I had mine run on a dyno today with surprising results. final #s are 99.24 torque and 68.15 hp. What was surprising is comparing to my dyno from last September. It was 98.74 torque and 68.03 hp. Last sept my setup was Bak, OEM exhaust drilled to stage 1, 182.5 main, 45 pilot, pms 3 1/4 turns, needle clip on 4th groove and manifold was only rounded out on the corners and not down to the aluminun.(rubber was left everywhere else)
Now the set up is BAK, Speedstar long drags, 182.5 main, 45 pilot, pms 3 1/4 turns, needle on the 5th groove and the intake is ported all the way down to the aluminum.
The main differances are the pipes and the intake. But not much differance in results. Only 1/2 ft/lb torque and .12 HP gain
My conclusion
1- The corners being rounded on the intake must be the most important part of the porting.
2- A good Stage 1 exhaust mod on OEM pipes will give as good of results as aftermarket pipes.
Don't get me wrong the bike runs GREAT. I just expected a little more with the mods (Pipes and full porting). Well at least I know my AFR's in all ranges are ok. Right now I'm a little rich at cruise range (13.7-13.8) so I'll kick the needle back a 1/2 groove to 4th groove w/2 silver washers.

thats not rich at all, cruise anywhere between 13 to 14, 14 for economy, 13 performance

im trying to understand something.

When i got my bike dyno'd, my numbers were 72.55hp and 95.59 fpt.

Now, compared to what other guys are posting, my HP's seem to be high, but bikes that are putting out 68-69hp are getting 3-4fpt more than me.

Does anyone have an explanation? Why would i have higher HP's and lower torque?

Pipe lenght can change torq numbers.

My 05 was putting out 75 hp 97 ftp, my new 07 is putting out 75 hp 98 ftp. You won't get much over 75 hp out of a stock engine without going into it. The torque is controlled a lot by the pipes, back pressure and all the other neat things you do to it.

TROB wrote:
im trying to understand something.

When i got my bike dyno tuned, my numbers were 72.55hp and 95.59 fpt.

Now, compared to what other guys are posting, my HP's seem to be the highest i've seen, but bikes that are putting out 68-69hp are getting 3-4fpt more than me.

Does anyone have an explanation? Why would i have higher HP's and lower torque?

1700 engine vs 1600 engine, just stock, 1700's are 10hp more and 6tq than 1600's
on avg, a stage 2 produces 15% increase in hp, but not 15% in tq, with a good ported manifold add another 5% for hp

Mine though is a 1600, but also running the 42hsr w/yost power tube and a Nemesis long throat manifold, so I'm close to a 35% increase and about 12% increase in tq

slezy wrote:
Pipe lenght can change torq numbers.

oh ok, that makes sense.

thanks!

Erbman02 wrote:
thats not rich at all, cruise anywhere between 13 to 14, 14 for economy, 13 performance

I'm guessing that moving a 1/2 groove on the needle should put me about 14-14.2. And won't effect performance but will effect mpg.

TROB wrote:
im trying to understand something.

When i got my bike dyno'd, my numbers were 72.55hp and 95.59 fpt.

Now, compared to what other guys are posting, my HP's seem to be high, but bikes that are putting out 68-69hp are getting 3-4fpt more than me.

Does anyone have an explanation? Why would i have higher HP's and lower torque?

Another important thing to look at when you get your dyno chart is when and how the HP/TQ come in. What you want to see is an imediate ramp in Tq and you want it to stay high across the chart with no big drop off. The HP should be a little spike and then turn into a gradual steady upward slope. Also in the upper rpm range when the Tq is coming down off peak HP should still be going up. Mine intersects at about 3500 RPM and 95Tq/64 hp And HP peaks at 4250 rpm.

davej wrote:
Erbman02 wrote:
thats not rich at all, cruise anywhere between 13 to 14, 14 for economy, 13 performance

I'm guessing that moving a 1/2 groove on the needle should put me about 14-14.2. And won't effect performance but will effect mpg.



Well, according to the tuning manual for the HSR carbs "Poor fuel mileage is another sign of an over-rich condition. Fuel mileage is usually measured at cruising speeds (65mph on a flat windless road) where the needle is the main mixture control. Poor mileage at these speeds can be corrected by fitting a leaner needle. Raising or lowering the needle has no effect on fuel mileage below about 70mph."

Granted, this is from the HSR book, but I don't see any reason this would not hold true for stock carb. I did try this on my 42, and it certainly held tru. This is the reason why I like this carb as well, I can change the needle to a richer one, and have performance across the board, but I preferred the leaner one to get my AFR closer to 14 for cruise. The richer one gives me a AFR of 13 for cruise. The part of the needle that controls cruise AFR is the straight portion just above the taper, by lowering it, that part will stay in the cruise portion to a higher rate of speed, but since the diameter is the same fuel flow will stay the same. The difference between each needle is only .01, such a very very small difference, but yet yields about 8 to 10 mpg difference, and changes AFR by approx 1 point. Too bad that there is no jet kit for stock carbs that offer this type of needle changes, would make a huge difference for tuning options. Thats why I've said before, the stock carb is more of a balancing act to get each ckt dialed in