vitos 240 bb or ken o connor porting

[636chris]

which will make more power and be reliable the vitos 240 bigbore kit or should i just send my head and cylinder to ken and get it ported and reworked?. also what supporting mods will be needed for both.

in the end id like to save a few bucks but still have a badass blaster.

 

[Puma]

I have been doing some research about kinda the same thing. From what I have read here, a properly ported stock jug and modified head will be faster than an out of the box Vitos big bore kit. You will need a good pipe and silencer and its reccomended to go with a bigger carb. Those supporting mods will be needed with the big bore also. The issue from what I understand is the Vito's jug has a poor port design. If you go the stock jug route, be sure to use a good forged piston, its more durable than a cast piston.

 

[636chris]

See the thing that got me was the vitos claimed 32 plus hp. which seems a little ridiculous . im thinking a good piston , reeds ,carb,and kor porting and head mod will be way cheaper than the vitos kit. But which is faster. I ride with a few 450s and i just flat out feel like i have no brute power. I love my blaster , i even ride it over my banshee. but i really wanna make this thing balls out but not break the bank too much

 

[blasterdemon7]

Porting a stock jug will outperform a non ported Vito 240 kit. You will have to build a bit more then that to run with the 450's.Ported stock jug, head mod,+3 stroked crank, 34-35 carb, right bend pipe. That combo will put a big smile on your face.

 

[636chris]

what else is involved with the stroker crank? im highly mechanically inclinded so im sure i could install it my self . btw does anyone know the top speed of a piped and jetted blaster with 20x sized tires mine topped out at 47 according to the speedo on our 4x4 kawi

 

[Blaner]

do both, port the 240! and get a 3mm crank.

You should be topping out near 60mph. they do not get much more than that no matter what you do, unless you give it long legs with sprockets and huge tires

 

[Awk08]

ported stock jug FTW !!!!!!!
if you wanna go +3 crank, i know ken at least, will require the complete motor to adjust ports and squish to that specific crank/rod
some like to do the crank themselves and throw the adjusted port cylinder on, or spacer plate, but you'll get better results letting the builder do it perfectly matched.
like stated above...carb/pipe/filter

the vito's kits have gone up in price recently, $575 as listed on vito's website, and out of stock, then there was the 240 piston shortage a while back, forcing some peeps to find a stock cylinder to run while waiting on pistons to be made
i'll pass on all that, and pass a non ported vito's on the trails !!!!!

 

['00 WO-YA!]

The only thing I'll add to this discussion is the fact that the stock bbk is an upgrade that can be upgraded again later with porting. Although a good ported jug may be stronger then what. With the ported bbk I'm sure it let's pretty impressive.
What about some of the other bbk on the market?

 

[sicivicdude]

Vito's big bore kits "out of the box" are kinda dismal. The setup has "12 ports" but the timing and area are both pretty subdued. It's not a stretch of the imagination to believe that a worked 200 cc engine can beat a non-worked 240cc engine....

There are a few advantages to going big bore/stroker and a few disadvantages...

One of the advantages of a BBK is TORQUE! small bore engines (especially ported) don't really have loads. Porting adjusts the rpm where the power comes in upwards *generally* reducing torque. Big bore engines (and particularly strokers) retain some vestige of this torque even as the powerband shifts upwards.

There's also lotsa POWA (possible). Increasing displacement by 20% will have an effect on the bottom line no matter what. A good example would be an unported BBK racing an unported stock cylinder, just the difference in displacement will make a large power difference. You HAVE to have porting on a stock cylinder to stick with a big bore kit in a flat out open race.

There are a few disadvantages too, as Awk pointed out. Pistons are not as widely available as "stock bore" pistons. It's not like I make a habit of burning through pistons every other day or anything but if you ride hard enough, long enough, eventually you're going to need to "freshen things up". Sometimes that's as simple as a set of rings but sometimes that's a new piston and a bore.

BBK's only have 3 overbores and that's only if you use a wossner piston, vito's pistons only have 2 overbore sizes. So any way you slice it, that's only 4 lives. I figure if you're good and lucky you can get a few years out a bore (with proper care and excellent maintenance) so 4 lives = ~10 years. That's not a TERRIBLE amount of time for a top end to last but it certainly is not as long a time frame as a stock bore can last with it's 9 overbores.

BBK's are EXPENSIVE! Forget the $575 from vito's (although that COULD be a bolt on thing) you've got to count the other upgrades NEEDED to properly run a big bore. In all fairness most would argue that the same upgrades are needed to run a stock bore engine but they're not just recommended if you go BBK, they're a necessity!

You need an upgraded carb (PWK 35-36 or TM 34-36) which requires an intake manifold, a modified air box, new throttle cable, and banshee petcock (not required but recommended).

You also need a good pipe (toomey's not terrible, dynoport, power pro's/F7/CT/trinityS4) to be able to flow all that extra volume.

The "add-ons" to support it are AT LEAST as expensive as the BBK itself.

Now, let me tell you my personal feelings on the matter..... I do ALL of my own work (except boring I have a local shop I use) and I've horsetraded stuff around to cobble together my blaster (so I didn't just drop $2k on fancy dancy new parts and pay some another $1k to put it all together!).

After riding my stroker BBK and letting other folks ride it (most of which have stock bore SOME of which are pretty wild), if it blew tomorrow, I'd be on the phone with the machine shop seeing how much a resleeve would cost.... sorry guys, but the big bore kit whoops mad ass. I get off of it every time I ride it and say "holy SH!T what a ride!"

 

[super noober]

Vito's big bore kits "out of the box" are kinda dismal. The setup has "12 ports" but the timing and area are both pretty subdued. It's not a stretch of the imagination to believe that a worked 200 cc engine can beat a non-worked 240cc engine....

There are a few advantages to going big bore/stroker and a few disadvantages...

One of the advantages of a BBK is TORQUE! small bore engines (especially ported) don't really have loads. Porting adjusts the rpm where the power comes in upwards *generally* reducing torque. Big bore engines (and particularly strokers) retain some vestige of this torque even as the powerband shifts upwards.

There's also lotsa POWA (possible). Increasing displacement by 20% will have an effect on the bottom line no matter what. A good example would be an unported BBK racing an unported stock cylinder, just the difference in displacement will make a large power difference. You HAVE to have porting on a stock cylinder to stick with a big bore kit in a flat out open race.

There are a few disadvantages too, as Awk pointed out. Pistons are not as widely available as "stock bore" pistons. It's not like I make a habit of burning through pistons every other day or anything but if you ride hard enough, long enough, eventually you're going to need to "freshen things up". Sometimes that's as simple as a set of rings but sometimes that's a new piston and a bore.

BBK's only have 3 overbores and that's only if you use a wossner piston, vito's pistons only have 2 overbore sizes. So any way you slice it, that's only 4 lives. I figure if you're good and lucky you can get a few years out a bore (with proper care and excellent maintenance) so 4 lives = ~10 years. That's not a TERRIBLE amount of time for a top end to last but it certainly is not as long a time frame as a stock bore can last with it's 9 overbores.

BBK's are EXPENSIVE! Forget the $575 from vito's (although that COULD be a bolt on thing) you've got to count the other upgrades NEEDED to properly run a big bore. In all fairness most would argue that the same upgrades are needed to run a stock bore engine but they're not just recommended if you go BBK, they're a necessity!

You need an upgraded carb (PWK 35-36 or TM 34-36) which requires an intake manifold, a modified air box, new throttle cable, and banshee petcock (not required but recommended).

You also need a good pipe (toomey's not terrible, dynoport, power pro's/F7/CT/trinityS4) to be able to flow all that extra volume.

The "add-ons" to support it are AT LEAST as expensive as the BBK itself.

Now, let me tell you my personal feelings on the matter..... I do ALL of my own work (except boring I have a local shop I use) and I've horsetraded stuff around to cobble together my blaster (so I didn't just drop $2k on fancy dancy new parts and pay some another $1k to put it all together!).

After riding my stroker BBK and letting other folks ride it (most of which have stock bore SOME of which are pretty wild), if it blew tomorrow, I'd be on the phone with the machine shop seeing how much a resleeve would cost.... sorry guys, but the big bore kit whoops mad ass. I get off of it every time I ride it and say "holy SH!T what a ride!"

i agree 100%, ported stroked bbk for the win, u gotta pay to play broski lol I:I I:I

 

['00 WO-YA!]

Vito's big bore kits "out of the box" are kinda dismal. The setup has "12 ports" but the timing and area are both pretty subdued. It's not a stretch of the imagination to believe that a worked 200 cc engine can beat a non-worked 240cc engine....

There are a few advantages to going big bore/stroker and a few disadvantages...

One of the advantages of a BBK is TORQUE! small bore engines (especially ported) don't really have loads. Porting adjusts the rpm where the power comes in upwards *generally* reducing torque. Big bore engines (and particularly strokers) retain some vestige of this torque even as the powerband shifts upwards.

There's also lotsa POWA (possible). Increasing displacement by 20% will have an effect on the bottom line no matter what. A good example would be an unported BBK racing an unported stock cylinder, just the difference in displacement will make a large power difference. You HAVE to have porting on a stock cylinder to stick with a big bore kit in a flat out open race.

There are a few disadvantages too, as Awk pointed out. Pistons are not as widely available as "stock bore" pistons. It's not like I make a habit of burning through pistons every other day or anything but if you ride hard enough, long enough, eventually you're going to need to "freshen things up". Sometimes that's as simple as a set of rings but sometimes that's a new piston and a bore.

BBK's only have 3 overbores and that's only if you use a wossner piston, vito's pistons only have 2 overbore sizes. So any way you slice it, that's only 4 lives. I figure if you're good and lucky you can get a few years out a bore (with proper care and excellent maintenance) so 4 lives = ~10 years. That's not a TERRIBLE amount of time for a top end to last but it certainly is not as long a time frame as a stock bore can last with it's 9 overbores.

BBK's are EXPENSIVE! Forget the $575 from vito's (although that COULD be a bolt on thing) you've got to count the other upgrades NEEDED to properly run a big bore. In all fairness most would argue that the same upgrades are needed to run a stock bore engine but they're not just recommended if you go BBK, they're a necessity!

You need an upgraded carb (PWK 35-36 or TM 34-36) which requires an intake manifold, a modified air box, new throttle cable, and banshee petcock (not required but recommended).

You also need a good pipe (toomey's not terrible, dynoport, power pro's/F7/CT/trinityS4) to be able to flow all that extra volume.

The "add-ons" to support it are AT LEAST as expensive as the BBK itself.

Now, let me tell you my personal feelings on the matter..... I do ALL of my own work (except boring I have a local shop I use) and I've horsetraded stuff around to cobble together my blaster (so I didn't just drop $2k on fancy dancy new parts and pay some another $1k to put it all together!).

After riding my stroker BBK and letting other folks ride it (most of which have stock bore SOME of which are pretty wild), if it blew tomorrow, I'd be on the phone with the machine shop seeing how much a resleeve would cost.... sorry guys, but the big bore kit whoops mad ass. I get off of it every time I ride it and say "holy SH!T what a ride!"

You just pretty much verified my thinking man. I can't really see where goin with the bbk is a bad investment. For the type riding we do it would likely last us plenty long & leave room for improvement in the future.

 

[Larry's Shee]

1. There is no replacement for displacement. I:I
2. Speed is only limited by cubic dollas.

 

[slickerthanyou]

With the possible issue of having the steel sleeve spin inside the aluminum, I'd wouldn't own one of those. Not everything vito sells id junk but the poor casting and issues even though it only happened once, would suck to drop $600 on the vitos ride it a few times and the sleeve spin, It is a chance you take!

I plan one day to go BBK, not knocking all brands, yes they can put out more power. And with some port work, pipe, carb, airbox, reedcage, and a long rod or stroked bottom just plain sick!

 

[EvilElvis]

or just buy a quadzilla LOL

 

[sicivicdude]

With the possible issue of having the steel sleeve spin inside the aluminum, I'd wouldn't own one of those. Not everything vito sells id junk but the poor casting and issues even though it only happened once, would suck to drop $600 on the vitos ride it a few times and the sleeve spin, It is a chance you take!

I plan one day to go BBK, not knocking all brands, yes they can put out more power. And with some port work, pipe, carb, airbox, reedcage, and a long rod or stroked bottom just plain sick!

I would be interested to see what happened to that cylinder. Whether it was poor casting (whether it means all are poor or only one batch are poor) or some outside force involved.

The amount of swage on a sleeve from the post casting cooling is ENORMOUS so either there was something wrong with that cylinder during the casting process, that cylinder had its sleeve replaced at some point and it wasn't interference fit properly, or it was internal damage (wrist pin caught a port for example and "jarred" the interference fit).

That was a single event however and the process used to manufacture vito's steel sleeve cylinders is the same as used to manufacture the factory steel sleeve cylinders. Theoretically, if it happened to an aftermarket jug, it could happen to a factory jug too!

 

[sicivicdude]

What about some of the other bbk on the market?

I should add to this point as well (as I normally do here, playing the devil's advocate!)

Vito's is NOT the only big bore kit available. There are several options in that arena. In my mind they are as follows in order from worst to best

Sleeved stock top end. Basically the stock 66mm sleeve is bored out of the aluminum and a new larger diameter sleeve is pressed into place. The cylinder is generally then ported (not just port matched) to get the most out of it. This has the distinct disadvantage of having the stock mid 1970's IT style port layout. Much can be done by a good porter but there are limits... there's not a lot of "meat" around the exhaust port for adding extra ports.

The next two are tied actually in my mind, they have good and bad.... argue with me if you will!

Vito's and Airsal BBK's The airsal kit has the advantage of a better port layout (design wise) but suffers from only being a 71mm bore and nikasil'd (which means NO overbores, just replating ). Also, the airsal kit has to have a spacer plate added below the cylinder even on stock stroke engines which we know is one more potential leak point....

Vito's retains much of the mid 1970's It port layout with a few notable exceptions. Vito's cast in triple exhaust ports into their cylinder. While the stock porting is poor (quality wise) and conservative (timing and area wise) they added material to the aluminum casting in a few vital areas to make what CAN be MUCH better than stock. Between the bottom "large" cooling fin and second "large" cooling fin the stock cylinder lacks enough aluminum to put in large triple exhaust port tunnels. Vito's added a large chunk of aluminum behind that area even though they didn't take advantage of that area in the stock format 8-|, the material is already there meaning porting can be taken to a relatively high level of tune without the risk of "breaking through" and ruining a cylinder. Unfortunately, the stock porting stinks and they didn't update the port layout when they cast it. It CAN be wild but it's not really wild out of the box....

Then we get to the LA Sleeve BBK (the complete replacement top end, not the resleeve!)

It has the updated port layout (similar to the airsal kit) but it's a full 240cc engine, has an iron sleeve allowing overbores, and has an improved cooling fin layout. The new LA sleeve kits also have a billet aluminum head that's machined out with an updated cooling fin layout as well.

Unfortunately, as you down that list, you go UP in price....

Also, I must add, Ken O'Connor Racing is not the only engine builder in the business. He does do top notch (and clean WOO WEE!) work but there are a LOT of engine builders out there, far more than the handful that get promoted on here as well! If you are considering getting an engine built by someone on this site, I recommend calling/emailing all of them separately and talking with each one about your engine goals. Get their input and feedback and make an informed decision about who you think will get you where you want to be....

 

[YZ Otis]

I would be interested to see what happened to that cylinder. Whether it was poor casting (whether it means all are poor or only one batch are poor) or some outside force involved.

Is this the spun jug you're talkin about? It was a very poor casting to start with, even by Vito standards. Looks to me like poor temp control of the alloy and the steel sleeve. The alloy didn't flow or bond to the steel. I believe there was some discussion about even being able to save it. Denny did some amazing clean up on that jug. I've been running a Vitos BB for years but if I hadn't found the loose casting slag in the transfers it wouldn't have lasted a minute, I wanted a little more grunt for the trails & dunes but didn't need a top end rocket for our guest Blaster. It's been thrashed for years and still runs good. Had one melt down when a young lady thought it was a 2 speed and ran it WOT at the dunes till it stopped ... LOL ... and she was so proud of shifting from 1st to 2nd

~

 

[sicivicdude]

Is this the spun jug you're talkin about? It was a very poor casting to start with, even by Vito standards. Looks to me like poor temp control of the alloy and the steel sleeve. The alloy didn't flow or bond to the steel. I believe there was some discussion about even being able to save it. Denny did some amazing clean up on that jug. I've been running a Vitos BB for years but if I hadn't found the loose casting slag in the transfers it wouldn't have lasted a minute, I wanted a little more grunt for the trails & dunes but didn't need a top end rocket for our guest Blaster. It's been thrashed for years and still runs good. Had one melt down when a young lady thought it was a 2 speed and ran it WOT at the dunes till it stopped ... LOL ... and she was so proud of shifting from 1st to 2nd

That's freek's cylinder, but I remember the sleeve having spun more than that... That really looks about like the casting flaw vito's has from the factory 8-|

The discussion was heating the sleeve and aluminum together, twisting the aluminum while holding the sleeve and then "pinning" the two together once they had cooled using the pins made for "repairing" cracked cast iron castings. Sounded like a plan fraught with danger or having the sleeve not lined up after the two cooled. I guess you could have heated them again if they didn't line up the first time but sounded like it wasn't going to work too well anyway.

ANY air cooled 2T top end can fry if you run it a 9k rpm for 30 minutes LOL they're not made exactly for that I:I and I can't fault any manufacturer for that one....

 

[636chris]

SO the verdict is to bb or not ? or stroker with reworked stock cylinder and head ? maybe ill just wait for something to pop up on the classifeilds

 

[mmajay]

I think you will be plenty happy just getting your stock jug ported with a stroker crank and big carb along with the pipe of your choice, your wallet will thank you too. Unless your mx raceing or drag raceing in competition and need that slight edge i see no need for dropping big money on a BBK.