Pulley mod: 84/85 vs. 86/87 Spree

Post by **noiseguy** » 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.

spreeman · Post by **spreeman** » Tue Aug 30, 2005 8:38 pm

i love the idea, post later and tell us how it worked

MySpree · Post by **MySpree** » Wed Aug 31, 2005 12:29 am

if it works do you think i could send u my pully so u can shave for me? ill py you.

vette76 · Post by **vette76** » Wed Aug 31, 2005 12:41 am

um u have an 85 rite?
needs to be an 86-87
u can do it slightly less precise with a grinder.lol

deathwish · Post by **deathwish** » Wed Aug 31, 2005 10:19 am

i want to do this to mine to but i have no clue where to shave......

vette76 · Post by **vette76** » Wed Aug 31, 2005 2:33 pm

noiseguy, i dont know if it will fit but the sb pulley is MUCH bigger then even the center pulley. i can measure it if u would like.

Post by **noiseguy** » Wed Aug 31, 2005 4:31 pm

I think I've got measurement that you sent. It's about 3" diameter. I'm just not sure it would fit the Spree cases. The center pulley is about 2.55" in diameter. I'll take a pic of the thing assembled when I get it back together.

I pulled .10" off the pulley, and reduced the idle to a bare minimum; otherwise it trys to turn the rear wheel. Launch is obviously slower, but the kicker is that it just doesn't have the juice to push past 30 MPH with the setup. The engine is trying, but not getting there.

I'm going to play with my little pile of jets and the tuned pipe to see what I can get. I need to run down some heavier clutch springs to try to compensate for the pulley mod. And a 1" longer belt might be good to find too.

Otherwise, I need to run down a larger piston to push the crank a little harder. Just switching to a 41mm flat-top piston from a later Spree would probably help, though. I'd love to find a 43 or 45mm piston to swap in.

Also, I'm wondering if the carb design isn't the reason for the crummy response I get with the K&N. The '86/87 carb is different than the earlier one, and I'm wondering if that isn't part of the problem.

MySpree · Post by **MySpree** » Wed Aug 31, 2005 5:11 pm

i have the middle gold one... i have said many tomes on this site my spree is a mix mached engine!!!! its 86 parts and 85 parts!!!!!! and yea

vette76 · Post by **vette76** » Wed Aug 31, 2005 5:12 pm

well soooorrry,lol

MySpree · Post by **MySpree** » Wed Aug 31, 2005 5:17 pm

haha i dont have a flat top piston hahah mines brand new and it came like a hemi!! i have massive accel and massive speed!!! if i hold both brakes and if i hold the scooter with my feet it still wants to creep for ward!!! idk why. after i got the newtop end and carb it is awsome... i have a jet that was made my my freind and its awsome!!

vette76 · Post by **vette76** » Wed Aug 31, 2005 7:05 pm

a hemi goes by the head. a flat top = more compression.

MySpree · Post by **MySpree** » Fri Sep 02, 2005 10:07 pm

ok so how was your spree? faster but no low end?

vette76 · Post by **vette76** » Fri Sep 02, 2005 11:21 pm

from what i remember when i had both my 84 an 87 running at the same time they were both as fast. the 87 got there quicker tho.

Post by **noiseguy** » Sat Sep 03, 2005 12:01 pm

They all have a sort-of hemi combustion chamber. Maybe you meant that you got a domed piston?

MySpree · Post by **MySpree** » Sat Sep 03, 2005 5:49 pm

no like a hemi! it was a little more i had a choce between 2 and i took the more expensive one. and what differencs did you see when modding the pully!