HELP need jet specs!

[Stavissimo]

I have a Yamaha gp760 that I am trying to get on the water before the summers over

I am running the aftermarket exhaust from factory pipe that was made to fit on blaster 2s and the gp760
I also am running a Ada girdled Head with 35cc domes.

Factory pipe has an instructional manual for this installation but I already blew a cylinder with the jet specs they recommended.

If anyone has experience with this pipe could really use some help. Thank you!

 

[Half flip95]

blew the cylinder?
like it exploded?

if you are looking at the right instruction manual it cant be that far off. you might have other issues

http://www.factorypipe.com/t_carbtuning.php

 

[Stavissimo]

Wow didn’t know that... so if I run 37 domes I could run 93 octane fuel

The 35CC Domes requires 100+ Octane Fuel!

That's 200+ psi Compression.

The Stock 760 Engine with Stock Head and Stock Compression alone needs at least 93 Octane with the Factory Pipe installed.

Read and Heed:

"Factory Pipe Instructions GP760 / WaveBlaster II IMPORTANT NOTES
1. You must run fuel with a minimum octane rating of 92 (premium pump fuel). Running a lower octane fuel can cause detonation and serious engine damage.
2. Always warm up the engine prior to full throttle/high speed operation. "

Wow didn’t know that... so if I run 37 domes I could run 93 octane fuel ?

 

[Stavissimo]

blew the cylinder?
like it exploded?

if you are looking at the right instruction manual it cant be that far off. you might have other issues

http://www.factorypipe.com/t_carbtuning.php

Yeah cylinder had a small crack on one side and lost compression. Already replaced rebuilt engine new seals/gaskets and all. I did put 93 octane though with the 35cc domes... not sure what happened there, would just running a stock head instead of a Ada girdled make my life easier? Thanks

 

[Half flip95]

you had the cylinder re-sleeved?

incorrect jetting or low octane usually = melted pistons

 

[Stavissimo]

Re sleeved? The new cylinders do I believe

 

[Half flip95]

ok, put it back together with your stock head and run it on pump gas. just go easy on it and see what it does then make adjustments from there

 

[Mdavies_02]

Yeah cylinder had a small crack on one side and lost compression. Already replaced rebuilt engine new seals/gaskets and all. I did put 93 octane though with the 35cc domes... not sure what happened there, would just running a stock head instead of a Ada girdled make my life easier? Thanks

As per ADA website. Pretty simple to see if you get 37cc domes and run 93 octane you will find trouble once again...

Stock head may be your best option.