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Anyone with experience with ProBuild YS servicing?

Just wondering

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extra slim20/05/2020 12:26:32
510 forum posts
49 photos

Hi Guys

Just about to send one of my YS's off to Probuild for a service as it is playing up.

Suspect it needs, new regulator inners, bearings and possibly a ring, I know it will be pricey, but just wondering what others experiences are?. and whether the engines came back a la John Haytree days??

Any information will be helpful

Jon - Laser Engines20/05/2020 12:42:21
5678 forum posts
273 photos

about 2 years ago a friend of mine wanted a regulator diaphragm for his 91 and was basically told to buy a new engine as they dont keep parts. At least that is the story i was told.

extra slim20/05/2020 12:52:41
510 forum posts
49 photos

gulp...ouch... thanks for the reply though Jon..

malmaz20/05/2020 14:58:04
34 forum posts
5 photos

2 years ago I had a Ys160 in an aerobatic model that the wings folded in, hence model hit the ground.

Engine suffered a bent crankshaft, priced the repair at Probuildcrook, was advised by a club member to email Ys in Japan, got an instant reply with a price, £100 including my postage return cost from UK to Japan and back.

A fortnight later got the engine back and it run like a brand new motor, excellent service from the makers.

Martin Harris20/05/2020 15:01:03
9603 forum posts
258 photos

YS diaphragms seem to be listed for a couple of engines that I've looked at on the Pro Build website and not unreasonably priced - I wonder if your friend's was an unusual or older version? Hopefully ES's engine will be catered for...

Jon - Laser Engines20/05/2020 16:34:20
5678 forum posts
273 photos
Posted by Martin Harris on 20/05/2020 15:01:03:

YS diaphragms seem to be listed for a couple of engines that I've looked at on the Pro Build website and not unreasonably priced - I wonder if your friend's was an unusual or older version? Hopefully ES's engine will be catered for...

Not sure to be honest. Could have been a discontinued version etc, i just got the sob story as he had to order the part from the us i think

extra slim20/05/2020 16:54:59
510 forum posts
49 photos

Japan is a good shout, the world is a smaller place these days, nothing like a factory service .. I'll see if I can contact them.

Peter Jenkins20/05/2020 17:06:46
1708 forum posts
314 photos

Extra Slim you might want to ask the same question on the GBRCAA forum. There are a lot of YS users on there. I know some use Probuild but not sure who else is used. I don't take too much notice of YS issues as I'm electric.

FlyinBrian20/05/2020 18:44:56
685 forum posts
4 photos

I have bought spares from Central Hobbies in the USA at what seemed reasonable prices. Dont know if the do servicing / repairs themselves but maybe worth a try. Central Hobbies

Former Member20/05/2020 19:47:07

[This posting has been removed]

Richard Clark 221/05/2020 05:45:49
424 forum posts

Spares are always a problem with what you might call small 'fringe' outfits such as Probuild. I quite like YS engines but such reports (I've seen several over the years) are the reason I've never bought one.

And even some big ones. Bosch's sole UK importer "Sorry, we don't keep spare lithium batteries for that drill, it's quite old".

Do these idiots think we only need replacement parts for NEW drills?

extra slim21/05/2020 11:06:09
510 forum posts
49 photos

thanks all for feedback.. I think it will be heading off, back to the land of the rising sun for a refurb.

extra slim08/07/2020 12:38:46
510 forum posts
49 photos

Hi All, Just an update. and for information really for anyone else with a YS

I decided to send my 63s back to the factory after a very prompt response from Mr Yamada himself .. Cost about £15 to send it and due to covid, it took nearly 3 weeks but I was in no rush.

A further 2 weeks later, Mr Yamada issued me an invoice for a far reaching range of items, showing it was worn, new head (no liner in them), piston, ring, conrod, disc valve, O rings etc.. which I was kind of expecting, to the tune of approx £115 (which I was kind of expecting)

Postage back from Japan, was super expensive at £30, but took just a few days... so all up, about £160.. but what other option did I have?.. The price alone in the UK for the same parts were £188!... so I was satisfied I had made the right decision.

Anyway, upon running it up, I still had problems!!.. (I know right!).. I turned the air blue, contacted Mr YS who said sorry and to send it back as he had bench tested it.

It became hardly worth it given the cost of postage, and I was convinced it was the regulator... Mr YS very kindly offered to send a complete replacement regulator, so with that in mind, against all advice on the web, saying you need to be a NASA professor to understand and take to bits the reg, and you need 'special' cleaning agents and a laboratory.. I took it apart and found a spec of crud in there... removed it, and it seems to be running as expected now...


A bit of hassle, no argument with YS, as it ran up on return to me for a couple of minutes before the problems started again, so it is how you respond to issues which is more important as things happen..

Just thought this may be useful for anyone else, thinking about options with YS's

Glow Engine29/07/2020 23:28:58
9 forum posts

I think you did the right thing going direct to the YS factory.

RC Japan are a very good company to deal with for spares.

Since I switched to the YS70FZ three years ago, I have never had any running problems with it.

YS now use a fixed regulator, which is preset, you can't fiddle with it, making setting up the engine just like an OS four stroke.

Andy Stephenson22/11/2020 14:04:34
294 forum posts
43 photos

For a lockdown project I'm going through my collection of long neglected engines. I have now come to my YS63S which had a stuck intake valve. I decided to strip it down and clean it out. Surprisingly for the high nitro content which has been through this engine there was no rust in the internals apart from a slight amount on the surface of the push-rods. On reassembling it was all going well until I came to fit the back plate which incorporates the rotary valve. On tightening the bolts I noticed it became tight to turn the crank. By process of elimination I discovered that the rotary disc was binding on the big-end of the conrod but not on the crank pin which drives it. I put this down to the crankshaft having moved backwards very slightly on removing the prop driver. No amount of tapping the back of the crank will solve the problem and the gasket is intact. The only cure to this I can think of is to make a thicker gasket unless anyone has had this problem and solved it.


Edited By Andy Stephenson on 22/11/2020 14:05:28

Glow Engine22/11/2020 14:43:43
9 forum posts

Sounds like the rear bearing is not seated all the way into the crankcase.

You shouldn't really have to make thicker gaskets, if it originally didn't have them in the first place.

If the engine was mine, I'd strip it down again, put the crankcase in the oven. When nice and warm, lightly tap only around the outside of the bearing cage. If you can measure the depth of the bearing face to the rear crankcase, this will give you an idea if it's moved any, if it doesn't look visible.

Martin McIntosh22/11/2020 17:28:51
3639 forum posts
1248 photos

I have quite a few YS motors, a 53, about four 63`s and three 110FZ`s, one of which is going into my latest build. The only one I had to send back to Probuild was the 53 which obviously had a blockage near the regulator which I did not manage to find. Since then I have only had to buy a 110 conrod from them, a rather stronger one from the 91 which is otherwise the same. The only real problems have been bearings breaking up and sourced them locally. Hope that I can still get parts from somewhere because I need a couple of throttle arms.

Edited By Martin McIntosh on 22/11/2020 17:30:40

Andy Stephenson23/11/2020 10:31:50
294 forum posts
43 photos

Removing the crankshaft may damage the bearings as it's so tight, heating may help but the bearings are still good, so I reassembled the engine with the thicker gasket so I will see how well it runs.


Martin McIntosh23/11/2020 16:00:33
3639 forum posts
1248 photos

I suspect that you have burnt oil on the crankcase behind the bearings. This is normally due to needing a blowtorch to get the thing hot enough to enable disassembly. For reassembly on any engine I put the new bearings in the freezer, heat the case with a hot air gun and they should simply drop into place. I would not run your motor if the rear bearing is not fitted correctly because the crank pin will be out of alignment with the conrod and it will soon fail. Bearings from a UK suppier are cheap so get some more and try again. These are highly stressed motors and anything not quite right could easily result in a broken crankshaft, even a weak start can do this.

Engine Doctor23/11/2020 16:18:27
2674 forum posts
44 photos

As Martin says , Dont run your engine with the rear bearing not seated properly . If the bearing is not seated properly then the crank and con-rod will be out alignment and will wreck the engine . Did you change the bearings when you stripped it down ? If you did then check that the replacement bearing is the same width . A thick gasket to make up the clearance  is a bodge and will end badly .


Edited By Engine Doctor on 23/11/2020 16:19:03

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