Piston Slap Help

[blasterboy 2000]

from what i could hear. it sounds like it needs a bottom end. in doing so. it would make it run better and. even make you know for sure whats in you'r motor. so new cranks bearings new rod. new wrist pic bearing on the crank. and new seals. and a fresh bore and piston and rings would make it run very nice. even if you think u dont need a bottom end rebuild i would do it just to make sure. won't hurt at all only in the pocket if you dont do it then it blows up from something in the bottom end. im not a expert but i hope this helps

 

[quadsrus1]

from what i could hear. it sounds like it needs a bottom end. in doing so. it would make it run better and. even make you know for sure whats in you'r motor. so new cranks bearings new rod. new wrist pic bearing on the crank. and new seals. and a fresh bore and piston and rings would make it run very nice. even if you think u dont need a bottom end rebuild i would do it just to make sure. won't hurt at all only in the pocket if you dont do it then it blows up from something in the bottom end. im not a expert but i hope this helps

Kind of funny that you say that i was planning on getting it running for this winter season then i wanted to do a complete rebuild bottom end and top end but i guess my complete rebuild is coming sooner then anticipated but i think im going to tear it all apart do a new bottom end Wiseco Complete Bottom End Rebuild Kit - Dirt Bike Motocross 1998 Yamaha Blaster 200 - Motorcycle Superstore and a new top end Wiseco Piston Kit | Rocky Mountain ATV/MC and while i have it all apart i think i may go ahead and paint the frame and bring it back to life as a new bike

 

[1995blaster]

i would ask around on here but 500+parts is wayy to much

 

[quadsrus1]

i would ask around on here but 500+parts is wayy to much

Yea i was thinking the same thing i think im gonna go ahead and do it myself to save the money

 

[yamaha28]

I think its an excellent idea! Doing it yourself gives you experience that could help you later on. Good luck!

 

[quadsrus1]

I think its an excellent idea! Doing it yourself gives you experience that could help you later on. Good luck!

Experience is what i need seeing as though i want to be a small engine mechanic and the bottom end is the only thing i don't know how to do as of now it kinda scares me hahaha

 

[scotj77]

Ok i'll give you some advice here and not bounce around. Have you pulled the top end after your rebuild? Are you sure you put the piston in the right direction? Did you just take the old piston off and put the new one back in? Do you know if it was stock bore? answer these questions and i might be able to help more

 

[quadsrus1]

Ok i'll give you some advice here and not bounce around. Have you pulled the top end after your rebuild? Are you sure you put the piston in the right direction? Did you just take the old piston off and put the new one back in? Do you know if it was stock bore? answer these questions and i might be able to help more

NO i have not pulled the top since rebuild i just did the build yesterday yes piston in right direction arrow pointing to the exhaust took old one out put new one in as informed to do so by mechanic yes it was stock bore

 

[scotj77]

ok... pull the top end again and have someone measure the bore properly not with a set of calipers. they need to use a micrometer and measure the piston to see if you are out of specs on the clearance. leave the head on if you can that way you won't waste the head gasket. if it is out of specs order the size piston your machinist tells you to order then get the cylinder bored to fit the piston after you get the piston.

And if your crank is givin out you should probably see some evidence of that when you pull the top end again. Good luck man. keep me posted

If your topend is in specs then we will go over bottom end rebuild procedures

 

[quadsrus1]

ok... pull the top end again and have someone measure the bore properly not with a set of calipers. they need to use a micrometer and measure the piston to see if you are out of specs on the clearance. leave the head on if you can that way you won't waste the head gasket. if it is out of specs order the size piston your machinist tells you to order then get the cylinder bored to fit the piston after you get the piston.

And if your crank is givin out you should probably see some evidence of that when you pull the top end again. Good luck man. keep me posted

If your topend is in specs then we will go over bottom end rebuild procedures

Ok so im just gonna go get it bored and make it easy lol and how do i know if i need a new bottom end how can i check to find out thanks for the advice

 

[scotj77]

no up and down play at all in the crank. NONE!!! turn the crank and listen for a smooth sounding turn or is it crunchy soundin. crunchy is bad. there can be some side to side play but not a lot. Look at the thrust washers on either side of the rod where it attaches to the crank do they look like the same thickness. if one is thinner looking you have bottom end trouble.

 

[quadsrus1]

no up and down play at all in the crank. NONE!!! turn the crank and listen for a smooth sounding turn or is it crunchy soundin. crunchy is bad. there can be some side to side play but not a lot. Look at the thrust washers on either side of the rod where it attaches to the crank do they look like the same thickness. if one is thinner looking you have bottom end trouble.

Thank you very much rep for you not to be a A$$ towards any body else that helped but you were the most detailed and quite helpful very helpful Thanks

 

[scotj77]

no problem bro pm me with your questions from now on. that way i don't miss it. i log on everyday after work.

 

[quadsrus1]

no problem bro pm me with your questions from now on. that way i don't miss it. i log on everyday after work.

Thanks bro here is a question for you quick if i remove all the tors wires but leave the big box on the top of the will it still run right

 

[super noober]

Ok so im just gonna go get it bored and make it easy lol and how do i know if i need a new bottom end how can i check to find out thanks for the advice

not to be a a$$ to u either but didnt i say that on the first page? lol 8-|

 

[blasterboy 2000]

i would ask around on here but 500+parts is wayy to much

for sure 500 is way to mch i spent 500 on mine but thats wisco everything. a bore a head mill. a new rod and rod berrings cranks berrings. seals everything and im also geting it all painted to. and its around like 600 cause my uncle is painting it and buying a tommey t4 for me.

 

[xjma]

Thanks bro here is a question for you quick if i remove all the tors wires but leave the big box on the top of the will it still run right

on a 98 you disable the tors by just unplugging it. You can remove the little brain under the hood if you'd like. If by "the big box on top of the" you are referring to the big thing on top of the carb, then yes, it will run fine if you keep that there...it's just kinda annoying when you are playing with the jetting to get the carb in and out. It's not necessary to remove that thing - with the tors unplugged it won't affect anything, but if you want you can get a new throttle cable and carb cap....you'll have to add an idle adjust screw as the idle adjust is currently in that big thing on the top.


did you take any pics of the cylinder before you changed the piston? if the rings were seized....it most likely needs a bore. you said that there was no play on the rod...rotate the crank to feel the bearings. If the rings seized it was probably running lean and low on oil....and if the rings were low on oil then the crank was low on oil as well. When you pull the head again and you rotate the crank, look to see if the crank has any oil on it. Normally there should be a little bit of oil pooled in the bottom of the crank. This comes back to jetting....you obvoiusly need a larger size main jet or you could spend all this money on making the motor perfect and then ruin it again in a few hours, or less!!

Do you still have the oil injection system or do you pre-mix? Stock exhaust on that one?

 

[quadsrus1]

on a 98 you disable the tors by just unplugging it. You can remove the little brain under the hood if you'd like. If by "the big box on top of the" you are referring to the big thing on top of the carb, then yes, it will run fine if you keep that there...it's just kinda annoying when you are playing with the jetting to get the carb in and out. It's not necessary to remove that thing - with the tors unplugged it won't affect anything, but if you want you can get a new throttle cable and carb cap....you'll have to add an idle adjust screw as the idle adjust is currently in that big thing on the top.


did you take any pics of the cylinder before you changed the piston? if the rings were seized....it most likely needs a bore. you said that there was no play on the rod...rotate the crank to feel the bearings. If the rings seized it was probably running lean and low on oil....and if the rings were low on oil then the crank was low on oil as well. When you pull the head again and you rotate the crank, look to see if the crank has any oil on it. Normally there should be a little bit of oil pooled in the bottom of the crank. This comes back to jetting....you obvoiusly need a larger size main jet or you could spend all this money on making the motor perfect and then ruin it again in a few hours, or less!!

Do you still have the oil injection system or do you pre-mix? Stock exhaust on that one?

I plan on buying a piston and getting it bored to the size piston i buy i plan on pulling the cylinder off again today or tomorrow it is oil injected but i want to remove that and pre-mix so how would i do that also yes it is stock exhaust

 

[scotj77]

dude don't waste your time buying the piston until you have it measured to make sure. you don't want to waste bores on your cylinder by jumping up a few sizes or risk having the next size piston be too small and still have too much clearance. you are playing on a slippery slope... believe me I've been there done that when it comes to makin mistakes and I try to keep others from wasting thier money.

 

[quadsrus1]

See i was planning on ordering the piston and when it gets here take the piston and cylinder and get them to bore it to the piston