Sleeve for a 4hp "Kool Bore"

[Flexmod3]

Hello, I recently started restoring a B&S motor. Thanks to your site I was finally able to figure it to be a 4hp (10 stamped on head) Kool Bore. After pulling it apart and looking it over, their was at least 1 score in the cylinder deep enough to warrant a aggressive hone if not re-bored. So, I'm going to get it re-bored and was wanting to get a sleeve so I don't have to fool with looking for special pistons.

The subject was touched here (http://www.oldminibikes.com/forum/briggs-stratton-engines/51802-sleeving-coolbore-block.html) But left me still a little cloudy on the subject.

I'm wondering if anyone know a sleeve and piston type that will work in these motors? I figure it depends on what you bore the cylinder to and how big of a piston you get to fit in their. I'm not making this a power house or anything so, stock sizes on sleeve/piston are fine. (However will probably be upgrading to billet lifters and Raptor 3 connecting rod, if I can find em cheap enough. Again for longevity and since I'm in their.) If anyone can point me in the right direction it would be greatly appreciated. You can't imagine how much yall already have! :thumbsup:

Thanks for your time in advance.

 

[roccosbike]

Welcome to OldMiniBikes,your block is the same size as the 5HP briggs externally.The crank and the bore are a little smaller but you could swap in a 5HP crank and bore it to accept the 5HP piston.Basically you would be making a 5HP briggs motor, by doing this connecting rods and pistons become very plentiful.Finding parts for the 4HP is limited and no internal raptor parts other than cam and lifters will work on the 4HP Briggs unless you change the crank and bore size.

 

[Flexmod3]

Welcome to OldMiniBikes,your block is the same size as the 5HP briggs externally.The crank and the bore are a little smaller but you could swap in a 5HP crank and bore it to accept the 5HP piston.Basically you would be making a 5HP briggs motor, by doing this connecting rods and pistons become very plentiful.Finding parts for the 4HP is limited and no internal raptor parts other than cam and lifters will work on the 4HP Briggs unless you change the crank and bore size.

Thank you! Yall got some cool stuff goin on here. Glad i can be apart of it!
:thumbsup:

Ok that makes things simpler....I think. So get it bored to the 5hp specs for the piston. Now if that's the case, and the housings are the same dimensionally, then their should be enough of the wall to get a sleeve inserted? Again doing this to avoid the specialty piston. And probably an obvious answer but want to ask so I know for sure. You said that the block was the same. Is this the same for the heads? Or would I swap to a 5 after I got it bored out?

Again, Thanks for all the help in advance!

 

[roccosbike]

The head will work well for torque,if you want to build it for higher RPM the 5HP head will work better.These guys have all the parts you need to make it happen sleeve and all....American Power Sports - Karting Parts & Accessories

 

[Flexmod3]

The head will work well for torque,if you want to build it for higher RPM the 5HP head will work better.These guys have all the parts you need to make it happen sleeve and all....American Power Sports - Karting Parts & Accessories

Thanks for the link and the info! Will leave the 4hp head for now if it wont have any negative effects. Ah, now the fun of online comparison shopping. However, I for the life of me cannot locate what the sleeves are listed under. :hammer:
Care to point me in the right direction?

Thanks.

 

[metal man]

Rieken's Racing: Raptor Aftermarket Parts - OUT2WIN.COM

 

[Ibanez616]

Incase it is a period correct engine for a restoration, I would ditch it and find a 5hp to play with.

 

[Flexmod3]

Rieken's Racing: Raptor Aftermarket Parts - OUT2WIN.COM

Thanks! Will check out what all they got to offer.

Incase it is a period correct engine for a restoration, I would ditch it and find a 5hp to play with.

While I had not intended it to be in the beginning its more or less turning this way. Already spent enough change on de-rusting the gas tank, finding gaskets and bushings local, etc.. So while it's not a "resto", we will just call it my project! But I get where your coming from. Had I done some better research before I started tearing it apart and such, I would of just ordered a new block. Hind-sight eh? :doah:

 

[Briggsboss]

there are some 5hp iron bore blocks under $50. actually saw somthing a few day ago in the parts section. 5hp iron block and crank for $50,powerded coated,,,may have been an animal engine if im not mistaken.

 

[Flexmod3]

there are some 5hp iron bore blocks under $50. actually saw somthing a few day ago in the parts section. 5hp iron block and crank for $50,powerded coated,,,may have been an animal engine if im not mistaken.

Ah. Well really wanted to get back on this but geez, 50 bucks beats the piss out of what I'm about to spend! You saved my checking account for at least a week. I'll watch the buy/sell here and ebay. See if I cant snag me a decent 5hp steel block.

Thanks for the moment of clarity! :doah:

 

[Flexmod3]

Update

Well been scrounging around for sales and ebays. Managed to find a motor locally! Guy said it was originally on a log splitter, but is out of town and unable to give serial/model numbers or check if it's a I/C block. But for the price I'm getting it at, meh. Can always use spare parts right? :laugh:

Was wondering if anyone is good enough to tell me anything about it form a shoddy picture? Maybe just me dreaming.....

Alls I see is the dreaded Red X, sorry.

Oh boy, take 2...

 

[hemigremmy]

Alls I see is the dreaded Red X, sorry.

 

[The Restore Kid]

I probably have a 4 horse piston with good rings..

But like Rocco posted.. The 4 and 5 horse blocks are essetially the same.. The 4 horse has a slightly tighter bore, which is perfect, if you want to punch the block out.. You can buy 5 horse power pistons all day long... All you have to do, is buy a 5 horse piston, then have the block punched out to match.. Put your new piston on your existing connecting rod...

Walla.. instant brand new 11 cubic inch 4.5 horse power.. :lol:

 

[Flexmod3]

I probably have a 4 horse piston with good rings..

But like Rocco posted.. The 4 and 5 horse blocks are essetially the same.. The 4 horse has a slightly tighter bore, which is perfect, if you want to punch the block out.. You can buy 5 horse power pistons all day long... All you have to do, is buy a 5 horse piston, then have the block punched out to match.. Put your new piston on your existing connecting rod...

Walla.. instant brand new 11 cubic inch 4.5 horse power.. :lol:

Hehe. Ok that makes enough sense. But wouldn't I still want that sleeve pressed so I wasn't running that untreated 5hp piston on bare Alum bore?

Ah another question. Thinking about looking to get a a bearing cover to replace the standard bushing one I have. Would that force a crank swap as well?

 

[sludgeboy]

Flexmod3, are you set on american iron? I know I personally like my Tecumsehs (when they run properly) but there is nothing wrong with a nice B&S. Another alternative is Harbor Frieght has $99 specials once in a while on 6.5hp engines. (Predators 212cc) They are cheap and UGLY but you can't go wrong on the price. They sell hop-up kits to increase the hp also for little money.

 

[Flexmod3]

Flexmod3, are you set on american iron? I know I personally like my Tecumsehs (when they run properly) but there is nothing wrong with a nice B&S. Another alternative is Harbor Frieght has $99 specials once in a while on 6.5hp engines. (Predators 212cc) They are cheap and UGLY but you can't go wrong on the price. They sell hop-up kits to increase the hp also for little money.

No, it just that I've got a stripped, ported, seated, and new gaskets for the 4hp I got sitting in my basement. And I'm not really one to just go out and buy a new motor when it was free to begin with, and already has time and money invested in it. Only reason I'm gunna get that other one Monday, is it's a steal for what he wants! Ill prob spend more in gas getting to it and back then I'll pay for the motor. Gotta love spring cleaning! XD

 

[rmm727]

Hehe. Ok that makes enough sense. But wouldn't I still want that sleeve pressed so I wasn't running that untreated 5hp piston on bare Alum bore?

Ah another question. Thinking about looking to get a a bearing cover to replace the standard bushing one I have. Would that force a crank swap as well?

I believe they make a trick bearing for what you want to do. try aps karting.

 

[Flexmod3]

I believe they make a trick bearing for what you want to do. try aps karting.

40MM NTN AXLE BEARING and 50MM AXLE BEARING (CCVI)
(under BEARINGS>EUROPEAN AXLE BRGS & CASSETTES)
Mean those?

Update! : Yay! found myself a complete rolling Doodlebug frame less a motor in pretty good shape! Going to get it picked up tomorrow!

So now needs the info, boring out to fit a 5hp piston. Sleeve or no? And could I run a sidecover with a bearing with my stock crank (dual bushing) or does it have to be replaced with one specifically for a 1 bearing/1 bushing

 

[rmm727]

Go to apskarting.com

type in AP2072

$3.95

 

[Flexmod3]

Go to apskarting.com

type in AP2072

$3.95

Ok, sorry man and thanks for SKU num. :bowdown: I'm still a bit new to all this and going through that big of a catalog, I'm hoping I'm looking at the right stuff. :hammer: