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Old 04-07-2019, 05:37 AM
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Default Another trick up our sleeve

Back when I used a Fox 40 there was info regarding how to modify the hsn profile to help with overy rich midrange fuel metering. In essence you would sand or machine the hsn to create a longer taper. This caused the carb to meter less fuel as the throttle opened just off idle up to the upper midrange throttle position. I plan on using the same technique to modify the 100 hsn on my 82 if I experience problems in midrange rpms. Increase the taper length if too rich, decrease the taper length if too lean. It WILL work, I made my Fox 40 run like a swiss watch throughout the rpm range.

In addition saito used different sized low speed needles in the same carb body on several engines so we have more options for tweaking fuel metering than might be readily apparent.
Old 04-07-2019, 05:50 AM
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Sr
check your PM
Old 04-07-2019, 05:52 AM
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Originally Posted by Glowgeek
I plan on using the same technique to modify the 100 hsn on my 82 if I experience problems in midrange rpms. Increase the taper length if too rich, decrease the taper length if too lean. It WILL work, I made my Fox 40 run like a swiss watch throughout the rpm range.

In addition saito used different sized low speed needles in the same carb body on several engines so we have more options for tweaking fuel metering than might be readily apparent.
FA-82 has the same 29 mm bore as the FA-100. You should be able to tune the FA-100 carburetor for the FA-82 if you can adapt the FA-100 intake pipe.

Last edited by SrTelemaster150; 04-07-2019 at 05:54 AM.
Old 04-07-2019, 05:54 AM
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Although the 12mm carburetor/manifold is good for 200 RPM withe the 12.7:1 CR engine, the breathing ability of the modest 10.7:1 CR was not improved enough to benefit from the improved induction.

Couldn't it be that what you were seeing was that the higher cr was just burning the fuel more efficiently and therefore more fuel could be introduced without causing an overly rich condition? I'm not familiar with how increased cr increases breathing ability.

Last edited by Glowgeek; 04-07-2019 at 06:12 AM.
Old 04-07-2019, 06:53 AM
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Originally Posted by Glowgeek
Although the 12mm carburetor/manifold is good for 200 RPM withe the 12.7:1 CR engine, the breathing ability of the modest 10.7:1 CR was not improved enough to benefit from the improved induction.

Couldn't it be that what you were seeing was that the higher cr was just burning the fuel more efficiently and therefore more fuel could be introduced without causing an overly rich condition? I'm not familiar with how increased cr increases breathing ability.
You cant' just introduce "more fuel". More fuel with the same volume of air will reduce power output. You have to admit more air with the fuel to maintain the proper A/F ratio to make more HP. The required A/F ratio does not change with CR.

The higher CR will evacuate more exhaust gases and since it will be starting with a smaller combustion chamber volume as it leaves TDC and begins the downstroke, it will have a better start on induction of the fresh air/fuel charge.

Last edited by SrTelemaster150; 04-07-2019 at 07:00 AM.
Old 04-07-2019, 07:29 AM
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Originally Posted by SrTelemaster150
You cant' just introduce "more fuel". More fuel with the same volume of air will reduce power output. You have to admit more air with the fuel to maintain the proper A/F ratio to make more HP. The required A/F ratio does not change with CR.

The higher CR will evacuate more exhaust gases and since it will be starting with a smaller combustion chamber volume as it leaves TDC and begins the downstroke, it will have a better start on induction of the fresh air/fuel charge.
Ok, Volumetric Efficiency.
Old 04-07-2019, 08:21 AM
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Default Different Saito 65, What is it?

I picked up a damaged Saito 65 that is different than any of my other ones. It came in a blue box that says FA65 MK and has the skinny black muffler. The immediate difference is the carburetor but it looks like the mounting and intake manifold (tube) may make it interchangeable. The HS needle is broke off and am not sure where the fuel intake nipple should be. If they are interchangeable then maybe I should update it if I can find a newer one because I do not see this engine on the list at the McGregor site to buy new parts for it. Any input will be appreciated......Thanks, Mike in Michigan

Old 04-07-2019, 09:14 AM
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M, I may have one of each, I'll see if parts will switch. Carbwise at least
Old 04-07-2019, 09:39 AM
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Just sold a pair of 65s that I had since day one. One was used a bit, the other brand new. Both of those had the early carbs. I still have a pair of the later 65, both are used but not much. If you need parts let me know, I am not far from you, just A bit North.
Disposing of a pile of Saitos, don't mind parting any of them out.

Almost certain the carbs will interchange but Dave should let you know on that.

The later 62 and 65 use the same carbs iirc.

Last edited by Jesse Open; 04-07-2019 at 09:43 AM.
Old 04-07-2019, 11:59 AM
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Originally Posted by mirion
I picked up a damaged Saito 65 that is different than any of my other ones. It came in a blue box that says FA65 MK and has the skinny black muffler. The immediate difference is the carburetor but it looks like the mounting and intake manifold (tube) may make it interchangeable. The HS needle is broke off and am not sure where the fuel intake nipple should be. If they are interchangeable then maybe I should update it if I can find a newer one because I do not see this engine on the list at the McGregor site to buy new parts for it. Any input will be appreciated......Thanks, Mike in Michigan



Saito 65's with stock carbs


Saito 65's with intake pipes and carbs swapped, a perfect no issues swap.


Early carb metering slot, it has a very clean, linear mid range.

Mike, the compression ratio on that early 65 is 10.5 to 1, they run great.

Last edited by Hobbsy; 04-07-2019 at 12:25 PM.
Old 04-07-2019, 12:25 PM
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Thanks Dave,

Seems I had swapped them at one time on these but that was long ago.
Old 04-07-2019, 12:34 PM
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Saito 65 fuel inlet, early
Old 04-07-2019, 12:47 PM
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The pair I recently sold were both HC . The one that had been run was on an Astro Hog Bipe. Nice running engine.
One of the two I have left is also HC but it has the later carb.


Edit:
I had never really paid much attention to the 65, just ran it. The early carb difference was quite obvious. Otherwise I hadn't noticed there were other differences aside from the carbs It was Dave who told me what to look for.

Last edited by Jesse Open; 04-07-2019 at 01:49 PM.
Old 04-07-2019, 02:26 PM
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If I want to make an exhaust pipe for my FG-30, what would I use? I mounted the engines today, found the fuel nipple doesn't rotate so may have to use larger line and wire tight it very tight as there is a sharp end at the floor of the nacelle where the carb enters it. On the B-25 I am modeling it has a single stack out the side, one on the right outboard and one on the left outboard. The one on the right will need to com up and run behind the engine and out the left side of it (facing the front), while the left on just comes up and bit and exits the right.

The exit is right about where the bolt is on the left and right on the firewalls.



Old 04-07-2019, 03:00 PM
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Any chance for a better detail pic?


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Old 04-07-2019, 03:34 PM
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Originally Posted by acdii


That's gonna be one sweet airplane! What's the span going to be?
Old 04-07-2019, 03:49 PM
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Thanks for the input everyone, that is good news because I don't think I am going to find that needle anywhere. Now to see if I can scrounge a new style 65 carb. I really appreciate all of the knowledge you guys readily share.
Old 04-07-2019, 04:09 PM
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Originally Posted by Glowgeek
That's gonna be one sweet airplane! What's the span going to be?
101". Nearly finished with the top of the nacelles, needed the engines mounted to align the cowls, and found that the mufflers would require a rather large cut out and want to avoid a weak cowl. Another problem trying to work out is the throttle servo location. The linkage will be really close to the tank floor and where the 2 strokes would have a box in front of the firewall where the servo can go, the FG-30 is right against the firewall. I also had to add 6MM ply behind the 8MM ply firewall that it came with.

Now the question I have about the tank size wont get answered until I have the engine stand and run the engines through a few tanks to see how long a tank lasts. If I can get better than 10 minutes on a 14 ounce tank that gives me more room in the tank area to work with.


One thing I am confused on with the FG-30 is the manual says to insert the threaded rod into the throttle for the choke, except, there is no threaded rod with the engine. It does pull out like the manual says, but no rod.
Old 04-07-2019, 05:44 PM
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"There is no replacement for displacement"
sorry guys, but that is only true when talking "Maximum Effort", money can make more HP

here is the proof>> you can have a 600HP 454 Chevy, the next guy can have a 1000HP 350 Chevy,

BTW, there are many 1200 and 1400 HP 4 cylinder engines out there


Jim

Last edited by the Wasp; 04-07-2019 at 06:12 PM.
Old 04-07-2019, 05:54 PM
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Or a 3.5l V6 that produces 385HP and 470ftlb of torque, and that's stock. A simple mod and a tune can produce nearly 500 HP at the wheels.
Old 04-07-2019, 05:54 PM
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Originally Posted by mirion
Thanks for the input everyone, that is good news because I don't think I am going to find that needle anywhere. Now to see if I can scrounge a new style 65 carb. I really appreciate all of the knowledge you guys readily share.

Is the NEEDLE all you need?
Old 04-07-2019, 06:10 PM
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Originally Posted by Jesse Open



Is the NEEDLE all you need?
The needle is all I need if I use the original carb. I assume that the fuel nipple is on the needle assembly and I would need that also but am uncertain how many parts are involved. Because I am unfamiliar with this carb, I should probably pull it apart to see what else may be damaged. What is the recommended procedure to pull out the retaining clip that holds the barrel in, a small needle nose maybe?
Old 04-07-2019, 06:15 PM
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Originally Posted by acdii
Or a 3.5l V6 that produces 385HP and 470ftlb of torque, and that's stock. A simple mod and a tune can produce nearly 500 HP at the wheels.
Now you are talking forced induction.
Old 04-08-2019, 02:24 AM
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Originally Posted by Glowgeek
That's gonna be one sweet airplane! What's the span going to be?
About the same if it just crawls off the runway and cruises through the wait awhile bushes/trees,it's always the first section that you find on a recovery mission just kidding.Bruce you should have got two small wire tools,one has a flat blade screwdriver tip for the hsn and the other is threaded for the choke.Tuning one is very different to our fa engines.

Jim i went for a ride on the duke last sunday with two mates,one on a ktm 1290 v-twin and the other on a stroker harley with a lot of ground clearance and sticky race rubber.It may sound funny,but as a group we like to go 'slow around corners' harley hunting (well,i spose you would call them victims) and it was a sunny afternoon up in the hills.Our first targets appear and a pizza van whizzes past in the opposite direction.I was already smiling but then i remembered your pizza post and started to giggle in my helmet,there's no way you can drive or ride fast like that,so you got cursed over a beer later cause the harley rider creamed me.
Old 04-08-2019, 02:44 AM
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Originally Posted by mirion
The needle is all I need if I use the original carb. I assume that the fuel nipple is on the needle assembly and I would need that also but am uncertain how many parts are involved. Because I am unfamiliar with this carb, I should probably pull it apart to see what else may be damaged. What is the recommended procedure to pull out the retaining clip that holds the barrel in, a small needle nose maybe?
If you want to send me the carb, I will either fix it or send you a later style carb. I may have to make a new needle valve assembly. You can send me a PM.

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