OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Tech Talk Numbat's Masport rebuild

I cleaned the bore and piston up a little, unfortunately i busted a ring taking them off, so i guess now i need to check for std or oversive and order a set, maybee a hone while were at it.

The frame is fair the handle mount on the left is a homemade item which will be replaced.

Despite the rust she still throws a nice blue spark.

I did a cat scan and Skittle the No2 mouser approves, not game enough to try that with No1 he would tear me to pieces.

The new Victa sure looks nice in blue I blew most of the dust an stuff off with the air comp, just needs a wipe down i use WD40 and a soft cloth.

Is that the briggs and stratton 2 stroke variant of the masport? I have one of those, they are almost as good as the rover suzuki 2 stroke in my books!

Can you tell us more about the engine, I did not know Briggs did a 2 stroke.

They did one 2 stroke they look sort of like a quantum but withth the air filter on the wrong side I have only ever run mine once one day it will be rebuilt again!

I would love to know more about that, Grumpy, do you know about these?

Looks like quite an interesting one, I cant work out to much from the picture, I'm guessing it may be reed-valve?

Ha ha ha good one Numbat,I saw the funny side of that.Can I borrow your cat scanner,it may solve a few problems I have here with some of my mowers.

Ty

Briggs and one of the Japanese comapnies went in together with the 2 stroke motor. Started out 4hp then was upped to 5hp. Wikipedia has some info on there about the who and the why. I think if you search briggs 2 cycle in google it will come up.
Also read something about torro wanting to use their motors for commercial machines and they will be making them again.


I definately want to get my hands on one of those motors.
Same with the Suzuki motor.

hi Joe

Unforunately i don't know the hostory of this mower other than it was bought new in Armidale NSW and used to cut a couple of acres of Caravan park lawns until such time as i acquired her, I used it on our lawn and the empty block next door for roughly 5 years with no problems it was quiet happy to at low-med revs manicure the nature strip, then take the catcher off lift the frame up to max and slash through foot high grass at about 3 quarter throttle, can't say i ever needed to run her flat out, it has a surpsing amount of grunt for a 2 stroke, hopefully i find a bit material on it and get her up and running again.

Ian

Hi Mr Davis

I know very little of anything so the kids & grandkids keep telling me any information I'm able to access i will gladly share, I have had the mower for roughly 5 years, prior to that it was used as a caravan park mower here in Hervey Bay and was basically given to me when they upgraded, I cleaned the air filter and put in a new plug and she didn't miss a beat all those years until the carby pretty much fell off, if there is any any specific pictures you would like i will be only to happy to oblige.

One thing that has me tossed is lack of serial numbers, a solitary number 2 on the underside of the crankcase, I havn't as yet cleaned the gunk off the top, my guess is there will be a number 1 under the flywheel, the Briggs & stratton logo although easily found has no writing or numbers just a blank logo.


cheers Ian

Hi Ian, Being a Briggs, I would expect to see some form of number string stamped into the metal engine cowl (The metal cover that goes ontop of everything, and has the Briggs stickers)

That number, plus any photo's of the top of the cowl will help work out anything we can about the engine, then we can help you as you work your way throught the repair.

Also, no chance you took any pics of the mower before it was pulled apart?

Hi Blumbly

A couple of days back that cute little kitty tore me to pieces while hanging out the washing, she was nearly free to a good home deal, she got me a beauty both legs and one arm, I managed to position a size 9 roughly in the mid section and lifted kitty skywards as she gained altitude i made a dash for the back door, I've come a gutser off my dirt bikes and lost less blood that, that darn cat had claws like talons they have since been clipped by darling wife/nurse/cat breeder.

Ian

Hi Mr Davis

As luck would have it i pressure washed most of the bits and pieces that came off yesterday, I'll just finish this coffee and head over to the shed with camera and see what i can find, I backed up all my pictures onto a 1 terrabyte drive recently all 27,000 of them so somewhere in there i'm pretty sure there is a pik or 2 of her, i have been looking for piks of my old Howard Junior cultivator in there as well to pop into the appropiate forum.

cheers Ian

Hi Rodeobob

Thanks for the info I'll check it out, now i have the serial number it should make things a bit easier, I noticed you live in Sunshine, i was resident of sunshine myself for a number of years.

cheers Ian

Ty, I can't see from those pictures whether it has a reed valve. I've listened to a couple of Utube videos of them, and they idle implausibly well for a port-controlled engine, so I wouldn't be surprised if they are reed valve. You can work it out from where the intake port is located. If it is very, very low on the cylinder, or directly into the crankcase, it will be reed valve.

We might see pictures that show where the intake port is located, or show the intake system dismantled, at some point.

Meanwhile I've read on the internet that the engine was simply a Komatsu that Briggs marketed for a while (1987-1991). It is unclear whether Briggs actually manufactured or assembled the Komatsu engine themselves for a while during that period. The Briggs code dates Ian's as August 1988.

In fact, that would be 23/08/88 would it not?

In which case that mower is 23 years old, in one week!

Looking at the model code,095722, would that follow the normal procedure?

If we exclude the leading zero (maybe used to ID a 2-stroke?) that would be 9ci, Base 5, Vertical Shaft, Float Carby, Mechenical Gov, Sleeve bearing, Recoil starter.

Yes, your code reading is correct Ty. The generation would be 6, not 5, because they started with zero, not 1 (e.g. the famous 60102 engine was first generation). The people who invented the Christian calender made the same mistake you just did, by the way: the inventors started with the year 1 instead of the year zero, so in fact the third millenium started in January 2001, not January 2000, and all of the parties were a year early. It was mildly amusing at the time. However they were apparently several years out with their estimated starting point for the calendar anyway, so I don't suppose another error of just one year was of much importance.

I think it probably was indeed 9 cubic inches, and I've read that it was 5 hp - Komatsu's idea of mild lawnmower tuning was perhaps a bit more aggressive than Briggs' would have been, but it idled very nicely and two-stroked smoothly under very slight acceleration, so I'd say it was a success. I don't know how it would compare with other Japanese two stroke mower engines such as the Suzuki. I suspect it would be a lot easier to get parts for the Suzuki.

The leading zero on the model number might have meant anything, I suppose. I didn't manage to figure out with certainty whether Briggs ever assembled the engine in the US. If they didn't, I don't see how they managed to have a full manufacturing date on the engine, since the whole date string would have had to be stamped in Japan and it wouldn't have reached the US until weeks or months later. On the other hand if Briggs had built it they'd have had the line/plant designators on the end of the date string, and they aren't there, which suggests it was assembled in Japan.

There is a quote from the current Stratton family member on Wikipedia, saying that the venture with Komatsu was not a success because the strength of the Japanese currency (Yen) made the engine unaffordable in the US. Their 10-year agreement only ran for 4 years.

Ian, the KDC on the base of the cylinder may mean Komatsu Dresser Company, which was a joint venture between Komatsu and Dresser, intended to supply very large mining haulers. If so, I don't have any idea why it would be on this product.

I take it the rectangular port is the intake. It is not especially low on the cylinder, and has a definite cut-off on the lower side, so it looks like a piston-controlled port to me. Does it have a reed valve in between the carburetor and that port? If not - that is, if you can see straight through from the air intake side of the carburetor to the cylinder when the throttle and port both open - it is a port controlled, crankcase induction 2 stroke like a Victa, Villiers, etc. (it just runs better than they do).

It appears B&S only stopped using the engine because the strong Yen made it too expensive - I haven't seen any suggestion that they were unhappy with the engine itself.

Briggs and Komatsu got together on this engine. Theres a whole story about it on Wikipedia.
I would say that these engines were made in a KDC factory.