YS120 tuning guide

[leckylee]

Hey Lee,
What did the experts say about the bubbles coming from the regulator thingy next to the carb?
There were definately no bubbles in the line before it.

I did ask the retailer originally that question and they said "I would not expect there to be bubbles in the line" I have recently asked again but they have not commented.

[raptorheli2]

if you have bubbles you have a fuel delivery problem, changing fuel will not fix it.

what clunk do you use?

cheers

[leckylee]

if you have bubbles you have a fuel delivery problem, changing fuel will not fix it.

what clunk do you use?

cheers

It's not a magnet if thats what you mean, thats not the issue because it goes into the reg with no bubbles and comes out with bubbles.

[Steve]

A very good competion pilot told me he takes something out of the check valve to give his YS more pressure too the tank, not that I would ever need to do it, but I have done what it says in the instructions...........

If you want to increase the tank pressure on YS engines, then you shorten the fuel line between the back plate and the check valve from the dimension stated in the instructions. You don't take anything out of the valve. There's only 2 things in it - a spring and a diaghram, and both are essential for its operation.

I've read about this on other forums and the differences in performance are reputed to be barely noticeable at all, but the increase in tank pressure can sometimes cause other issues like regulator problems.

Not worth doing in my opinion.

[leckylee]

If you want to increase the tank pressure on YS engines, then you shorten the fuel line between the back plate and the check valve from the dimension stated in the instructions. You don't take anything out of the valve. There's only 2 things in it - a spring and a diagram, and both are essential for its operation.

I've read about this on other forums and the differences in performance are reputed to be barely noticeable at all, but the increase in tank pressure can sometimes cause other issues like regulator problems.

Not worth doing in my opinion.

Cheers dude so thats why the 120 needs exactly 10cm of tube because that is the exact pressure the the regulator requires thanks for the info. why don't they give you this info in the manual then we would all understand what is going on. perhaps they don't want you to know. anyone know the max touque band of this engine yet??

[speedy jon]

It should be in the manual mate :-) Was in the manual for my ys91 srs and sr engines. So would have thought it would be in yours.


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[leckylee]

sorry dude think you missed the point the 10cm is in the manual, it was the reason for the 10cm i was getting at, the more info the better then we can all get a better understanding of how the engine and regulator works, then we don't have to moan at the retailer when it runs crap like mine

[leckylee]

I wonder why the early OS Pumped engines had Perry pumps
I'm not trying to cause a bun fight but it seemed a better system in that it kept the fuel and crank seperate

[raptorheli2]

perry pumps were a nightmare. if you got a good one you had a good engine but probably 10-20% of people didn't. my own ones i only ever had 1 leak in the 6 engines i had so i was fortunate with mine.

the best OS pump system was simply having no pump it was that unreliable for most.

back on topic-

without knowing specifics other than it runs like crap-

first thing i would do is re-do all plumbing work inc a fuel magnet. you shouldn't be getting bubbles in the fuel. if you are you maybe have an air leak in the reg somewhere.

cheers

[leckylee]

I have heard people say that the pumped os engines were bad, i guess I have just been lucky. Maybe the Reg has a leak, I can't see where from the engine side of the Reg who knows.

[jwatts007]

Had mine in the air today, Lee stick with it and get the problem sorted, it will be well worth it, mine was ballistic today, it took me by surprise, never flown such a powerful thing, the damp air we had this morning really set it alight, the header tank is back on, and some new clunks are on there way, my flights though were cut short with a severe leaning to the right, think the V Bar is playing up, so I will have too sort that now, I set the needles 1.5 out on the main and 1.20 for the middle, such a smooth running engine as well.................

[leckylee]

Had mine in the air today, Lee stick with it and get the problem sorted, it will be well worth it, mine was ballistic today, it took me by surprise, never flown such a powerful thing, the damp air we had this morning really set it alight, the header tank is back on, and some new clunks are on there way, my flights though were cut short with a severe leaning to the right, think the V Bar is playing up, so I will have too sort that now, I set the needles 1.5 out on the main and 1.20 for the middle, such a smooth running engine as well.................

sounds good dude i'd l;ove to see it

[sirricardo]

Hey Lee,
If there are no bubbles going into the reg (as we saw) and the fuel is pressurised. The only way the bubbles can get in, is if the engine side of the regulator has more pressure in it than the tank pressure.
If this the case, then you must have a leaky regulator - send it back dude.

[leckylee]

Hey Lee,
If there are no bubbles going into the reg (as we saw) and the fuel is pressurised. The only way the bubbles can get in, is if the engine side of the regulator has more pressure in it than the tank pressure.
If this the case, then you must have a leaky regulator - send it back dude.

Cheers dude they have asked me to send it back.

[Grant_beltcp]

Any new's on this at all? I'm having the same problem. No visable bubbles in the main line, but loads in the short piece after the reg.
It's running awefull and changing from rich to lean. Can't even get idle to stay running smooth at the moment.