Honda Spree and Elite 50 Forums

I was reading in the wiki about swapping the head off an 84-85 spree onto a later model for a bit higher compression. I have an 84 parts bike, so I'm thinking of giving this a shot. What size jet would be recomended for this swap? Thinking of maybe shaving around .010 off also.

Not really sure you need to upjet.

Do run premium fuel if compression goes past 140psi

I agree with TJ. Jetting should not be an issue.

Thanks for the help guys! It definately check compression once the head goes on. I'll update this thread if this ends up working out!

shane_lxi wrote:Thanks for the help guys! It definately check compression once the head goes on. I'll update this thread if this ends up working out!

Oh it works alright

I don't think you have to shave .010 off of the head though

I was under the impression that you shaved the '86-'87 head .020" and just swapped on the '84-'85 head. no shaving required.

Awesome, even better if I dont have to take a trip to the machine shop. Thanks alot guys! Ordered my headgasket today, so as soon as that get's here, I'll pop the '84 head on there and try it out . I love freebies!

shane_lxi wrote:Awesome, even better if I dont have to take a trip to the machine shop. Thanks alot guys! Ordered my headgasket today, so as soon as that get's here, I'll pop the '84 head on there and try it out . I love freebies!

My friends 1987 spree had a compression reading of 125psi.

Swapped to a 1985 head and the reading was 150psi

Any problems with rings or anything after the swap? That's a pretty big jump in compression.

shane_lxi wrote:Any problems with rings or anything after the swap? That's a pretty big jump in compression.

Belt and clutch slippage from the newly added power was the only issue.

That much more power gain eh? I put ax24 vbelts in our bikes today, and lost 2mph off the topend for some reason, so I put our stock belts back in. Sooo, if I slip, I'll try and get a new oem belt. I don't think my clutch will slip @1200miles, but who knows til I'm there .

ps: ax24's are supposed to be 1/2"x24" right? My Gates ax24's are 1/2"x26", not sure if maybe that's the cause of power loss or not?

shane_lxi wrote:That much more power gain eh? I put ax24 vbelts in our bikes today, and lost 2mph off the topend for some reason, so I put our stock belts back in. Sooo, if I slip, I'll try and get a new oem belt. I don't think my clutch will slip @1200miles, but who knows til I'm there .

ps: ax24's are supposed to be 1/2"x24" right? My Gates ax24's are 1/2"x26", not sure if maybe that's the cause of power loss or not?

Did you measure the inside or the outside?

I didn't measure, package was labeled 26", prolly outside, but it is noticably bigger diameter than stock.

The stock Spree belt is 24.7244" X 0.4488", so a 26" belt is only 1 1/4" bigger for the pulley mod.

i have a sb50p and if i do pully mod by putting a se50p clutch in it and cutting the case will i need a longer belt and how much do i mill down the front inner pully

Bear45-70 wrote:The stock Spree belt is 24.7244" X 0.4488", so a 26" belt is only 1 1/4" bigger for the pulley mod.