supra5677
Pro
Posts: 1279
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posted December 23, 2005 10:08 AM
Y2K mods
Has anybody tried aftermarket cams alone on their bike?
What total can I expect from the Y2K mods, what are the specific parts?
How much horsepower can I expect from the 1270/1287 kit?
I'm trying to consider which is the best direction to go and still keep the bikes reliability..
anybody have any suggestions?
supra
   
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oldkawboy
Needs a job
Posts: 2125
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posted December 23, 2005 07:58 PM
Supra,
The Y2K mods were the things we did to our 12's when they first came out because not much was available from aftermarket sources.
Jim (Y2KZX12R) was the brains behind the mods and they consisted of reworking the stock air filters, modifying the stock school bus muffler, installing a heat blanket under the airbox, etc. Later we matched and cleaned up our stock rubber stacks, changed cam timing and fooled with the TPS..............Those were the days! :-)
With Jim's advice I removed my base gasket, degreed my cams and installed the usual bolt ons and the bike dynoed 183+ on pump gas. After 25,000 hard miles, it's lost less than 2 horsepower. Oh yeah, with Bears short stacks I ran 202mph at Maxton.
Most 1270's I know of make in the 190-195 range with the standard bolt ons. I know of one that has made 205+ with headwork. It all depends on how thick your wallet is. As far as reliability, they seem to be very, very good.
As far as aftermarket cams on a stock bore/stroke bike, Coby Adams says the stockers are hard to beat...and he knows his stuff!
Dan
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park12r
Expert Class
Posts: 124
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posted December 25, 2005 07:32 AM
 Edited By: park12r on 25 Dec 2005 07:34
i have few 12r buddies...
A)190bhp 98 ft/lbs-00, face lift to 02,muzzy full ti system,cam spockets,advancer,filter,block off plates,muzzys stock blue stacks,clean up head(very little),high com gaskets,muzzy clutch ki, 17,
B)190bhp 103ft/lbs-00,muzzys 1270,yoshi full system,cam spockets,filter,block off plates,,clutch kit,
same dyno..(both planning for the 2intake cams mod, porting , - crank blalancer .wonder how much bhp these 3 mods can help)
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Y2KZX12R
Needs a job
CompetitionCNC.com
Posts: 3762
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posted December 25, 2005 08:57 AM
Edited By: Y2KZX12R on 25 Dec 2005 08:59
Supra, Basically I just removed some of the bottle necks in the overall system. In mass produced products there are usually several compromises for cost and reliability etc. The mods as a whole made 172 hp. The resulst were colaborated on the dyno with another 12r that 20 min before had made 167 hp with just a Muzzy pipe bolted on. Several people from the board were there to see both run.
Someone somewhere might have it all from the file that was going around back then.
Like Dan said it was airfilters, timing,exhaust,etc. Sorry I dont think I have the file any more.
As for cams? I dont know much about results of aftermarket cams in a 12r except for what I've read on here. Lately I've been cruntching cam specs with some software for the 1375.
I just want to see what might be possable with different cam specs on a 1375 12r. I entered all the cams available that i've seen also, just to see what they graph too. When I measured the flow of the head ports on the flow bench years ago, I tested the valve openings all the way up to .45" on the intake and .4" on the exhaust, even thou the lift is .310"/.294" on the 12r, just in case I needed the info some day.
Interesting thing is that the 12r,s flow is real nice. There is almost no flow gain measureable by doing minor "cleaning up". And the flow gains are small by opening the valve past .310". The flow increase curve is very flat after .330" with only small % increases in flow after .350".
So from what I've seen, larger intake valves would make the most of bigger cams without going big on duration which makes low and midrange suffer. I'm still up in the air.
____________
Y2KZX12R
CompetitionCNC.com
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