stunthanger.com
Engine basics => Four strokes only => Topic started by: Andrew Tinsley on December 25, 2013, 03:00:54 AM
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Hello,
I have got hold of another Saito 62 C/L version. I need to run this in and keeping the revs down is not easy! I blocked off the venture of my first 62C/L version and took out segments of the blocked venturi to vary the revs. It sort of worked but an absolute pain in the ****. Just wondering if someone has a spare R/C venturi I could buy or borrow (all expenses paid!). It would make the running in process very much easier. I can then do the famous conversion which works so well on my first Saito 62.
Happy Christmas,
Andrew.
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I have a "Bob Reeves" conversion on my Saito and it is adjustable within 100 RPMs.
Joe
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Andrew,
I've broken in and flown several Saito's, from a .40 to the .72, and I no longer worry about choking it down with a throttle or anything. I simply mount the biggest prop that will fit during the initial break-in, and the prop load by itself limits the RPM. For example, to break in my .72CL, I used a 4-blade (!) APC 14x10 that I had laying around (don't ask why), and fired it up on stock venturi and a 10% nitro fuel. The engine developed only 6k RPM or so. After 2 tanks, I switched to a 14x8 Zinger; the RPM went up to 7k or so, and I ran it for 3-4 tanks like that. Then a smaller prop, etc, etc. The last run was on the intended flying prop at target RPM, and by then the oil coming out of crankcase was clear, which is a sign to me that the bench break-in phase is complete.
Hope this helps.
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Thanks Joe and Mike,
I have done the Bob Reeves conversion on my first .62 C/L. I must be getting past it , or too much Christmas cheer! The obvious thing to do is to swop out the Bob Reeves conversion and put it on the new .62C/L version. Or even simpler would be to use a big prop. I certainly am getting no smarter these days!
Mike, I just have to ask, what on earth are you doing having a spare 14x10 four blade APC just knocking around? I didn't even know that APC did 3 bladers, let alone 4 bladers?
Thanks guys,
Andrew.
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I flew a Smoothie with Saito 40 power. With Bob Reeves carb bolt screwed down to half Venturi it was 5 second laps on 60' lines. Screwed it in 1 turn check with tach. Still fast another turn towards Closed. Flew it and was doing 5.5 laps.
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Sorry, haven't checked the 4 stroke forum in a while, been spending my internet time looking for a new (to me) Dodge Caravan.
I do find it allot easier to do the break-in with an RC carb and keep one around just for that. I would be happy to loan it out if you would just pay postage. Costs around $5.00 for a priority small box which is what I use to ship carbs. The 56,62 and 72 all can use the same carb.
New Caravan is sitting in the drive so maybe I can get back to normal..
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Hello Bob,
Thanks for your very kind offer. An RC acquaintance has offered me the use of an R/C carb to break in my C/L 62. He is a fair weather flyer and it is pretty horrendous here in the UK, with storm after storm! So I am busy breaking in my new Saito, before some good weather appears!
Happy New Year,
Andrew
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I don't know what OS does now, but back when they first came out with the 4 strokers they said to put on a prop you planned to use for flyng, and keep the carb wide open while opening the needle to drop the RPM to 4,000. Then lean the needle in for a bit, then back to 4,000. I broke both my early open rocker 60 and my later 90 in this way and it seemed to work fine. I have also rebuilt a few Saitos for the R/C guys and I broke them in the same way.