MVVS 80 ccm
#3
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From: Praha, CZECH REPUBLIC
Hi friend,
We will see. I am so busy but I have to find time for new engine. I will be pleased to forward my experincies.
I had to make modification of header, now is done.
We will see. I am so busy but I have to find time for new engine. I will be pleased to forward my experincies.
I had to make modification of header, now is done.
#7
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Jan, thanks for the update.
Did you make the header yourself from 58cc parts? What muffler? It looks like 3204, but the 3204 muffler only has 25mm inlet, and I think the 80cc will need 28mm inlet diameter.
I am vey much expecting your results.
I did some checking on other 80cc engines, and very good results were obtained with MTW TD110 mufflers. No data on MVVS 80 yet! I have one 80cc engine left, but do not want to use it for testing because Lennart may need it.
Please keep us posted.
PS,
Here are the dimensions for the flange in jpg. If I print at 49%, I get the dimension just right off my printer.
Did you make the header yourself from 58cc parts? What muffler? It looks like 3204, but the 3204 muffler only has 25mm inlet, and I think the 80cc will need 28mm inlet diameter.
I am vey much expecting your results.
I did some checking on other 80cc engines, and very good results were obtained with MTW TD110 mufflers. No data on MVVS 80 yet! I have one 80cc engine left, but do not want to use it for testing because Lennart may need it.
Please keep us posted.

PS,
Here are the dimensions for the flange in jpg. If I print at 49%, I get the dimension just right off my printer.
#8
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From: Praha, CZECH REPUBLIC
Hi,
I had same parts from factory and my friend made header.
http://vyfuky.com/
My muffler has body like 3204 but different exit - it is wider
Input has different shape and is wider.
I am in brake-in period.
I have pation neighbours, I made brake-in on weekend with only 1 liter.
Jan
I had same parts from factory and my friend made header.
http://vyfuky.com/
My muffler has body like 3204 but different exit - it is wider
Input has different shape and is wider.
I am in brake-in period.
I have pation neighbours, I made brake-in on weekend with only 1 liter.
Jan
#9
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Jan the web page sais :"
CHYBA
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I sold one 80cc together with a MTW TD110 muffler and ball joint header. As soon as I have data, I will publish.
CHYBA
ERROR
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I sold one 80cc together with a MTW TD110 muffler and ball joint header. As soon as I have data, I will publish.
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From: Praha, CZECH REPUBLIC
#12
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From: Praha, CZECH REPUBLIC
Pe reivers,
It was only information about who made header for me. He doesn't make anything for models. His web dosnt work well. He lives 3 km from me.
I think MVVS 80 will be / is/ very good engine. I expect static trust more than 20 kg and 7,5 kW.
#13
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Jan, OK, it,s clear now.
I work with MTW parts, he calls "knuckle header". It is a 28mm diameter header of thin stainless steel with 90° bend and two ball joints that can be adjusted and soldered after the canister is fitted in place. Much better than flex tube which always leaks.
7.5kW would be wonderful power on canister. It is what 85cc gets on tuned pipe.
I work with MTW parts, he calls "knuckle header". It is a 28mm diameter header of thin stainless steel with 90° bend and two ball joints that can be adjusted and soldered after the canister is fitted in place. Much better than flex tube which always leaks.
7.5kW would be wonderful power on canister. It is what 85cc gets on tuned pipe.
#14
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From: Praha, CZECH REPUBLIC
Hi,
I was first time on sky. I have JAS propeller 26/9. I think I have to change it.I will buy Mejzlik 26/10. I checked turns - 6950. I have to be patient because engine is in brake- in period.
Starting is very easy.
Power / trust/ is very strong.
I was first time on sky. I have JAS propeller 26/9. I think I have to change it.I will buy Mejzlik 26/10. I checked turns - 6950. I have to be patient because engine is in brake- in period.
Starting is very easy.
Power / trust/ is very strong.
#15
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Thanks Jan, JAS 26x9 @ 6950 is about 9.25 hp, or 6.8 kW. Not bad for a 3204 canister
I received permission from a customer to test his engine with several mufflers.
Planned is:
Perform initial running in, then do some quick rpm peek tests with
TD110, TD75K, modified TD75K (shorter), Tuned pipe MTW T3. Props Mejzlik 24x10x3, 3W 26x10, 3W 26x12.
The 26x12 should fully load the engine.
There will be no time to do full power curves, and I also have to be careful because I do not want to risk damage in any way to the engine.
I received permission from a customer to test his engine with several mufflers.
Planned is:
Perform initial running in, then do some quick rpm peek tests with
TD110, TD75K, modified TD75K (shorter), Tuned pipe MTW T3. Props Mejzlik 24x10x3, 3W 26x10, 3W 26x12.
The 26x12 should fully load the engine.
There will be no time to do full power curves, and I also have to be careful because I do not want to risk damage in any way to the engine.
#16
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From: Praha, CZECH REPUBLIC
Hi,
I do not have realy 3204, my canister is different. I use 1:30 , brake-in. I use original setup for carburator from factory.
I will use Mejzlik propeler 26/10.
I do not have realy 3204, my canister is different. I use 1:30 , brake-in. I use original setup for carburator from factory.
I will use Mejzlik propeler 26/10.
#18
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last night I finished mounting the engine on the test stand. The choke lever interfered with the idle stop needle. The needle is needed on the stand, not in the plane where idle is determined by the servo. So I shortened the needle and made a new screw driver slot.
First test muffler is a modified (shortened) TD75K, which has the rear muffler wall as pressure pulse reflector at just 3/8" (10mm) from the header pipe outlet. Muffler first chamber volume now is 400cc (5 times engine displacement). This muffler was reconstructed to further test my, and Dick Hanson's experiments, with header outlet locations in combination with extremely small canister systems.
First test prop is a Mejzlik 24x10 three blade prop for small diameter, good swing mass, and light load that may suit the small volume canister.
With closed choke, Four flips did bring fuel (1:25 MVVS oil) to the carb and produced a wet hissing sound. My tank is located 5" below the carb level.
The ignition was fitted with two Li-ion Mn cells (3.8 - 4V each), without any programming and with battery test disabled. (plug and play).
Ignition on, third flip set the engine going on a relatively fast idle. I let it run that way until warm, then shut off the engine.
One hour later, the engine started on the second flip, without choking again. At that time, I called it a day.
First test muffler is a modified (shortened) TD75K, which has the rear muffler wall as pressure pulse reflector at just 3/8" (10mm) from the header pipe outlet. Muffler first chamber volume now is 400cc (5 times engine displacement). This muffler was reconstructed to further test my, and Dick Hanson's experiments, with header outlet locations in combination with extremely small canister systems.
First test prop is a Mejzlik 24x10 three blade prop for small diameter, good swing mass, and light load that may suit the small volume canister.
With closed choke, Four flips did bring fuel (1:25 MVVS oil) to the carb and produced a wet hissing sound. My tank is located 5" below the carb level.
The ignition was fitted with two Li-ion Mn cells (3.8 - 4V each), without any programming and with battery test disabled. (plug and play).
Ignition on, third flip set the engine going on a relatively fast idle. I let it run that way until warm, then shut off the engine.
One hour later, the engine started on the second flip, without choking again. At that time, I called it a day.
#19
Senior Member
Engine has run 2 hours at low power settings, with occasional short power bursts.
Idle needle needed to close 1/2 turn, H-needle opened one full turn. H-needle correction needed maybe because of the high oil content in the fuel.
on this very small 5C modified 45cc engine canister (14"header) the engine peaked out at 6400 rpm with the 24x10x3 (same load as a 26x10 mejzlik). Prop became quite noisy, 6250 being the noise rpm limit. Thrust estimate is in excess of 40 lbs with this combo.
Cold start without choke after 1 hour rest was on the third flip, indicating a still slightly rich idle. Good throttle response in all settings, with no idle burble above 1/3rd throttle (idle still a tad rich)
Low reliable idle at 1200-1300 rpm
[link=http://prme.nl/video/80-lowidle.MPG]low idle movie[/link]
High idle at 2500 rpm
[link=http://prme.nl/video/80-highidle.MPG]High idle movie[/link]
Idle needle needed to close 1/2 turn, H-needle opened one full turn. H-needle correction needed maybe because of the high oil content in the fuel.
on this very small 5C modified 45cc engine canister (14"header) the engine peaked out at 6400 rpm with the 24x10x3 (same load as a 26x10 mejzlik). Prop became quite noisy, 6250 being the noise rpm limit. Thrust estimate is in excess of 40 lbs with this combo.
Cold start without choke after 1 hour rest was on the third flip, indicating a still slightly rich idle. Good throttle response in all settings, with no idle burble above 1/3rd throttle (idle still a tad rich)
Low reliable idle at 1200-1300 rpm
[link=http://prme.nl/video/80-lowidle.MPG]low idle movie[/link]
High idle at 2500 rpm
[link=http://prme.nl/video/80-highidle.MPG]High idle movie[/link]
#20

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From: Såtenäs, SWEDEN
Hi Pe.
Very interesting
What about vibrations. As other 75-80-85s?
I saw on other treads that some engines has high vibrations level, but they sorted some of it out a little by not using standoffs and reinforce the engine box/firewall etc.
// Lennart
Sweden
Now I found the videos too. Nice.
Very interesting
What about vibrations. As other 75-80-85s?
I saw on other treads that some engines has high vibrations level, but they sorted some of it out a little by not using standoffs and reinforce the engine box/firewall etc.
// Lennart
Sweden
Now I found the videos too. Nice.
#21
Senior Member
I did not notice excessive vibration other than the engine power pulses at low idle. These of course are in line with the extra cubic inches of the engine, and the larger prop that resists spinning up when it gets a power pulse. Engine pod construction should bear this in mind. This is no 40cc!
#25
Senior Member
I will continue with same 24x10x3 prop and 3204 muffler, again on full length 14" header. I have now 3/4 liter 1:25 fuel through the engine, and it feels smooth, but not silky yet.


