Big bore vs 4 mil HPE drop in kit

[holeshot]

Decking the 760 cylinder doesnt effect blowdown period which cannot be ignored. Yes it lowers port timing and can help slightly. Lowering the cylinder drops the sleeves further into the intake and transfer cups. It also raises primary compression, adds pumping losses and reduces case volume, not good for low end.
HPE 4 and 5 mil long rod kits lift the cyl up out of the intake and transfer cups substancially, increase crankcase volume, address blowdown period and port timing, the long rod dwells shorter at bdc which improves intake cycle. The list goes on. Basically im saying my 4 and 5 mil kits are not the same as other 5 mil builds you may have ridden.

 

[orangefinger]

I have owned and rode 61x/61x 62T/61x 62T/Team Scream BB 61x 64X/64X 760 Ported 62T/ 61x 876 cc BB 4mm >> prior to the " $$$ Stuff "

The combo I liked the most was TS 62T/61x BB 781cc , the engine felt light and extremely powerful , with a great snap right of the bottom, all had been run with B-pipe , enhancer, 144 Mag etc ..... second was the 64X Ported 760 by Paul , the power band came a tad later but very hard till the end..... I thought these both compared the most

the 87cc was a completely different beast due to 4mm

I am unfamiliar with some of the newer set ups but that just my experience

 

[SmittySX]

Dont leave out the 760 if you are looking for a budget freestyle engine. Granted, any combo of 61x, 62t, 64x has potential to be great, 61x is last for me. Below is a ported 760cc (62t), b pipe, OEM pump, OEM carbs, msd enhancer, etc. Your basic "modded superjet" drive line, just in a lighter hull.

 

[rowsto]

Dont leave out the 760 if you are looking for a budget freestyle engine. Granted, any combo of 61x, 62t, 64x has potential to be great, 61x is last for me. Below is a ported 760cc (62t), b pipe, OEM pump, OEM carbs, msd enhancer, etc. Your basic "modded superjet" drive line, just in a lighter hull.

Strange that you and I have 2 completely different opinions, perhaps different riding style, maybe my 760 was a piece of poo, who knows. Seems some people swear by the 61x and others by the 64

 

[holeshot]

I would be willing to put a 4 mil with ported 760 cyl up against a big bore 781 for comparison. No case porting so its an even comparison.
The 4 mil would have a brand new crank, crank seals, pistons and bore, essentially a new motor. The big bore guys are stuck with an old crank i guess.....

 

[alano64]

Thanks to everyone chiming in, I'll probably end up with the HPE 4 mil on a ported 760 cylinder like Roseand. Keep us updated.

 

[thomps33]

I would be willing to put a 4 mil with ported 760 cyl up against a big bore 781 for comparison. No case porting so its an even comparison.
The 4 mil would have a brand new crank, crank seals, pistons and bore, essentially a new motor. The big bore guys are stuck with an old crank i guess.....

Will you have any motors at WF available for a test ride?

 

[thomps33]

I'll post more on this in a week or so, but I have an HPE 4mil kit on the way with a ported 760 cylinder(that hasn't been decked) I'll be running.

Sent from my SM-G920V using Tapatalk

Any ride time with this motor yet?

 

[holeshot]

Will you have any motors at WF available for a test ride?

I think so

 

[jagerauto]

Well I've finally got my 4mil dialed in enough to brag about it a little. So here we go. Tons of power, lots of low end hit. I need a slightly larger impeller, I think I have a 10/16 hooker on it now. I'm running all the basics and also a dasa intake, oem 46mm mikunis, and a solas pump. 62T cylinders bored over to 82mm which should put it right at 760cc. The first day out on the water the carbs were so far off, my wires didn't have a good connection on the plugs, and my water box is cracked and has a leak. With all that, it sounded like total ass but I was still surprised that something that was running the way it was had the power that it did. I still need to get the water box welded, so that's next on the list to try to get the bottom end crisper.

When I was thinking about the long rod setup in the beginning and gathering opinions I got a lot of the "won't have that low end punch with a long rod"... But not only is that not true, but even if it were I'm on a heavy super jet in surf that has to carry speed into anything to make anything out of it so, what does it matter. Of course I weigh all of 145lbs soaking wet with my gear so, I could be a bad example for the low end.

Extremely happy with the HPE 4Mil stroker kit, and Hobson is extremely helpful. Can't wait to report bad with a more dialed in report!

 

[masterblaster]

Knew u would dig that setup for the money hunter

 

[Quinc]

Well I've finally got my 4mil dialed in enough to brag about it a little. So here we go. Tons of power, lots of low end hit. I need a slightly larger impeller, I think I have a 10/16 hooker on it now. I'm running all the basics and also a dasa intake, oem 46mm mikunis, and a solas pump. 62T cylinders bored over to 82mm which should put it right at 760cc. The first day out on the water the carbs were so far off, my wires didn't have a good connection on the plugs, and my water box is cracked and has a leak. With all that, it sounded like total ass but I was still surprised that something that was running the way it was had the power that it did. I still need to get the water box welded, so that's next on the list to try to get the bottom end crisper.

When I was thinking about the long rod setup in the beginning and gathering opinions I got a lot of the "won't have that low end punch with a long rod"... But not only is that not true, but even if it were I'm on a heavy super jet in surf that has to carry speed into anything to make anything out of it so, what does it matter. Of course I weigh all of 145lbs soaking wet with my gear so, I could be a bad example for the low end.

Extremely happy with the HPE 4Mil stroker kit, and Hobson is extremely helpful. Can't wait to report bad with a more dialed in report!

Those girdle bolts are sweet!

 

[jagerauto]

Hit me up I can get you some

 

[speedysprocket]

Those girdle bolts are sweet!

He has to wear leather gloves to work on his engine...!

 

[jagerauto]

He has to wear leather gloves to work on his engine...!

Doesn't help tho

 

[Quinc]

Hit me up I can get you some

Too rich for my blood!

 

[jagerauto]

Too rich for my blood!

Cheaper than replacing a head shell cuz the rusty chrome nuts start to eat at the anodized finish on the head. Never understood why chrome was a good idea.. Lol these are stainless and not that expensive

 

[Quinc]

Cheaper than replacing a head shell cuz the rusty chrome nuts start to eat at the anodized finish on the head. Never understood why chrome was a good idea.. Lol these are stainless and not that expensive

I am impressed you found stainless in 8x1.25! Okay I am intrigued now, how much are they?

 

[tomski]

Well I've finally got my 4mil dialed in enough to brag about it a little. So here we go. Tons of power, lots of low end hit. I need a slightly larger impeller, I think I have a 10/16 hooker on it now. I'm running all the basics and also a dasa intake, oem 46mm mikunis, and a solas pump. 62T cylinders bored over to 82mm which should put it right at 760cc.

Your photo shows a 61X cylinder.

 

[jagerauto]

Your photo shows a 61X cylinder.
View attachment 316229

Lol oops my bad. I never know the difference I get all mixed up when talking about 62T and them having X cylinders. Lol