'Blaster 61x/61x to 62T/61x for more bottom end?

[jpswift1]

I was hoping you guys could give me some advice on what direction to go with my 'Blaster. I currently have a 61x/61x with a 718 Jet Maniac rec ported top end and milled stock head to about 165 PSI. I have a 10/16 Hooker prop, Solas intake grate, Pro Tec ride plate, and Riva Red pipe. I'm happy with the setup now and it runs and ride nice, but I'd like a little more bottom end hit. I am currently hooking up dual cooling, I got a Factory B pipe w/ Mod chamber, and a Hooker 9/16 prop in hopes that this combination will give me a little more low end hit.

Should I..............

A. Leave the 61x/61X setup that I currently have and just go with the mods that I'm currently adding that I mentioned above?

Or............

B. Put the ported Jet Maniac 61X cylinder on 62T bottom end cases (that I will have ported) with dual 38's in addition to the mods that I mentioned above?

Will ported 62T cases with dual 38's be worth the money and time and give me noticeable extra hit down low that I want? Thanks in advance for the input!

 

[kevbo]

I would bore the nozzle and note how quickly the pipe responds to throttle inputs. Adjust the impeller pitch if needed. The Mod pipe and lower pitch impeller should turn over 7000 rpm so the stock rev limit needs to be raised. A pair of 44s, even stock 760 carbs will make the pipe hit a little harder but it wont be 100% without a mag pump stator. I dont think you will ever get enough power in a blaster. A little more power in a standup will actually wear you out where a blaster never will.

 

[jpswift1]

I would bore the nozzle and note how quickly the pipe responds to throttle inputs. Adjust the impeller pitch if needed. The Mod pipe and lower pitch impeller should turn over 7000 rpm so the stock rev limit needs to be raised. A pair of 44s, even stock 760 carbs will make the pipe hit a little harder but it wont be 100% without a mag pump stator. I dont think you will ever get enough power in a blaster. A little more power in a standup will actually wear you out where a blaster never will.

Thanks for the input. I didn't even think about boring the nozzle. Would a smaller cone have the same effect as boring the nozzle?

I thought about a mag pump stator, but didn't want to spend that much money. You're right about never having enough power in a 'Blaster. That's why I bought a nicely modified Superjet with a 62t/61x with a Factory B pipe and I also built a 'Blaster and I swapped an ported 1100 Yamaha triple in it. I just want my 701 'Blaster to hit a little harder down low so I can launch off the waves a little more in Lake Erie. When we get big waves in the Great Lakes, they are very close together, not spaced out farther like when you're riding in the ocean, so the more low end hit really helps you launch better.

 

[Pro-pulsion]

I went through the ported 62t cases thing and just this past summer went back to stock 62t case configuration. I personally prefer the stock case porting. After I did my porting work which took lots of time and I made sure to be as meticulous about it as I could be. In a back to back test last summer because I was replacing my crank seals, I went back to stock ports by having all that work fill welded, something about the way it was running made me suspect maybe the porting was just slightly different offsetting airflow value between both cylinders. I really didn't notice any changes in terms of gains or losses but it did make the ski run a little better/smoother. It also makes me wonder if case porting shortens crank life because you are taking away some fuel mixture from directly entering the crank bearings and sending it straight up the transfer ports right out of the gate. Just a thought though, no proof to back that up. Going with the 62t cases has it's benefits, the dual 44's really work well when set up nicely. I just did a complete re-tuning of a friend's Blaster with a B-piped 701, 62t cased with dual 44's and an MSD enhancer, Riva head popping at 180 compression and v-force reeds. Changed his water settings by closing solidly the screw at the bottom... the one by the floor of the engine compartment and middle screw, opening the top one about 5/16 of a turn from closed and properly calibrating his carbs. On a stock 144 pump, stock pump cone and old school small hub impeller that ski would leap out of flat water. Not like a SJ, but it would get the hull out with only the ride plate still in.

I was really impressed how well it responded to the new tuning. The previous owner had the carbs a little bit off from where I set them and totally opposite pipe setup. It was ok that way, but wouldn't surprise you every time you hit the throttle. Now it does, he tells me all the time it's a whole new beast to him and catches him off guard every now and then when he touches the go lever lol. He used to have a 61x/61x 701 Blaster as well, it worked well but not quite as well as this one does. It was similarly set up other than had a single Buckshot 46 carb on it, same pipe, not sure of water settings though, stock milled head popping at about 180 compression, MSD enhancer and can't remember what reeds and cages, it did work well it just didn't work as well. That Buckshot carb was a pig to tune too, new kit inside and still finicky to get right on the balance point of running well across the board. Very temperamental almost every other day with changing atmospheric conditions, had to constantly tweak the mixing screws until it finally seemed to work well enough for all ranges on most days.

 

[jpswift1]

That's exactly what kind of feedback I was looking for. I also never even thought about the point that you raised about the possibility of shortened crank life. I think I'm going to eventually switch over to a 62t bottom end and dual 38's.

Did you happen to remember how much more fuel the 62t/61x ski used compared to 61x/61x ski?

 

[Pro-pulsion]

That much I don't know on the Blaster hull but what I do remember is when I tried a single carb setup on my SJ the fuel consumption seemed to be about the same. But the 61x base doesn't flow as much as a 62t so there is that to keep in mind. When you go with 62t cases you will be getting a better flowing case design. The natural requirement to more airflow for proper fuel mixture is more fuel. I wouldn't be too concerned with that though. On stock 38's with open flame arrestors not the stock airbox, and jetted for the B-pipe my RN gets about 1 hour 15 minutes of run time on the stock 18 liter tank (4.76 U.S. gal.) My friend's modded out Blasters typically get on a stock tank around 2 hours of run time and then he refills. His Blasters are the one I mentioned above, and his second runs a set of Novi 48's, modified cases being filled voids with an 84mm bore to get him in the 760 size range on a 62t bottom end. That ski I'll be re-tuning this year to the same pipe settings and completely redoing the carb setup as well. Right now, the one I tuned already last summer well outperforms this one with the Novi carbs. I don't recall if it has ported cases.

 

[jpswift1]

Sounds like 38's wouldn't be a game changer when it comes to fuel consumption. When I go through the 61x/61x engine on my 'Blaster again I think I'll swap the bottom end over to the 62t that I have. It sounds like the Superjet is the same as mine when it comes to fuel consumption. I have the same exact set up that you have and if I'm easy on the throttle (which is hard to do) I can get a little longer than and hour and half or run time, but it's usually right around there.

 

[Pro-pulsion]

Mine is a little bit harder on fuel but I have a couple of very small extras I did inside to increase airflow slightly. Before I did any of these mods, my fully stock SJ setup was giving me about 2 hours on a tank as well just doing what we do, surf style freeride. Blipping the gasser for the waves, no long haul one throttle position riding. The on/off throttle use will be the best fuel economy for us. If you're on the throttle full time, it usually means your hull is also in the water full time. That's a lot of drag and chugs some hefty fuel to push through it lol