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Saito FA-82A versus FA-82B

Old 11-03-2012, 08:26 PM
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cphdrider
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Default Saito FA-82A versus FA-82B

Question... What is the difference between the Saito FA-82A and FA-82B? I know the A version back plate is black plastic, is there a problem with the plastic reason for changing to metal?Is there any internal difference or anything else?
Old 11-03-2012, 08:56 PM
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the pope
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Default RE: Saito FA-82A versus FA-82B

Hi , newer style cam box. As far as I know the internals are the same but my newer 82 runs smoother then the old . Cheers the pope
Old 11-03-2012, 09:04 PM
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fredscz
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Default RE: Saito FA-82A versus FA-82B

I think there were reports of the back plate warping and not sealing well. I never had a problem with mine and I had and have several in use. Shouldn't make much difference either way on a Saito 4-stroke. The new plastic replacement back plates appeared to be slightly thicker or made a little more robust.I do believe the new metal backplates will fit the older engines.
The crankcases have a different designed cam cover like some of the other newer model engines but I have read that a lot of the parts are interchangeable between the two models.
I have had several of both the 72 and 82 A and B versions and they run the same.
JMHO
Fred
Old 11-03-2012, 11:11 PM
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w8ye
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Default RE: Saito FA-82A versus FA-82B

The cam pivot shaft is longer in the 72 and 82 "B" models to go along with the different style cam box.

AFAIK the old unique "A" parts are no longer available? So if you have a wreck that destroys some part, unique about your "A" model, you will be converting it to a "B"?


List of Unique parts . . . .
Backplate
Carb mounting screws
Back plate gasket
Cam cover gasket
Cam cover
Cam pivot shaft

However all the old and new parts except for the crankcase and backplate are used on other size Saito engines and can be utilized for repair.

I have changed many back plates on 72 and 82 engines to the "B" (aluminum) one but the rest of the engine (cam box) remained the "A" style.

Early on, I had to make the rear backplate gasket and use cab mounting screws from the 91 to change the plastic backplates to aluminum.


Old 08-11-2013, 01:01 PM
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cphdrider
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w8ye, I have a Saito 82B with approx. 10 flights and the compression has dropped 60%. I checked the valve clearance which was OK and readjusted them to .003". Everything is smooth turning over with no sign of a bearing problem. Would you suggest replacing the piston ring, or, does it even have a ring? Also, what about the valves and how to I check them for leakage?
Old 08-15-2013, 08:43 AM
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wcmorrison
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Compression is very hard to measure on these small engines. If the carb is not open it will seem like it has lost or has low compression. And yes it uses a ring. I suspect your engine is just getting broken in. If it runs and produces top expected RPM it is just fine. You probably have a couple of years to go. Read the instructions and use the recommended fuel. I always use a bit of Castor or a Castor blend, some Castor is good.
Old 08-17-2013, 05:14 PM
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Rudolph Hart
 
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Agree with that.I have 2x82's with well over 100hrs each and they still run as good as new.
Old 08-19-2013, 09:15 PM
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Ernie Misner
 
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Yes, make sure the carb is open when you turn it over by hand to check for compression. Also, it is possible to feel good compression when turning in one direction but not the other - if the ring (and gap ends) has turned just righ on the piston.
Old 03-28-2014, 05:04 PM
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martin_solo
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Any body else have felt that the Saito 82b runs smoother then 82a? I never got the 82a because I have heard many people say it shakes a lot more then the 72 and 91s. The 82a was lighter then then 72a, now it seems the 82b is heavier then 72b, so I wonder if Saito made a better balanced crank for the B version. I fly c/l and the vibration of the 82a is not acceptable and I have been wondering if the new 82b is running much smoother then 82a.

Martin
Old 03-28-2014, 07:37 PM
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Ernie Misner
 
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I haven't heard a thing about the "a" not running smooth. Mine is a smooth operator anyway. I put the alum. backplate on recently just for the fun of it. AFAIK nothing internally would make the "b" any smoother. People with rough running Saitos usually have the bottom end set too rich, or the tank is not in line with the carb resulting in a fat bottom end. I think the 82 has one of the best overall reputations of any engine out there.
Old 03-29-2014, 02:28 PM
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blw
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I have a first year 82a that I recently broke in. It has less than an hour on it and is surprisingly smooth. This is going to be a very good engine.

The 82 is lighter than the 72.
Old 03-29-2014, 03:15 PM
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BLW, Glenn has a 82B he got from me for whatever that's worth from a look/see point of view. The only advantage of a 82B I can think of is that the crankcase may be a little stronger in a crash.

There is no difference in the cyl/piston, crankshaft/rod, carb assembly, or the cam itself.

I think 82's are wonderful engines. I would take a 82 over a 91S any day.
Old 03-29-2014, 06:06 PM
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martin_solo
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I am sure for R/C the 82a is a mighty fine engine! However I just want to find out if any one else other then Pope noticed if the the 82b runs smoother.

If there is no typo error, the Factory published weight has some interesting differences:
82a list as 462g and it is lighter then 72a and 72b both listed to have the same weight of 470g
82b list as 476g, 14g heavier then 82a.

14g is not much, but if they made a heavier better balanced crank and perhaps a lighter piston for the new Engine it could explain the weight difference and the smoother running that Pope, above, has reported.

In the c/l community the Saito 40,56,62, 72 and 91s are well known and super duper engines. C/L models are far less robust then R/C models in the nose, our models are narrower and we only use hard engine mounts. If we use regular R/C mounts that absorbs the vibration, the engine does not run well for us. C/L is all about Precision and small details makes big difference. Some very experienced c/l flyers tried the 82a, which has the Saito 100 piston, and reported that it shakes too much for our application. Unfortunately 4S engines are not as popular for c/l flyers today and I have not heard of any one that have tried the new 82b for c/l. So before I get one and be the first to try I am trying to gather more information from you guys that might have experience running the 82a and 82b.

Any way thank you for sharing your thoughts.

Martin
Old 03-29-2014, 10:18 PM
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Ernie Misner
 
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Originally Posted by w8ye View Post
BLW, Glenn has a 82B he got from me for whatever that's worth from a look/see point of view. The only advantage of a 82B I can think of is that the crankcase may be a little stronger in a crash.

There is no difference in the cyl/piston, crankshaft/rod, carb assembly, or the cam itself.

I think 82's are wonderful engines. I would take a 82 over a 91S any day.
Hi Jim, just curious why the 82b crankcase is stronger. Alum. backplate or changes to the cam housing area? I can see why the original 82 is lighter than the 72 - although a larger bore (29/27mm) the 82 has a slightly shorter stroke (20.4/20.6). So the counter balance might be a hair smaller. The engineers must have had some extra time on their hands when they decided to de-stroke the 82 by only .2mm.
Old 03-29-2014, 11:03 PM
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The pope here again, 4strokes do chug a lug more than 2 strokes . Having said that the 82 would have to be my favourite engine . Some people do report that some do shake more than others .As for its use in c/l I can't say but if other 4 strokes are used than this engine should be OK as well . Get 1 , I don't think you'll be disappointed . Good luck and keep us informed . Cheers the pope
Old 03-29-2014, 11:05 PM
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Martin don't get your knickers in a knot.The 82 will be as smooth as you tune it,particularly the low speed needle.Mine are silky smooth except for a small band of vibration at low rpm.You spend all your time at max rpm? no dramas.

The instruction manuals can be a bit hit and miss in every way.They used to list a saito 30sc at something like 22,000rpm max.

popey is good at drawing maps of tasmania as well
Old 03-30-2014, 01:26 AM
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Originally Posted by Ernie Misner View Post
Hi Jim, just curious why the 82b crankcase is stronger. Alum. backplate or changes to the cam housing area? I can see why the original 82 is lighter than the 72 - although a larger bore (29/27mm) the 82 has a slightly shorter stroke (20.4/20.6). So the counter balance might be a hair smaller. The engineers must have had some extra time on their hands when they decided to de-stroke the 82 by only .2mm.
The small cam box cover makes the crankcase stronger in front of the cylinder.
Old 03-30-2014, 02:36 AM
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Originally Posted by Old Fart View Post
Martin don't g. your knickers in a knot.The 82 will be as smooth as you tune it,particularly the low speed needle.Mine are silky smooth except for a small band of vibration at low rpm.You spend all your time at max rpm? no dramasdidn't have that thingy down there u would them on a island and throw rocks ae instruction manuals can be a bit hit and miss in every way.They used to list a saito 30sc at something like 22,000rpm max.

popey is good at drawing maps of tasmania as well
R u trying to get me into trouble there Old fart? I haven't drawn too many maps of tassie (well since school anyway ) .I have seen a few though , some a bit scary looking and some worse . U know the old saying (I think from the dali lama ) that if women didnt have that thig down there u would put them on a island and throw rocks at em .(I think im gonna get into trouble here ) Cheers the pope

Last edited by the pope; 03-30-2014 at 02:39 AM. Reason: why not
Old 03-30-2014, 06:21 PM
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Originally Posted by Old Fart View Post
The 82 will be as smooth as you tune it,particularly the low speed needle.
Words of wisdom, fer sure.
Old 08-23-2018, 10:48 AM
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I have a Saito 82a that ran beautifully - lots of power and no vibration.- then I had a small fire at the house and a neighbor called the fire department who put the fire out with fire extinguishers and the caustic chemicals ate the prop drive, corroded the bearings and appears to have attacked the crankcase. So I want to replace the crankcase, bearings and prop drive - the 82a crankcases seem to be unavailable so does anybody know how many parts I need to order to change to an 82b crankcase? Is it a 1 for 1 swap?-- Thanks for any help.
Old 08-23-2018, 01:50 PM
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cphdrider
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Originally Posted by gmeyers View Post
I have a Saito 82a that ran beautifully - lots of power and no vibration.- then I had a small fire at the house and a neighbor called the fire department who put the fire out with fire extinguishers and the caustic chemicals ate the prop drive, corroded the bearings and appears to have attacked the crankcase. So I want to replace the crankcase, bearings and prop drive - the 82a crankcases seem to be unavailable so does anybody know how many parts I need to order to change to an 82b crankcase? Is it a 1 for 1 swap?-- Thanks for any help.
I have learned a lot about Saito 82 engines since I started this thread in 2012. Do your self a favor and keep your engine for spare parts and find you a nice used engine. I have one listed now on RC Groups that is like new. If interested, go to RC Groups, classified, Saito 82. Or, email me [email protected] for pictures.
Old 08-23-2018, 05:33 PM
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Originally Posted by cphdrider View Post
I have learned a lot about Saito 82 engines since I started this thread in 2012. Do your self a favor and keep your engine for spare parts and find you a nice used engine. I have one listed now on RC Groups that is like new. If interested, go to RC Groups, classified, Saito 82. Or, email me [email protected] for pictures.

Looked at your listing on RCU - bit pricy for a used engine but then again you say it's barely used -- BUT it looks like one of your other prospects has sent your paypal account the money so it's probably gone by now. Thanks anyway.

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