Hey i have a 95 banshee,

rigth before i took it to the shop to get the top end done, the compression was only 89. it wouldnt kick start. i got it bored 20 over stock with wiseco pro-lite pistons and cometic gaskets. When i got it back the compression read 92 with 3hrs on it. checked today after 10hrs and it is around 90 or 92.

it only starts when i clean the carbs and if i kick it 5mins after i shut it off. When you let it sit for around 30mins it is hard starting. when i take it on the trails and shut it down to let it cool for 10mins, it won't start. IT ONLY STARTS WHEN I CATCH IT IN GEAR!!!

I called 2 shops and they said that the shop that did my motor didnt bore it out enough and they have to go bigger they messed up.

but i am wondering if the gauge is wrong and something else is wrong that wont let it start good. but we went over everything and found nothing wrong.

SO IS IT LOW COMPRESSION ?? even though it is newly rebuilt?

thanks,
brent

 

I am not sure but you dont really say how the bike goes if it was really low in compression it wouldnt have much power and wouldnt run very good low compression in my opinion wouldnt make it hard to start I need more info but I dont think your problem is low compression and what the other bike shops said sounds pretty weird good luck getting it right

 

Yeah once it starts it is all good. Just as fast if not faster than my friends 95.

 

atv shops told me they dont start at 100 and mine should be 150.

but there isnt anything else i can think of that would be wrong because me and my dad went over every thing pretty much.

 

I would suspect either a **** poor bore and hone, improper break-in, or a bad gauge. Recheck your compression with another gauge to eliminate the possibility of a bad gauge. But with having to catch it in gear to get it too start, tends to eliminate that possibility.

If it's a bad bore, i.e. too LARGE, you would be back in the same boat as before with loose pistons and blow-by dropping your compression. I would contact the machine shop that did your work and ask them, just exactly what they did. For a bore that size I would set it up with a .0025"
clearance.

If your bore was too small by even .003 the pistons won't go into the bore, and if it were set-up with a very tight clearance, about .001, would probably would have siezed it the first time you rode it, due to the pistons expanding and sticking in the bore.

I would say dis-assy is your next step to get to the root of your problems, something isn't jiving. Also check your gauge too.

 

I would disassemble the top end and check the ring end gaps with a feeler gauge and check the piston to cylinder clearance with a good caliper. Did you assemble the engine yourself or did the shop do it fo you? Make sure the rings are .020 over also, I have seen piston/rings not match.

 

I broke it in for 10hrs. They told me to just hit the powerband and shift dont hold it. So i did what they said, and they said the piston would seize if i did it wrong. so i am pretty sure i broke it in right.

they put my motor together. and the shop sends out the jugs for boring, then they get them back and put in the pistons and everything.

as far as the gauge, i am taking it over to my friends today and am going to try it on his banshee and see how it turns out. if it is higher than mine i know something in the top end is wrong, and ill take it to the shop that did it.

 

I know what you mean there! I have rebuilt an old Suzuki RM125 2 stroke and have the exact same problem. When I first lit it up it had good compression, after a short while very little and it's heck to get started. I'm pretty sure it's the honing job but I dont know really what to do about it either.

 

I had a similar experience with my Mojave after I had it bored .40 over. The problem with mine was the JUNK Cometic head gasket. I replaced it with an oem gasket with a little copper spray gasket and it has been fine ever since. Never more than two kicks to start no mater how hot or cold. Good luck.