Big Bore Installation Guide

[85spreeelite]

You will need the following tools:
 
ratchet set with 8mm, 10mm, 12mm, 14mm sockets
screwdriver phillips head and flat head
needlenose pliers 
 
you will need to take your seat off and then the rear rack followed by the plastic faring.
 
take exhaust off followed by the fan and engine shroud (plastic covers for the cooling fan and the engine)
 
take spark plug out
 
take cylinder head off using 10mm socket (4 bolts)
 
tap cylinder gently and remove cylinder.  simply lift it straight up and off piston.
 
take needlenose pliers and remove c-clip on left side of piston.  take something rather pointy and tap out piston pin from the other side so that it also comes out from the left side.
 
remove piston
 
place a rag into engine case by the crank so that nothing falls into it.
 
scrape any old gasket material off the engine case to make way for the new polini base gasket.
 
you can either place the piston rings onto the piston while off the connecting rod or after you place the piston onto the connecting rod.  this is up to you.  whatever is easier.  REMERBER THAT CHROME PISTON RING SITS ON TOP WHILE CAST IRON RING SITS BELOW.
 
VERY IMPORTANT-  ARROW ON TOP OF PISTON FACES TOWARD THE EXHAUST PORT (FORWARD PART OF CYLINDER)
 
place new c clip onto right side of piston using needlenose plier
 
make sure piston pin bearing is place (top of connecting rod)
 
place piston (with arrow facing forward towards exhaust port) on top of connecting rod while at the same time sliding the piston pin in from the left side to connect it to the connecting rod.  slide it all the way in and then place new c-clip onto left side of piston to secure the piston in place. make sure you have a rag inside the engine case just in case you drop something it will not go too far into engine.
 
make absolutely certain that both c-clips are securely in place to secure piston.  if c-clips come loose they will damage both the cylinder and piston.
 
place base gasket onto bottom of cylinder (you do not need any gasket sealer) you can use name brand Gaskasinch to help hold gasket into place if needed.
 
locate channel guides within piston ring grooves and slide piston rings into place.  squeeze them into place while gently sliding cylinder down over the piston (be sure that exhaust port faces forward)
 
while holding one hand over top of cylinder, use the other hand to turn the cooling fan.  observe how freely the piston goes up and down.  it should slide relatively easily.
 
clean top of cylinder off.  place head gasket on top (again, no gasket sealer is needed).  place cylinder head over and slide cylinder bolts into place.  hand tighten all 4 bolts.  then use ratchet to secure bolts into place (tightening each a little at a time).  I dont remember the foot pounds of torque but if you are using the 1/4 drive ratchet you tighten until you can not tighten any more (within reason)
if you are not sure you could contact your local motorcycle/scooter dealer for instructions on how much to tighten the bolts. 
 
replace the spark plug
 
replace the exhaust
 
replace the fan and engine shrouds
 
before putting the side faring and seat back on, start up and test drive.  dont go too fast. you just want to make sure you put it all back together correctly.  be sure to break it in properly for 200-300 miles before you go all out.
 
during break-in you may want to place a capful of excellent quality 2 stroke oil into the gas tank.  This is of course in addition to the excellent quality 2 stroke oil you put into the oil reservoir.  you can pick up this oil at your local motorcycle or scooter dealership.
 
The 70cc kit may or may not come with a jet ( I dont remember).  if it does, it may or may not fit your carb.  the polini cylinder kit is a universal kit designed to fit many different scooters.    you can also get a jet drill kit to increase the size of your factory jet in the event the jet in the kit does not fit.
I recommend you do this.  you see, having a bigger jet gives your cylinder more protection as it feeds it with more fuel/oil.
 
check how good your air/fuel mixture is by checking your spark plug after a high speed full throttle run.  color of plug should be a nice chocolate brown.  this is very important.  any signs of white color on the spark plug indicates you are running too lean.  if you go too long like this you will damage your cylinder.  solution: increase jet size until you are running a nice chocolate brown.
 
hope this helps.
 
good luck

[MySpree]

uhh have you looked iin the tec docs... i have one liek that with pics but it doenst say anything about upjetting.... so shweet! i jsut say up jet.... i dont say about the plug color...

[hrnytrtlsgsxr]

you fail to mention that they have the jet sizes with airbox or not in the packaging so it's a no brainer.Also i use two stroke oil and lube the cylinder a little before installing it over the piston. That's so if you want to do a compression test it will be more accurate to a wet test.

[noiseguy]

Did you get your kit running? I thought the kit includes size 90 and 100 jets for tuning.

[darat]

yeah i am running a 87 main jet..

[MySpree]

darat is it finally jetted rigth or do u still needs jets?

[85spreeelite]

I am still waiting on the carbs I bought from greg. They should be here this week, and when he called he said that its being rebuilt as we speak.


So let me get this right....A 87 SE50 is a dio?

[noiseguy]

No.

[darat]

no it is a dio based engine. i wish it was a dio wow i could have some fun.

[fizzle]

do they sell big bore kits for sprees?

[85spreeelite]

* NAW!