'97 Elite bored .25 over

[teeoce]

I picked up a '97 Elite SA50P for cheap - it had no compression. I took off the cylinder and head, and sure enough the top ring was cracked. The cylinder walls were tore up of course so I am having it bored .25 over. My first question is does .25 over mean it is going to have a .25 (1/4) of an inch larger diameter bore? So would it be correct that .25 over would bring it to 67cc?

With the bored out cylinder, can I run the stock filter and jet or should I get a larger jet and a higher flow filter? Any suggestions? And is the exhaust on the P supposed to open up one full inch with the dremmel? The previous owner tried to grind it out but it doesn't seem that large.

Also, people always talk about the idle jet being the hardest to clean. Where exactly is the idle jet?

Does anyone know what is wrong when you try to use the electric start and it just goes "click?"

Thanks for all the help.

[evilone]

No way! .25 over may be 1/4 mm not inch. .25 over will bring bore to 41mm. 65cc piston would be about 46mm. I'll leave the other questions for someone else. I only answered the .25 over size because I had to do the same thing.

[Wheelman-111]

Greetings:

Teoce says: I picked up a '97 Elite SA50P for cheap - it had no compression.
How cheap is cheap?

I took off the cylinder and head, and sure enough the top ring was cracked. The cylinder walls were tore up of course so I am having it bored .25 over.
.25 what? American and Metric systems differ. If you live in the US and your figure is accurate, then yes, your cylinder will be enlarged by a quarter of an inch in diameter. or about 6.36 mm. That would require a quite different piston and top-end gasket kit, as sold in the aftermarket. There are, in fact 46 and 47 mm pistons from the aftermarket and the displacement result is roughly 63 or 68 cc respectively. A freer-flowing intake tract will improve performance IF - * see below.

However is it possible that the machinist said .025? That's typical of a first or second "oversize" piston, often available from the manufacturer. It's not going to change the engine displacement a lot but should be enough to remove the scars from the cylinder walls. In that case, put everything back as it was.

Whichever size is selected, a good machine shop will first bolt the cylinder up in a jig and apply the same torque to the bolts as if it were being installed on the engine before boring. Otherwise, the cylinder bore will distort when it is tightened down, resulting in poor performance at best and a shortened engine life - sometimes VERY short - at worst.


With the bored out cylinder, can I run the stock filter and jet or should I get a larger jet and a higher flow filter?
*If you're getting a 46 or a 47mm piston, a size bigger main jet is a good idea. The filter and the jet are interdependent. Freer-flowing air from the intake = more air gets into the engine. Same goes for enlarging the engine size. More air needs a BIT more fuel. One or two jet sizes up. Richer does NOT mean faster, but a balanced mixture does. Lean = hotter = rapid engine failure and a long walk home. The point is, if you make a change in displacement, intake and/or exhaust restriction, you need to consider how it affects the mixture. Specific situations require more information than you've given. There's no telling the effect the P.O.'s Dremelling of the exhaust port, but I'll bet it's not good.

Also, people always talk about the idle jet being the hardest to clean. Where exactly is the idle jet?
Look in the Technical section. Find your service manual, Chapter 4: Fuel System. It sits right beside the main jet circuit.

Does anyone know what is wrong when you try to use the electric start and it just goes "click?"
From my own experience with about 30 different vehicles, the cause is a weak battery 95% of the time. If you;re lucky it might be a moldy connection. Old, poorly-maintained batteries go bad and can no longer hold a charge. Jump it with another vehicle and I've got 50 cents that says it will spin over, presuming your piston isn't smeared on the cylinder wall.

Hope this helps.

[Kenny_McCormic]

Honda overbore pistons are in MM. .25 over is .25 millimeter over. .25MM is almost .010"

[maddog]

the stock 12mm carb does not have a seperate pilot jet just a main jet, the stock airbox has a restriction on the intake cover which needs to be cut out, you can pull the starter out, hit the start button to see if it works could be a weak battery.

[teeoce]

Thanks for all the help guys that clears a lot of my questions/concerns up. I will just run the stock setup. How wide can you open the exhaust and is it obvious where to cut out the airbox (it didn't come with one I'm in the process of finding one)?