Tarno carb

I just noticed a friend of mine is selling this. I sent him a message about it. I will repost latter.

I am at work right now, so i dont have it in front of me. Picked up the complete carb, round backplate reed holder, and mount piece from ebay uk awhile back. The firewall mount bolts to the crankcase, which in turn holds the reed holder into the crankcase, then the carb threads to that holder. The firewall mount is like a tall engine stand and holds the motor out so the carb clears the firewall.

Just think rear induction motor, like a sportsman or olympic .15 , then picture the induction setup on the back of a standard 049 with a long/ tall firewall mount to allow the induction to clear every thing

It looks like it could screw into a Tee Dee carb body also.

cribbs74 wrote:Joe, I can't see why a reed assembly would be needed if it bolts to the backplate. A mount would be required i'm sure.

From the picture(s), it looks like the reed adapter part(s) replace the entire backplate and tank/reed assy on GBs, BWs, etc. An external tank is needed. The instructions don't mention product or Surestart engines either, probably an indication of the age of the kit.

The auction mentions that the 1/2AR carb isn't suitable for TD's due to the idle screw and fuel inlet. However, I'll take that as a challenge!!

Here's what the seller sent me.
Hi Joe,
It will fit the Tee Dee carb body but the fuel line nipple and the
low speed needle will be facing the prop. You could stop the engine
to make carb adjustments and probably rotate the fuel nibble but It would
be more practical to get the correct carb.

Here is a pic of my Tarno AR setup I have. The pic is self explanatory for the assembly. You can see the round reed holder the Ebay seller mentions. your repositioned idle screw and nipple on the carb and the tall or long firewall mount I tried to explain.

Cool stuff! That pretty well clears things up for me.

How often would the low idle screw need to be adjusted anyway?

One question, maybe dumb but, I'll take that chance....

Is it possible to block the venturi on a TD and screw that reed holder into the back of The crankcase? Is the reed holder threaded? I don't see any mounting holes on it.

I realize it would be easier to do it to a reedie just thinking about different options.

cribbs74 wrote:Cool stuff! That pretty well clears things up for me.

How often would the low idle screw need to be adjusted anyway?

Thats a good question, I haven't mounted those pieces on a motor yet. Alot of variables there. weather, prop, fuel, ect.

I dont think that piece would fit into the Tee Dee back area Ron. Not threaded, wrong depth maybe, to big around it looks.

The reed holder slips in and has a lip on it to keep it from plunging inside the crankcase to far.

Reed holder slips in, then you add a standard backplate gasket, screw the stand to the back of the motor, add carb during one part of that assembly.

PV Pilot wrote:

cribbs74 wrote:Cool stuff! That pretty well clears things up for me.

How often would the low idle screw need to be adjusted anyway?

Thats a good question, I haven't mounted those pieces on a motor yet. Alot of variables there. weather, prop, fuel, ect.

I dont think that piece would fit into the Tee Dee back area Ron. Not threaded, wrong depth maybe, to big around it looks.

The reed holder slips in and has a lip on it to keep it from plunging inside the crankcase to far.

Reed holder slips in, then you add a standard backplate gasket, screw the stand to the back of the motor, add carb during one part of that assembly.

Ahhh! I see.

cribbs74 wrote:
How often would the low idle screw need to be adjusted anyway?

The Tarno carb doesn't have any low end adjustment, it is only a throttle stop. So once a servo is connected you would never touch the screw.

The 05 RC carbs (available from Bernie) are much better as they do have an airbleed adjustment for the low end.

Thanks Kris!

For me, it just seems usless to have that idle screw as such. It should have been designed in as a low speed mix. Most folks, when setting up for rc, just back that screw out till the carb barrel closes and then they can kill the motor by radio, as well as adjusting idle by radio trim button.

Just a odd not needed screw that could have been used for a much better purpose.

PV Pilot wrote:For me, it just seems usless to have that idle screw as such. It should have been designed in as a low speed mix. Most folks, when setting up for rc, just back that screw out till the carb barrel closes and then they can kill the motor by radio, as well as adjusting idle by radio trim button.

Just a odd not needed screw that could have been used for a much better purpose.

The main purpose of the screw is to hold the throttle barrel in place and keep it from falling out.
The 05RC carb (by cox) has the same screw but also an additional screw for adjusting the low end mixture, i.e. an adjustable airbleed.

I bid so high that I thought for sure I would win it. I was wrong

Someone really wanted that Tarno AR carb!

The prices on the Tarno carb are just crazy, once collectors get an idea there doesn't seem to be any limits...

The Tarno carbs aren't any good anyway, they have a design flaw in the way that they corrected for the low-end mixture twice and neither is adjustable. They have different diameters above an below the throttle barrel, to give it a leaner low end, which is fine, but then they also added a large, non-adjustable airbleed hole on it...

Surfer_kris wrote:The prices on the Tarno carb are just crazy, once collectors get an idea there doesn't seem to be any limits...

The Tarno carbs aren't any good anyway, they have a design flaw in the way that they corrected for the low-end mixture twice and neither is adjustable. They have different diameters above an below the throttle barrel, to give it a leaner low end, which is fine, but then they also added a large, non-adjustable airbleed hole on it...

Kris, I've followed your threads on some other forums regarding your TD05RC Yellow Jacket and I was curious if you did an A-B test of a Tarno equipped TD with Muffler vs. the TD05RC in actually flyability. Also, I seem to remember that you might have tried using a St.Petersburg Special ( Brand N ) on the Yellow Jacket.
Your experiences would be very interesting to hear..
Steve...

John G is planning to do a comparison between the two carbs.

I have only bench run the Tarno carb and modded it to give a richer low end, but really you do want to have an adjustable airbleed. The 05RC carb is then better, but it is a little dangerous to adjust the airbleed on a running engine. The stock 05RC has a very odd feature of the "muffler" it doesn't seal against the cylinder and does little other than look good. I therefore sealed it against the cylinder and that makes i quieter and stops the exhasut oil from drooping all over the engine. I quite like it but it is a little picky on the propsize and there are vibrations around 16-17000 that you want to stay above, yet not reach too far above 20000rpm in the air. An APC 5.7x3 is a fairly good match in terms of the load on the engine.

It runs like a typical cox engine though, you have to have it on rich side at all time and when you get it just right all you can hope for is a few good minutes near the end of a flight. The Norvel is a totally different engine. The .061 is both lighter and more powerful (with its larger capacity), plus it loves to rev. They can also run fully leaned and in the air this translate into something that simply leaves the cox in the dust. Once I tried an old Norvel in the Yellow Jacket there was no going back. I love to make laaarge loops with the engine doing +20000rpm on a 5x4 prop pulling straight up into the clouds...

I find gmark mufflers also seal terribly.

The g-marks are a dream compared to the 05RC. There is an intentional gap of about 0.2mm all around the cylinder on the cox...

Surfer_kris wrote:The g-marks are a dream compared to the 05RC. There is an intentional gap of about 0.2mm all around the cylinder on the cox...

Really?
The gmark .03 is really fiddly muffler and soft screws make tightening hard and then there is the fact it is 2 piece.
Lovely engines but muffler is annoying.
Also the engines have SPI but te MFG included mufflers?
I should just take it off but I am a sucker for cute and with the muffler the engine I cut as heck.