Whats the stock bore for 2003 yamaha blaster?
- Thread starter rustler2580
- Start date
Yeah my english in txt is not so good lol.Sorry.But its best to have a pro match it and hone it out.There are scuff marks inside that need to be honed out and oiled for a proper brake in.I did see some full top end rebuilds with head and matching piston on ebay.
Yes I would bore it and go next size up.I:I
I understand your english fine its just that im trying to understand everything else your talking about because i have never owned a blaster before this one and therefor never had to buy a piston for one or have it bored out and sh*t so trying to understand it all
One of the first things I purchase for any of my toys jet ski truck bike ect. is a repair manual.I always revert back to it for info when I need it.No pun intended what so ever.I still half to look stuff up all the time and Im sure I allways will.
Take the jug to a machinist, have it inspected and measured.
If it needs boring he can tell you what size piston you need.
You may just get away with a hone, plus new piston!
Free manual, take your pick!
http://www.blasterforum.com/threads...ce-and-owner-manuals-download-for-free.17325/
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Only when they are in the expanded state.
When fitted within the cylinder they mimic the bore size.
Unknown to many, the top of the piston where the rings fit into the lands, is quite a bit smaller in diameter than the skirt, thus allowing gas blowby.
The reason for this is to force, the rings outward towards the cylinder to make them seal.
Ya im hoping to just get away with getting it honed out, To me it really dont look like it needs to be bored out, So hopefully ill just need to get it honed out. Gonna take it to one of my local shops around here and have them tell me if i need to get the top end bored out or not.
If it does need boring, it might then pay to go with a forged piston.
You should have the piston in hand before boring commences, as forged pistons require a little more tolerence, due to their expansion properties.
ok well like i said going to take the top end to a local shop first to find out if it does need boring and i will go from there.
FYI, difference in clearance between cast piston and forged is only about .001". Forged pistons expand less than forged.
Why do you need a new piston?
Why do you need a new piston?
i recommend a forged piston we just pulled out the second and last cast piston we'll ever use. They like to explode after some use in the high rpm. they tend to let go at the intake side ports but ive had them even snap at the stronger exhaust side.
OOOOOOOOOOOppppps
MAJOR MISTAKE. Forged expands more than cast. :-[
Classic case of, left hand, not knowing what the right hand is typing.
Sure beats some of the explanations that I have read recently. At least I understood what you were trying to say.
The wiseco piston has to be fitted with larger bore size.It expands more than the oem cast piston.On some of the newer wiseco pistons they are bonded with a armor glide skirt coating which you can run a tighter bore with.It should have recomended bore size on the piston pachaging in any case.
I would also recomend going with a forged over cast.Cast pistons or oem are britle and when they blow the piston exlodes leaving you with possibly more parts to replace and having to change rod and bearings.Then you would need to split the case.They may make a size wiseco that will fit your bore size.But in any case while its in need of repair boring with a quality piston is going to give you more power.But I can understand budget and just wanting to get that thing running.I would also recomend mixing the gas and ridding the oil pump if not allready.
Forged vs Cast expansion prediction is in the alloys used in the manufacturing of the piston.Different metals expand differently.Forged is a stronger heavier product that will take more abuse than cast.But expansion rate is less predictable.Cast expansion is more predictable but not as durrable especially in a high performance 2 stroke.My next rebuild definatley going to look into the newer coated pistons.Should cut down on them funky 2 stroke engine noises.
I would also recomend going with a forged over cast.Cast pistons or oem are britle and when they blow the piston exlodes leaving you with possibly more parts to replace and having to change rod and bearings.Then you would need to split the case.They may make a size wiseco that will fit your bore size.But in any case while its in need of repair boring with a quality piston is going to give you more power.But I can understand budget and just wanting to get that thing running.I would also recomend mixing the gas and ridding the oil pump if not allready.
Forged vs Cast expansion prediction is in the alloys used in the manufacturing of the piston.Different metals expand differently.Forged is a stronger heavier product that will take more abuse than cast.But expansion rate is less predictable.Cast expansion is more predictable but not as durrable especially in a high performance 2 stroke.My next rebuild definatley going to look into the newer coated pistons.Should cut down on them funky 2 stroke engine noises.
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Cast piston, or forged piston, if it drops anything into the crankcase then a case split is in order.
Forged pistons will take a lot more abuse than their lesser cast cousins, but when a forged one dies, it usually makes a good job of it.
!
Forged pistons will take a lot more abuse than their lesser cast cousins, but when a forged one dies, it usually makes a good job of it.
!
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i realize this thread is 10 years old but for anyone who reads it a 66mm wiseco piston is actually 65.94mm .06mm smaller than 66mm, if the bore is EXACTLY 66mm the wiseco piston will have 2.36 thousandths clearance. wiseco reccomends 2 thou. my machinist sets them at 3 thou.
