Pro-tec head.. Will I notice a difference between domes? Will it be safe?

[SMV RYDER]

I am running 36cc domes at 8600 feet above sea level with zero detonation while running 91 pump fuel. It’s the weekend so I can’t call pro-tec but does anyone think I can get away with a 34cc or possibly a 32cc dome on pump 91 or getting to wild for pump gas?
I will call on Monday but just super curious if anyone has a answer. Thank you.

Pro-Tec Cylinder Head Dome Yamaha 760 / 1200 (65U) – Pro-Tec Performance

Pro-Tec C2 / C3 cylinder head dome. Fits Yamaha 760 (64X) and1200 (65U) non-powervalve engines. Currently out of stock on 30, 36, 38, 40, 42 & 44cc domes.

pro-tec.us

 

[john zigler]

61x cly, or 62t? Stock porting, or ported? What is your riding style? Do you just blip the throttle and jump waves, or hold for WOT runs? What is your timing at? Stock CDI or MSD?

We are @ 700 feet here and run 35cc domes on a stock 62t cly with no issues. I add a little bit of timing, and recommend NO long WOT runs.

I would sure think @ 8500 feet you would be fine with 34cc domes. Not sure about 32's.

 

[Storbeck]

You should also specify the displacement of your motor. Your link is for domes that fit at least an 84mm bore (753cc) and probably can go a little higher than that, a 753+cc motor will have a higher compression ratio with any given done size than a 701.

 

[Storbeck]

Also be careful taking advice from people accustomed to b pipes and ada heads. (With that said John Ziggler is one of the guys I WOULD listen too)

That looks like a type 9, combined with that head, another guy I'd be asking is @MTRHEAD

I don't know if anybody is going to be able to speak for the high elevation though.

 

[SMV RYDER]

61x cly, or 62t? Stock porting, or ported? What is your riding style? Do you just blip the throttle and jump waves, or hold for WOT runs? What is your timing at? Stock CDI or MSD?

We are @ 700 feet here and run 35cc domes on a stock 62t cly with no issues. I add a little bit of timing, and recommend NO long WOT runs.

I would sure think @ 8500 feet you would be fine with 34cc domes. Not sure about 32's.

I am still learning all the terms.. It’s a 760 so 64x? Ported. I do a bit of both, love hitting wakeboard wakes but love just holding her WFO as well. Still a noob and don’t know where my timing is at, sorry about that. I am using a stock cdi with rev limiter adjustments, it just got installed and going to set the rev limiter at 8500..

So being in Wisconsin you are probably running 91 to 93 octane from the pump with the 35cc domes? I like to hear that! My wife was born in Oconomowoc/ lived on Lac La Belle her whole life.

I think I am going with 34cc per your recommendation.

Thank you

 

[SMV RYDER]

You should also specify the displacement of your motor. Your link is for domes that fit at least an 84mm bore (753cc) and probably can go a little higher than that, a 753+cc motor will have a higher compression ratio with any given done size than a 701.

Thank you. It’s a 760 (753cc) also didn’t know it wasn’t a 760….

 

[SMV RYDER]

Also be careful taking advice from people accustomed to b pipes and ada heads. (With that said John Ziggler is one of the guys I WOULD listen too)

That looks like a type 9, combined with that head, another guy I'd be asking is @MTRHEAD

I don't know if anybody is going to be able to speak for the high elevation though.

Thank you. I feel this is definitely an odd set up but I like it. She f’ing rips mid to top for sure. I am running a 9/15 solas impeller but need a wee bit more down low.. I am still learning jetting and tuning tricks for the carbs so I feel I can get it better but the B pipe will probably be the fix.. we will see
This awesome website helped me identify it was a type 9. I will hit up MTRHEAD as well.
Jet skiing at 8K is just a challenge.

 

[john zigler]

I am still learning all the terms.. It’s a 760 so 64x? Ported. I do a bit of both, love hitting wakeboard wakes but love just holding her WFO as well. Still a noob and don’t know where my timing is at, sorry about that. I am using a stock cdi with rev limiter adjustments, it just got installed and going to set the rev limiter at 8500..

So being in Wisconsin you are probably running 91 to 93 octane from the pump with the 35cc domes? I like to hear that! My wife was born in Oconomowoc/ lived on Lac La Belle her whole life.

I think I am going with 34cc per your recommendation.

Thank you

Ok, sorry as I "assumed" you had a 701 of some type. 760 is different. I am going to respectfully bow out here as I am really unfamiliar with build at your elevation, and do NOT want you thinking what I say here is good advice for your build. You need to learn about reading piston wash, and looking for detonation. I wish you luck.

 

[SMV RYDER]

Ok, sorry as I "assumed" you had a 701 of some type. 760 is different. I am going to respectfully bow out here as I am really unfamiliar with build at your elevation, and do NOT want you thinking what I say here is good advice for your build. You need to learn about reading piston wash, and looking for detonation. I wish you luck.

Thank you very much for your honesty. I appreciate it. Heck may be just leave it alone and just rip it..

 

[Quinc]

Check out the zeeltronic ignition. You can adjust the timing to give you that bottom end power you want before it gets on the pipe. @Jr. sells them with customer specific tunes.

 

[kevbo]

Thank you. I feel this is definitely an odd set up but I like it. She f’ing rips mid to top for sure. I am running a 9/15 solas impeller but need a wee bit more down low.. I am still learning jetting and tuning tricks for the carbs so I feel I can get it better but the B pipe will probably be the fix.. we will see
This awesome website helped me identify it was a type 9. I will hit up MTRHEAD as well.
Jet skiing at 8K is just a challenge.

Bore your nozzle, that will give you more thrust. It may be difficult to find anyone who has done meltdown testing at 8000 feet but adding a little compression and reducing the pump load is the path I would take.

 

[bored&stroked]

We have one superjet in the group running 220psi domes on a 760 and 91 octane. Its all about how you use the throttle.

 

[rhugo21]

If it works fine, leave it how it is and go rip