fj1200 turbo "thug"

[backstreetheros]

try and answer a few questions here...
the hot fuel was only an idea, i think i'll just go for a separate resivoir.
does the plenum sides lead to a venturi? i don't know what your talking about. 

the plenum is linked directly to the carbs and the plenum outlets are bigger than the carb inlets to make sure all the carb holes arnt blocked if slightly out of line.
the 4 tubes you see coming off the plenum are pitot tubes. two pressurize the carb diaphragms with (plenum) boost pressure) and the other two, one goes to pressurizing the carb float bowls to equilise the pressure inside, above and below the carb intake. the other goes to the fuel pressure regulator to cross reference the fuel pressure with the boost pressure so the fuel pressure is always higher than the pressure in the carbs (air pressure)

the regulator i used is a Malpassi Petrol King boost referenced model with a single carb outlet (although i have four carbs i have one fuel inlet pipe)
the pump i bought on ebay off a guy who said he took it off his GSXR turbo drag bike. its a brass gear driven pump, i believe made by seaflo.

the turbocharger used is a Subaru Impreza TD04 with a built in adjustable wastegate. standard mounting flanges (in case the turbo blows up) but completely custom manifolds.

the dump valve i believe is a bailey model
the boost pressure switch controlling the ignition retard under boost is a Wizards of Nos normally open switch.
the jets are standard as are the carbs.
needle position is standard as is the pilots. the only thing i've adjusted is the idle screws.
the bike is being sent to my local mechanic for re-jetting and fine tuning of boost and fuel pressure and ignition map. hopefully we can get a dyno figure then.

i think to get it running a bit better i need to adjust the fuel pressure regulator down (i've bought a fuel pressure gauge for this very reason)

still a fair amount of work before its ready to be sent away for jets and dyno.

i had alot of problems with my fuel tank over pressurizing due to it not being vented. a potential bomb! hence why i'm going to make a new tank (or set of tanks)
then i can ensure it has the correct vents, return lines and feeds.
need to find a liquid filled boost pressure gauge as the one i have nearly shakes itself off its mounting on idle. i could connect this to the plenum and maybe it wouldn't be so erratic.

my MOT tester said don't bother putting a speedo on it because you can just use your satnav.
i have the ignition all wired up on a key now and the alternator wired so i dont have to deal with a flat battery and touching wires together all the time! haha.

[backstreetheros]

just re-read. the pitot tubes are not into the venturi, they are just piped to the outside of the plenum, not ideal i know but i imagined it would be way too difficult to get the pitot tube sizes perfect for the air pressure to be accurate.

remember this isnt a drag bike, its a hardtail. so i don't think its worth the trial and error on putting them into the path of flowing air to get it perfect.
i'm not after 100% performance with this bike as the style of the bike isnt exactly suited to full on drag power.
i'll be happy if i get an extra 50hp over standard and it runs right (and makes alot of noise )

[Seanextra]

All good thanks for sharing, Just interesting to see what you have done. This is all new ground for me also, its great to see a living breathing project with pictures as it evolves. I am still getting all my bits and pieces together and holding off on a few big dollar items till i get closer to needing them. I have read alot of Turbo builds with Carbs ( Blow Thru ) and nearly all of them have ended up with either stock or close to it Jets and Settings. a bit of progressive retarding to keep that deadly pinging away and mucked about mainly with pressure to the carbs etc to get the fueling right or as close as possible thru the full rev range. I think that is the area that needs the most effort. 

Have you thought about a priority breather valve for off boost intake>?? seen some good ones made out of 2 Stroke Dirt bike reeds on to the plenum simple and fool proof fix and you can get a good used set pretty cheap. I'm sure it would help down low with your road application.


Regards Sean

[backstreetheros]

bloody bikes!.
i've not had chance to do anything as been on the catch up with work,
moved into a new lockup this weekend so have a bit more space and hopefully peace and quiet to work on the bike!
its not been forgotten!

i've had a think about a priority breather valves and although a good idea i think its way over complicating things...
and if im wrong and i can't get it set up right on the road, i'll make one and fit it! 
i'll look further into getting it to run right after i've made it ride-able!
i no longer have a little sump drain plug guard on the bottom of the motor now as the bike ground out going into the new workshop