got2dv8
Anybody using U1 cams? Intake duration 44/72 is same as 851 kit/sp but with more lift (10.85) and pretty darn close to the 888SPS and SP5 (53/71 11mm). The exh duration 74/44 9mm again similar to 888SPS and SP5 (77/42 9mm).
Thoughts, comments, rocker donations...
Robert
griff851
Robert they are 748sps cams. You'd be ringing its neck all the time to ride where the power is. You need to ask yourself seriously where are you going to ride this machine, and at what rev range you are going to want usable power. Because changing cams is a pain in the arse. Personally for a road bike I wouldn't use them. I used the S4/ST4 cams and I have great power from 6-9½K and it still spins out to 11k effortlessly (remember anything over 10K and case life starts to come into play.) The engine seems to love 5-6K around town.
The boys with 996sps cams will be able to tell you what they are like.
Griff
got2dv8
Yes, I want a screamer engine. I will be getting new (to me) cases so I don't mind the revs. I have a 900ss for meaty mid-range. Now I want a higher revving missile. I just figured since these are so close to G cams that they should be decent and hold the power up top. But, I don't have experience with 4v cams. My purpose will be a street/track bike but who knows.. I could just end up binning all my extra parts and riding it stock😯 . Only time and $$ will tell. I basically want a big-bore 748 as I liked the power characteristics of the one I had. I like having different bikes for different moods and I want to be able to stomp johnny-rocket-boy on his R1 from time to time. For now I just have to hope to get lucky and meet a newbie with a ZX6 with my SS.
Robert
brad black
i think it'd be worth running that inlet with the bigger g exhaust if you want to rev it, but you need heads that work with them too.
Mr.R
Hi Robert,
If you really want a 'Screamer' motor, why not drop a 748 crank into the cases, with your 94mm topend it would give you an 853 cc ultra short stroke unit which would suit the 748SPS cams...
However I've got this mental picture of a hand granade with the pin already pulled 1/2 way out. 😯
I'm firmly in the more power per rev camp, when building a Desmoquatro motor, there's NO substitute for cubes, a good big one will always beat a good little 'un.
As Brad has said though the G exhaust cams are the way to go if you really want a rev hungry 12.500 rpm monster motor.
Steve R
got2dv8
I picked up the cams because I figured they were close to the SPS/SP5 and G cams. Not really knowing much about how the degrees alter the power characteristics. I'm pretty much a greenhorn when it comes to cams. It's not a simple task trying to piece together a motor with various performance bits...and one variable can alter/effect the other. Still, I am trying to basically build an SPS/SP5 motor (because that is an obtainable goal). I've got two different heads to work with; modified 748 heads and stock 851 heads currently fitted with 33/29. I can also get some 888SP/916 bare heads. I've got an assortment of pistons from standard 94 to 916 (94) to SP5 hc. I've got larger valves 34 with 30's in the works. Two sets of tb's with access to some dual inj also. In the process of getting a close-ratio gearbox and some cases. Just trying.. hoping to fit the right pieces of the puzzle together to get a really nice strong motor. I really don't want to mess with porting and am just wondering if 888SP heads will have the proper porting that I need.
I don't really know what the fark I want to do, so I am just acquiring bits and learning what I can and hopefully will find some direction to head.
Robert
marvin
Start collecting spare rocker arms now Robert!
And order your MBP collets!
got2dv8
Marvin,
Good advice... I did start bidding on rockers... But I then came to the conclusion that grabbing one here and there (and not always knowing what you are getting) could end up being more expensive than getting my bad rockers re-plated.
Once I figure out what head configuration I will run then I will have to figure something out with the rockers. As for collets... will be looking into that when the time comes... and $$ comes... or if. Actually that's the guy.. hey his name too.. who would be doing my rockers.
Damn, if my spark plug threads weren't f&*ked by the previous owner I'd be riding an 851/888 now and have a lot more money. But, what fun is that!
Robert
