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[turbobike] Nitrous Problems - warning, long post

Jon Jarosz (jjarosz@camhydro.com)
Thu, 15 Apr 1999 16:06:22 -0400

I know this is strictly a turbo list, but I can't get any help on my other 
list because no one else is using nitrous, so I'm sorry if it doesn't 
apply.  Here's the history of the bike:

Year 1:
Stock 1988 Yamaha FJ1200, 1188cc's
K&N filters
Dynojet stage III kit (I can't remember needle & jet sizes, but it was what 
the kit recommended)
Accel coils
Vance & Hines Supersport Kit, Quitech II baffle
Factory ignition advancer
Bike dyno'd 113 horsepower to the rear wheel, 13, 000 km's on motor, approx 
18 degrees Celsius outside

Year 2:
Same as above, but with nitrous kit, phase II jets bike dyno's 150 
horsepower exactly to the rear wheel, approx 30,000 km's on the bike, 
similar dyno conditions, different dyno - ignition advancer removed 

Year 3:
My darkest hour.  Bent valves, scorched pistons, burnt seals, blown clutch 
at dyno shootout (103 to the rear wheel, 148 with the NOS, phase III jets = 
approx 50 horse rating), twisted swingarm, chain lets go drag racing big  
 mess etc

Year 4:
"streetfighter" polish & port
degreed cams/slotted sprockets
stainless valves, complete head rebuild - new seats, seals, guides, etc
bike bored to 1219cc's, new Wiseco's
Dyna coils & Taylor leads
Supertrapp Stealth stainless exhaust (I know I know but it was the only 
complete stainless system for the bike) 14 plates - dyno'd to remove flat 
spot with V&H pipe - 6 hp gain across midrange
phase IV nitrous jets - on paper, 68 bhp gain
heavy-duty billet clutch, new chain & sprockets, clutch spring conversion, 
115 to the rear without the juice, 154 with, 80 pounds torque no sauce, 100 
pounds with

I have stock carbs, and they're synched yearly.  New plugs gapped 
correctly, etc.  The bike runs like a dream.  43,000 km's on the bike, 4500 
km's on rebuilt top end.

Is this motor maxed-out for what I've done to it?  Why is it staying at 
around the 150 mark?
This fall I'm going to either turbo or blower it, but I'm pissed off with 
these results for this year.

Thanks for the help.

Jonny Nitrous