air/fuel ratio

[beast30]

Well I had my 00' husky on the dyno a few weeks back, I wasn't really impressed with the numbers thats for sure. 91 Hp and 102 tq, which from last year drop almost 10hp and 15 tq........The only thing different from a year ago was i installed those big city thunder baffles, perhaps not the best decision I've made, but what the hell.


So I'm planning on chopping the orginal baffles a few inches and going back with those. My question is that (hopefully i can get the attachment to post) my air/ fuel ratio isn't to bad off but was thinking of upping 1 intermediate jet size to compensate for the lean condition between 3000-4000 rpm. I don't have a tch on my bike but in 3rd gear going about 35MPH it seems to miss alittle. Everything checks out on the carb, clean and no intake leak. Currently have V&H big shots 2/2 exhaust with a .295 inter and a 68 main.

The other thing I went to adjust my idle today and check the position of my accell pump. I ended counting the full turns in on the accell pump adjustment and found it to be at least 5-6 turns out from lightly seated. I know for a fact that I didn't adjust it out that far a few months back. The screw was so loose it almost popped out (no spring tension). So I adjusted out 2 turns and it seems to be good went out for a ride afterwards.

 

[Raywood]

That's a great looking fuel/air mixture. Between 13-1/14-1 is right in the zone.
Changing your intermediate jet won't alter you mixture much between 3-4000. If you really want to adjust something it would be the airbleed but your line looks great to me.

:2thumbs: :2thumbs: :2thumbs:

 

[alhall88]

I agree with ray, looks good. I have an 02 bung and an air/fuel meter that I can ride with and monitor the readings and the best results I've found is when I target the 2000 to 4000 rpm band. It does go a little lean up top but really I don't spend alot of time there so there isn't going to be any engine damage. Now if I was a drag racer my thinking would be different.

 

[dogvet]

68 main isn't big enough. Go up to 70. You've lost a quite of bit of torque right in the sweet spot due to the pipes. You want it a bit rich on the top end to aid in cylinder cooling.

Just my opinion......

 

[KDF]

I agree with ray, looks good. I have an 02 bung and an air/fuel meter that I can ride with and monitor the readings and the best results I've found is when I target the 2000 to 4000 rpm band. It does go a little lean up top but really I don't spend alot of time there so there isn't going to be any engine damage. Now if I was a drag racer my thinking would be different.

What range do you spend your time in....? I tend to be right aroung 2500-3500 most often. Never below and rarely above (unless I am really on it).

KDF

 

[alhall88]

What range do you spend your time in....? I tend to be right aroung 2500-3500 most often. Never below and rarely above (unless I am really on it).

KDF

same here but there is a science to air fuel readings and although dogvet is correct its always a compromise somewhere. I'm just stating as long as I'm not running to lean on the higher rpm band I would rather have the bike running in the sweet spot where I spend most of the time.

 

[Raywood]

I would rather have the bike running in the sweet spot where I spend most of the time.

 

[Fibersnake]

Well I had my 00' husky on the dyno a few weeks back, I wasn't really impressed with the numbers thats for sure. 91 Hp and 102 tq, which from last year drop almost 10hp and 15 tq........The only thing different from a year ago was i installed those big city thunder baffles, perhaps not the best decision I've made, but what the hell.


So I'm planning on chopping the orginal baffles a few inches and going back with those. My question is that (hopefully i can get the attachment to post) my air/ fuel ratio isn't to bad off but was thinking of upping 1 intermediate jet size to compensate for the lean condition between 3000-4000 rpm. I don't have a tch on my bike but in 3rd gear going about 35MPH it seems to miss alittle. Everything checks out on the carb, clean and no intake leak. Currently have V&H big shots 2/2 exhaust with a .295 inter and a 68 main.

The other thing I went to adjust my idle today and check the position of my accell pump. I ended counting the full turns in on the accell pump adjustment and found it to be at least 5-6 turns out from lightly seated. I know for a fact that I didn't adjust it out that far a few months back. The screw was so loose it almost popped out (no spring tension). So I adjusted out 2 turns and it seems to be good went out for a ride afterwards.

Interesting chart and numbers for sure, but one item that caught my attention is that the Torque/HP chart on the upper section appears to be showing the intersect at approx 4500 RPM. If this is correct, can not understand why since the intersect point for torque/HP is 5252 RPM, did they provide any more details as to why IMHO the strange intersect lines?

 

[HDLARRY]

The reason it did not cross at 5252 RPM is that the torque and HP ranges are not the same. TQ range in 0-110 and HP is 0-100.

 

[rhinoevans]

Do i not know how to read the A/F ratio. Is the dip below the line a "rich" condition???

 

[rhinoevans]

What is you CAM size?

 

[Fibersnake]

The reason it did not cross at 5252 RPM is that the torque and HP ranges are not the same. TQ range in 0-110 and HP is 0-100.

Understand that they are different scales, however torque and HP will always intersect at 5252 RPM, no exceptions, hard rule and general if the chart shows such intersecting anywhere other than that hard number, general an indications that the dyno is not recording properly due to program is off for some unknown reason.

Also normally the torque and HP use the same scale and it is the plot lines that give the appropriate reading for each to the bar graph. Do not know why they would have two different scales and then adjust the RPM to come up with a match. So it this was not an error and the operator put a skew in as such, questions then becomes, what is the actual RPM for each of the readings and how does this relates to the cooresponding a/f ratio?

Anytime that a RPM is posted for a chart and there is an intersect of the HP and Torque it will be at 5252 and if not something is wrong. Hard rule with no exception due to how HP is cacluated (RPM * Ft Lbs /5252). There is no exception and the only time you will not see them intersect if the speed does not reach the 5252 RPM. Also Torque will be falling at the 5252 and HP will rise be rising.

With the chart posted are we to take it that the maximu torque was reached at a little above 4000 RPM and the max HP is at what appears to be 5200 RPM and then starts falling off from there? So in short which, if either graph is an accurate representation of the RPM for those readings and thus how does it correlate to the a/f ratio so that I indeed know that where my adjustments and area of concern are?

Does one make and adjustment on the carb at based on the torque scale or the hp scale is the a/f RPM scale off all together and thus one may be making adjustment for something that is actualy occuring 700-1000 rpm laters?

Do not know how the dyno and program made the chart read such, but no question on the 5252.