APIA

I have what I believe to be a vintage 65 Sportster NIB. The mixture disc adjustment and the high speed needle are on the same side of the carb. (not remote) There is no pressure tap on the muffler, it is the stock muffler. Looking at the MECOA site at the parts breakdown, I noted that there is a boss on the muffler extension for a pressure tap. From experiences of you Sportster Guru's is this a good place for the pressure tap or is there a better place for it. I have not yet drilled the hole until I find out if this is a good location. I have read that on the muffler body is a better place to locate it. Any input is appreciated. I have also read that there are too many segments or discs (baffles) in the muffler and by removing them the transition greatly improves. The K&B-1L plug comes with the engine, however I also read that an OS-A3 works better. Will this engine pull around an 8# airplane. I know that this is a bushing engine and is no powerhouse but I understand that it makes a lot of torque based on the long stroke... Thanks
-Tom

turbo.gst

My Feedback: (8)

Hi Tom,

I have an original Sportster .65 also. The main difference is that the case does not have the bronze bushing-- and now the remote needle. They added it too the later design. You need to run extra oil by todays standards( no less than 20% oil) I use 22% cas/syn blend or 20% castor. I drilled the boss on the muffler extension for the pressure tap. There may be a better place to place it, but it works fine there. I have ran mine with the stock muffler( baffle in place) and without. It is louder and more powerful without the baffle. I have been able to use K&B r/c plugs with good results with either 5 or 10% nitro fuels. I have never flown it on an 8 lb plane. I guess it would depend on what type of plane and the type of flying.

It has been an incredibly consistent engine. NO dead sticks in some 16++ years of use. The throttling is very smooth and linear, but it just won't wind up like some strong .61 schnurles. I use a 13 x 5,or 6 prop and a BCM sport muffler. I am very happy with the Sportster.65. In fact, I bought a couple of extra to have on hand. I don't know if its fits everyones needs as a 61 sized engine, but I sure like mine.

regards,
turbo

APIA

Hey Turbo, Thanks for the info, I currently run Omega and add 2oz of castor to the mix. Sounds like this is going to be a keeper. I plan to install this engine on an old Andrews Aeromaster Biplane. The airplane came with an OS 61 Max H, however, it has a Semco Flow thru muffler which is outlawed. I have had this Sportster for some time and thought "why not". From everything that I can get my hands on about this engine, The reviews are very positive as long you are not looking for a speed demon engine. I will find out how it carries 8# thru the air... Thanks again
-Tom

Capn America

My Feedback: (3)

Its one of my favorite motors. Its going into a miss america p-51 right now. Mine has a j'vec muffler on it. Loud and runs like a pro.

NM2K

My Feedback: (14)

There was a time when this engine was referred to as the poor man's four-stroke. It loves to swing large props without protest. Try a 14x6 and you will be amazed at the results.

I bought a used one a while back. Don't know if it is the bushed or unbushed version. Doesn't matter anyway. As the other fellows said, keep it sloppy with some castor oil and you won't notice the difference between the two versions.

A friend of mine built a Sig Kadet Senior and put one of these early version Sportster .65s on it. You would think that it would have been too much power, but it turned out to be an excellent match for rough field flying. The .65 could get that Kadet Senior off the ground in the tallest grass, but did not unduly stress the airframe if left to rev up a bit before throttling back. It was a symbiotic/synergistic combination that was truly enjoyable.

My wife's Ben Buckle Red Zephyr is powered by a K&B .28 Sportster. Another perfect match. ROG's with ease.

loughbd

There aren't two versions of the K&B 65 sportster. None of them ever had a ball bearings. All were plain streal shaft running in the aluminum crankcase. None of the Sportsters had ball bearings. They also had a chromed PISTON running in a plain aluminum cylinder. Referred to as a modern "slag" engine. Rubber head gasket (O-ring). This was the last series K&B made before they went out of business and Brodbeck sold the company to Mecoa.

w8ye

My Feedback: (16)

There were some Sportsters floating around a few years ago that had one ball bearing with a bushing in the front. They were made for drones.

loughbd

I have two of those engines. Bought them on e***. They came with Goldberg Mig27 foam airplanes. They do not have a ball bearing in them.

The original RCMAT (radio control model air target) which were big foam deltas came with the K&B61 and those were ball bering engines. A friend of mine in the Air Force Flew them for the Army at Fort Lewis, WA. I got to watch him fly them several times. They were used as targets for the mini guns ( they lost every time) and against ground troops using small arms (they almost never were shot down). They came with R&S radios on military frequencies and two airplanes per box. I have pictures somewhere of a K&B 61 that was hit by a 20mm round.

William Robison

My Feedback: (3)

Bruce:

There were indeed two versions of the K&B Sportster 65. The first did have the crank running in the plain aluminum of the case, without castor oil they wore out quickly. The later production had a bronze or brass bush cast into the front of the case. Easy to tell them apart, just pull the prop drive washer. You either will see the yellow color of the bronze, or you have the earlier plain case.

If yours is the plain case run the engine with 20% castor oil, if it's bushed you can use a castor/synthetic blend.

DO NOT run any plain bearing engine without castor oil in the mix, all the K&B Sportsters are plain bearing engines.

Bill.

loughbd

w8ye said they had a ball bearing and they don't and never did. I never saw bronze that color. Brass maybe but not bronze. Bronze is more brown in color. Mine are the last bunch K&B made and they have no bushing. Maybe Mecoa uses a bushing but I never saw one from K&B with a bushing.

William Robison

My Feedback: (3)

Bruce:

I never saw brass that color either. It was faint in the original picture so I enhanced it to show better. The picture was taken before I got a decent digital camera.

I stripped the head screw threads in mine, it was the early one with plain aluminum. My LHS manager told me about the later ones being bushed, so instead of using Heli-coils I bought the new case. It came with the brass/bronze insert. This was before Johnny Brodbeck sold out.

I’ve never seen one with a ball bearing on the crank either. But I’ve heard of them from a couple sources. Maybe they were just test samples, never a production item.

Bill.

PS: Instead of coming out and telling Jim (W8YE) he’s full of crap why don’t you just say you’ve never heard of one with a ball bearing? Much nicer. Wr.

w8ye

My Feedback: (16)

WR
I'm the one that approved Loughbd's (who is on moderated status) post.

I got to thinking and searched the files. CRRCBOATZ had a HB with the single BB that he called me about some years ago. I got it confused with the Sportster.

I found the single BB drone engines. They were HB's

I added a correction in my 1st post in this thread.

Jim

loughbd

I just checked what I wrote and I didn't see the word crap in there anywhere. Didn't see where I said he was full of it either. Amazing how you can see those words.

Rough??? I said that K&B never made a ball bearing sportster and they didn't. Now if you think that's rough, you might want to take up another hobby. There is too much false info being put out on RCU and the new guys read it, take it as gospel, and perpetuate it. Then gets passed around so much it becomes fact. Like nitromethane makes an engine run cooler. That has been spouted so much half the world thinks it's true. Or the latest, castor oil causes corrosion. That will be around forever now.

Maybe if people checked BEFORE they posted things it wouldn't be so "rough".

NM2K

My Feedback: (14)

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Where did I say that the K&B Sportster engine had ball bearings?

Yes, there are two versions of the K&B .65 Sportster. One has an unbushed case, the first version. The second version utilizes a traditional bushing in the crankcase.

loughbd

Artisan, No one said you did say it had a ball bearing. w8ye did. Read the posts a little better

cdr101

I have several KB 65 sportsters and love them. I first encountered them while flying Target Drones in the US Army. I've read about the long break in required, but to be honest, in the army we would bolt them in, squezze out every last RPM for hand launch, and with a 12x 6 and 15% nitro, never realy had many quit in flight, although they were flown wide open for the most part.
Here's my question for Sportster 65 gurus out there........... I purchased the bushed crankcase from MECOA, but read somewhere that the later models also had bushed conecting rods. Mine all have plain aluminum conecting rods. Can anyone confirm if this is true? Want to to confirm before I order a rod from mecoa only to find it is identical to what I have. Also, has anyone tried drilling an oil hole in the rod of the SPortster 65...... if so any guidance? i.e. what size, where, etc. It looks like there is plenty of "meat" to drill a hole, just concerned about creating a bur inside. Any help appreciated!!!!!