Yamaha VF250 SHO Short Shaft Build Thread

[InjectorService]

I wanted to share with you all a project that I have been working on. A couple years back I had purchased a Yamaha 250SHO, with the intent of playing with it and turning it into something unique. Today, I can tell you it has made some great progress and should be well on its way to becoming complete.

The largest portion of this project was cutting a little over 4" out of the midsection. The mid starts out as 16 7/8", and is now 12 3/4". All this is done while retaining very similar to the factory oil capacity of 6L. On a typical 2-stroke, this is a much more manageable task, but factoring oil flow, the oil sump itself, water & exhaust all into one unit was not quite so straight forward.

Some other stuff we are doing to it includes solid mounts, brass bushings all around.

As far as I can see, this is the first time someone has done this to a Yamaha 4.2L, in fact I can't actually find any 4-stroke that has had the mid-section shortened in the same fashion. Hopefully this work will be done soon, and I can get to installing the re-freshed powerhead, and cleaning up a bunch of the factory "junk" under the cowl.

All of the custom fab work credit goes to a gentleman of the name Derek Lord (Instagram Hydrostream_rebuilds), he has been a pleasure to deal with, if you are in Canada and need some work done, I highly recommend you speak to him.

https://i.postimg.cc/P5vRgqcy/IMG-20230219-141153-824.jpg (https://postimg.cc/YvkRgttL)

https://i.postimg.cc/MT5P7fM6/IMG-20230219-155723-164.jpg (https://postimg.cc/MMcmxTmN)

https://i.postimg.cc/ZR4svxqs/IMG-20230219-155728-722.jpg (https://postimg.cc/FfCV2c30)

https://i.postimg.cc/XNDxnb9z/IMG-20230316-193901-599.jpg (https://postimg.cc/PNY1M03W)

https://i.postimg.cc/6qShcr9X/IMG-20230401-194553-116.jpg (https://postimg.cc/wRXJTsyf)

https://i.postimg.cc/YqGR9s3q/IMG-20230401-210513-373.jpg (https://postimg.cc/vcyf2Xkp)

https://i.postimg.cc/28swB7cd/IMG-20230401-210523-896.jpg (https://postimg.cc/QHq521rV)

https://i.postimg.cc/Cxb4CnX3/IMG-20230401-210551-132.jpg (https://postimg.cc/218vryzG)

https://i.postimg.cc/L50x7d3G/IMG-20230310-191502-945.jpg (https://postimg.cc/MfV0MF4Y)

[oldschoolltv]

Subscribed. Nice work.

[Instigator]

I like it.

There is a bunch of fans of that motor.

Please keep us posted.

[CharlieN]

Very nice,
As a welder/fabricator who is not afraid to climb out of the box I find it rewarding to see someone undertake a task like this.
Is the shaft on that engine necked down or full diameter allowing for an easy re-spline?

[canuckr]

Charlie.
It's necked down. It will be cut and welded.
I've only run across 1 Yamaha driveshaft that's not necked down. And it's ironically on a chopped down V4 I did for the wife's Viper.

[InjectorService]

Some CAD design on the snout.

https://i.postimg.cc/6QTFXPR2/IMG-20230404-183748-539.jpg (https://postimg.cc/KKS07J0x)

https://i.postimg.cc/KctwxBKN/IMG-20230404-183802-441.jpg (https://postimg.cc/ThYCcyJL)

Exhaust

https://i.postimg.cc/PxwcL8Sd/IMG-20230404-183818-259.jpg (https://postimg.cc/zbqp63mQ)

Final product (end cap will come off, it's just there to keep everything straight)

https://i.postimg.cc/BQsy6bHG/IMG-20230404-183821-787.jpg (https://postimg.cc/QV4SYXf6)

[oldschoolltv]

Looking good what boat will this go on?

[Greg G]

Subscribed. Very cool.

[DrexelSST]

This is awesome! I am going to be putting a Yamaha SHO on my 1980 Sleekcraft and would love to have a shorter shaft on it.

[InjectorService]

Unfortunately I don't have a hull yet. The long-term goal would be to get one of the following hulls and supercharge the Yamaha.

1. Talon 22
2. Liberator 22 (maybe 21 if the price is right)
3. Cougar 21 (if the price is right)

I'm also considering leaving it with no supercharger and running it on a STV Euro. But I'd have to confirm the weight beforehand. Guys are running HPDIs and Optimaxes at around 500lb, but this is probably a bit heavier.

This is sort of a premature project, but Derek presented me the opportunity and I couldn't say no.

[canuckr]

This is awesome! I am going to be putting a Yamaha SHO on my 1980 Sleekcraft and would love to have a shorter shaft on it.

Take it apart. Throw it on a pallet and stick it in the mail.

[InjectorService]

A little more snout work now that Derek is done shoveling the snow..... :cheers: :p

https://i.postimg.cc/CKwcT1kB/IMG-20230408-142341-631.jpg (https://postimg.cc/NKP6RQNB)


https://i.postimg.cc/qvs15nhH/IMG-20230408-142346-687.jpg (https://postimg.cc/18z0g8rv)


https://i.postimg.cc/sfLHQ3dq/IMG-20230408-142349-490.jpg (https://postimg.cc/BtxBR9vB)


https://i.postimg.cc/Bn9hpNvC/IMG-20230408-142352-362.jpg (https://postimg.cc/tYktC3W1)

[MarineX]

Hey Injector, I am a buddy of D lords, been cool going over to his shop and see this unfold, and keeping it hush hush! Lol

[tnelsmn]

Hey Injector, I am a buddy of D lords, been cool going over to his shop and see this unfold, and keeping it hush hush! Lol

The project is no longer under wraps!

[InjectorService]

Hey Injector, I am a buddy of D lords, been cool going over to his shop and see this unfold, and keeping it hush hush! Lol

Your lucky, I wish I lived closer. It's been killing me not seeing it in person.

It sounds like the midsection will be shipped back to me maybe later this week. Then off to powder, getting bronze bushings installed, the chaps and lower unit will be sent later. I think the driveshaft has been cut and welded already as well.

I'm hoping Derek can do the lower the way I want, should turn out pretty sweet if that's possible.

[mistah_max]

super cool project.

i know of a guy with a supercharged SHO on a 21 cougar that would be very interrested in this setup.

btw im the guy with the 22 talon who sent you my ecu earlier this year for a flash. cant wait to rig the SHO on the talon a try it out!

[DrexelSST]

Unfortunately I don't have a hull yet. The long-term goal would be to get one of the following hulls and supercharge the Yamaha.

1. Talon 22
2. Liberator 22 (maybe 21 if the price is right)
3. Cougar 21 (if the price is right)

I'm also considering leaving it with no supercharger and running it on a STV Euro. But I'd have to confirm the weight beforehand. Guys are running HPDIs and Optimaxes at around 500lb, but this is probably a bit heavier.

This is sort of a premature project, but Derek presented me the opportunity and I couldn't say no.





Yamaha says these units weigh 505lb, and with your short shaft modification... I would assume that you would be able to shave a few pounds off that number. Definitely interested in seeing what the total weight comes out to. Luckily for me, when my sleekcraft was rebuilt, it was rebuilt following the build of the only person i've seen put a yamaha 250 SHO behind it. So it's setup for the weight :)

[mistah_max]

im pretty sure i saw 534lbs real weight including cowl and oils. posted by TUFF maybe?

[Greg G]

Always wanted someone to hang that motor on a scale and get a real weight #

[canuckr]

I forget the exact numbers but it was lighter than the 300R by 10-20 lbs IIRC.

[InjectorService]

I will definateley get a weight on it once it is back. I wanted to get one before it left, but the scale I ordered came broken, and I wasn't going to let that hold up my shipping. I might have another option to weigh a stock motor though.

EDIT: And thanks for the business Max, nice to see you on SnF as well!

[Dave S]

Nice work..... Project.......There is a 18 foot Baker for sale........$1200 good boat for this.......:cheers:.......

[InjectorService]

I haven't been posting it here in a bit, maybe some of you have followed along on Instagram. But here is the latest update:

The lower unit is complete. There was no filler used, only aluminum. The plan here is to mirror polish the case.

https://i.postimg.cc/cHXz6SKh/photo-2023-05-08-16-50-30.jpg (https://postimg.cc/3401bzF0)


https://i.postimg.cc/rFdHy7qG/photo-2023-05-08-16-50-30-2.jpg (https://postimg.cc/XpbLQHGX)


https://i.postimg.cc/Y9qX5sXW/photo-2023-05-08-16-50-32-4.jpg (https://postimg.cc/Ff8gcDXr)


https://i.postimg.cc/Hs7S15tB/photo-2023-05-08-16-50-32-5.jpg (https://postimg.cc/GHdPk4Vy)


https://i.postimg.cc/FRWPNVqn/photo-2023-05-08-16-50-33-2.jpg (https://postimg.cc/7Gz1N0qg)


https://i.postimg.cc/qBFmFQ2N/photo-2023-05-08-16-50-33-4.jpg (https://postimg.cc/DmqdJrjh)


https://i.postimg.cc/90sJqFcd/photo-2023-05-08-16-50-33-5.jpg (https://postimages.org/)


https://i.postimg.cc/6prYyXgZ/photo-2023-05-08-16-50-34.jpg (https://postimages.org/)


https://i.postimg.cc/x8X6CbVj/photo-2023-05-08-16-50-34-2.jpg (https://postimg.cc/FkQyCzKw)

[InjectorService]

The assembled unit. And clearance check.

https://i.postimg.cc/XYxGq1jL/photo-2023-05-08-17-01-43.jpg (https://postimg.cc/HrcsP278)


https://i.postimg.cc/L8mgHFph/photo-2023-05-08-17-02-03.jpg (https://postimages.org/)

[TwzteD]

Hell yeah awesome job man, the four strokes are the inevitable future I'm glad somebody is doing stuff like this because eventually everybody else will have no other choice.

[MarineX]

Hell yeah awesome job man, the four strokes are the inevitable future I'm glad somebody is doing stuff like this because eventually everybody else will have no other choice.

Yup, 4 strokes are the covid shot of the outboard world.

[mistah_max]

did you get that cone from MCR performance in ontario?

[canuckr]

did you get that cone from MCR performance in ontario?

Supplied by the originator of the post. They are nizpro cones. Injector service is also a Nizpro dealer, offers tunes and gets Nizpro parts.

[mistah_max]

Supplied by the originator of the post. They are nizpro cones. Injector service is also a Nizpro dealer, offers tunes and gets Nizpro parts.

ok cool. i knew blake is a nizpro dealer. the tuned my ecm in feb. MCR is a new performance shop that just opened and they offer a similar fully welded nosecone. it may be that he's also a nizpro dealer and he get his cones from them also. not sure, but its nice to see some performance parts available in canada for those SHO's

[Jamescole]

Nosecone fab looks really good! Great job Derek.

[DrexelSST]

Any update on this build???

[canuckr]

At the moment we are getting dicked around by freight companies. But that should be sorted out by tomorrow.

[InjectorService]

I received a care package from Derek today, finally after fighting with shipping companies for a couple of weeks. Hopefully this means we can continue with the project as planned!

https://i.postimg.cc/tT9Sqz7K/photo-2023-05-30-10-38-27.jpg (https://postimg.cc/Z9DFjp8H)

[InjectorService]

Got the paint stripped off the lower unit, off to polishing. I'm not sure how it will turn out as it is very pitted, but we're going to try!

Midsection was also dropped off for powdercoat so should see that back soon. Once I get it Ill bring the trim unit & lower pan for paint match. Then bronze bushings, reassemble. By that time the block should be back from machining, reassemble. Id say mid July would be a good time for a first fire.

https://i.postimg.cc/xdTdyd5S/photo-2023-06-21-12-25-42.jpg (https://postimg.cc/dhpvJwgW)

[InjectorService]

Small update again. Powdercoater messed up, painter messed up. So more delays but some stuff is assembled. Powerhead is together. Bronze bushings are in, should be some big progress next week.

https://i.postimg.cc/DZ9YpYPt/20230728-141700.jpg (https://postimg.cc/wykV72PV)

[InjectorService]

HERE IT IS! What you've all been waiting for! The first ever 15" Yamaha SHO!


https://youtube.com/shorts/3wiF_wF6DbA?si=pHjYU9mbmqpnXpLA

[DrexelSST]

What kind of hull is this going on? I can't wait to see it hit some impressive numbers. This is huge for the Yamaha sho platform.

[CharlieN]

That will be a fun ride.

[mistah_max]

imo this should be gettin way more attention then it is!

this is one of my 'go to' threads when i log on here.

can wait to see it done!

[oldschoolltv]

I know it is a niche market but Yamaha and Merc need to make us a 15 inch motor. Eventually all the old motors we use will die off.

[724Bravo]

Awesome work there Eh!!

I'm a SHO fan and a Yamaha OB guy for that matter, I'm in my 60's and have run all of the mfg's and Yamaha has always been my first choice.

What you have transformed this SHO to is just amazing and I the rest of us can't wait to see this baby run. :thumbsup:

I have a new 22' Liberator hull on order to be rigged by myself and the standard recommended motor is a Mercury 300r, I would love to throw a tuned 250SHO with a nose cone on it but have reservations about the performance as far as numbers go.

Has anyone that has installed the be it Bob's or Nizpro nose cone seen any great performance increases out of it ?

I did find one thread in a Yamaha Bass Boat forum and there was no top speed gain but did see better cooling water flow and temps.

Anyway, keep up the great work, and Thanks

[canuckr]

Awesome work there Eh!!

I'm a SHO fan and a Yamaha OB guy for that matter, I'm in my 60's and have run all of the mfg's and Yamaha has always been my first choice.

What you have transformed this SHO to is just amazing and I the rest of us can't wait to see this baby run. :thumbsup:

I have a new 22' Liberator hull on order to be rigged by myself and the standard recommended motor is a Mercury 300r, I would love to throw a tuned 250SHO with a nose cone on it but have reservations about the performance as far as numbers go.

Has anyone that has installed the be it Bob's or Nizpro nose cone seen any great performance increases out of it ?

I did find one thread in a Yamaha Bass Boat forum and there was no top speed gain but did see better cooling water flow and temps.

Anyway, keep up the great work, and Thanks

You have a DM re: nizpro cones and numbers.

[X-DEWAR-X]

Awesome work there Eh!!

I'm a SHO fan and a Yamaha OB guy for that matter, I'm in my 60's and have run all of the mfg's and Yamaha has always been my first choice.

What you have transformed this SHO to is just amazing and I the rest of us can't wait to see this baby run. :thumbsup:

I have a new 22' Liberator hull on order to be rigged by myself and the standard recommended motor is a Mercury 300r, I would love to throw a tuned 250SHO with a nose cone on it but have reservations about the performance as far as numbers go.

Has anyone that has installed the be it Bob's or Nizpro nose cone seen any great performance increases out of it ?

I did find one thread in a Yamaha Bass Boat forum and there was no top speed gain but did see better cooling water flow and temps.

Anyway, keep up the great work, and Thanks

Derek coned the SHO gearcase on my Venom for me last fall. I gained over 10MPH on topend. Overall stability and drivability of the boat were drastically increased as well.

[DrexelSST]

Awesome work there Eh!!

I'm a SHO fan and a Yamaha OB guy for that matter, I'm in my 60's and have run all of the mfg's and Yamaha has always been my first choice.

What you have transformed this SHO to is just amazing and I the rest of us can't wait to see this baby run. :thumbsup:

I have a new 22' Liberator hull on order to be rigged by myself and the standard recommended motor is a Mercury 300r, I would love to throw a tuned 250SHO with a nose cone on it but have reservations about the performance as far as numbers go.

Has anyone that has installed the be it Bob's or Nizpro nose cone seen any great performance increases out of it ?

I did find one thread in a Yamaha Bass Boat forum and there was no top speed gain but did see better cooling water flow and temps.

Anyway, keep up the great work, and Thanks

There are a couple Yamaha SHO Liberators out there, but nobody has really documented the performance difference VS a 300R. I would love to see someone take on that job. And then supercharge the SHO with the new 525hp tune and then see what it can really do.