3 into 1 exhaust jota

That Mez bloke was the bloke who did the porting on that Motodd Mark 5 race bike that Alan Cathcart won a world title on, Bath Tube style head. BTW that bike was for sale a little while ago.
He did the head on the Mk4 that i recently purchased. That reminds me I have some work to do on it!
 
That is a stunning photo, Red. And the time dedicated to the ex sys makes it probably one of the most expensive parts of the race bike!! I'm guessing they are smaller ID headers exiting the head than stock?
 
That is a stunning photo, Red. And the time dedicated to the ex sys makes it probably one of the most expensive parts of the race bike!! I'm guessing they are smaller ID headers exiting the head than stock?
no headers are larger then standard but we did weld up the exhaust ports and reduced the head diameter on the exhaust valves, been a lot of work go into flowing the cylinder head
 
Probably stepped headers, it produces a pulse that is timed to arrive when the valve timing overlaps. There are formulas that help with designing this effect for a particular rev range, and then you start experimenting to get real-world effects. Swirled Circular collector design does the same thing, and inlet length has a similar effect. Variable inlet even more so. There was a Yamaha 1000 that had an electrically controlled exhaust chamber as well. There must be millions of variations available no wonder there was all those dino pulls.
 
EXUP - Yamaha's variable exhaust back pressure system on the FZR1000s. Then there's variable valve timing and probably inlet length - so you can have max torque in every part of the rev range from idle to redline!!
 
There was a Yamaha 1000 that had an electrically controlled exhaust chamber as well. There must be millions of variations available no wonder there was all those dino pulls.
Yam EXUP, Doug and myself started tinkering with the exhaust electric gated assembly, controlled by new variant iis module. Completed some basic engineering and decided the old 180, would yield more from other improvements, as Redax has carried on in spades, also Steve B as i understand it. Also had included the iis with exhaust header temp real time readout and control loop function, main impetus was to mitigate cracked inlet stubs, destroying piston crowns. Think the average temp was around 450C external first bend on the headers. j
 

Attachments

  • 2009_0112IISTB1200001a_TALCD.jpg
    2009_0112IISTB1200001a_TALCD.jpg
    44.5 KB · Views: 21
Back
Top