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Non-modified Spree Top Speed

Posted: Wed Sep 02, 2020 4:08 pm
by 52north
I've got an 84 Spree restored to factory condition. New piston and rings, original exhaust (cleaned), original final drive gearing, carburetor and airbox. I weigh around 175lbs and it tops out at 25 mph. It is not an Iowa Spree. It starts easily and runs smoothly at idle, mid and wide open throttle. #68 main jet. No bogging at any point. I don't want to modify the scooter other than maybe installing a 1/2"x24" drive belt. I'm looking for any tips on how to get this Spree running efficiently so I can reach 30 mph.

Re: Non-modified Spree Top Speed

Posted: Wed Sep 02, 2020 4:30 pm
by bonesv
52north wrote: Wed Sep 02, 2020 4:08 pm I've got an 84 Spree restored to factory condition. New piston and rings, original exhaust (cleaned), original final drive gearing, carburetor and airbox. I weigh around 175lbs and it tops out at 25 mph. It is not an Iowa Spree. It starts easily and runs smoothly at idle, mid and wide open throttle. #68 main jet. No bogging at any point. I don't want to modify the scooter other than maybe installing a 1/2"x24" drive belt. I'm looking for any tips on how to get this Spree running efficiently so I can reach 30 mph.
How many miles on the new bore?

Re: Non-modified Spree Top Speed

Posted: Wed Sep 02, 2020 5:36 pm
by 52north
Cylinder was in good shape so I only honed it. Probably only 5 miles on it since rebuild.

Re: Non-modified Spree Top Speed

Posted: Wed Sep 02, 2020 8:45 pm
by Meatball
I would run a compression test after the hone/ring job to see what the bore is doing before I look to other areas.

Re: Non-modified Spree Top Speed

Posted: Thu Sep 03, 2020 12:36 am
by 52north
Compression is definitely low at 100 psi.

Re: Non-modified Spree Top Speed

Posted: Thu Sep 03, 2020 1:52 am
by bonesv
52north wrote: Thu Sep 03, 2020 12:36 am Compression is definitely low at 100 psi.
There's part of your top speed problem........of course the belt width being within spec is the other part. The piston rings have to be properly seated to achieve best compression.

Re: Non-modified Spree Top Speed

Posted: Thu Sep 03, 2020 3:37 am
by Meatball
Not sure where you got your rings from. Theres alot of junk kits on the market. Below is a the only kit I would use to refresh a spree. Pretty cheap too!

https://www.ebay.com/itm/Honda-Spree-NQ ... Sw~4hb1LMv

Re: Non-modified Spree Top Speed

Posted: Thu Sep 03, 2020 10:44 am
by 52north
Meatball wrote: Thu Sep 03, 2020 3:37 am Not sure where you got your rings from. Theres alot of junk kits on the market. Below is a the only kit I would use to refresh a spree. Pretty cheap too!

https://www.ebay.com/itm/Honda-Spree-NQ ... Sw~4hb1LMv
That’s the kit I have in it. The new kit did not provide an expander ring so I assumed it was not required with the new piston and rings. Are guys using their old expander ring with this kit?

Re: Non-modified Spree Top Speed

Posted: Thu Sep 03, 2020 5:08 pm
by vintagegarage
You did fine.. you just use the two rings that came with the kit, nothing more.

Re: Non-modified Spree Top Speed

Posted: Thu Sep 03, 2020 5:26 pm
by 52north
I might just pull the top end apart again to see if I can find the reason for low compression. This might also be why after a week or so of sitting I can’t start the scooter without spraying mixed fuel in the carburetor. Possibly not enough suction to suck the fuel into the cylinder.

Re: Non-modified Spree Top Speed

Posted: Thu Sep 10, 2020 1:14 pm
by 52north
I'm trying to find a cylinder with less wear. I think I need cylinder P/N 12101GK8670 but don't know if A or B will be stamped on it. Anyone know what the service manual is referring to when they talk about the A or B mark on the crankcase mating surface that needs to match the cylinder?

Re: Non-modified Spree Top Speed

Posted: Sun Sep 13, 2020 6:49 pm
by mousewheels
What the manual is saying is to look at the crankcase mating surface of the *cylinder* and note if there is an "A" or "B" mark on it.

What I found is that "A" and "B" cylinders have slightly different bores and were mated to slightly different piston diameters at time of original assembly. I think it was due to a parts selection 'binning' to optimize production yields. Thus a minor cylinder over size would be matched to a slightly larger piston. The differences in size were below the normal factory oversized piston/ring sizes of 0.25mm and 0.50mm over norm sold for 'way down the road rebuilds'

Thus if replacing a cylinder before 'rebore/rebuild' time, Honda wants the service tech to note the size, and make sure the cylinder is the optimum fit for the 'A' or 'B' sized piston that was assembled at the factory for the engine in hand.

As supporting data, Honda parts used to list A and B cylinders AND A and B pistons as replacement part options.

Link below has finer detail on sizing:
http://www.hondaspree.net/phpBB3/viewto ... 315#p87315

Re: Non-modified Spree Top Speed

Posted: Sun Sep 13, 2020 10:02 pm
by mousewheels
On the practical side - assuming your Spree has normal wear, the A or B cyl and piston match likely is no longer important. The piston will have worn, and any lower mile cylinder also has wear. Again the part size difference was not large.

You would likely get the closest fit by sourcing an oversize piston/ring set, and have your existing cylinder bored to fit.

Re: Non-modified Spree Top Speed

Posted: Mon Sep 14, 2020 11:47 am
by 52north
Thanks for the explanation mousewheels.