40hp modded Yamaha

[proprider]

​well done!!

Thanks!

[Instigator]

Gorgeous motor!

Came out killer!
Very clean.

I ran stock/mod/pro back in the day and always liked the guys that thought outside the box.

What is min weight in your class??

More modifications have developed on this motor since this thread was made. It's been a very fun project! https://youtube.com/shorts/8qtSRunjS9Q?feature=share

[Instigator]

Tom, his is a lay down.

No torture to the knees!

Ha HA ..she's long gone ..great boat though . Thats killer that you have gotten that far with the Yam , look forward to some video when you get it dialed in . The kneel down days are gone for me I'm afraid !

[proprider]

Gorgeous motor!

Came out killer!
Very clean.

I ran stock/mod/pro back in the day and always liked the guys that thought outside the box.

What is min weight in your class??

Thanks! No minimum weight in the 850 class. It’s a lightweight package with a lot of response due to the loop charge design. Check out the custom made intake. The factory intake and reeds are a major “choke” to the engine. I have to run 4 peddle reed cages, per rules, so I stuffed Yamaha Banshee reeds directly between the carbs and the crankcase. Engine seems to really like the modifications

[Instigator]

What does your rig weigh, race ready, less driver?

If you have no weight min’s then you’re running Pro??

I think when I ran BSH it was 360 w/driver w/a 20H.

Totally understand the difference between cross flow/deflector motors and loopers.

I loved my 20H cross flows bought bought a 22 cu in Yamato 80 looper when they first hit the states and what a difference!

20lbs heavier and a club foot so they were slower on top end bolt it’s powerhead on a Merc mid/case and see what happens!

Night and day!

I ran a few races w/a sliding pipe on my Yamato and what a low budget blast!

Did the same with V-6 pleasure motors.
Cross flow to looper and never looked back.

[Instigator]

Another Great example of crossflow to looper would be the 44XS Merc crossflow, four-cylinder against the OMC 45 cu in looper.

Even though it was only a two banger they wouldn’t let it race with the Merc.

I was at the race in Dayton Ohio when they first released the 45 motor.

They did an exhibition run with a 45 on a D Mod Hydro against two D Mod Mercs.

They gave the mercs a half straight away Headstart and by the time they were out of the first turn the 45 OMC passed both of them!

From then on out it was only legal in stock in a sit down tunnel boat that was 100 pounds heavier! Funniest part to me was the first couple years their kilo records were the same :-)

[proprider]

Another Great example of crossflow to looper would be the 44XS Merc crossflow, four-cylinder against the OMC 45 cu in looper.

Even though it was only a two banger they wouldn’t let it race with the Merc.

I was at the race in Dayton Ohio when they first released the 45 motor.

They did an exhibition run with a 45 on a D Mod Hydro against two D Mod Mercs.

They gave the mercs a half straight away Headstart and by the time they were out of the first turn the 45 OMC passed both of them!

From then on out it was only legal in stock in a sit down tunnel boat that was 100 pounds heavier! Funniest part to me was the first couple years their kilo records were the same :-)

I was around, and at Dayton, when all that happened. APBA really underestimated the power of that 2cyl. looper. It was Jerry Weinant that drove it on his Hemp boat. Seemed like that was the beginning of the end of big manufacturers involvement in Stock Outboard racing. Bittersweet times!

[proprider]

Had a great day of testing and made a lot of progress. Tested several props and hotter spark plugs. Very happy how it went! https://youtu.be/klfXIU8-Irs , https://youtu.be/fLL0OH8MDnc

[proprider]

After several races and testing, the engine is maintaining good compression. I think my little Yamaha is happy!

[proprider]

The Yamaha took a 1st place finish against some tough competition. Pulled hard throughout the race. https://youtu.be/YT8eFIDF6X8

[pcrussell50]

Plan to test next weekend, if water levels allow me. Hoping to hit mid to upper 80's after some break-in and tuning.

Attachment 233956Attachment 233957Attachment 233958

Mine looks like the one in the first picture But I love it anyway.

Yours looks amazing. Congratulations on what seems to have been a very successful build.

-Pete

[proprider]

Thank you

[LittleCharger]

Did you weld up the front half to accommodate the Banshee reeds? Looks real clean would like to do that to a 56er similar to what I've seen Tim Kurtz do.

Thanks! No minimum weight in the 850 class. It’s a lightweight package with a lot of response due to the loop charge design. Check out the custom made intake. The factory intake and reeds are a major “choke” to the engine. I have to run 4 peddle reed cages, per rules, so I stuffed Yamaha Banshee reeds directly between the carbs and the crankcase. Engine seems to really like the modifications

[LittleCharger]

The Yamaha took a 1st place finish against some tough competition. Pulled hard throughout the race. https://youtu.be/YT8eFIDF6X8

Congrats...clean start and got right down to business, loved your set up with the yamaha from the first time you posted it back in 2011 lol...you should come over and try a race in Ontario some time

[proprider]

Did you weld up the front half to accommodate the Banshee reeds? Looks real clean would like to do that to a 56er similar to what I've seen Tim Kurtz do.

Yes, I got my inspiration from Tim