POD TYPE & JETTING SPECS FOR XJ BIKES (sticky this)

1982-83
Maxim/Seca 400 DOHC
UNI PK-92 pod kit
Mains 122.5
Pilots 42.5
Screws 3.5 turns

 

need to know what kind of exhaust system for those jet sizes, to get the whole picture
thanks

 

Will also need to know the overall condiition of the engine (particularly the compression), your altitude, typical weather for your area as all those factors will affect the efficiency and power output of your engine. There are too many variables to just start a "this is your engine, this is your air filter, these are the jets you need" type of list.

 

I have yet to see anyone back up a modification with quarter mile times.
How many racers do we have here?
I ran a 12.8 @ 107 MPH on my 900 "back in the day"
it had stock air cleaner and a Kerker exhaust, don't know the jets.
what a fun bike!

 

thats what Yamaha did

 

True, but Yamaha wasn't tweaking the carbs for best performance / efficiency. They were mass producing clones that would perform almost exactly the same for each unit that rolled out the door.

 

straight pipes with no muffs/baffles and I live in MI. I've never heard of anyone doing a compression check before jetting...

 

I think in my seca 550 racebike, there are 132 mains in the carbs with the needle up two notches. Motor specs are FJ600 engine with wiesco 652 pistons, lots of headwork. Head milled .050,umm forgot the specs for cam timing, had adjustable ignition timing, forgot that too. FJ600 carbs with K&N filters. Spec2 exhaust. That bike loved the drag strip. It did 11.7 at 107 mph. It was quite the sleeper. Took it to Brotherhood raceway one day and a ninja 250 pulls up next to me, You can hear them betting on the bikes over the PA. One guy bets 4 hotdogs on the 250. I look back to him with 5 fingers up, meaning a 5 second head start. He told me later that that race cost him 40 bucks I have raced against and beaten a gsxr 750 once. Went down the strip in a full tuck expecting to see this guy just blaze past me. I went thru the lights just then the gsxr comes past with the owner staring at my bike as we get the time slips I gotta get her running again!!!!

Btw those times were done with Willow roadrace gearing on it!!. That bike could launch, very rarely would I ever get to turn one and not be in the lead This was back when vintage class was unlimited displacement

Sean

 

I have been looking at a set of pod type filters, for a stock standard XJ900 (1984) used for commuting (80-100Km/h) daily and the occasional weekend run, do i need "re-jet"? I notice when the absorbtion material in the muffler (4into1) wears out it appears to run richer? Ie., i don't need the choke on to start it.
PeterN