K & B engine
 

anyone know any thing about this motor the k & B it is a 45. It seem to have only one needle vavle. does this control the low speed and high speed togeter?
Bill</p>

RE: K & B engine
 

Does it have a green or silver head?

Is there a throttle arm on the carb?

Show us a picture

RE: K & B engine
 

There should be a brass disk oposite the high speed needle valve.  The disk is moved with a little ecentric screw at the 12 o'clock position.  The disk is attached to a tube inside of the spray bar that has a cats eye opening that is the adjustment for low speed and mid range.  The adjustment range is quite small.  I don't remember whick way is lean or rich. Go to MECOA.COM and look at the user guide for the .45 Sportster; it will tell you how to adjust it.  Run this bushed engine with 4oz/gal of castor and 10-15% nitro and you will have a long lived reliable engine. Make sure the o-ring on the disk assembly is snug.

RE: K & B engine
 

I have a pair of K&B .65 Sportsters. The sportster engines all run very well if ran on the right fuel. Most airplane fuel at retail stores is going to be a synthetic blend or all synthetic. These engines do not like these kinds of fuels. Its best to run an all-castor fuel with no more than 15% nitro. My .65's run hot on 15% nitro and performance is about the same on 10% nitro 20% oil (half castor half synthetic) I've heard they run best on all castor fuel with little to no nitro.

My engines are from military drones and need the idle disks changed but will swing a 13x6 or 13x7 prop easily. That .45 should be able to spin an 11x6 or 11x7 well.

Is there a remote needle or is the needle on the carb body? The newer sportsters have a remote high speed needle which uses an idle disk but not an eccentric screw (if I remember right). If the main needle in on the carb body, the eccentric screw doesnt change the idle mixture much - it only moves a little bit in either direction. With the Eccentric screw centered, clockwise richens and counterclockwise leans the idle mix. Start it in the middle and run it until warm. Set the high speed mixture to peak RPM and richen 2-3 clicks THEN set the low-speed mixture. The low speed mixture controls the fuel mixture up to about 3/4 throttle. If it transitions from low rpm to high rpm real rough and smokey, lean the idle disk about 1/4 of its travel.

These are good, torquey 2 stroke engines that will swing bigger props than would normally be ran on an engine this size.
Hope this helps.

RE: K & B engine
 

The engine design is such that I would highly suggest running a low nitro glow fuel with 20% castor oil in it, no synthetic oil or blends. 10% nitro is probably a good way to go.

K&amp;B used a couple three different carbs on the engines over the years.
The Perry Carb was quite popular for a long time.
it has a brass disc opposite the needle valve you use for setting the idle mixture. But you seldom needed to mess with it.

K&amp;B later used a carb of their own on the engines. Like shown here for example on the .65 engine.

http://i248.photobucket.com/albums/g.../KandB6501.jpg

RE: K & B engine
 

My .65's have K&B carbs on them identical to the one in that picture.. This seems to be the most common carburetor I've seen on older sportsters.

earlwb: That sportster .65 looks like one of the real old ones - the head fins are huge compared to the two .65's I have.. Has that engine even been ran? It looks pretty new.

RE: K & B engine
 

I bench ran it many years ago to see if I wanted to use it on a Goldberg Ultimate biplane or not. But the Ultimate had the weirdest problem that I was never able to solve. the engine would always quit if you did a roll too fast. Loops, inverted, knife edge, slow rolls, four points, tail slides, spins, etc all worked no problem. it was fast rolls that would kill the engine. i tried a different fuel tank, and different engines. i eventually tired of it real quick and sold it to someone else. Anyway if you flew it and avoid the rolls you were OK.
weird huh? I ran a Fox 60 eagle III, a Fox Eagle IV 74, a OS 1.20 four stroke and it did the same thing with all of the engines.
Anyway, I ought to put the K&amp;B 65 on something one of these days.

I have four K&amp;B 20 Sportster engines and they all have Perry Carbs on them. I was going to run them on Royal B-17 but the plane got crushed when i was moving.

RE: K & B engine
 

I have to replace the mixture disks in both of my .65's and I looked at a Perry carb to replace the K&B carb but the Perry and the updated K&B carb's cost the same. Any difference in performance between the Perry and the K&B carb?

RE: K & B engine
 

ORIGINAL: earlwb


I have four K&amp;B 20 Sportster engines and they all have Perry Carbs on them. I was going to run them on Royal B-17 but the plane got crushed when i was moving.





Dang Earl that's a shame. Anybody know why K&amp;B is so adamate about not using muffler pressure on their sportster motors?

RE: K & B engine
 

I know a lot of the old ones didnt have a muffler tap from the factory and the more modern ones come with a pressure tap on the exhaust adapter. I dont know why you would NOT want to use a pressure tap even with good fuel draw. Both of my .65's have pressure taps. I only run one of them right now and I use the pressure line. I'm hoping I'll be able to get one to run with the tank under the engine.

RE: K & B engine
 

I know a lot of the old ones didnt have a muffler tap from the factory and the more modern ones come with a pressure tap on the exhaust adapter. I dont know why you would NOT want to use a pressure tap even with good fuel draw. Both of my .65's have pressure taps. I only run one of them right now and I use the pressure line. I'm hoping I'll be able to get one to run with the tank under the engine.




About 15 years or so ago I drilled and tapped the muffler extension of my 65 sportster for a pressure tap nipple. LaterI had to sendit back to K&amp;B for some minor issue and when I got the engine back the technician included a note which emphatically stated not to use a pressure tap. I thought the engine engine ran well with it.

RE: K & B engine
 

The one in the picture look like the one I have. Is that A perry carb?

RE: K & B engine
 

No...that's the K&B carb...the original (early ) version with the high speed needle valve mounted on the carb.

Later versions have a remote needle.

RE: K & B engine
 

It is a good thing I took a look see at my old K&amp;B Sportster 20 engines. My memorymust be going bad as I had totally forgotten that these engines had the K&amp;B carb and not a Perry carb on them. I remember now as to why I got them, they were cheap, but the carbs had a dual detent making them perfect for multi-engine planes. usually the excess engine vibrations would cause the spring loaded needles on the Perry carbs to move around on you.

K&amp;B back then like most engine manufacturers was not including a muffler pressure tap. But later they all started doing it. Note the muffler extension has a spot for drilling and tapping to install a pressure fitting.

http://i248.photobucket.com/albums/g...ster_20_01.jpg


A Perry carb looks like this one here, this is a later model as the needle has a skirt on it hiding the spring tensioner under it. The spring keeps the needle from moving. But excess vibrations can cause the needle to turn when you don't want it too. But for single engine applications with a balanced prop, it works just fine,
http://i248.photobucket.com/albums/g...ry_carb_01.jpg

http://i248.photobucket.com/albums/g...ry_carb_02.jpg

The brass disc is what you turn to adjust the idle mixture on a Perry carb. Just a tiny bit of turning on the disc is all one normally needs, don't try big turn movements, just little tiny incremental adjustments.
http://i248.photobucket.com/albums/g...ry_carb_03.jpg

RE: K & B engine
 

I guess I should mention some of the stuff about the K&amp;B Sportsters as I found out about them. K&amp;B attempted to engineer the engines to turn larger props like a 4 stroke engine would. So they tend to like larger props. So a Sportster 45 would tend to like 11x7, 12x5, 12x6 props and maybe even a 13x5 or a 13x6 too. it is not a high rev'ing engine.
The instruction sheet<span class="msg"> recommends a 11x7 but can handle a 12x6 with good rpm no problem.</span>

The other thing was K&amp;B's accountants apparently got involved and on the ones I looked at, they apparently chromed the piston and not the cylinder sleeve. The cylinder sleeve is aluminum not hardened steel. Sp castor oil is a must. It saves a little bit on the cost. But the piston tends to be the high stress and wear point then. Especially the part of the piston next to the exhaust port. So you need to use 20% to 25% castor oil in the glow fuel, to help prevent problems with the piston peeling the chrome plating off. By keeping the engine RPMs lower the piston is less likely to start peeling its chrome plating off. Run the engines rich for a while during break in and keep the RPMs extra low, say 6,000 RPMs or so for a while too.

Also these are bushing support crankshaft engines so the castor oil helps to lube the crankshaft and it doesn't ooze out of the front of the engine so much.
So you really need to use low nitro glow fuel with 20% to 25% castor oil for lubrication in it.

here is a old thread about them: http://www.rcuniverse.com/forum/m_272455/printable.htm

and here is a exploded engine view drawing of them: www.google.com/url

RE: K & B engine
 

Earl has the words of wisdom

More Sportster stuff below The break down mentioned above

RE: K & B engine
 

So far, my sportster .65 has been a decent engine... though changing fuel tank styles took a bit to get working right but otherwise powerful enough to do what I needed it to do. The .65 sportster on my boat will turn a 13x6 at roughly 10,200-10,400rpm.

The all-castor fuel these engines like is tough to find at a retail store. Almost nobody carries it nor will they order it. Closest thing I found was 1/2A fuel which has too much nitro and only comes in 1/4 pint or 1/2 pint bottles.

I'll be making my own fuel and if anyone wants some all-castor fuel, let me know.

RE: K & B engine
 

Our local big hobby shop started selling all sorts of Powermaster fuels. Some of the mixes are similar to Fox manufacturing or SIG fuel blends too.
http://www.powermasterfuels.com
If I remember I was pleased to see some fuel blends wtih 25% or 28% castor oil in it too.
I also like the metal fuel cans too, as they fit my flight box nicely.

But yeah many hobby shops have become somewhat limited in fuel selections with the recession going on and all, they had to limit their inventory costs.

RE: K & B engine
 

The problem I have found in talking to the guys that run all (and I mean all) of the hobby shops in the area. When I asked for an all-castor fuel they looked at me funny. At least around here, nobody uses it so they don't order it and one guy looking for something this "rare" doesnt warrant them to order any. Some places wont order fuel in gallons even because of hazmat fees. Fuel that would cost $20 a gallon ends up costing over $30. Apparently they think everyone's running ball bearing ABC engines where all that synthetic oil isnt a big deal.

RE: K & B engine
 

I forgot to mention earlier, that performance-wise the old K&amp;B carb and Perry carbs are about equal for all intents and purposes.

I actually think the stores push synthetic oil fuels as with higher nitro percentage fuels, it causes the engines to rust out on the inside faster. So they get to sell more engines. Most people don't repair the engines, they just buy new ones instead. Plus keeping one type of fuel reduces their inventory costs as well. But like you stated, they probably do not see guys running older engines much if any nowadays.

Being way up there in MN makes it tough, no easy solution for you there. Being way down here in Texas, where he have a almost year round flying season, gives us more choices in fuels to use. Plus PowerMaster is made here in Texas too.

But with the K&amp;B Sportster engines castor oil is really needed due to the aluminum cylinder. The castor oil tends to form a varnish like coating that the engine designers were taking advantage of to prevent the aluminum cylinder sleeve from wearing out prematurely.
Other older more vintage engines need castor oil too. McCoy and Testors is one example, they have plain steel unhardened cylinder sleeves that wear out fast without castor oil. Many old bushing engines with iron pistons actually need the castor oil, I remember guys trying synthetic oils in a old engine, only to have it's compression go away, as the engine wore off the castor oil varnish layers that was letting it work good.

RE: K & B engine
 

I run in the winter time - snow is great to play in. I plan to make my own fuel for all of my engines as soon as the wife will let me spend the money on it. Its more work, but I'm willing to do it as I want to keep my "never wore an engine out" rep going.. (lol) I have an old Fox .40 that I'm trying to find a piston and liner set for. It did run but during the last run the glow plug element melted and broke off scoring the cylinder wall. Fox doesn't make a sleeve set for this engine anymore, either.

RE: K & B engine
 

Some of the Fox engine models haven't really changed all that much for many years now. The C frame or small case .40 is one example, I don't think there was any changes except to the carb since it first came out, The large case 40/45/46/50 engines did have a few changes along the way though. But for about 20 years the engines are the same except for the carbs. The bushing versions of the 40 and 45 had a different rod and crankpin on them. The earliest wart engines were different to, but I think it was the crankcase more than what was inside. Oh yeah, they did change the head button over time, they had high compression and lower compression versions over the years.
I see parts for the engines pop up on Ebay from time to time.