1983 B&S Flathead (130200 series) Breakdown/Rebuild

[LeeMajors]

When Poboy and the others mentioned the easy checks for seeing if you have a decent engine (starter or carb fluid sprayed in the carb or in spark plug hole), did you think to notice whether it had decent compression when you pulled the starter rope?

Mine didn't. It pulled too easily (and wanted to keep 'coasting' as there was almost nil compression to stop the flywheel) but I didn't really care.

I think you can hone these and go through several oversizes before the block is toast. Let me get back to you on some references.

I'd already bought it and started pulling it apart by then. And I did yank the starter cord a few times and it actually had pretty good compression? I mean it definitely didn't try to keep spinning. You can see the scuffs and scratches in the pics and I think they look a little worse then they are? All of them are smooth to the touch except 1. But of course it's that 1 that concerns me.

Also while researching new rings and pistons etc... I found an article, or two, which were talking about wrist pin boss failures on the older Briggs pistons above 3600rpm. Apparently Briggs contracted Federal Mogul to redesign the pistons and these are what you'll find in the Raptor III's. So I figured since I'll probably need to replace the piston I might as well get the "Good" one, right?... Well I can't find these darn things to save my LIFE!? The only place that had anything close so far was ARC and they only have the "Non-Chromed" version which doesn't work with the Aluminum cylinders. Does anyone know where I can purchase a Chromed Piston replacement for the Raptor III?

---------- Post added at 02:27 PM ---------- Previous post was at 02:20 PM ----------

Hellion, I have another question for you too... Are the older Briggs flathead 8hp and 11hp I/C as good as this 5hp is? Or are they not worth messing with due to difficulty finding aftermarket parts? The reason I ask is because I can get an 8hp (not running) for $10 and/or an 11hp I/C (also not running) for $25-$30 right now and add a few more projects to my stable, if they worth fooling around with..?

 

[Hellion]

Hellion, I have another question for you too... Are the older Briggs flathead 8hp and 11hp I/C as good as this 5hp is? Or are they not worth messing with due to difficulty finding aftermarket parts? The reason I ask is because I can get an 8hp (not running) for $10 and/or an 11hp I/C (also not running) for $25-$30 right now and add a few more projects to my stable, if they worth fooling around with..?

They're basically not worth it. They don't have the following and popularity of the 5 hp flatties and therefore don't have nearly as much aftermarket hop up parts. I haven't really looked all that much to be honest but they don't come up often in generic searches such as "Briggs performance" and the like.

If you think you could fix these engines and then flip 'em (you'd be surprised the prices Briggs's will fetch on fleabay), that might be your bag. Depends on what's wrong with them.

I don't recall ever seeing an 11 hp horizontal engine...

Does anyone know where I can purchase a Chromed Piston replacement for the Raptor III?

Supposedly Burris makes both types of pistons; chromed and plain aluminum.

 

[LeeMajors]

They're basically not worth it. They don't have the following and popularity of the 5 hp flatties and therefore don't have nearly as much aftermarket hop up parts. I haven't really looked all that much to be honest but they don't come up often in generic searches such as "Briggs performance" and the like.

If you think you could fix these engines and then flip 'em (you'd be surprised the prices Briggs's will fetch on fleabay), that might be your bag. Depends on what's wrong with them.

I don't recall ever seeing an 11 hp horizontal engine...




Supposedly Burris makes both types of pistons; chromed and plain
aluminum.

Awesome brother! You're the man! Thank you. And you're correct!... upon further review that 11hp is a vertical shaft. Thx for pointing that out to me. So today I spent a good bit of time at the local "U-Pull-It" in their small engine section, and let me tell you, what a disappointment! They basically just have everything thrown on top of everything else! There was literally NO WAY to walk through it!? It was ridiculous! More like a scrap yard then a U-pull-it. And on top of that I really didn't know exactly what I was looking for, or not looking for, for that matter..? So it wound up being a big waste of time. I was hoping to find an axle really or maybe some wheels? Idk? But I didn't see anything I could use. All the lawn tractor axles were setup for use with vert shaft engines or had diff's? Nothing like what we use on go-karts. So I guess I'll just have to order one? Do you have any recommendations for where to buy and/or what size, keyway style, etc...? Hollow or solid? Idk the 1st thing about this stuff bro and I feel a little "in over my head" on this part. Like, what hubs, and bearing's and is there a universal type of mounting bracket that I can weld to the frame , etc..etc...etc...? Do I need threaded ends or plain ones? There's sooo many options!!!!?

 

[Hellion]

Awesome brother! You're the man! Thank you. And you're correct!... upon further review that 11hp is a vertical shaft. Thx for pointing that out to me. So today I spent a good bit of time at the local "U-Pull-It" in their small engine section, and let me tell you, what a disappointment! They basically just have everything thrown on top of everything else! There was literally NO WAY to walk through it!? It was ridiculous! More like a scrap yard then a U-pull-it. And on top of that I really didn't know exactly what I was looking for, or not looking for, for that matter..? So it wound up being a big waste of time. I was hoping to find an axle really or maybe some wheels? Idk? But I didn't see anything I could use. All the lawn tractor axles were setup for use with vert shaft engines or had diff's? Nothing like what we use on go-karts. So I guess I'll just have to order one? Do you have any recommendations for where to buy and/or what size, keyway style, etc...? Hollow or solid? Idk the 1st thing about this stuff bro and I feel a little "in over my head" on this part. Like, what hubs, and bearing's and is there a universal type of mounting bracket that I can weld to the frame , etc..etc...etc...? Do I need threaded ends or plain ones? There's sooo many options!!!!?

Gimme that white flag! Whew, that was a crazed, hysterical block of text. Try making them into little paragraphs, especially if you change the subject.

I'm not even sure at this point where your project is going. Scratchbuilt frame?

Most go kart parts are universal stuff. You can get standardized axle bearing hangers to suspend your rear axle from.

Hollow axles are big bucks. I'd go solid, threaded on both ends with the appropriate keyway for a sprocket. Go to BMI or GoPowerSports and look around. Being a member here gets you a 10% discount at GPS. Code: DIYGOKARTS

 

[chancer]

Also check out Kartfab.com. He has free plans, and how to videos.

 

[LeeMajors]

Gimme that white flag! Whew, that was a crazed, hysterical block of text. Try making them into little paragraphs, especially if you change the subject.

I'm not even sure at this point where your project is going. Scratchbuilt frame?

Most go kart parts are universal stuff. You can get standardized axle bearing hangers to suspend your rear axle from.

Hollow axles are big bucks. I'd go solid, threaded on both ends with the appropriate keyway for a sprocket. Go to BMI or GoPowerSports and look around. Being a member here gets you a 10% discount at GPS. Code: DIYGOKARTS

Hehehee! I was having a moment. And yes I'm planning to scratch build the frame. I'm going to loosely base it off of the '97 Tony Kart Extreme. But with a bench seat and the engine centered in the rear (maybe a little to the passenger side?).

Thank you for the axle info. There were so many different options it was a bit ridiculous.

Also check out Kartfab.com. He has free plans, and how to videos.

Thx man... I'll take a look at that in a bit.

Lastly, I have some updates... the engine is officially stripped down
But it's not in the best shape. I'll UL pics later tonight but let's just say this guy must not have changed the oil for about 20yrs!? The amount of sludge in the crankcase was staggering. And I'm like 99% sure that it was debris in the oil that damaged the cylinder wall because the piston skirt, on the same side, was toast. It's got matching scratches but they're way deeper on the piston then they were on the cylinder. So my options are grab another motor or get the replacement parts for this one. And I still haven't decided so we'll see? I'm gonna price the piston on Burris' website and weigh my options. I'll keep you guys posted. And as always thanks for the replies

 

[LeeMajors]

...................... MAYBE a valve job, and definitely PnP'ing the ports and head (especially after seeing those casting flaws)
Lee resist all urges to do any kind of porting in the intake port of that engine..... it is already too big, clean up with a light sanding and thats it, when you pull the carb look at the difference in sizes and you will see what I mean, flow being pulled tru that small diameter in the carb then dropped into that big port and fuel can drop out of suspension, I have seen people have to go to larger jet to try to cure this ( this was racing flat heads), and check the top of that carb right along the casting line that runs the length of the carb , if it has the number 2 cast into it ,it is the best carb ( as far as flow) that ever was produced and it is found mostly on tiller motors .
Good Luck these engines are easy builds
Kenny

Thank you again for this reply. I finally got it cleaned up a TINY bit and it's got a number "3" cast into it and there's also a "2" stamped into one of the spring loaded pieces on the top, right above the flat-head screw in the pics below. The "3" is actually cast into the body of the carb though so I'm sure that's the number you'd spoke of. So do you know anything about these particular carbs? Any way to mod them, etc...? Lmk? And thx again!

 

[LeeMajors]

Sorry fellas these are the pics I forgot to UL last night....

 

[LeeMajors]

Pics cont. ^^^

 

[big-d]

11hp horizontal shaft I/C Briggs.

 

[LeeMajors]

11hp horizontal shaft I/C Briggs.

Omg... THAT'S the one! And I just looked at the ad again and it's got the mounting plate on the bottom! So it IS indeed horizontal shaft! Awesome! Great find big-d! ty! I still don't think I'll wind up buying it because of it's lack of aftermarket support but it's definitely good to know that they do offer that variation..?

 

[Hellion]

Hey Lee, that's not really bad wear on your piston. Do the scratches catch your fingernail, at least?

I'd want to see the cylinder walls to compare. If there's remaining factory cross-hatching visible on the cylinder walls, that's a good sign. You may be able to get by with a cylinder hone and refurbishment of the rotating parts.

How's the crank journal look (where the connecting rod rides)? Any signs of galling, scoring or oil starvation? What about where it rides in the case; pto and flywheel side bearings? Check for scoring there as well. Check the camshaft as well.

Also, some 'sludge' in the bottom of the crank case is kinda what you want to see. That's where it usually stays and doesn't circulate and is also hard to drain out, apparently. I had some too--a relatively thin layer. But change your oil early and often!

 

[LeeMajors]

I have a question for the B&S gurus out here:
Is it true that the Raptor II/III came from the factory with a billet connecting rod?
And do any of you know, with certainty, that it would fit the standard 5hp Flathead? Thx

Also here's a quick preview of the block work w/lots more pics to come:

 

[Hellion]

Nice. Best shaved "eyebrows" photo ever. Looks glorious!

Do tell how you did it. Polishing compound?

 

[chancer]

That Does look nice!

 

[LeeMajors]

Nice. Best shaved "eyebrows" photo ever. Looks glorious!

Do tell how you did it. Polishing compound?

Thanks!
As a matter of fact YES! At the very end of course, but yes...and believe it or not I was being a cheap bas%@#! and wound up doing a majority of the work with small metal hand files! And some grinding stones in a cordless drill (which btw I absolutely DO NOT recommend) which really sucked because you simply don't have enough control. Especially while working around that mating surface and the fact it's aluminum, it's just a recipe for disaster... I got LUCKY and didn't scratch the deck but I came very VERY close. So yea, don't do it that way.

That Does look nice!

Thank you!
I'll post pics of the entire process. I also shaved the head a tad and cleaned up the deck a bit too, just so I had a good flat mating surface for the new head gasket. I still need to hone the cylinder just to break the glaze but I decided not to bore it and just got the chromoly rings. I plan to reuse the original piston. Now I'm just need a billet con rod and new oil seals, and I'm still researching my carb options. Not sure if I'm going to mod this one or buy aftermarket? I finally found the casting mark on the original carb and it's a #3. Idk if that's good or bad but I'm sure a little more flow can't hurt it. I have however read that these pulsajets aren't the best, but then again Hellion did mention that these "slide" type carbs were decent so idk? What do you guys think I should do?

 

[LeeMajors]

Okay before I get started I came to a realization last night, AFTER putting in all this work, that my exhaust valve guide is completely shot. The valve literally RATTLES around inside the guide! And I'm really not sure what to do because that's not an "at home" or "DIY" type of fix? The exhaust valve itself is also toast and in most likelihood the reason for the guide being so fudged up. So needless to say I ordered new valves and I'm still weighing my options... do I just run it loose, or do I get the guide replaced? Idk? I'd love some input/feedback on this... and the last 10 questions I've posed! But I won't hold my breath
^^^Sarcasm^^^ Mmmmmm.....

Alright, now for some pics of the shave and deck. I went with an old school trick I'm sure many, if not all, of you are familiar with. One which has caused many of debates over the years but put simply; It Works. Thick glass table top + sand paper = FLAT
If it's good enough for the automotive world (and yes I have seen it done and hold up on many of heads/blocks) then I'm sure it's good enough for an ol'Briggs flathead. Also I apologize ahead of time for the picture quality and lack of organization but I just wanted to git'er done, so here they are:

 

[LeeMajors]

^^^Pics cont.

 

[LeeMajors]

^^^ And more pics...

 

[big-d]

Progress looks great! I don't have an answer to you question though.