Big bore vs stroker

[JohnnyBertone]

Okay so I'm planning for my next rebuild and I'm considering the Vito's racing 240cc kit. I found this for $200 more which includes the 240cc kit and a 3mm stroker. I'm curious to know which would yield more of a gain in power since I don't have a case splitter aside from a flat head screwdriver and a mallet
So opinions on big bore kit vs a stroker please to help make my decision. Is the stroker kit really worth the extra money and Extra effort? Or is it only worth it if the bottom end goes?

 

[joeak47]

A 240 kit runs awesome when properly set up. That 3mm stroke adds up to 1/8 of an inch. Not much, but everything helps. Adds a little bit of torque, but not a lot. You benefit more from the stuffing blocks on the crank.

However,

My suggestion is....

Get your stock cylinder properly ported and your head re-chambered into a high compression "Hemi" head.
These two items coupled with a quality pipe and PROPER JETTING will run circles around that kit, and save you money in the process all while using the stock carb.
With the money you save, you can purchase Vforce 4 reeds,a Uni -filter, new plug, extra jets, and put money back in your pocket.

 

[joeak47]

Porting and head re-chamber with a quality pipe and proper jetting will double your stock HP. VERY FUN!
Also... with a stock cylinder, you will have lots of over bores (extra bore sizes) in that cylinder for future rebuilds.

 

[JohnnyBertone]

Well i already have the vforce 4 reeds full FMF gold exhaust K&N filter, as well as a ram air mod to the airbox (just removed the upward scoop on the box) and bumped up the jets so everything aside from motor mods are pretty much top of the game. Just wanted to determine if the big bore was worth it or if I should just port and mill the factory top end. I know milling the head would make a ton more compression because now it's the same amount of fuel oxygen being compressed in an even smaller compression area but I never knew what porting the head would do. Thanks for the suggestion I'm going to look into that now rather than a big bore kit

 

[JohnnyBertone]

Also a side note, which is a better higher flow filter? A K&N or a uni flo foam filter?

 

[Fast6hand]

Also a side note, which is a better higher flow filter? A K&N or a uni flo foam filter?

Go with the uni. It might not flow as good, but it will protect the motor better from unwanted debris.

 

[joeak47]

JohnnyBertone...

Its not head porting its head "Re-chambering".

The combustion chamber of the head is completely re-machined to a different shape (Hemi) , a squish band of proper width and angle is added, and the combustion chamber size is reduced (to around 18cc - 23cc's).

After this is done, you will be able to create a large amount of power, and run 93 octane pump fuel. No need for aviation fuel what so ever.

If you just mill down a stock head with its poorly shaped combustion chamber, all you'll get is detonation. Don't do that. Trust me.

You already have some great parts. That pipe works awesome with the porting and head re-chambering.
That K&N is good, but I prefer the Uni filter. The Vforce 4 reeds will feed the porting well.
Expect around 30+ HP with RELIABILITY!

Hell, I'd say your half way there. Now give this guy below a call for the porting and head re-chambering. While your cylinder is there, have a new piston fitted to the bore. Its worth doing it while the other work is being performed and doesn't break the bank.

Give Ken a call and tell him what you want. Great prices! FAST turn around too!
Don't waste your time with your local shop that takes two months or more, and not have it right when you get it back. Most shops suck.

Here you go... \/ \/ \/

http://www.kenoconnorracing.com/

You'll thank yourself later.

 

[dirtysquared]

Alot of people here run a stock stroke\ bore motor that is ported with a rechambered head. Hell I'm one of them. The results of that work are damn impressive and very noticeable.

With the cash you save from going this route, you can upgrade your suspension and other things like that as you see fit.

 

[jus_me]

I'll third these suggestions. Head rechambered and a well ported cylinder and you will be smiling from ear to ear.

The parts you already have paired up with the head and cyl work and you will have yourself a trail eating machine. No need for a larger carb either..

 

[best]

Ditto that. Joe's advice is square. Add a rechambered head on what you've got and you will fly. I've done the milled stock head and it is a waste of time and effort. RECHAMBER that head. Heck, don't go crazy on the volume and you can even run on regular.

As far as HP per dollar, the head mod is had to beat and is a basis for any gains to follow.

Steve

 

[JohnnyBertone]

How do I go about rechambering the head? I saw the video on the porting and I'll send away for that when I can but I keep seeing rechambering the head to a hemi head with no direction how to do so

 

[blasDa]

How do I go about rechambering the head? I saw the video on the porting and I'll send away for that when I can but I keep seeing rechambering the head to a hemi head with no direction how to do so

Easiest way would be to send it to Ken O'connor and he'll do a bang up job for $60.

 

[jus_me]

Yup, here is one that showed up yesterday.

 

[blasDa]

Yup, here is one that showed up yesterday.

Sexy!

 

[joeak47]

That looks great!

 

[joeak47]

You could try porting it yourself too with templates that Ken has. However, if you don't feel confident doing it yourself, just send him your cylinder.