Konrad

I admit, I have been known to improve them to the point that they don't run[X(] !


I stiil fly a lot of glow!

Back to you.

All the best,
Konrad

FNQFLYER

Why oh why do people "hot rod " Saitos???.  Me I go for ceramic pistons and needle rollers and "blue print the engine" and then feed the beast chemical steroids (nitro).  The next step in the equation is the prop, proper balancing and getting the right one for the desired effect is the way to go. My best effort was getting Bolly to make a 12.5 x 5.5 f/glass prop to my specs which enabled my YS 53 to turn 13,000rpm on "standard" Ys fuel.  I did a similar thing to the YS 63 and built a 13.5 x 6.5 for similar results with "standard fuel" BUT when we upped the nitro to 40% that was a whole new ball game.
I find that most of the modern 4 strokes are pretty good out of the box and only need fiddling with props and fuel to get the best IF you want consistent reliability. 

Hobbsy

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710, you just don't unnerstan the "GearHead" mentality, the only reason that needs to be offered for modifying something is simply because you can.

Konrad, Bill Robison said that a 45 degree baloney cut would work just as well as a bell mouth. The little .40a has the velocity stack cast as part of the carb, it is a convergent cone about 7/16" long tapering down to the venturi. I do have a bit for my Dremel that would put a perfect bell mouth on the FA .40 air inlet. As Festus Hagen would say, I'll stew on er for a while.

mike early

i agree that the 45º cut is not a bad approach. maybe round the inside and outside edges off though.

Hobbsy

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Thanks Mike, I'll do it and show you the result.

blw

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Like this?

blw

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Like this?

earlwb

I am impressed BLW, When you blow up an engine, you do it up right, no half-way to it.


My engine failures were mostly the rod letting go, a crankshaft that broke, or a piston that came apart inside the engine. I haven't blown the top off a engine yet. But I still have time though.

Hobbsy

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Here ya go Mikester, the best I could do on short notice and hand holding a Dremel. It should have the desired effect even though we may never know it. Sorry about the fuzzy pic.

PS, I completely dismantled the carb and then blew it out with NAPA carb cleaner.

mike early

I am sure it's some tight work. definately better. sharp edges are to be avoided. no hurry, since it's the worst winter in recorded history....

blw seems to have the technique down pat.

Hobbsy

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Thanks Mike, the wind today is straight out of the north and my wood pile is dwindling fast.

spaceworm

Wow! What were you doing with it to make this happen? Was this a case explosion, under the piston, or did the cylinder blow off and take the piston with it. What happened to the wrist pin, did it shear out of the piston, or is it just not shown.

Merry Christmas to You and Yours.

Sincerely, Richard

blw

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You would need a blast shield for that one. Somewhere I have a video of a small 2 stroke that was left wide open and lean in somebodies garage. It was surprising how long it lasted.

That pic is a YS 120 that I got from RCU. It was fed 80% according to what little info I have. Maybe Jim saw it too and remembers more facts.

blw

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You would need a blast shield for that one. Somewhere I have a video of a small 2 stroke that was left wide open and lean in somebodies garage. It was surprising how long it lasted.

That pic is a YS 120 that I got from RCU. It was fed 80% according to what little info I have. Maybe Jim saw it too and remembers more facts.

Hobbsy

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Here is a shot of the convergent conelike velocity stack on the .40a, the convergence doesn't show very well. Its actuall about .5" to the spraybar. Speaking of coldest winter Mr. Harley is sitting there all cleaned up and noplace to go. This time last year I had ridden to Fredericksburg 3 or 4 times, not this year yet. It seems like last minute Christmas Honey Do's are going to eat up my day today.

Richard, shoot me a PM with your Ph # and I'll give you a call when I get a minute, Thanks, Dave

JohnB96041

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earlwb

hey BLW, did you save the top half that blew off?
You could weld it back on again.
It can't make it any worse now for sure.

FNQFLYER

Guys, I do understand the need to "modify things" I guess it it a genetic thing with the male of the species, but I do like fellow competitors who modify engines with out considering what they are looking for or looking for alternatives (parts) that might fit from other engines.  On the Saito bell mouth thing we have been using a variety of factor bell mouths (velocity stacks here) on Saitos other than those that they were originally supplied with.  Doing this harks back to the days when we didn't have access to the metal or machines we have today.
On tha engine blow up the best I have seen (in model engines) was at an Old Timer do where a guy with a Playboy endurance model that was powered by a Mc Coy 60 blew the entire cylinder of the crankcase about 3 secsonds after release and showered the spectators with a mixture of nitro and other nonspecific combustables.  The fuel tank was a baby's dummy (pacificer) and the fuel was pumped into it under pressureand the fuel line clamped prior to start and flight, the engine was started on the prime, the clamp was removed and the a/c released.  Now consider that this was a AUD 1,000 engine (modified in the USA) and this was its second flight, good stuff.  
Yes I understand the need "to improve" things in fact there is a Sper Tiger 34 heli engine that is getting some loving attention prior o be used at the next SAM 1788 do at Easter next year

BTB have a good Xmas guys raining a bit here my mate down the road had a little bit the other day (250mm in 12 hours) but reckons today will be a little bettersince 0500 has had 100mm in the paddock The down side of living in FNQ but it means more un contested time in the shed when I am home.  And for the record this little black duck preferer rain to snow any day

Merry Christmas and a better new year to all 

FNQFLYER

Guys excuse the spelling in the previous post, I think I would quite pass an RBT test just now, will get the other 1/2 to drive into the shop this AM I think 

spaceworm

The gearheads at Road and Track would drain the oil out of their race car towing hack when it had met it's expiration date. They would put a brick on the accelerator and start 'er up. Would run it 'til it blew up. I recall a Dodge hemi going through a whole tank and then only slowed down a little. I think they gave it a decent burial after that.

Sincerely, Richard

Rudolph Hart

710? that's the blonde who walks into an autoparts store and asks for a 710 cap for her engine??

Rudolph Hart

Merry xmas to all here and a better year to come.

No apologies needed fnq,that four x is powerful swamp water.Quick translation,btb is bye the bye i think and 1/2 should mean the handbrake.

Hobbsy

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Merry Christmas to all and may we all get Saitos for Christmas. My wife is a Christmassy person.

w8ye

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My wife has little pretties all over the place along with Christmas cards and gifts for the 25 kids, grand kids, great grand kids, and spouses

Hobbsy

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As if 7 kids weren't enough we adopted our neighbors and their kid, their parents live in California and Road Island so they just kind of adopted us as pseudo parents. They're Navy people that both work at Dahlgren. Good feeling though.