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RCGF 10cc - conversion to Walbro carb - where to buy parts?

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Old 11-15-2017, 03:42 AM
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sandal
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Question RCGF 10cc - conversion to Walbro carb - where to buy parts?

Hello,

I have an RCGF 10cc with the "old" type of carb, and I would like to use a Walbro carb on it. I have seen conversion kits where you get a new backplate and a Walbro-style carb.

Do you know where I can buy just the backplate? I already have several small Walbro carbs that could work well, and I only need the backplate.

Thanks!
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Old 11-15-2017, 04:51 AM
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Both top notch outfits with great reputations, and should be able to sell you any part you need -
https://www.valleyviewrc.com
https://www.rcgfusa.com

I would offer that the carb that comes on the 10cc rear exhaust engine is a Walbro clone with a 10mm or so venturi, that is 3-4 times the size it needs to be. To get good throttle response requires a super rich low speed mixture. After many hours messing around trying to civilize this engine, it was discovered that if you slowed the throttle opening using the same process you would on wing flaps or gear doors, allowed for a dramatically leaner low speed mixture.

Those with automotive hot rod experience might relate to a comparison of having a 1050 Holley carb on a 302 small block, using mechanical secondaries. When the carb is opened quickly there is a complete loss of vacuum causing the engine to fall flat on it's face. In the caes of the 10cc RCGF, slowing the carb opening allows the engine to maintain vacuum, resulting in a much more desirable acceleration.

Worth noting is the slow carb opening is not noticeable in use, and the engine handles nicely, much like bigger rear carb engines, and flip starts easily. -Al
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Old 11-15-2017, 06:43 AM
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sandal
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Al,
thank you for your tips! I will contact both Valley View and RCGF USA, hopefully they will be able to help me. I found the crankcase and backplate as a kit, but that means I will have to pay $25 + shipping to Norway for the backplate, which is a bit steep to be honest

While we're at it; I can't understand why so many engine manufacturers put huge carbs on their engines. The carb I intend for the RCGF 10cc is a Walbro WA-80 (7.14 mm). I have used this carb on my MVVS 26cc, and it lost only 300 rpm compared to the original 9.53 mm carb. The 300 rpm loss was easily compensated by the fact that the engine ran smoothly at all rpms, and it handled small or large props equally well. I would take a "too small" carb over the standard ones any day.
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Old 11-15-2017, 10:50 AM
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I'd LOVE to hear about your results with that 7.14mm carb! Be sure to post them here.

Totally agree regarding the "too small" carb vs. the one that's "too big". The engine with the too small carb will make nearly the same power at WOT, possibly more power through low and mid range, and will be WAY friendlier in use. -Al
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Old 11-15-2017, 03:11 PM
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Are these 10cc engines very reliable ?
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Old 11-15-2017, 06:30 PM
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I'd recommend a 20cc or bigger for a first gasser (DLE, RCGF, Valleyview), but if that can't work for some reason, a lot of guys have fallen in love with the 10cc Evo engines.

The issue is metering the tiny amounts of gasoline these little guys use, in amounts that will keep them happy at all throttle settings.The 10cc class engines have been out for a while now, were under development for years prior, and NOBODY has it completely right yet!

The Evo has no choke, and for that reason, as well as the fact it has the front carb, it requires an electric starter (unless you have the patience of a saint). It also makes significantly more power on top, turning a 13x6 to about 10.5k

The baby RCGF turns that same prop about 8500. But has significantly better throttle control through the entire mid range. The Evo does really well on idle and at WOT, but between the 2 can be inconsistant. Fine for a lot of sport flying, but lacking when it comes to hard acrobatics/3D. Overall, even though it makes less power, I prefer the way the RCGF handles, but would not recommend it for a first gas engine. It's fine when you get it figured out, but it proved it can be a huge handful prior to that point.

As far as reliable, that's kind of subjective. They stay in one piece just fine. They do not use parts. The Evo, my engines anyway, were always looking to be tweaked a little here and there, on both the high and low. The RCGF stays put much better that way.
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Old 11-28-2017, 01:58 AM
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Update:
RCGF USA have been very helpful, and they are sending me the parts I need. This means that I will have two complete backplates, one with the RCGF rotary carb and one with the 7.14 mm Walbro WA-80. I'm looking forward to comparing them and seeing how the engine runs with the WA-80. It will take a few weeks before I get the parts, and I might decide to wait until the white stuff on my lawn is gone, but as soon as I have tested the engine, I'll let you know how it runs!
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Old 11-28-2017, 05:05 AM
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Worthy of note, when installing the Walbro carb, many advise the use of some sort of thermal break between the engine and carb. I laminated about 1/4" if fiberglass scraps together with some CA and carved one out from that. A stack of gaskets may work as well, or, see what happens without!
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Old 11-28-2017, 07:19 AM
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Al, that sounds like a good idea. I had a Roto 25V a few years ago, and it had three fibreglass spacers between the crankcase and the carburettor. I'll see what I can find on eBay, or carve one myself like you did. Shouldn't take long with a dremel

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Old 01-06-2018, 02:41 PM
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Default RCGF 10cc carb replacement

Hi Sandal,

Do you have any updates on the Walbro WA-80 carb replacement? I just purchased an RCGF 10cc side exhaust and with updated RCGF CARB from RCGF USA. I read your thread about retrofitting with a Walbro WA-80 carb but hadnt seen any of your updates on this retrofit. Im thinking about retrofitting mine exactly as your doing, would just like some confirmation on this before I commit to it.
Questions:
1. Why isnt the stock updated RCGF clone carb any good?
2. Why do you need to buy another backplate for the
. reftrofit?
Yoyr timebto respond to tghus will be greatlt appreciated!

KOKOFLYER

QUOTE=sandal;12386890]Update:
RCGF USA have been very helpful, and they are sending me the parts I need. This means that I will have two complete backplates, one with the RCGF rotary carb and one with the 7.14 mm Walbro WA-80. I'm looking forward to comparing them and seeing how the engine runs with the WA-80. It will take a few weeks before I get the parts, and I might decide to wait until the white stuff on my lawn is gone, but as soon as I have tested the engine, I'll let you know how it runs!
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Old 01-08-2018, 01:57 AM
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Hi kokoflyer,

1. The stock updated carburettor is probably fine, but I want to try the smaller WA-80 to see how the engine runs. In some cases, engines run smoother, are easier to adjust and handle large props better with a smaller carburettor. The most obvious disadvantage is that max rpm may be lower. To me, a smoother running engine more than outweighs the loss of rpm. In my opinion, most engine manufacturers put huge carburettors on their engines. A 10 mm carburettor on a 10 cc engine is (again IMO) much bigger than the engine needs, particularly the RCGF 10cc which seems to be built for larger props and relatively low max rpm. I used the WA-80 on my MVVS 26cc a while ago, and I only lost 400 rpm with the 7.14 mm WA-80 compared to the standard 9.53 mm carburettor. The first series of the MVVS 26cc was sold with the WA-80. Some engines seem to work well with large carburettors and use 11 to 13 mm carburettors on 26cc engines. Others "drown" when you hit the throttle. Summed up: My personal (although very limited) experience with using smaller carbs on petrol and glow engines indicates that a smaller carburettor usually makes the engine more user-friendly, but with a small loss of rpm.

2. My engine came with the first generation carburettor (rotary), which has a completely different carburettor mount than the Walbro-style engines. If you have a newer RCGF 10cc with the Walbro-style carburettor, you do not have to replace the backplate. All Walbro WT and WA (and clones) carburettors, except the really big ones, will fit without modifications.

Hope this helps!
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Old 01-08-2018, 07:22 AM
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Dear Sandal,
Thanks for your time for your response to my inquiry.
glad you clarified that no mods were required for the Walbro carb retrofit. Maybe a worthwhile option if the stock carb is too finickyy. Top rpms are also not my concern either, but a trade off for a better adjustable carb is paramount!

regards,

kokoflyer
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Old 01-08-2018, 07:47 AM
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To clarify, a "stock" carb could be a barrel or a butterfly type carb, depending on which version of the 10 that you get (side exhaust vs. rear exhaust) and when you bought it. The 2 type carbs use totally different design backing plates to mount, so that must match the type carb you want to go with if changing from one style to the other.

Judging by my own experience (on a late model rear exhaust model w/butterfly type carb) the butterfly type carb is very picky, and thus difficult to handle. Handling will improve if you hang in there long enough to get used to it. This is very likely due to the fact the butterfly type carb venturi is WAY bigger than necessary.
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Old 01-08-2018, 07:49 AM
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do you have some video?
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Old 01-08-2018, 08:29 AM
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Hi Ahicks,

Thanks for your reply. I previously read your threads on this subject which I found to be very helpful. Based on your input, I decided to purchase the rear exhaust model from RCGF USA. I didnt want to want to take any chance of any fitting interefences between rear exhaust muffler and the
WA -80 carb. Since I just purchased it last week, I should be getting the latest RCGF clone carb. What are your thoughts of this carb, or were your previous comments in this thread about inconsistent needle settings based on a different style of carb?
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Old 01-08-2018, 05:37 PM
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The carb on the rear exhaust engine is the latest, is the one I have, and the one I found way too big. That's me though. I believe it's made by ZAMA.
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Old 01-08-2018, 06:23 PM
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Ok, got it,
Ill see how mine pans out, cant wait!
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Old 05-04-2019, 07:58 AM
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Default I did it, works great, but needed some adaptation...

https://pretorian435.blogspot.com/20...hallenges.html
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Old 06-09-2019, 09:11 AM
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Congratulations on your success! The WA80 is discontinued, do you know if a walbro WA82 would also work?
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Old 06-09-2019, 10:12 AM
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Answered my own question, it doesn't as it has a 12.7mm venturi.
Do you know if all the WA carbs have the same mounting bolt hole pattern?
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