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Old Mar 25, 2015, 07:56 AM
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I convince things to work
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Easy enough to push down a valve with your finger while turning the piston to TDC on the compression stroke. Alternative, with a little bit patience, the compression pressure will eventually leak away.
But removing the plug allows you to better Judge when you are in TDC.

Theoretically, it does not have to be in top as the base circle of the cams is supposed to be a true circle, but usually folks use TDC to make 100% sure the follower is not by accident resting on the cam flanks.

Brgds, Bert
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Old Mar 25, 2015, 08:21 AM
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I HATE GLOW PLUGS!
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Quote:
Originally Posted by Cbfn1 View Post
I have a question on adjusting the valve gap.
Does it haveto be the compression stroke?
Or can it be the exhaust stroke as long as both valves are closed?
I'm guessing that the glow plug has to be removed if it's the compression stroke.
Both valves will be open at the top of the exhaust stroke.

I just watch for the overlap, then turn 360.

You can also slowly bring up the piston on compression stroke until the compression leaks off. That will hold the piston + or - about 12-15 of TDC. Just find the approximate center of the "rocking motion".

Plenty close enough for setting valve lash
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Old Mar 25, 2015, 08:34 AM
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Both posts^^^^^^^
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Old Mar 25, 2015, 09:52 AM
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Thanks.
Letting the compression slowly leak off is something I didn't think about.
I was wondering how it was done with the glow plug in.
Thanks again.
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Old Mar 25, 2015, 09:54 AM
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Why wait? Push on a valve and let it out.

Greg
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Old Mar 25, 2015, 06:24 PM
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I HATE GLOW PLUGS!
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Quote:
Originally Posted by gkamysz View Post
Why wait? Push on a valve and let it out.

Greg
True that, but if one is setting up CDI W/a degree wheel the lazy way, (as I cited above) sometimes the rocker covers are still in place.

While setting lash, the valve could be depressed to save the few seconds it takes for the compression to bleed by.
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Old Mar 25, 2015, 07:50 PM
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Ahhhhh, found one!

Bill
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Old Mar 26, 2015, 02:30 PM
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FG-21 update

After taking out the tanks 4 times and checking the lines and never finding anything I decided that the fuel delivery system was fine. The FG-21 was still missing in the mid range so I thought the low end was too rich so I leaned it out about 2 min and flew it, was slightly better so I landed it and turned it another 2 min and it didn't get any better but actually worse. I landed and reset it to my initial setting and leaned out the top end about 3 clicks and took off. Ran a little better so I landed and leaned it out 2 more clicks and took off again and it was even better. I landed and leaned it out 2 more clicks and now it is set! smooth idle, great transition and solid top end. On the ground I'm getting 1500-1635 rpm's and a peak of~ 9,250 and peak in the air I got 10,938! I was flying it with the cowling off and peak temp was 135* F. I flew it with the cowling on and the temp climbed up to a peak of 223* F. I don't like this so I am going to work on some baffling. If I fly this weekend I'm going to swap out the prop to a 16x6 and see how it works.

A friend of mine brought out his radar gun and my first high speed pass was 88 mph. After readjusting the high speed the next was 92 mph. After the last adjustment I had 4 consecutive runs of 95 mph! This combined with very reserve flying time of 10 min, I love it! I could easily fly for 30 min at a time but I might need a chair! Thanks Guys for all your input!
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Old Mar 26, 2015, 08:27 PM
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Quote:
Originally Posted by md_cobra View Post
FG-21 update

After taking out the tanks 4 times and checking the lines and never finding anything I decided that the fuel delivery system was fine. The FG-21 was still missing in the mid range so I thought the low end was too rich so I leaned it out about 2 min and flew it, was slightly better so I landed it and turned it another 2 min and it didn't get any better but actually worse. I landed and reset it to my initial setting and leaned out the top end about 3 clicks and took off. Ran a little better so I landed and leaned it out 2 more clicks and took off again and it was even better. I landed and leaned it out 2 more clicks and now it is set! smooth idle, great transition and solid top end. On the ground I'm getting 1500-1635 rpm's and a peak of~ 9,250 and peak in the air I got 10,938! I was flying it with the cowling off and peak temp was 135* F. I flew it with the cowling on and the temp climbed up to a peak of 223* F. I don't like this so I am going to work on some baffling. If I fly this weekend I'm going to swap out the prop to a 16x6 and see how it works.

A friend of mine brought out his radar gun and my first high speed pass was 88 mph. After readjusting the high speed the next was 92 mph. After the last adjustment I had 4 consecutive runs of 95 mph! This combined with very reserve flying time of 10 min, I love it! I could easily fly for 30 min at a time but I might need a chair! Thanks Guys for all your input!

G'day Mate,
I run a 17x6 on mine, but it sounds like you want speed, so try a 16x8.
I think you are over revving your engine, 10,938 RPM's in the air is too fast, you will get valve bounce, & damage a great engine.
If you prop it for 9,500 RPM in the air, it will run sweet, & you won't damage anything.
Just my opinion, so don't get upset. But it sounds like you would be better off with a 2 stroke.
Cheers
Al.
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Old Mar 27, 2015, 12:02 AM
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Al, this engine is brand new. I didn't know the engine was unloading like that. I am still on the break-in prop, so yeah I am going to go to a bigger prop (16x6). I can't stand the sound of a 2-stroke, that's why I got the saito. I wasn't originally going for speed but a friend of mine was given me grief about it being a slow turd. So when my other friend came out with his radar gun I wanted to see what she would do. My normal flying speed was 73-75 mph and was turning a tic over 7800 rpm. I have 4 hrs of run time so I just checked the valves and they were good. I also added some Marvel Mystery oil in push rod tubes. I really like this engine and want it to last a long time. Plan on some flight time on Sunday, will post back then.
Cheers
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Old Mar 27, 2015, 03:00 AM
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Sounds like it needs a lot of running in, 2 clicks here 3 there, I wouldn't have chanced it, a bit of ground running wouldn't do any harm,,,
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Old Apr 04, 2015, 11:49 AM
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Tuning Saito 80 GK

Thought I would go over this Motor and tweak it out , since have not flown it but a couple of times in the last yr. Low end needle is good NO hesitation from Idle to WOT.
Using Omega 15% , at wot , i kept turning High Speed needle CW bit by bit , listening for an increase in rpm's, Once the engine seemed to be at highest rpm , I turned Needle CCW couple of cliks [ to go back rich ]. Letting it idle for a short time , ran it back to wot and did the pinch - died Immediately too lean . I then CCW on needle half turn restarted , starts quickly- ran her up again, quick Pinch wanted to slow dwn.

I am up to 4 turns CCW and with a quick Pinch at wot , still the rpm's drop ? Runs fine with alot of SMOKE [ using OS F plug].I had a short piece of fuel tubing on HS needle as at one time suspected an air leak- I cut another New piece of tubing a bit longer , as org one has been on for a long time.
My hangar 9 digital tach was giving me various readings, while engine running smoothly , so put tach up .

I CCW 5 turns on HS needle , a quick pinch - slows down - blowing alot of smoke.

Fast Idle and quick pinch rpm's Increase , which tells me low speed is correct as there is not hesitation.

Never have been satisfied with my tuning on this engine..
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Old Apr 04, 2015, 12:15 PM
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If the low speed needle is a tad on the lean side, the barrel will not back away from the end of the spray bar to allow full rich on the HS needle. To prove this, back the LS needle a half tun (the idle will be real rich) and try to richen the HS. If you can now richen the top end, that is the problem. You can compromise and run the LS a little rich so you can run the HS richer. A more drastic solution is to grind a less sharper taper on the LS needle to cure this. but be careful not to overdo this as this will richen the mid range.

Not sure but if the LS needle had at one time screwed in too hard and bell mouthed the end of the spray bar, the same symptoms may occur
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Old Apr 04, 2015, 01:22 PM
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Quote:
Originally Posted by Arceenut View Post
If the low speed needle is a tad on the lean side, the barrel will not back away from the end of the spray bar to allow full rich on the HS needle. To prove this, back the LS needle a half tun (the idle will be real rich) and try to richen the HS. If you can now richen the top end, that is the problem. You can compromise and run the LS a little rich so you can run the HS richer. A more drastic solution is to grind a less sharper taper on the LS needle to cure this. but be careful not to overdo this as this will richen the mid range.

Not sure but if the LS needle had at one time screwed in too hard and bell mouthed the end of the spray bar, the same symptoms may occur
There is no taper on the LSN. The end is flat. The slotted hole in the "cats eye" is what determines low speed mixture as the flat end of the LSN exposes more of the slot.
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