HPE Stage 2 and Dual Powerbombs

[James Findling]

Set up as is.
'01 Superjet
Riva
Riva Dual Powerbombs with dual pulse lines with Fly flame arrestors
Riva Dry Pipe
Riva Girdled Head @ 175 psi @ 81mm @ 35cc domes
Riva Groovy Ride plate
Riva Intake grate
Riva Rear mini Sponsons

My buddy was riding this ski harder than I would've. I'll add pics but it looks like detonation from too-hot cylinder walls. (He was riding like 2-3 miles flat out, I was worried but couldn't keep up without running my ski hot.) Pistons and cylinders are toast. They were 175ish each. (Sounds tired) Now the front is 40 psi and the rear 160 psi roughly. The plan is I have a HPE cylinder to swap, ported out stage 2 matched up with ProX 82mm pistons without a boost hole. The plan is to sell the Riva girdled head and domes, sell the Riva dry pipe. Swap to a new ADA girdled head and new Factory Limited Pipe. Most likely add MSD Enhancer and Lightened Flywheel. Before I do I was curious about running dual Powerbombs on this setup. (It's overkill right.) Any baseline specs for these carbs? I am not very carb friendly. Also what domes to run? It's hard to trust ADA when they sent me "35cc" domes that took my '09 SJ from 170psi stock to 215psi.

Any help or advice would be appreciated.

 

[James Findling]

Thanks for the help guys. No wonder I think this forum is useless!

Just kidding I was trolling for help. Thanks for chiming in homies.

 

[Turtle]

maybe if you posted in the right section you may have gotten a better response? Just a thought

http://www.x-h2o.com/index.php?forums/driveline.29/

 

[D-Roc]

135 mains 75 or 72.5 pilots 2.5 n/s with 115 spring should give 20-21 psi pop off


Sent from my iPhone using Tapatalk

 

[///M3]

Saw this ski on craigslist in VA, never understood what that shirt or towel was wrapped around the top of the pole..

 

[x2mafia]

What jetting are you currently running. Are they 48's? Are you running stock stroke? Your post is kinda confusing so i think thats why no one replied. I had a 5mil HPE motor running a TNT V2 pipe. Your setup is kinda funky with all that riva stuff which is also why I think no one said anything.

I was running 122.5 pilots 117.5 Mains 2.0 NS and 95 gr springs but I had a little more motor than you. Without knowing the jetting its hard to say what killed the motor but not much will last 3 miles WOT.

Ive seen 35cc domes take a 2014 superjet to 235psi

 

[James Findling]

maybe if you posted in the right section you may have gotten a better response? Just a thought

http://www.x-h2o.com/index.php?forums/driveline.29/

I mean it is my ski that I'm building back up. I mean it's not from the ground up though. I'll post there. Thanks.

 

[James Findling]

Saw this ski on craigslist in VA, never understood what that shirt or towel was wrapped around the top of the pole..

Yeah I got it maybe in June of 2017 like maybe an hour west of Annapolis, MD. I thought it was a good deal... the rope is for tows because it the dry pipe pops the coupler literally every season. You're just on borrowed time on season 2. It blew the coupler like two months after. Luckily it was close and I towed it with my other SJ. The guy was even like, "if you're good you can take the hood off and hold it under your arm and limp it home with the other hand" hahah.

 

[x2mafia]

How are you gonna reply to the 2 people that literally had nothing constructive to say then totally skip the only comment with a glimmer of hope to solve your situation lol

 

[James Findling]

How are you gonna reply to the 2 people that literally had nothing constructive to say then totally skip the only comment with a glimmer of hope to solve your situation lol

My bad I was out at dinner. I have to actually think about the constructive comments. I was going to post something like hold up gimme a minute but I figured it was a waste.

 

[x2mafia]

Haha gotcha

 

[James Findling]

What jetting are you currently running. Are they 48's? Are you running stock stroke? Your post is kinda confusing so i think thats why no one replied. I had a 5mil HPE motor running a TNT V2 pipe. Your setup is kinda funky with all that riva stuff which is also why I think no one said anything.

I was running 122.5 pilots 117.5 Mains 2.0 NS and 95 gr springs but I had a little more motor than you. Without knowing the jetting its hard to say what killed the motor but not much will last 3 miles WOT.

Ive seen 35cc domes take a 2014 superjet to 235psi

No idea on jetting. I know they are Powerbombs but I don't know if they're 48s. Going to be stock stroke.

This will be the setup if anyone has opinions lemme know.
Ada Girdled Head with ??? domes (need to figure out)(new)
82mm Pro X pistons without boost port
Factory Limited Pipe (new)
HPE Stage two ported 61x cylinder
62T cases stock (stock cases '01 SJ)
62T cases are stock but with both pulse lines tapped like a 760
Dual Powerbombs (jetting unknown)
Riva Intake (Whatever the Bombs are sitting on)
Polished prop, ??? (No idea what it is)
Lightened stock flywheel, need to find someone to lighten it or maybe buy one.
MSD Enhancer (is there a reason not to install this?, how does it effect characteristics with porting) (new)
Reeds? (Might as well replace them if they're stock, since they're 17 years old. Was thinking Boyesen- Carbon Tech or Pro Series dual action? Or something else?)(new)

I might as well pull the whole engine because it makes sense. Have to do lightened flywheel anyways. Sounds like I might as well pull the carbs and refresh them and figure out jetting. I'm already going to pull the exhaust manifold because I'm going to sell the whole Riva dry pipe.

Building for freestyle and surf riding. Doesn't need to be high strung because it is back up boat. 93 octane and reliability would be nice.

It's long winded and maybe confusing but I'm trying to tell y'all everything in a clear, concise way. The more information the better. The questions I have I can't seem to find the answers to, that's why I'm here.

 

[James Findling]

In my opinion the old setup blew because of overheating the cylinders walls causing detonation from the cylinder walls. Keep in mind it only put up 175 psi in each hole with the Riva setup, stock bore 35cc domes. I could post pics later. I suppose I might know more once I pull the cylinder. Getting the head off it looked like the pistons had detonation from the cylinder walls. Very light damage, cylinder walls have visible scoring but the walls feel smooth, but not perfect obviously. Below the plug on the piston it's fine. (BR8HS) I wasn't riding the ski at the time but it was being driven at high speed for too long of distances without cool down.