Pulley mod: 84/85 vs. 86/87 Spree
Posted: Mon Aug 29, 2005 10:31 pm
Vette had pointed this out before. Don't know why I didn't pick up on it. I modded my pulley (far right) to the largest diameter. Mine's an '84, I believe '85 uses the same pulley:
The pulley in the center is used on 86/87 Spree and the SB50. If you go to the Honda dealership and get a drive face pulley, this is what you get regardless of year, for about $10 brand new.
The center pulley is much more mod-able. It's larger in diameter and can thus run a taller ratio in front. On the old drive pulley (right) I could only shave .03" from the face before running out of belt. I can remove .125 from the newer pulley before running out of belt. This is how guys build 40 MPH Spree. I'm going to have .10" shaved at work and try it out.
I realize that .03" doesn't sound like much, but this is enough on these scoots to increase top speed by about 3 MPH, so .10" should increase top speed by almost 10 MPH.
The other big difference between 84/85 Spree and 86/87 is the flat-top piston used in the later models, which is superior to the dished earlier version. The dished piston also limits how much you can shave from the head. I may be removing that next to replace with the newer style.
The pulley in the center is used on 86/87 Spree and the SB50. If you go to the Honda dealership and get a drive face pulley, this is what you get regardless of year, for about $10 brand new.
The center pulley is much more mod-able. It's larger in diameter and can thus run a taller ratio in front. On the old drive pulley (right) I could only shave .03" from the face before running out of belt. I can remove .125 from the newer pulley before running out of belt. This is how guys build 40 MPH Spree. I'm going to have .10" shaved at work and try it out.
I realize that .03" doesn't sound like much, but this is enough on these scoots to increase top speed by about 3 MPH, so .10" should increase top speed by almost 10 MPH.
The other big difference between 84/85 Spree and 86/87 is the flat-top piston used in the later models, which is superior to the dished earlier version. The dished piston also limits how much you can shave from the head. I may be removing that next to replace with the newer style.