Before 255's are installed, SHOW ME WHY NOT ,,
#11
02-03-2010 | 11:43 PM
Extreme HDF Member
George, in view of the fact that you have an '09 with lower (higher numerical) gearing than '07 and '08 Touring models, the SE-255's may have less appeal for you than owners of the earlier models who have installed those cams.
The lower gearing multiplies torque faster on your bike than the older models. Baker Transmission has an explanation of this mechanical advantage to explain the benefit of going to a lower than stock gearing by changing the compensator sprocket:
http://www.bakerdrivetrain.com/drive...-sprockets.htm
I mention the gearing difference because the dyno sheet comparison won't provide a valid comparison to how that cam will accelerate your bike compared to an older 96" six-speed Touring model with the same cams, SE 255's or others for that matter.
HQ-525 cams were introduced specifically to take advantage of the lower gearing of the '09 and '10 models. With the later closing intake valve, the torque band is moved farther to the right than would be the case with the SE 255 cams.
Good luck with your research.
Edit: This post is NOT to say why you should not install the SE 255 cams. Frankly, since you have them already it's unlikely that you'd spend $300 to buy different cams IMO. However, the different gearing in the '09-'10 Touring models may be relevant to you and others in their cam choice.
Edit 2: If you use the BigBoyz website information, the '09-'10 has a 3% mechanical advantage over the '07-08 based on the lower (higher numerical) gearing. In essence, and all else being equal, the stock '09-'10 will ride as if it has 3% more torque than an '07 or '08, at least in the riding ranges most use. Due to gearing, the newer models' top speed will be 3% less than the older models'.
http://www.bigboyzcycles.com/Gearratio.htm
The lower gearing multiplies torque faster on your bike than the older models. Baker Transmission has an explanation of this mechanical advantage to explain the benefit of going to a lower than stock gearing by changing the compensator sprocket:
http://www.bakerdrivetrain.com/drive...-sprockets.htm
I mention the gearing difference because the dyno sheet comparison won't provide a valid comparison to how that cam will accelerate your bike compared to an older 96" six-speed Touring model with the same cams, SE 255's or others for that matter.
HQ-525 cams were introduced specifically to take advantage of the lower gearing of the '09 and '10 models. With the later closing intake valve, the torque band is moved farther to the right than would be the case with the SE 255 cams.
Good luck with your research.
Edit: This post is NOT to say why you should not install the SE 255 cams. Frankly, since you have them already it's unlikely that you'd spend $300 to buy different cams IMO. However, the different gearing in the '09-'10 Touring models may be relevant to you and others in their cam choice.
Edit 2: If you use the BigBoyz website information, the '09-'10 has a 3% mechanical advantage over the '07-08 based on the lower (higher numerical) gearing. In essence, and all else being equal, the stock '09-'10 will ride as if it has 3% more torque than an '07 or '08, at least in the riding ranges most use. Due to gearing, the newer models' top speed will be 3% less than the older models'.
http://www.bigboyzcycles.com/Gearratio.htm
Last edited by Harleypingman; 02-04-2010 at 11:50 AM.
#13
02-04-2010 | 07:22 AM
#16
02-04-2010 | 05:31 PM
Extreme HDF Member
The TW54H isn't theoretically a bolt-in cam, as Andrews claims it needs "hi-lift" springs. OTOH, with a .555" lift, only .05" more than the SE255 which is a true bolt-in cam, there may be no problems. Some claim you can go as far as .575" with the stock beehive springs. That said, the 42° intake close spec would likely lead to a decrease in low-end TQ in a stock engine.
Last edited by iclick; 02-04-2010 at 05:36 PM.
#17
02-04-2010 | 07:12 PM
#18
02-04-2010 | 07:18 PM
It's a straight forward job if you take your time.
