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saito 1.20 rpm problem

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saito 1.20 rpm problem

Old 09-10-2008, 07:32 PM
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damnbatteries
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Default saito 1.20 rpm problem

I have a saito 1.20 that I had a crash with and I can't seem to get top rpm out of it. I tached it at 8'000 rpm's but it should top out at around 10'500 thats where it tached out when it was new. It's only had about a half gallon of fuel thru it, I'm running a 15 x 6 wood prop and 30% heli fuel. I've checked the gaps on the intake and exhaust valves and adjusted them the engine does not leak anywhere, it idles just fine and the transistion from idle to full is great there is no hesitation at all, using a O.S. type F plug and sidewinder fuel. I hope somebody out there can help me work this out.
Old 09-12-2008, 07:36 AM
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David Bathe
 
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Default RE: saito 1.20 rpm problem

10'500 sounds like an awfull lot of R's for a 1.20 4stroke.
Are you absolutely sure? Different tachs supply different readings from different positions against different backgrounds.
I certainly would never rely on one to be accurate.
Anyway, it's WAY to much IMO.
8.5-9' is a far better, realistic area.
Try a 16x6 APC and see what you get.

As a side note, you said it was new, only half a gallon through it. I hope you weren't screwing those R's out of it.
Would do some harm as it wouldn't have even run in. That could be your answer.
Old 09-12-2008, 08:02 AM
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Edwin
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Default RE: saito 1.20 rpm problem

Gonna agree with David. Pretty much on everything he said. I have four saito 1.20's. I prop all of them for around 8k to 9k rpm. I currently run 16x8 apc with about 8200 rpm. They last a lot longer if you dont try to get evey bit of rpm out of them. What kind of fuel are you using?
Edwin
Old 09-12-2008, 09:54 AM
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jaka
 
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Default RE: saito 1.20 rpm problem

Hi!
15x6 is way to small for a 1.20 four stroke engine,at least at sea-level. 16x6 or 15x8 is the best prop for it for most airplanes. 16x8 is a little too large.
Old 09-12-2008, 11:09 AM
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Gray Beard
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Default RE: saito 1.20 rpm problem

I would say your tach is off but if you had it at 10-5 and after the crash using the same size prop and the same tach you are only getting 8 then you may want to send the engine in to get A check up to see if you didn't maybe bend something?? That has been known to happen.
Old 09-12-2008, 02:58 PM
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damnbatteries
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Default RE: saito 1.20 rpm problem

Thanks for all of your replies, my dad was over last night and I told him about my problem and he reminded me that I used his tach after I broke the engine in a couple of years ago and he told me that his tach was always off. I'm pretty sure all of you are right about the rpm's. I really appreciate all of your help.

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