mikstr

Heads have already been ported and decked 0.015"....

As for the weight, I have been tabulating the weight loss and estimate the wet weight (tank full) to be just over 400 lb (will confirm in the spring)

FL02SupaHawk996

shoot, that's were I thought some additional power might be hiding

Did they cut fresh seats for the new valves?

mikstr

yes, I had them refresh the seats (new valves and tappets all around). The guides were also replaced on the exhaust valves. The intake valves (and piston pins) are DLC coated (for reduced friction). All chains and bearings have been replaced (including the replacement of two tranny and the water pump bearing with ceramic hybrids for reduced friction). Crank has also been balanced. (to new rods and pistons).

Not much has been overlooked.... As I said previously, the biggest thing holding back the peak hp numbers (IMO) is the low rpm of the torque peak (now at 6750, which is even lower than stock) and its subsequent efect on the high-rpm "over-run. I am quite certain that simply replacing the intake runners with shorter units (as the Mori or short HPower units) and retarding the intake cam by say 2 dgrees (moving lobe center to 109 degrees) would move the torque peak rpm up by 500 or so rpm and instantly get the bhp numbers up by 5 or more. As I seldom rev teh bike to top-end, this would be a step backwards for most of my riding, however.

FL02SupaHawk996

Nope, I'd say you've done everything but possibley optimizing the cam timing...ask Roger where to go to find more power cuz if anybody knows he will...RC

mikstr

The Yosh (lobe center) cam specs are 110 degrees exhaust adn 108 intake. I asked the tech to set the intakes to 107 (had them set at 106 before as per advice from tech at Yosh USA) in order to bring the power down in the rpm range (which has obviously worked). I could simply have them set to 108 or 109 for more overlap and hence better high-rpm breathing, but that would essentially take power from the los and mids and shift it up in the rev range (although it would give better peak hp number due to the multiplier effect of rpm used to calculate hp).... Would likely be worth it for a track bike but not on teh street

FL02SupaHawk996

True and you don't want to loose that low-end grunt...

Have you considered oversized valves? That's the only thing I can think of to extract more power by making it breath better.

mikstr

Thought about OS valves but IMO those would only help at high-rpm. The larger ports would, I think, actually take away from low-rpm power due to the reduced velocity...

FL02SupaHawk996

Take my word for it. The OS valves don't take away the low end grunt. If I get on it at all it's nearly impossible for me to keep the front wheel down in 1st gear now

mikstr

I don`t doubt for a second the potency of your engine. The fact remains, however, that a larger orifice, for a give engine speed, will have lower velocity, hence the cylinder filling will be reduced (albeit slightly), as will the volumetric efficiency (and hence the torque). The same principle applies to the header diameter on the exhaust side, a smaller header diameter will tend to produce more low-end, a larger one will improve high rpm breathing at the cost of low-end.

FL02SupaHawk996

Then you need STG2 cams for more duration for your little holes

mikstr

Stage 2 cams would not only also work against low-end and mids, but would also work against crankshaft durability and longevity (as per Roger D) since aggressive cams are teh root of crank problems on hopped-up VTR engines (not elevated rpm or compression as some would have us beleive)

mikstr

As I keep forgetting to scan the dyno sheet, I took a picture of it. Here is the link:
http://s784.photobucket.com/albums/y...t=P1140026.jpg

FYI, I manually re-drew the torque curve (in red) to the same scale as the hp curve (since the torque side uses a different scale (?????) , which visually distorts the results).

cheers

revhead1957

Very impressive! Power right where you need it for everyday riding.