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how to make an iowa spree run over 25
Posted: Fri Apr 03, 2009 4:34 pm
by forewheelerdude
so i got a 1986 spree (iowa). i have tried to find documents on here describing the difference between iowa and a non iowa spree but i could not find much. i heard that there was some kind of restrictor washer in the exaust some where? idk but i drilled through two baffels in the exaust and i got nothing out of top speed, still 25. i was wondering if anyone knew how i could get it to go above 25. (besides driving down a hill)
Posted: Fri Apr 03, 2009 4:52 pm
by bradthreee
I dont know for sure but I think that the restriction is the muffler itself. You should get an unrestricted muffler off of another spree non iowa model.
Maybe someone else can chime in.....
Posted: Fri Apr 03, 2009 5:14 pm
by devenex
The washer is in the opening that goes to the motor, so you have to take it off to derestrict.
Drilling the baffles will only help after the the motor is derestricted.
Posted: Fri Apr 03, 2009 7:09 pm
by Kenny_McCormic
Iowa differences, IIRC according to the service manual the muffler is less efficient design(less power), the rear end gearing is different, I think they may have changed the compression ratio as well, check the service manual spec lists.
Posted: Fri Apr 03, 2009 10:36 pm
by noiseguy
Iowa has a washer in the muffler. That's the most obvious bit. There are also some slight changes in porting.
Check muffler for washer in header pipe. To get to 30 MPH, next step is to machine down the head to a .020" piston / head running clearance and modify pulley per Adv Tech Docs. Much over 30 and you should buy a new scoot.
Posted: Sat Apr 04, 2009 3:12 pm
by mousewheels
The 'slower' gearing is the same ratio as all 84-85 sprees. But for 86/87 some got a lower reduction. Made a table from service manuals.
Posted: Sat Apr 04, 2009 3:19 pm
by evilone
I don't have a Spree but that's some good info.
Posted: Sun Apr 05, 2009 12:02 am
by mousewheels
I don't have a Spree but that's some good info.
Thank evilone, If by chance the double reduction gear ratios will help here they are. I posted this into a gear thread by Wheelman awhile back
Posted: Sun Apr 05, 2009 12:41 am
by Kenny_McCormic
The easiest way to make a Iowa do over 25 is to put it in the back of a truck
Posted: Sun Apr 05, 2009 12:50 am
by chevyguyjay
first pic is a iowa muffler. the other is a 87 muffler. the 87 is the best for stock mufflers. notice the bigger pipe as it goes to the muffler itself. 
Posted: Sun Apr 05, 2009 8:04 pm
by toboggan
Will the '87 mufflers fit on an '86?
Posted: Sun Apr 05, 2009 8:21 pm
by Kenny_McCormic
All spree mufflers interchange. Only parts that differ is the 87 body and the 84/85 and 86/87 cranks/cases dont interchange. Gearing is different in the 84/85, reeds are smaller in the 84/85, piston/head is different in the 84/85, some minor wiring differences(early and late fuel gauge senders are different). But everything excluding the cranks and tank senders fits all years.
Posted: Sun Apr 05, 2009 8:25 pm
by toboggan
Alright, thank you!
Posted: Mon Apr 06, 2009 7:20 pm
by forewheelerdude
thanks for all the info. GREATLY appreciated! also one more question about the differences between the 85 and 86 heads- i was wondering since i already shaved .020 off my 85 spree if the whole sleeve head and piston would fit on my 86 spree?
Posted: Mon Apr 06, 2009 8:20 pm
by noiseguy
forewheelerdude wrote:thanks for all the info. GREATLY appreciated! also one more question about the differences between the 85 and 86 heads- i was wondering since i already shaved .020 off my 85 spree if the whole sleeve head and piston would fit on my 86 spree?
Yes, they interchange.
Also, I have one last speed pipe (expansion chamber) for the Spree, which should get you some more top end. See the For Sale section for details.