B1 1200 build questions.

[blaster121]

Im building a 1200 b1 currently and have only done the 1100, im reading conflicting things about tubing and waterbox diameter. Is 3in the whole way necessary/mandatory? Or is 2inch sufficient? Also are the shorter rhaas mounts needed or just lowered center gravity ideal? Thanks in advance! The old sticky builds are gone or I just couldn't find them.

 

[WFO Speedracer]

Okay the reason the lowered mounts are needed is because you are putting a plate on top of where the mounts bolt to the hull , I believe they are using 3/16 plate so when you bolt everything up the rear mounts just have holes the stock bolts go through then the mount sits on top of the plate , on the front mounts those are extended forward and the plates are drilled and tapped for the front mounts, the old front mount location also have just holes and the plates bolt to the old locations, its the same thing I did on my 300SX conversion basically .

Long story short , you are raising the mounts up 3/16"higher with the plates so the mounts need to be 3/16 shorter than the stock mounts to compensate .

The other way to do it is the link below , using the ADA adaptors, these of course use stock mounts.

https://www.adaracing.com/yamaha-engine-mount-conversion-3-cyl-blaster

 

[blaster121]

Okay the reason the lowered mounts are needed is because you are putting a plate on top of where the mounts bolt to the hull , I believe they are using 3/16 plate so when you bolt everything up the rear mounts just have holes the stock bolts go through then the mount sits on top of the plate , on the front mounts those are extended forward and the plates are drilled and tapped for the front mounts, the old front mount location also have just holes and the plates bolt to the old locations, its the same thing I did on my 300SX conversion basically .

Long story short , you are raising the mounts up 3/16"higher with the plates so the mounts need to be 3/16 shorter than the stock mounts to compensate .

The other way to do it is the link below , using the ADA adaptors, these of course use stock mounts.

https://www.adaracing.com/yamaha-engine-mount-conversion-3-cyl-blaster

Ok that makes sense, i thought the project is just bought came with ada but now that its here it will be on top of someone's plate they made or I haven't seen. Is 3inch exhaust piping necessary??

 

[WFO Speedracer]

Yes the three inch exhaust tubing is pretty much necessary, that 's what those engines were designed to run , you will lose performance if you restrict the exhaust flow.

Those lowered mounts were originally for my Blaster ll 1200 build , I changed my mind and have decided to go the ADA route on mine with stock mounts, either way will work.

 

[blaster121]

Yes the three inch exhaust tubing is pretty much necessary, that 's what those engines were designed to run , you will lose performance if you restrict the exhaust flow.

Those lowered mounts were originally for my Blaster ll 1200 build , I changed my mind and have decided to go the ADA route on mine with stock mounts, either way will work.

Does anyone make a water box with 3 in and out?

 

[blaster121]

Does anyone make a water box with 3 in and out?

Or is 2inch in and out with 3in tubing sufficient? So far i 100% regret buying this project lol I've done kawasaki a couple times just wanted something different.

 

[WFO Speedracer]

I don't mind helping you here and there but , this site is chock full of builds and info from people who have already done this swap , I can guarantee this has already been covered many times , that being said follow the link and start reading .

Detailed 'Blaster 1100 Build (how Yamaha could have done it)

After I completely rebuilt my first 'Blaster and did a 718 Jetmaniac ported 61X/61X, I completely fell in love with it. I spent my last two Summers on Lake Erie and smaller inland lakes around the Buffalo, NY area learning how much fun the 'Blaster is. It does everything that I want to do and...

www.x-h2o.com

 

[john zigler]

Reach out to the Rad Dudes, they can make you a water box.

 

[WFO Speedracer]

Yamaha Wave Raider 1100 Port Side Exhaust Muffler Waterbox Blaster Conversion | eBay

Yamaha port side waterbox, removed from a '95 Raider 1100. GJ1-67550-00-00 GJ1-67550-01-00.

www.ebay.com

If you don't want to spend a small fortune on the Rad Duded box.

 

[kevbo]

A two stroke with a good tuned pipe needs back pressure to work so a very quiet/restrictive muffler can be used. Single pipe triples don’t qualify so they will be throttled by back pressure, even worse than a four stroke would be. That’s why Yamaha used massive exhaust hoses. The same can be seen on the early 650-701 single carb twins. Those used untuned exhausts and had much larger downstream hoses than seadoo and Kawasaki used on much faster boats.

 

[WFO Speedracer]

One more thing and forgive me if I am wrong here but I am working from memory but I believe the Rad dudes boxes were just 701-760 waterboxes with bigger inlets and exits tig welded in , most of the Yamaha sitdowns except for the Blaster, VXR , Wavejammer and the Waverunner lll had the nicely made round aluminum waterboxes.

If I remember right they were doing this because Waveraider boxes were getting hard to find and at the time the demand was really high , now , not so much.