Anyone stroked their Vmax?

[Stites]

Tried doing a search, nothing. So, is it possible to stroke a Gen1 motor? If so? By how much?

Not trying to stroke one like a Harley... just maybe 1/2" or so to add some more torque.

 

[davesax36]

Look in the motor section of the 85-07 technical area. I can also send you sean's motor upgrade spreadsheet. That will answer many questions as well.

 

[Rusty McNeil]

We did mine 5mm stroke, to 71.1mm with Seans help, advice and coordination of machine work and speccing parts.

I think he said it could go even a little beyond that.

The 5mm stroke didn't require any relief work on the case or crank I don't think.

Arias Pistons (13:1) had to be special made due to change in "pin to piston top" dimensions.
The "Morley Muscle" rods he had made were stock length.





We bored 7mm, to 83mm (Re-sleeve job required) at the same time and ended up at 1539cc.

It hasn't been on a dyno but it runs VERY well...I'm sure the torque should be in the 110-113 range considering the stock stroke 1500, 11.3:1 PCW Tourmaster supposedly makes around 105 TQ.



I think Sean has an option where you can install a crank only with 1 or 2mm stroke without even pulling the heads or pistons, just split the cases, which apparently is possible with the available piston to valve clearance.
This also raises the compression some too.

As far as I know Sean is the only vendor that offers a stroker crank option.

And even if you sent the crank straight to Fallicon or someone like that you'll still not get all the experience, advice and support needed to pull the whole package together like Sean provides.

 

[Stites]

Wow, y'all are awesome! I think that might be one of the first mods I do when the time comes.

 

[one2dmax]

I normally don't do many strokers. The best bang for the buck is usually just the big bore.

 

[Rollie]

I stroke mine most every time I walk by it.

 

[davesax36]

The pricing might not be current, but here's what Sean originally sent me when I was getting ready to do my transmission swap.

 

[wildweasel_pt]

I stroke mine most every time I walk by it.

He he. I was thinking of that but by respect to you all i refrained myself from stating it... :rofl_200:

 

[Stites]

Quite okay - I work with some real characters, so after a day busting each other's chops, a little *** here and there is just icing on the cake.

 

[VMAX Eddie]

I stroked mine today....*good vmax, niiice vmax, oh you like that baby?...oohh yeah!"

 

[marsmax85]

I stroke mine most every time I walk by it.

I didnt want to be the first admit it but I stroke both of mine at the same time :eusa_dance:

 

[dodgediesel59]

I have a buddy with a 1570 stroker and he has broken 2 crank shafts so far. That is the only concern I have with too big of a stroke on these engines. You can get one of these sleeved to a 1570 on a stock stroke, so in my mind the huge dollars for a stroker crank really don't pay out that well in the end.

 

[1967vmax]

Hi i dont have a stroker but i do have a 1500 pcw big bore and it makes gobs of power and torque. Honest if i only had my vmax ride i would not do it the reliability goes away an even more so on a stroker. I just bought a zx 14 and it has just as much hp at the wheel as my vmax does the torque is less but for what i paid for my vmax motor is what i paid for my zx 14 so its something to think about before you do this mod.

 

[88vmx12]

I had to quit stroking her every time I went into the garage, my wife was starting to get jealous.

 

[Rusty McNeil]

Hi i dont have a stroker but i do have a 1500 pcw big bore and it makes gobs of power and torque. Honest if i only had my vmax ride i would not do it the reliability goes away an even more so on a stroker. I just bought a zx 14 and it has just as much hp at the wheel as my vmax does the torque is less but for what i paid for my vmax motor is what i paid for my zx 14 so its something to think about before you do this mod.

In what ways did you lose reliability on yours?

Just curious, I haven't lost any at all on mine.....about 1500 miles on it so far...

Admittedly what I have lost is peace of mind, always worried about beating the hell out of it which I was not scared to do at all when it was internally stock...

The only real problems I've heard with the big motors is a rash of sleeves that slipped down in the case and caused problems.......I think one of the sleeves is not able to be "stepped" so it has a shoulder to rest on when inserted...so it just relies on tension/friction/case pressure to hold it in place...

 

[Stites]

Just to let yall know - I don't even have a Max yet. I'm still looking into things that can be done to one, and I'm leaning toward adding a little bit of stroke to one. Which is totally opposite of my normal way of thinking. I never caught onto people putting dern 5 or 6"
cranks in their Harleys and flogging the crap out of them - that's a grenade with the spoon popped out, if you ask me.

No, what I envision is that extra 7mm or so, whatever the engine can hold without having to have reliefs milled into it - that's where I get worried about reliability. But if you take a 1500 big-bore and add those extra 7mm of stroke, you'll end up with a 1657cc engine. The extra stroke does bring the power curve down in the rpm range, but then it would add torque as well due to the extra displacement and better leverage on the crank. Plus, the lower rpms would seem to actually ADD life back to the valvetrain since there's less risk of floating a valve.

A bit extreme? Yep. Sure is. But then I've not heard of anything bigger than a 1570 engine, and that's all from the bore. I know a crank swap is very invasive... while in there, it's also a good time to put in a Venture gearset, stronger rods, gapless piston rings(maybe???), and noodle around with this nagging idea of making a belt drive system that allows the user to put on a new belt without having to pull the wheel/swingarm/etc.

Yes. I think too much.

 

[one2dmax]

1630cc been done a few times. 3000cc done at least once that I know of. You're not reinventing the wheel. These bikes have been around for a very long time and pretty much anything that can be tried has been!

+9mm was tried and didn't survive. +5mm will be what you want for max stroke increase. The increased power was good but the cost was a lot more then just doing the big bore. I have a stroked crank I got back from prep not too long back. I hope to be putting it together in a few months and see what this round of experiments would do.

Gapless rings have more friction so the standard rings do fine. If you're trying to go all out and turbo/supercharger then perhaps it might be worth trying.

Stronger (and longer) rods are worthwhile and a few selections out there (We sell Carrillo, Pauter, and our own version). We have a variety of trans gearings depending on what you want. The stock gearing is ok and even better with our overdrive conversion. On my next big motor build for myself I plan to do another of the later model venture complete sets which spreads out the gearing even more with a less aggressive top end then the overdrive setup.

The belt drive was done by one of the guys on here not too terribly long back but if you plan to make much power I would highly suggest against it. The chain is far far stronger. You'll also want to install solid engine mounts and a rear engine mouting/strut plate to ensure it won't move back and let the belt/chain slip off.

 

[Stites]

3000cc?!?!?! I'd love to see/hear that thing launch!

Thanks for letting me know about the 5mm limit. I have much to learn still.

 

[Rusty McNeil]

Sean



With my 5mm stroke and 81mm bore, how would my motor do if I ever decided to go to the bigger bore like 85-86mm?





The long rod thing?
I really have no idea what the real advantage of long rods is?



Is it just to decrease the rod to cylinder angle and lessen side loading on cylinder wall wear, raising reliability, or is it more about increased dwell time at TDC?



And considering with my stroke the wrist pin and retainers were moved up (decreased compression height) into the oil ring (We used aluminum button wrist pin retainers if you remember) am I at the limit already for rod length?

 

[Stites]

Yeah, all of the above on longer rods. Plus I think longer rods move your torque curve up some and allow for higher compression with the same gas - how high I have no clue.

Years ago Hot Rod magazine built a GM 352 out of a .030 over 400 with a 327 crank, and a set of long rods from a Ford 300-6. They explained all this in the article. On 87 octane, that motor put out 412hp with 12:1 CR, NO detonation whatsoever.

Someone back n the day also made a long-rod kit for a Yamaha YZ125. With that change and a little getting, thatcthing would scream, hang with a 250, even. So yeah, long rods are a good thing(Feel free to twist that statement to your liking )