When pulling thru with hand clock wise have compression when pulling thur counter-clock wise no compression.
Is this normal??

Tim

It can be quite normal
Make sure the Throttle is open when you try it - If the throttle is closed, It won allow any air to enter the cylinder to be compressed.

Off Topic but another tip for you if you aren't aware of it:
Is it a new engine? and are you familiar with the 100?
If it is new - you may find it vibrates a lot at low RPM's - Some of the 100's do that and some don't - it's caused by an extremely rich low speed needle setting - Once you get it broken in and lean out the low speed - they become smooth runners (One of mine took 4 full turns of the LS needle to get it to the correct place)

Some are shakers regardless of the LSN setting.

Even when I lean mine out so much that it hesitates or dies on transition, it still shakes like the devil -- so much so that I've had to add some milled aluminum rails to the front of my Mojo 60 profile to avoid the damned thing disappearing into a blur at anything over half throttle.

All the usual things have been done (prop-balance, new bearings, etc) but it's still a real pneumatic drill.

However, another FA100 in our club is smooth as silk.

Likewise another guy from a club up country bought two FA100s. One shakes like hell, the other is smooth as silk. Both have been run in the same, use the same fuel and even swapping props makes no difference.

Go figure. Some shake, some don't -- and it's not always down to tuning.

Still a *great* engine though.

yeah, I love my 100 - its really a great powerplant.

This vibration has to do with the engine's internal balance right? So isnt there a way to re-calibrate the crank counter weight to ease the vibration?

Liquid, you're opening yourself to "the LS needle syndrome" attack. You're brave man!

Yep, mine is too. It's not outrageously bad but it vibrates easily as much as the much more powerful YS 1.10. It's got a beautifully smooth idle though. 1500 - 1600 rpm and it doesn't miss a beat. Smooth as silk.

But at WOT, up around 9200 rpm, she starts blurring alright.

For Saito Club eyes: the LSN is as lean as I can get it before transition suffers.

Well, yeah - I dont really fall for it , but its true that saitos come with a uselessly rich settings which differs from engine to engine.. (a guy with a screwdriver at final control at Satio factory??)

I re-tune all needles before firing the engine up for the first time, then fine-tune it to the leanest & meanest.. But some engines are simply not balanced mechanically inside. therefore you cant get rid of vibration no matter what.

I see people say "i havent touched the LS needle".. well chap; then you didnt tune it IMO..

If that were the case, I would send it back under warranty.

[/quote]
I remember a japanese friend once told me why its done that way and for good reason.But thats another story.
Must be really cold in Istanbul right now.Haven't been there for more than 10yrs.I remember always enjoying a good fish steak by the bosphorus.It was really something.
Happy Flying!

Im actually in UK (again), and will return to Istanbul in 2-3 weeks.. My first job when I get back? Disassemble and re-assemble my saito 100 I did a bearing job right before I left for UK; and since then Im paranoid about the conrod position - I think I put it backwards

I hear that its nice in Istanbul right now; getting all the weather updates from my fly bud

After replacing the LSN and the spray bar -although brand new- in my Saito 100 I managed to have a decent lean low speed tunning and hence good idling at 2 - 2,200 rpms.

However, I would agree that this engine has an internal vibration issue maybe because of not being best crankshaft callibrated (at least mine).

With less than 5 gallons of fuel through it I am about to replace the bearings for the third time!!!. Crankshaft becomes quickly very lose to the bearings and engine rattles.

I really do not care about the engine being destroyed (i.e. rod brake-down because of the problem) but I really do care about my plane in case of engine failure (a nice GP Super Skybolt costing 330 euros).

Stelios

Where are you getting your bearings??

I know the stock bearings don't seem to last long but I replaced mine over a year ago with a set from rc-bearings.com and had no problems since.

I don't think the vibration is a balance issue -- it's not so much due to unbalanced mass as it is to the huge torque pulse that accompanies each combustion stroke. The FA100 is a *very* light engine for its displacement so it tends to transfer these torque pulses directly to the airframe.

A heavier motor (like the OS or Magnum) won't shake so much but I'll keep my Saitos thanks ;-)

Xjet; Im with stelios on this. There might be a balance issue on the counter-weight.

Even the best bearings will become rubbish rapidly in a hostile enviroment.

I personally never buy bearings from hobby shops or online stores. I go down to industrial ball-bearing stores, and buy with a brand name. NSK, NTN, SKF are my choices (which are used in 99% of glow engines on the market today)

And you can virtually find any type of bearing you want for much less money than any online hobby store or online glow engine bearing store..

Have you actually checked the prices at [link="http://www.rc-bearings.com"]RC-Bearings.com[/link]?

The standard [link=http://www.mcintoshcentral.com/rc-bearings/catalog/product_info.php?cPath=81_87_100&products_id=682&o sCsid=7df4c546af9182f6099c34ea333f7085]FA100 bearing set[/link] is just $8.97 and (as I said) I've yet to wear a set of these bearings out.

Even better, for under $29 you can get [link=http://www.mcintoshcentral.com/rc-bearings/catalog/product_info.php?cPath=111_116_126&products_id=836 &osCsid=7df4c546af9182f6099c34ea333f7085]FA100 ceramic bearings[/link] which will last a *whole lot longer* than steel ones.

I challenge you to find prices like this for bearings of equivalent quality at your local industrial bearing shop -- and if you do, please give us the address of that shop ;-)

Well; If you think about it in a realistic manner, with shipping and handling it will cost abit more than $8.97

I drove my car right to the door of the store and bought my stainless steel set for 10 or 12 USD. which are the same bearings (codes are the same thus the brands.).

If I had bought 5 sets, the set price would probably go down abit more..

If you have easy access to a local industrial bearing shop, you may get it for the same price range.

I've probably said this before, but some Saito engines have been mounted with wrong timing on the camshaft. If there is something wrong with the timing, this will lead to heavy vibrations between 50-80% throttle. I had a "shaker". The vibrations were so heavy that it damaged the rear bearing. But I realigned the timing and the problem disappeared.

Now thats worrying.I can explain the setting of the LS needle at the factory but the timing gear thats another. My 100 was smooth running before I traded it in for the 125.You know, my 82 has the same characteristics as yours,the vibration peaks at 80%.Looks like I'll have to check the timing then to see if they set it right at the factory.I'll check the other engines still in the box if any are out too.

Before i proceed though , did you set the timing different from the recommended setting or was the factory setting different from the recommended setting?

BTW did you see any change in throttle transition,topend rpm and idling rpm after retiming the gear?



Thanks for sharing.

That is surprising, to say the least.

Has anyone else ever found a Saito's timing set incorrectly from the factory?
(Not to say I doubt you, I just wonder how common that could be.)

Hi Everybody,
My trusty Saito 100 just started making some nasty noises. Started vibrating pretty good and it feels rough went turned over by hand. I can tell it isn't right. I've never rebuilt an engine before but would like to try with this one. It's been a real great engine for over three years and I just installed it in a new airplane about three months ago.

I bought the ceramic bearings from rc-bearings.com. What else do I need? Are there any instructions out there on rebuilding? Any special tools required?

Thanks in advance!

I have or have had every Saito single from .30 to 2.20 except for a .65 and 1.80 and have never seen this, I also have several twins and one triple.

I have 5 Saitos and the .82 is the only shaker. Any further leaning of the low speed needle results in a bog in transition as mentioned above. The .82 sits in my engine pile. I've completly disassembled it and everything checked out OK.

Well, checked out all my saito singles- three 82s , three 125s , one 220 and they all check OK. I won't bother with the twins.

Anyone thinking of checking, please don't remove the camcase to "have a lookie inside".Reassembly can be tricky. Remove the backplate and cam covers.Rotate the crank 90degrees either side from TDC and check cam travel. If they are equal, you're alright.

Yes Tim, my 82 still "shivers the timber" out of my plane.

The crazy thing is that although my FA100 shakes like the devil, my 82 is *smooth* as silk. Even on the nose of a tired old profile (which can be twisted and bent easily by hand due to oil seeping into the wood), the 82 hardly vibrates at all.

I wish I knew why some Saitos shake so bad and some don't -- even when they appear to be identical.

You know behind the back of my head I remember there was this talk that the position of the prop in relation to the crank sometimes does wonders in balancing out the vibration of some engines.Could this be the hit and miss guys are getting?

I retarded the timing by one tooth on the wheel. After that, the operation became smooth like silk. Power was still good. However, according to the manual it's not supposed to be like this. There is no problem with piston / valve clearance. Just check this before you turn it over to be on the safe side.

The reason for this shaking between 50-80% could be that the timing is set in a way that some hot combustion gases are not expelled though the exhaust cylcle. This will give detonation due to higher temp in the cylinder during the compression stroke. Higher temp will give predetonation until the RPM gets so high that combustion delay will cause the peak pressure to come to correct position. During lower RPM, the then during compression will decrease, hence no detonation.

Bigger prop and the problem will increase.