Big bore Spree piston?

PimpinSpree · Post by **PimpinSpree** » Sun Aug 03, 2008 8:03 pm

maddog wrote:A larger piston will do nothing unless you can change the gear ratio!

it will on a spree. A spree is a turd taking off. If im on a slight incline, mine doesn't want to go anywhere. Plus then you could do the pulley mod for a little more top end

Post by **noiseguy** » Sun Aug 03, 2008 9:58 pm

OK, so the cooling jacket is over the head and cylinder, and seals at the combustion chamber. Still wondering how the cooling pump works... it would have to be electric.

keithw · Post by **keithw** » Thu Aug 07, 2008 11:32 pm

The 3mm over piston arrived today. I had already bored the cylinder and was just waiting for the final hone to size. I opened up the exhaust port and raised it a ring width plus a little bit. The piston has no logo or makers name on it. Looks to be of reasonable quality. Had to trim the head gasket and my .020" shaved head did not clear. Went back to the stock head. Installed it on the Pal. I had the fixed tuned pipe on it and it was a bit doggy. Then I remembered that with the port raised the pipe needed to be longer. Put the adjustable pipe back on and made it longer. Upped the main jet from 80 to 85. I think the propper expression would be "oh my word". I upped the main jet to 90 and now it four strokes pretty good, just fine to break it in for a bit. Added a couple caps full of extra oil in the fuel tank. I'll run this tank of gas out then I'll see what it will do.

keithw

Post by **noiseguy** » Tue Aug 12, 2008 6:28 am

So was the performance improvement from the porting or the larger piston? I guess the larger piston would improve bottom end, with the porting helping up top.

keithw · Post by **keithw** » Tue Aug 12, 2008 9:09 am

noiseguy wrote:So was the performance improvement from the porting or the larger piston? I guess the larger piston would improve bottom end, with the porting helping up top.

That would be my guess also. The bore increase only added 10% or so to the displacment. Not really enough to make a big differance. I expect that most of the change was from the porting. Also, on this engine I already have opened up the intake manifold, derestricted the air cleaner, and have a tuned pipe. The exhaust port was pretty much the last bottle neck. I've got another cylinder that is only .5mm over with the same porting. I'll try it later.

I am currently running way rich and adding extra oil to the gas tank getting it broken in. I may have the piston just a little tight in the bore. It has soft siezed a couple of times. I pulled the cylinder and piston to take a look. There was a little scaring on the exhaust side of the piston skirt. I polished the damage off and put it back together. If it does it again I'll pull it again and hone the cylinder out another .001" or so. This piston came with no documentation so there is no telling what kind of alloy it is and how much clearance it needs.

keithw

keithw · Post by **keithw** » Tue Aug 12, 2008 11:33 pm

Got a question for those who are more experienced that I am. I'm working on getting the 3mm over piston broken it. I've got a 95 main jet in the carb and it is running way rich. The problem I'm having is that when I get going the engine will die. It isn't siezing as it is still turning over. If I back way off the gas and coast a little it will light off again without hitting the starter button. As long as I'm light on the throttle it runs fine.

I'm wondering if that with that large of a main jet I am draining the float bowl faster than fuel can flow through the float valve? I'm about ready to lean it out some and see what happens. Any ideas?

keithw

brad_659 · Post by **brad_659** » Fri Aug 15, 2008 12:24 am

Dac wrote:they have water cooled cylinder, heads, a water pump, and a Radiator.

This is a godly spree...

"homemadepowa" made this bike, its a spree, with a dio motor, thats a huge 100 something cc water cooled set up.

Not an elite, but you get the idea.

that scooter is wayy to badass...whats it top speed?

keithw · Post by **keithw** » Fri Aug 15, 2008 8:39 am

Found the fuel problem. I teed into the vacuum line going to the petcock with a vacuum gauge. At WOT there isn't enough vacuum to keep the petcock open. I'll pick up a vacuum check valve today to put in the line. I guess the derestricted air box and intake was just a little much for it.

Got the main jet at 85 and it's running pretty well. Tweeked the drive ratio some more. At 30 mph the engine is turning about 6000 rpm. That should put me pretty close to the 60 mph mark at top end. I'm glad this one has the variator.

keithw

keithw · Post by **keithw** » Fri Aug 15, 2008 9:52 pm

A vacuum check valve from the car parts store fixed the fuel feed problem. I installed it at the manifold in the vacuum line going to the petcock.

For break in I had installed the heavier weights in the variator. This made it shift about 6000 rpm limiting the engine speed. I put the lighter ones back in this afternoon. Now it shifts up at about 8000 rpm. I'll see about getting out in a few days for some speed runs. Not sure if I want to go for maximim rpms yet but it will be interesting to compare the acceleration curves with the old cylinder.

I'll try to not get too frisky and burn up the cylinder.

keithw

steffen707 · Post by **steffen707** » Wed Feb 11, 2009 12:52 pm

Dac wrote:they have water cooled cylinder, heads, a water pump, and a Radiator.

This is a godly spree...

"homemadepowa" made this bike, its a spree, with a dio motor, thats a huge 100 something cc water cooled set up.

Not an elite, but you get the idea.

What kinda headset is that? Looks AWESOME.