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Ops Maxi 30

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Old 05-05-2014, 07:57 PM
  #1  
nick.henderson
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Default Ops Maxi 30

I know, nothing exciting, been done before..
Just to say how painless it was, all mods done with hand tools or a bench drill.
Standard Rcexl ignition and opto isolator.
Standard head button tapped out to 10mm for CM6 plug. Copper washer under plug to limit protrusion of plug into combustion chamber. May get a new button machined one day as thread is not awfully deep and it would do away with the need for the copper washer.
Head fins cut back using a Starrett hole saw so as to allow plug socket to fit.
Spacer for the pickup started life as a 2" x 5/16" flat stock. Sliced off a 1/2" wide strip and persuaded it into shape using sockets, hammers and a vice with the jaws open. Crankcase at this area is tapered so had to relieve the back edge so the pickup was running parallel to the crank.
Chinese Walbro clone for 12 USD as the original DelOrto's have no choke. Soldered up the bleed hole in the choke plate to give more suck. Modified the choke and throttle arms by welding on sheet stock to the originals.

Starts well, crisp throttle response, seems to pull like a train on a Biela 18 x 10.
Tacho batteries flat so no figures.
Test flights soon.
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Old 05-06-2014, 03:54 AM
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captinjohn
 
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I never owned a OPS 30cc engine, but I would say I think they are far better built than some of the cheap engines made in China. Take good care of it & use good oil. Make sure good cooling is good in the cowl & I think the engine may last a very long time. My 2 cents!
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Old 05-07-2014, 02:45 AM
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nick.henderson
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Bang for buck these are one of the best conversions around, and its not just me that says so. The Maxi never really took of as a glow but converted over to gas, it definitely gives good value. This is the first one i have converted, i have 4 more waiting!!
The head button could really do with being re-machined but that's all. However this is only necessary on the 10mm and up plugs. If you stay with the glow size spark plugs....no need.
Good oil is not available here so Shell Advance SX 2 mineral oil is used at 40/1. It seems to work just fine. Cooling should be fine but with the tropical temperatures here, i never tune for max power. I always run a fair bit rich to help keep things cool....er!! Again, this approach seems to work just fine on my other glow and gas engines.
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Old 05-08-2014, 10:52 AM
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I got a never ran Bully 35cc engine. I am setting it too run on gas. It was set up for glow! I have a feeling it will be a sweet engine. Capt,n
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Old 05-08-2014, 12:39 PM
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I just picked up a Magnum 180, (30cc) engine that I am going to convert to ignition. I've contacted Ken Lambert about changing the crankpin and putting a roller bearing on the rod. I haven't decided whether I want to run it on gasoline or methanol yet..... Sometimes the converted glow engines run hot on gasoline because they have less cooling fin area than a "made for gasoline" engine.

AV8TOR
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Old 05-10-2014, 06:59 AM
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captinjohn
 
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The Bully 35cc engine is already set up for gas....full bearings inside just like a high quality chain saw. But it was not a saw conversion. Capt,n
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Old 05-21-2014, 11:55 AM
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JeffH
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Does your Bully have the glow type carb and adapter? I might be interested in them both.
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Old 05-21-2014, 07:06 PM
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Yes I have the adapter & the delroto glow carb. Please PM me for details. Thanks John
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Old 12-08-2014, 04:57 PM
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I did one a while back. I put it on a big Kaos. It did the plane with dope and dacron. It tuned out great. Best flying airplane I ever made. Unfortunately it was jinxed. Once I took of with the radio set on the wrong plane. The ailerons were reversed. I repaired it. Next flight the wing departed the rest of it in flight. Lawn dart.

The engine ran great, still does. I experimented with compression ratios by making different head disks. I did not make much difference.
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Old 12-08-2014, 05:31 PM
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Hey guy,

I sent you a PM about some Stihl 65cc Four Mix four stroke engines I have for sale. Did you get it?

Thanks and Happy Holidays,
AV8TOR
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Old 12-14-2014, 09:48 PM
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bcchi
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Originally Posted by captinjohn View Post
I got a never ran Bully 35cc engine. I am setting it too run on gas. It was set up for glow! I have a feeling it will be a sweet engine. Capt,n
Hi John,
We done a bunch of Bullys years ago.Some were real good some not so good.Never did find the difference never tried much.Think I stll have a new Bully kicking around the shop.
Merry Christmas
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Old 12-23-2014, 07:46 PM
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bcchi, I guess I better check this thread more often. I think I have a carb that may work good on my Bully 35cc engine. I have not been working on it lately. I am working on finishing up my 4cyl holt. Lots of small parts to do yet. I will try to post photo or so on here.

Merry Christmas & I pray for a good New Year for you & all....RC friends included! Capt,n
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Old 11-26-2017, 07:28 PM
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nick.henderson
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Hi Jim,

here, im sure this will be just fine. And the price sure is!!!

https://www.ebay.com/itm/Carburetor-...AAAOSwDFBaBQpW
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Old 11-27-2017, 09:30 PM
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Thanks for the link Nick. If you "are sure this will be just fine", that is good enough for me!

I have been trying to log onto this page for two days. No success until now. Hence the late reply.

Jim.

Edit: I am still unable to delete the following text. Can anyone explain what it is and how I can avoid it?






































































































































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Old 01-31-2019, 01:04 AM
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Default OPS Maxi 30 cc now running!

After some frustration, I now have mine running very nicely. Starts super easy; however, I have to work on the choke control so that I can use it properly. It needs some kind of lever and clip arrangement.
Running on AvGas @ 30:1 with Stihl two stroke oil.
8500 RPM on 18 x 6 prop.

Video here:
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