
I make my living building road race cars but find I do not like posting on most car forums since I do not live in the mainstream.
But this site has a better grade of people than I find in most of the automotive world.
I have a thread on the Glastron forum that is one of the highest read projects. For a long time I did not write of some of my work that I thought would be considered controversial till some questions came up how I did things. I now realize how many do want to see projects that go that step beyond the norm.
I still do not post much here since I do not consider my projects as main stream performance. Who knows, maybe my next boat project will belong on this forum.
But I for one love to see you and others going through a development project. Cool stuff.

[Mr. Demeanor]

Does anyone know how much timing the Yamaha ignitions pulls out at higher RPM's?
I have put a timing light on and with the boat strapped to the trailer and prop only partially loading pinned the throttle. With timing set at 26 degrees can can see it start to retard as rpm increases but I have never held to say 7k rpm.
I need to make a test wheel.
Im a little fearful of going over 26 degrees but if that really only 24 degrees at 7k then I would try it.

[baja200merk]

I cant help you on a v4 and when I need help on a V6 I call your neighbor Don!

[Mr. Demeanor]

Im just going to have to put a small wheel on it and see. Prob the same as the V6.

[Markus]

Does anyone know how much timing the Yamaha ignitions pulls out at higher RPM's?
I have put a timing light on and with the boat strapped to the trailer and prop only partially loading pinned the throttle. With timing set at 26 degrees can can see it start to retard as rpm increases but I have never held to say 7k rpm.
I need to make a test wheel.
Im a little fearful of going over 26 degrees but if that really only 24 degrees at 7k then I would try it.

I don't know if or how much it pulls timing - it is supposed to be mechanical advance only.

Wayne Taylor set drag engines to 27 degrees. I have not seem much benefit of going above what the service manual says, though.

[powerabout]

I don't know if or how much it pulls timing - it is supposed to be mechanical advance only.

Wayne Taylor set drag engines to 27 degrees. I have not seem much benefit of going above what the service manual says, though.

Hi Markus

Its the nature of the ignition design some advance and some retard.
Merc know the diff so they have the cranking spec. OMC say only do it at RPM

[Mr. Demeanor]

Ill shoot little video showing. I wondered if it was just the ignition not "keeping up" as the piston speed increases.

Ill have to ask Wayne if they set them statically or running at rpm. Im betting there is a 2 degree difference.