as i was reading on here

[odinxxix]

i was reading on here someplace that noiseyguy pointed out differences in the 84/85 & 86/87 heads and pistons, it also stated that guys were getting good performace by putting 84/85 heads on their 86/87 sprees what kind of performace are we talking about? i know this will raise compression, but will we get higher top speed, better take offs,better power band, or all the above? i have a 1986 that runs great but if i can get better all the above by just bolting on a head from 84/85 im down for that.!! is that all that needs done or is there other mods that need done before boltin it on? thanks for the input

[jesse8931]

is your spree stock ? if so probaly not much

[Bear45-70]

The high compression head need to be milled .020" to really be effective. Top speed difference will be maybe 1 mph but the torque increase should make a noticeable improvement in you acceleration.

Then again, the '86-'87 head has a better combustion chamber shape for producing power to it and you could be better off just checking your piston to head clearance and cutting the head and jug accordingly. At least that is the route I'm taking. I am not gonna use my '85 head, but a domed piston and cutting an '86 head to go on my '85 engine. Mainly because I think the '86 head is that much better than the '84-'85 head. With the domed piston and the cut head I will still have upped the compression and still have the better head.

Oh and the use of "high" along with compression is relative to a 2 stroke scooter that started out at 7.2 to 1, so an increase to even 8 to 1 is high compression relative to the original low number. Oh and premium fuel is not required with the new high compression as you need 9 or 9.5 to 1 before that becomes necessary. In 4 strokes high compression is now anything over 9.5 to 1, back in the '60s 10 to 1 was standard in a lot of engines and high compression was 10.5 or 11.0 to 1 or better.

[odinxxix]

yes mine is completly stock im not going to do any mods, i happy with it doing 32-35, but the thought of boltiong on the older head with out to much work for possible speed upgrade sounded good, or even faster take off it just sounded good and just wanted to know if thats how it worked o yea mine is a 1986 so i have the domed piston set up already. i was just wondering.

[jesse8931]

your better off to take 20 thousands off your old head

[Bear45-70]

your better off to take 20 thousands off your old head

I agree 100%. Order a head gasket, pull the head. Take it to the machinist, have .020" removed. Return home and with the new gasket and milled head, install the head. Instant higher compression and you still have the better shaped combustion chamber.

[jesse8931]

i did 20 thousands on my 84 and ported the intake and exhuast and it made more off the line power and gained 4mph then i bought the modded cdi gained 1mph so iam up to 35ish

[Bear45-70]

i did 20 thousands on my 84 and ported the intake and exhuast and it made more off the line power and gained 4mph then i bought the modded cdi gained 1mph so iam up to 35ish

I will bet the head counted for 1 mph at best.

[jesse8931]

well since i did the porting and the milling at the same time i cant say

[noiseguy]

I will bet the head counted for 1 mph at best.

I picked up about 3 MPH on an '85 Iowa with a modified head and stock piston. Top speed from 25 -> 28. Wee!

[odinxxix]

so basiclly what you all are saying is that if i mill the head .020 thousandths im just going to gain 1 mph and quicker take off. since i cant do that myself kinda seems unworth doing it for the cost. im not looking to do major mods unless the job scene picks up and i can get back to work. eventually i would like to try and put in a whole dio rear end motor and all if that can be done. ive seen peeps just swap motors and the i seen the gear swap posted. y couldnt you just pull the spree rear out and put in the dio rear? think im jumping around here better go before i ramble to much more LOL.

[Wheelman-111]

Greetings:

A Dio swap is a noble endeavor. Costly and rarely found without some luck.

Among the Dio and other variated scooters' advantages are the dual reduction gears and the constant velocity transmission, both of which the Spree lacks. The parts don't cross-fit.

Maintaining a more stock configuration has its rewards too. The affordable big 44mm bore kit, some challenges in the intake & exhaust, a bigger rear tire and perhaps the taller '87 gears put a respectable 40 MPH within reach. Something to consider if you can't find or afford to... Wait for it:

Dude! Swap in a Dio!!

[odinxxix]

Wheelman lol thats good, anyway are you talking 87 spree gears? and im looking for a dio but dout i find it, ive check salvage yards and talking to people around here to see if maybe they have one thats been wrecked but no luck yet, maybe in my future will be the 44mm big bore then lots or reading on how to manage the intake and exhaust ports and new muff..


edit: ? will i also have to shave head with the 44mm big bore? just want to get all my ducks in a row before i decide to start this project when the money camoe available.

[chevyguyjay]

my advice if u do go with a shaved head, stick with the 84-85 head. they have a more closed chamber than the 86-87 head.

[Bear45-70]

my advice if u do go with a shaved head, stick with the 84-85 head. they have a more closed chamber than the 86-87 head.

True the chamber is smaller on the '85 and earlierhead because of the dished piston it was used with. But it is a know fact that the '86 and newer head is a better design than the earlier head, producing more power.