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Here's the porting we need in the 500 & 750
Posted: Sun Jan 20, 2013 8:35 am
by Suzukidave
Re: Here's the porting we need in the 500 & 750
Posted: Sun Jan 20, 2013 10:01 am
by tz375
Interesting barrel Dave. Looks like a crankcase reed motor with 4 main transfers and three exhausts but the split rear boost port is interesting. What is that one from? Is that an Arctic Cat by any chance?
Here's a few more..
Top left is Honda RS125 race bike. No exhaust valve in the wide bridged exhaust port with eyebrows.
Top right is 96 Yamaha TZ250 with 6 transfer ports, 3 exhaust ports
Bottom one is from an Aprilia RS250 twin street bike. 4 transfer ports. Very wide bridged exhaust with 3 stage valve and eyebrows reaching past the transfers.
All three use single rear boost ports.
Re: Here's the porting we need in the 500 & 750
Posted: Sun Jan 20, 2013 2:25 pm
by Craig380
Wow, the porting in that Aprilia RS / Suzi RGV cylinder is something else

It's not grinding, it's
sculpture
Even if Suzuki had developed the triples' porting like it did with the 250A models, that would've been quite something.
Re: Here's the porting we need in the 500 & 750
Posted: Sun Jan 20, 2013 7:05 pm
by Suzukidave
tz375 wrote:Interesting barrel Dave. Looks like a crankcase reed motor with 4 main transfers and three exhausts but the split rear boost port is interesting. What is that one from? Is that an Arctic Cat by any chance?
I really need to start putting a description on my pictures i grab off the net .. saying that , i dont know what the cylinder is from but it was interesting .
Re: Here's the porting we need in the 500 & 750
Posted: Sun Jan 20, 2013 11:07 pm
by tz375
Re: Here's the porting we need in the 500 & 750
Posted: Mon Jan 21, 2013 3:53 pm
by Suzukidave
I know it was Suzuki's desire to keep the engine block as narrow as possible so they skewed the transfers , measuring the RS250 block across just how much wider would the block have been across with the better porting ? But i suppose the point is moot as there really wasn't the technology then to design such a engine was there .
Re: Here's the porting we need in the 500 & 750
Posted: Tue Jan 22, 2013 9:43 am
by Suzsmokeyallan
Re: Here's the porting we need in the 500 & 750
Posted: Tue Jan 22, 2013 2:14 pm
by Suzukidave
Oh Yeah .. pop,pop pop... CR500
Re: Here's the porting we need in the 500 & 750
Posted: Tue Jan 22, 2013 2:28 pm
by Suzsmokeyallan
Yup and with some gentle massaging of the ports and other minor mods you can take the stock 70HP up to around 90HP.
Re: Here's the porting we need in the 500 & 750
Posted: Tue Jan 22, 2013 2:38 pm
by Suzukidave
humm 1500cc triple with 270 hp .. ok who's going to volunteer to kick start it

Re: Here's the porting we need in the 500 & 750
Posted: Tue Jan 22, 2013 3:58 pm
by tz375
That is remarkably similar to several years of RM250.
Re: Here's the porting we need in the 500 & 750
Posted: Tue Jan 22, 2013 9:47 pm
by Suzsmokeyallan
Richard after you ride open class 500cc two stroke power, everything else feels lame. Modify it for more power and improve the handling to match and and then stock open class suddenly feels weak.
Its hard to describe but once you've felt it, it can become VERY addictive.
Re: Here's the porting we need in the 500 & 750
Posted: Tue Jan 22, 2013 11:20 pm
by tz375
Allan, too much power is just that - too much to use effectively.
That's why I don't want my GT to make more than 150 in street form. 77 down, 73 to go

Re: Here's the porting we need in the 500 & 750
Posted: Wed Jan 23, 2013 12:16 am
by Suzsmokeyallan
You can never have too much (usable) power, it only becomes too much if you can't deliver it all to the ground in a controllable fashion.
Re: Here's the porting we need in the 500 & 750
Posted: Wed Jan 23, 2013 8:40 am
by Suzukidave
Its just the cost of fun if the power takes the knobs off the knobbie tire after every outing
