Author Topic: Saito .40 carb parts wanted... (Read 6542 times)

wwwarbird · « **on:** August 10, 2014, 07:39:42 PM »

I'm looking for a throttle barrel, arm, and other related parts for a Saito .40RC. I have what was originally and R/C version that has been converted to C/L. This one has the conversion with the plastic barrel insert and nylon screw in the stock throttle body. I'm wanting put the original throttle assembly back in it so if anyone has these parts and is willing to let them go, please let me know.

Thanks!

Steve Thomas · « **Reply #1 on:** August 11, 2014, 05:24:05 AM »

Hi Wayne, I've got a new Saito 40 R/C that I'm intending to convert for CL use in the near future - might be able to help you out.

Steve

Bob Reeves · « **Reply #2 on:** August 11, 2014, 08:12:39 AM »

Email me (click the little envelope <---) your address and I will drop what you need in the mail. I probably have 4 or 5 laying around that have been removed from carbs I modified. Need to check your needle assembly to see if the spigot has been shortened, if it has you will need to replace it. I can't help with a needle assy as I always cut the spigot down to make more room for the nylon screw.

Steve Thomas · « **Reply #3 on:** August 11, 2014, 03:28:02 PM »

Come to think of it, Wayne (and notwithstanding Bob's kind offer), is yours modified as per Bob's instructions? If so, we could just do a straight swap. That way, I'd be saved the trouble of modifying mine, and you'd get an as-new carb with correct spigot, needle assembly etc.

Steve

wwwarbird · « **Reply #4 on:** August 11, 2014, 09:06:55 PM »

Thanks guys, I just got home from work tonite. I'll try to get back to you here tomorrow night. I think maybe I'll post a pic of what I've got...

Bob Reeves · « **Reply #5 on:** August 12, 2014, 02:16:22 AM »

Quote from: Steve Thomas on August 11, 2014, 03:28:02 PM

Come to think of it, Wayne (and notwithstanding Bob's kind offer), is yours modified as per Bob's instructions? If so, we could just do a straight swap. That way, I'd be saved the trouble of modifying mine, and you'd get an as-new carb with correct spigot, needle assembly etc.

Steve

This is the way to go..

Haven't seen one personally but from what I have heard the only difference is he used a plastic (Delrin) insert rather than aluminum. The Delrin insert should be fine as long as the engine never starts backwards..

wwwarbird · « **Reply #6 on:** August 12, 2014, 08:33:10 PM »

Quote from: Steve Thomas on August 11, 2014, 03:28:02 PM

Come to think of it, Wayne (and notwithstanding Bob's kind offer), is yours modified as per Bob's instructions? If so, we could just do a straight swap. That way, I'd be saved the trouble of modifying mine, and you'd get an as-new carb with correct spigot, needle assembly etc.

Steve

Steve,

Sounds like a good plan, I'm up for the straight swap if that works for you. Here are some pics of what I've got, it's only got about 15 runs on it total. I'll just remove the entire assembly that will include the stock NVA, throttle body, and intake tube from the case and send it to you. Just PM me with your address info, I'll do the same, and I'll get yours in the mail.

EDIT: Steve, I just got to looking at your profile, are you overseas?

(Just thinking that if so, the shipping may not be worthwhile)

Steve Thomas · « **Reply #7 on:** August 13, 2014, 05:04:26 AM »

Quote from: wwwarbird on August 12, 2014, 08:33:10 PM

EDIT: Steve, I just got to looking at your profile, are you overseas? (Just thinking that if so, the shipping may not be worthwhile)

Yes, I'm in Australia. I'm not sure what the postage would come to, but I was hoping it wouldn't be too much given that we're dealing with fairly small items.

wwwarbird · « **Reply #8 on:** August 13, 2014, 09:43:59 PM »

Dang, that definitely makes it more complicated and more expensive than I was hoping.

Bob Reeves · « **Reply #9 on:** August 14, 2014, 01:50:19 AM »

Pull the needle valve out and remove the clicker clip (you both can keep the needles and clips as they are the same) and just stick it in a padded envelope.
Also do not send the rubber gasket, leave it in the engine.

Bob Reeves · « **Reply #10 on:** August 14, 2014, 04:53:22 AM »

Wayne, Just can't help but wonder if you are switching it back to RC because you are not happy with the way it runs? From your photos I can sure see why you may be having run issues.

wwwarbird · « **Reply #11 on:** August 14, 2014, 05:42:08 PM »

Quote from: Bob Reeves on August 14, 2014, 04:53:22 AM

Wayne, Just can't help but wonder if you are switching it back to RC because you are not happy with the way it runs? From your photos I can sure see why you may be having run issues.

Ok Bob, what'cha seein'? Other than this nylon venturi setup I've got this one set up exactly like the pair that are on my PBY. I'm even using the same prop as on the PBY, a Master Airscrew 10x7 three blade. Both engines run flawlessly and have great power on the PBY. The only difference is that on the PBY I'm using the stock R/C throttle assembly with it locked in the wide open position. On this airplane with the nylon screw setup it won't run well over about 8500 rpm and launching it there or any higher the thing is just a dog. FWIW, I do have the nylon screw adjusted to where the intake would be fully open.

Bob Reeves · « **Reply #12 on:** August 15, 2014, 04:08:46 AM »

Can you do us a favor, remove the carb and see if you can get a photo from the end like the one I am attaching. I'm wondering if whoever did the mod cut down the spigot? I have seen some try to drill a hole in the end of the nylon screw to accommodate the spigot rather than shortening it with really bad results.

BTW: Have posted this photo before, this was taken right after I arrived back from Brodaks in 2010. I was curious as to how much I actually had it choked down. The Saito 40 this intake was on flew a 560 sq/in profile to a 3rd place finish in Advanced.

As I have said, send me your address and I will send you everything you need to convert it back to an RC carb. This will be a good learning experience to see if your engine runs any better with an RC carb wired open. I will reserve my opinions until you are able to do a little more experimenting.

wwwarbird · « **Reply #13 on:** August 17, 2014, 09:22:05 PM »

I'll try to get you some photos here in the next day or two Bob. Out at the field today I did pop the assembly off just to look and make sure I had the nylon screw set where I'd thought. It was, backed out to what would equal a wide open setting with a stock R/C assembly.

I got a chance to double check things with some minor ground testing today at the field too. With the above combination it would not take one click of needle beyond 9000 rpm without sagging severely. Leaving it there at 8900-9000, it would randomly sag up and down on it's own, dipping all the way down to around 5500-6000 rpm at times.

I did make some progress today though. Leaving the needle at the same previous 9000 rpm needle setting I switched to a wood 11x5 Zinger and some Wildcat 15% nitro fuel and it was instantly MUCH better. It fired up and ran at about 10,200-10,300 with only the prop and fuel change. I then launched it at 9500-9600 for a flight and it was real close, maybe just a touch lean. Then it started raining, we'll see how it goes next time I get a chance to get out.

Bob Reeves · « **Reply #14 on:** August 18, 2014, 11:37:55 AM »

Quote from: wwwarbird on August 17, 2014, 09:22:05 PM

I'll try to get you some photos here in the next day or two Bob. Out at the field today I did pop the assembly off just to look and make sure I had the nylon screw set where I'd thought. It was, backed out to what would equal a wide open setting with a stock R/C assembly.

I got a chance to double check things with some minor ground testing today at the field too. With the above combination it would not take one click of needle beyond 9000 rpm without sagging severely. Leaving it there at 8900-9000, it would randomly sag up and down on it's own, dipping all the way down to around 5500-6000 rpm at times.

I did make some progress today though. Leaving the needle at the same previous 9000 rpm needle setting I switched to a wood 11x5 Zinger and some Wildcat 15% nitro fuel and it was instantly MUCH better. It fired up and ran at about 10,200-10,300 with only the prop and fuel change. I then launched it at 9500-9600 for a flight and it was real close, maybe just a touch lean. Then it started raining, we'll see how it goes next time I get a chance to get out.

I have said this so many times, almost afraid to post it again.. Wrong prop, running engine at too fast and wrong tank all equal exactly what you are experiencing. Put an 11-7 on it and choke the intake down to where it is running 8000 to 8500 with the needle set just to the rich side of peak. Fly it and fine tune the choke area for the lap times you and the airplane are happy with. After this, when you are still having issues with consistency replace the metal tank with a 4 ounce clunk on muffler pressure.

wwwarbird · « **Reply #15 on:** August 18, 2014, 05:21:07 PM »

Quote from: Bob Reeves on August 18, 2014, 11:37:55 AM

I have said this so many times, almost afraid to post it again.. Wrong prop, running engine at too fast and wrong tank all equal exactly what you are experiencing. Put an 11-7 on it and choke the intake down to where it is running 8000 to 8500 with the needle set just to the rich side of peak. Fly it and fine tune the choke area for the lap times you and the airplane are happy with. After this, when you are still having issues with consistency replace the metal tank with a 4 ounce clunk on muffler pressure.

Yes, I have read before that running them slower is your personal preference and program Bob. However, a few of us around here have had excellent and consistent results with many Saitos running wide open carb settings and with the right prop simply adjusting the needle from there. I personally have four airplanes with .40's and one with a .62 that all work very well this way.

Anyway, if I was to try your routine, "Put an 11-7 on it and choke the intake down to where it is running 8000 to 8500 with the needle set just to the rich side of peak", before you start your choking down process to end up landing at 8000-8500 rpm where are you starting out at initially with the nylon choke screw and at what RPM?

Bob Reeves · « **Reply #16 on:** August 19, 2014, 04:43:16 AM »

Go with whatever makes you happy, my carb parts offer is still good, just drop me an email with your address.

Most of the 40's I have had on my test stand would turn a Rev-Up 11-7 wide open at about 9 grand on YS 20-20. You can start with it wide open then work your way down. Screw in the choke then readjust the needle, keep repeating Choke->Needle till it is running about 8400. Fly the airplane and fine tune the RPM for the lap times you and the airplane are happy. The optimum RPM setting will depend on the prop, airplane, fuel, line length and your flying style. I personally like 5 to 5.2 second laps and adjust everything to get the airplane happy at the speed I am comfortable flying at.

As I eluded to earlier, you might check how your intake was modified. If whoever did the mod didn't cut down the spigot you will probably not be able to choke it down enough. The above photo shown just how much choke area I ended up with on what is basically a Brodak P-40. If he drilled a hole in the end of the nylon screw to clear the spigot the fuel has to make a 90 deg turn before it can get to the engine, I can't see this as anything but trouble. I have also said many times, 4 strokes need to suck as much fuel as possible on that intake stroke. Do everything you can to allow the engine to easily get fuel. No castor, low viscosity oil, high nitro (for a big bang) and tank plumbing with no restrictions.

wwwarbird · « **Reply #17 on:** August 19, 2014, 05:24:13 PM »

Thanks for the extra info Bob. I just studied your photo more closely and now I see how you have your spigot (spray bar, right?) cut off and sticking out just inside of the intake path. I'm going to check mine again but I'm pretty sure that it's like you say, the nylon screw has been drilled for the spigot. I'll let you know...

wwwarbird · « **Reply #18 on:** August 19, 2014, 08:14:02 PM »

I finally have some photos here Bob. Yes, the screw is definitely drilled for the spigot. It's not easy to see here but one photo shows the current nylon screw set in the fully "open" position and another photo is with the screw turned in as far as the drilled hole allows, which is about halfway down the spigot...

Bob Reeves · « **Reply #19 on:** September 08, 2014, 06:00:34 AM »

Sorry, somehow I missed your last post with the photos.. If it were mine I would pull the spray bar and cut down the spigot. It just needs to stick out enough so you can see it. Let the nylon screw work without restricting the fuel flow. All you need to pull the spray bar is a small vice and a 1/4 drive socket large enough the spray bar will pass through. It is just like the larger engines only smaller and I have instructions here.

http://www.tulsacl.com/SaitoCarb.html

wwwarbird · « **Reply #20 on:** September 08, 2014, 08:38:43 PM »

No problem Bob.

I finally got a chance to get back out to the field with the Challenger yesterday. During the intake "photo session" shown above I also pulled apart and cleaned everything including the filter and added new fuel lines. Everything looked fine, but I did get a tiny brown chunk of something out of the spray bar, made me go "hmm". I also switched and mounted a wood 11x5 Zinger prop. I chose the 11x5 Zinger because there are two other Saito .40 powered planes at our field that run beautifully with that prop.
First flight yesterday I fueled up with pink Wildcat 4 stroke 15% nitro fuel and launched it at about 8600 rpm. It ran really good and was dead consistent but the plane was flying a little slow for my liking. I didn't check my lap times but I usually feel good and end up settling in around 5:20. After landing that first flight I turned the needle in two clicks and when I went to tach it for the next flight my tach battery took a dump so I couldn't get a reading. It was still just a touch slow so I repeated the "in two clicks" routine for a few more flights until it all felt good. I did hit a point where I went back two clicks. At that point everything was running and feeling very good. It was pretty windy out there yesterday but I think I'm really close with it now. I'll check it with the tach next time out, but I'm thinking the sweet spot here ends up being about 9500 rpm. (BTW-all of this is with the nylon bolt adjusted flush with the inside bore of the venturi, in what would be the "wide open" position.)