SrTelemaster150

Not back-pressure persee. It does make a more dense A/F mixture available @ the carburetor inlet. Kind of like increasing atmospheric pressure ever so slightly. The biggest advantage is not allowing fuel to be sprayed to the atmosphere were it is wasted.

Hobbsy

My Feedback: (102)

The TurboHeader serves that purpose very well on the exhaust end. It prevents the intake charge from following the exhaust out.

Hobbsy

My Feedback: (102)

Glad you said that Dan, I was trying to figure out how to say that without saying, short time back pressure wave.

BJ64

I think that's what the rotary valve in my Rotax does - shuts the inlet from the carby before the crankcase pressure spews some of the A/F goodness back into the atmosphere. But that's 2-stroke tech. Prolly not applicable here...

BJ

Hobbsy

My Feedback: (102)

That rotary valve in you Rotax controles the intake timing the same as the intake port in the crankshaft of out two strokes.

spaceworm

Except those with reed valves, rear intake two strokes also have a rotary disc valve driven by a pin on the crank for intake control. My OS .80 has this. That engine could be reversed by relocating the crank pin to an alternate hole in the disc. My Yamaha MC from the 70's also had a rotary intake valve. I think YS engines have a rotary valve intake that enables the "supercharging" effect?
Sincerely, Richard
Club Saito #635; Saito 56, 100, 120abc, 130T, 180
YS F 120

Hobbsy

My Feedback: (102)

Richard, you're talking about a set up like this, my MAICO 125 had a fiber disc that served as a rotary valve, fed by a 26mm Bing carb. Note air intake tube going up to air cleaner chamber. You are correct about the YS, the rotary valve traps two intake charges in the crankcase to create the super charge effect, it's only about 35% efficient.

The MAICO had two stingers inside the muffler cap, one long and one short, that gave it a power band that went from 4,000 rpm to 8,200 rpm, whereas the Japanese competitors of the time had a spike at about 10,000 rpm. as the joke went at the time, you had to row your way around the MotoX track on the Japanese bikes using the gear shift lever. They got that right after while though.

acdii

So how good are the YS engines? I have a 110 I picked up cheap and looks to be in excellent condition.

spaceworm

No good at all, I will buy it from you cheap

Sincerely, Richard

Rudolph Hart

Ok do it on the os thread,they won the ugly muffler design years ago.

blw

My Feedback: (3)

The velocity stack is worth the price in the long run if you have problems with the fuel compartment getting covered in glow fuel.

Hobbsy

My Feedback: (102)

Barry, I grabbed two the other day while Horizon had them in stock, now I have one for a future engine.

SrTelemaster150

The old Cox reed valve engines would run equally well in either direction!

spaceworm

For whomever it was that was looking for Saito flex pipes, try this site: http://www.freelandacres.com/saito-180.html I found it looking for 180 parts, but they may have other size parts. Good luck

Sincerely, Richard
Club Saito #635; Saito 56, 100, 120abc, 130T, 180

BJ64

Yah - the rotary valve controls the intake timing... but.. when the boys open it out too much, she'll blow back through the carby. Same thing happens if you open the inlet port timing on conventional 2 strokes (old Villiers/Amyl did that).

The Rotax 256 (inline twin) is way peaky - nothing under about 10,000rpm, and all done by 12,500 or thereabouts. Plenty of gear-slamin

BJ

Rudolph Hart

Yeh it makes sense to burn it all,the engine bay inside by my cowled saitos is clean except for some fuel splashes during priming.

Bj i own up as well.Had a 93 gear driven cam version of the 750.The first 800"s were gear cam driven as well,sweet sound.These new lifestyle harley riders can make you wonder.It's either a plain black open face helmet and at every stop you spend ten minutes picking the bugs out of your face or,a plain black open face helmet with a strap on bottom half which can be a skull(favoured by many)or something like a gorilla mask.It rminds me of the old 'punch and judy' puppet shows.

BJ64

You can always tell a satisfied Harley rider by the bugs in his teeth... :

BJ

blw

My Feedback: (3)

Dave- that is always a good thing to do when they are in stock. Have you ordered from any of the British hobby shops online yet? I've made a few orders for Saito parts and the items themselves are slightly more expensive, but postage is cheaper. It balances out. The only downside is you have a longer wait for the package. I got an aluminum backplate for my 72 with all the necessary hardware. Those currency converters on the Internet are pretty accurate for pricing the dollar.

Still, good to hear Horizon had some and you got one.

Hobbsy

My Feedback: (102)

I haven't tried any British sites, I have ordered a couple of things from WholeSale Trains, they are a little slow but I got the parts.

spaceworm

Yeah, my old Amyl carbed bike had no air cleaner and spit back and caught on fire. With the carb on fire under the half filled tank I had some anxious moments until I put the fire out with a handful of baking soda. Wish I still had that bike.

Sincerely, Richard
Club Saito #635; Saito 56, 100, 120abc, 130T, 180

lgaines85

I've been looking for a saito thread. I'll have to read more of this a little later. I have a 180 that needs a good cleaning after being benched for two years. Can't wait to get it in one of my top flite war birds.

Rudolph Hart

Welcome 85 pull the backplate main needle and plug then drop it in some fuel for a couple of days reassemble and then pump some tranny fluid through it.If it feels ok when you flick the prop stick the glo on and listen to that nice messy/raw beat.

Richard i bought a second hand bsa 350 single that the previous owner had fitted and tuned back in 69,and my mate who dinked me there to pick up my new 350 would follow me back on his 500 matchy to my place.In short i had a big carby fire when i backed off on the way home so i was a bit late.

Hobbsy

My Feedback: (102)

Pete, I went back to using Corrosion X to preserve and to rescue gummed up engines.

This was the very first motorcycle that owned myself, a 1952 Indian Brave that was possibly a re-badged Royal Enfield. It was a 250cc flat head, three speed

spaceworm

Interesting that several of us seasoned Saito lovers had beginnings in four stroke bikes. Are we still longing for that unique sound? Wish I still had all my bikes, and most of my cars too. I do have all but two of my many small engines dating back to the 50's. Waxing a little nostalgic here, I am.

Sincerely, Richard

SrTelemaster150

My 1st was a brand new (Italian) '68 Harley Davidson 250cc Sprint.