Back into Sprees and looking to build.....

Mattedroom · Post by **Mattedroom** » Tue Jul 15, 2008 10:04 pm

First of all I have to say that it's great to see that there are still guys building these bikes. I was really, really into them back in 1992-1995 (I was 12-15 years old) and I just bought an 86 Spree.

Now that I am sort of grown up, I really want to make one fly. I know, Dio motor conversion is the way to go. But I don't want to go that route. I swear, back in the day, we had Sprees going 40mph without pulley mods. Only gear type mod was the 2.75 tire.

So far I have done the pulley mod (.09 off, a .5 belt with a little more length) and cleaned the muffler. I get it up to about 35 max. I plan on doing all the porting and milling the head soon enough, maybe the 2.75 tire trick.

I used to pull the air fuel mixture screw out and get more mph, but on this bike, it boggs to death, then I can't start it. What the heck? I also never see any of you mention doing this. We did it on several bikes back then and it always seemed to work. Could it be the crappy custom air filter that is in the bike? Something seems wrong.

Also, my family owns a machine shop. I have just about every tool needed to go crazy on this little motor. I can remember milling the head and not really thinking that it did anything, but I hear 5mph increase? But anyways, is there anything cool that I could make or alter, gears, pulleys, shafts, (crank is just to much a PITA to make) that could be a huge benefit?

I would like this bike to go about 45mph and not be too terrible off the line. And yes, in time I will do up a Dio motor, most likely on an Elite for fun. But as for now I want to re-live the Spree stuff.

I think I can hit 40mph easy, but 45 is pushing while keeping some low end power.

Thanks everybody for reading this long post.

Kenny_McCormic · Post by **Kenny_McCormic** » Tue Jul 15, 2008 10:23 pm

Do a plug chop to see where you are running, pulling off the air screw leans out the pilot jet (VERY BAD).

Mattedroom · Post by **Mattedroom** » Tue Jul 15, 2008 10:31 pm

I looked at the plug when I first got the moped. It was carbed up a little and I cleaned it.

I'll leave the screw alone. It runs fine when I put the screw back in. I am just trying to milk it for every little mph. (1 and 7/8 turns out)

Kenny_McCormic · Post by **Kenny_McCormic** » Tue Jul 15, 2008 10:33 pm

Lean is mean, mean on power but it tends to melt pistons.

keithw · Post by **keithw** » Wed Jul 16, 2008 1:06 pm

Dig into the tech section and build a tuned pipe. I used the calculator there and it came out great. I did lengthen the mid section about an inch. Rolling the cones and doing the welding is a bit fiddly but not horrible. Check my other posts for pictures of my pipe.

I milled the head on mine. Seemed to give it more low end but didn't do much for the top.

keithw

Post by **noiseguy** » Wed Jul 16, 2008 4:03 pm

Milling the head helped a lot on mine. Here's what I'd do on a stock engine based on my current understanding. I've done a few of these but not all:

1) Pulley mod

2) Clean up the exhaust port and clearance stock intake

3) Mill an '84 or '85 head to minimum clearance on a domed Honda replacement piston

4) SB50 manifold and reed set with early Elite carb

5) Experiment with tuned pipe

6) There's a 12T rear pinion gear in many cases. Check yours and swap out the 12T with 13T.

7) Look at making a full 25mm exhaust downpipe (current is 19mm and too small for 50cc, IMHO)

7) Experiment with raising exhaust port a little bit (1 or 2 mm to start)

8 ) An aftermarket '87-93 Elite jug and piston can be made to work with machining. It's about 5mm too tall currently.

Greg at uspmale@yahoo.com can supply some of this. Read up in tech docs on rest. Post back with your results; I'm interested in what you find out.

Mattedroom · Post by **Mattedroom** » Wed Jul 16, 2008 4:04 pm

I was thinking more along the lines of altering a Variator to fit on a Spree. Something like that. I don't think that a custom muffler will do much for me. I could machine a new larger piston, bore out and hone the cylinder. But then I have to really mess with the engine case for clearances.

Is there no way possible to fit a Variator on a Spree? Is the Inner diameter of the Variator too big for the crank shaft on a spree? Or is the transmission case just too small?

What's up with a Variator and a Spree?

Post by **noiseguy** » Wed Jul 16, 2008 4:05 pm

keithw wrote:DI did lengthen the mid section about an inch. Rolling the cones and doing the welding is a bit fiddly but not horrible. Check my other posts for pictures of my pipe.
keithw

You can save time on this if you buy a pocket-bike pipe off Ebay and modify it to fit. I used to make this pipe and that's what I did. Saves a *lot* of time.

A custom muffler is actually the best mod, b/c it allows you to pull up max RPM from around 8000 to around 11000.

Mattedroom · Post by **Mattedroom** » Wed Jul 16, 2008 4:38 pm

7) Experiment with raising exhaust port a little bit (1 or 2 mm to start)

I am not really sure about what you mean. The exhaust port that bolts up to the muffler, right? Move it up? Is this a grind away material thing, or is it an add a gasket (or thin metal) between the cylinder and casing.

burnt_toast · Post by **burnt_toast** » Wed Jul 16, 2008 4:54 pm

Mattedroom wrote:7) Experiment with raising exhaust port a little bit (1 or 2 mm to start)

I am not really sure about what you mean. The exhaust port that bolts up to the muffler, right? Move it up? Is this a grind away material thing, or is it an add a gasket (or thin metal) between the cylinder and casing.

there is exhaust boost port on inside of cyl, slightly raising it helps.

I agree with tuned pipe, that would net you best gains if done right.

no way to fit vari.. you would have to completely alter the pulley config and do some major machining

if you want to avoid the hassle and dio swap, install 9:1 gears and keep the rest stock and ride at 45-50mph easy getting 80mpg imo. but sometimes the hassle is half the fun so you decide

Mattedroom · Post by **Mattedroom** » Wed Jul 16, 2008 8:23 pm

Looks like the pipe is the way to go huh. So I cleaned mine for no good reason. I'll look into the pocket bike thing.

I am going to yank the motor soon and get everything going. I also need to paint this thing. It was red, and someone did the black half * job on it. It looks like crap.

That sucks about the vari. I have several cnc mills that I would love to use on this bike. But I have no clue what to make or do. I would also like to make a couple of something and sell them to whoever needs whatever.

Thanks, I will post back once I have accomplished something.

keithw · Post by **keithw** » Wed Jul 16, 2008 9:07 pm

With a CNC you should be able to make fixed front pulleys any size you want. Or a nice adjustable one with spacers like the early bug generator pulleys. For maximim speed you need to balance two things, engine rpm and gearing. You want the gearing just steep enough that you can just reach the engines peak rpm. Geared too steep and the engine won't get up to full power. Too shallow and the engine will turn really fast but you won't have any speed. What I'm doing is working on one then the other. First I made enough power to turn the engine to 11,000 rpm. Then pushed the rpm down with steeper gearing. This increased the speed. Then went looking for more power. Keep pushing the power up and the gearing to match. Having a good adjustable pulley will allow the gearing to be easily dialed in.

I went with making my own pipe from scratch to make sure it was correct for my engine. Taking one for another engine and adapting it should be better than stock but not necessarily the best. For head pipes I'm using 3/4" electrical emt. It's a pain to get the bent tight enough but the diameter is bigger than the stock pipe and matches the port fairly well. If I was going to adapt a pipe I would run the calculator to see what it thinks a good pipe would be then try to match it as closely as possible. Total length is critical. The tuned length varies about 500 rpm per inch. A couple of inches can make a big differance.

For those of us that want to make pipes, having prefabed flanges that bolt to the head would be great. Make the hole in the center stock size so you could either go with the stock size or open it up for larger pipe. Should be pretty simple to copy a stock one from the original pipe. If the price was reasonable I'd buy half a dozen. Cutting my own by hand is getting real old real fast.

Back when my friend was riding a dyno and designing tuned pipes they would get pipes from all the other makers for test. Some of the high dollar, nice looking pipes actually made less power than stock.

keithw

Kenny_McCormic · Post by **Kenny_McCormic** » Wed Jul 16, 2008 9:23 pm

What part of the bore kit is 5mm too tall? Would a 5mm bottom gasket fix this?

jstone · Post by **jstone** » Thu Jul 17, 2008 12:12 am

I think noiseguy needs to go back into production of his pipes

. I would buy one.

maddog · Post by **maddog** » Thu Jul 17, 2008 5:50 am

REMEMBER, when you install a bore kit on a spree you must convert that h.p. to the rear end in order to gain speed= you are building nothing but a blown engine! think before you build!!!!