blaster won't start, very high end customer

[nick4455]

I'm fixing a customer of mine blaster compression tested it and it only came back with 75 psi so I rebuilt the top end stock size and noticed a little bit of play so I ordered a 40 over had the cylinder bored and compression only rose to about 95 I read up that all need at least 120 for it to start I can't understand how I lost compression I tried everything from gasket kitsto shaving the gaskets and there's no change in compression its got a brand new clutch and starter gear please help anybody I need a lot of help this customer wants their bike back

I am a certified technician this one bike just has me so stumped

 

[Awk08]

I gotta ask, technician or not....you are holding the throttle wide open and kicking until the needle stops ?
reeds are good ?
tester known good ?

what did the shop bore the piston to cylinder clearence to ?

did they have the piston in their hands and bored to that exact pistons recommended clearence ?
some pistons have the clearence built in, and some don't.
thats why it's a must the shop has the exact piston in hand, before boring.


you can check piston to cylinder clearnce yourself.....

 

[nick4455]

yes the throttle was held wide openand every time I kicked until the needle stopped moving.... I gave the machine shop the piston and it was bored to the proper specs but one thing I forgot to leave out in the original post was that I found quarter ounce weight on all four valves

 

[speedyslyder]

18 years old your doing good as a certified tech as such a young age.
i would check the head for hairline fractures/or it might be warped/or leaking.
valves???????hope you mean reed valve and not exhaust valves that is 4 stroke territory.
got pics?

 

[Awk08]

I found quarter ounce weight on all four valves

i'm not following that ?

 

[speedyslyder]

lol 4 stroke or 2 stroke?
valves on 4 strokes can lead to loss of compression
blaster is 2 stroke/warrior is 4 stroke

 

[Awk08]

throw a teaspoon of 2 stroke oil down the plug hole and test compression again.
compression should rise once started and rings start to seat

 

[nick4455]

Its a 2t yes I mean reed valves they were almost like epoxyd to the reeds and one fell of getting sucked into the block which is the reason for the rebuild and I was able to remove it from the crank case

 

[nick4455]

And thank you speedyslyder, I just kinda fell into a real good job from a buddy of mine and it kinda took off

 

[speedyslyder]

if it is low on compression then this
gauge is faulty
wrong sized ring end gap/piston cylinder clearence
cylinder head is warped? check it
check for hairline fractures?//post pics ect
did 1 of the screws holding reeds off fall into cylinder as well?

 

[nick4455]

No screw just the weight and thanks I'll check the head now and possibly I'll get it decked

 

[nick4455]

Another thing I did was completely eliminate the tors and now I've got spark again

 

[speedyslyder]

No screw just the weight and thanks I'll check the head now and possibly I'll get it decked

you are confusing use with this "weight word'
there is the reed cage/reeds/reed stoppers/reed spacer perhaps and screws/with washers lol that is it

 

[speedyslyder]

what year blaster is it?

 

[nick4455]

Its a 93 and dude I don't know either that's why I came here because Evey one looks at me like I'm crazy when I tell them what I found they're just like washers stamped 1/4

 

[speedyslyder]

Its a 93 and dude I don't know either that's why I came here because Evey one looks at me like I'm crazy when I tell them what I found they're just like washers stamped 1/4

please get a pic i would love to see it
if it is a bar straight across they came with dual stage reeds and most people say to ditch them and still use the stock reed stoppers.
the straight bar allows the reeds to break much easier then they fall into the engine like you stated

 

[nick4455]

Okay I'll grab one tomorrow the bikes at my shop and I don't have a pick on me

 

[Blaner]

Something is off here. Im hoping the "weight" is just the reed stopper thingy. Have you done a leak test just for interest sake? Make sure your spark plug thread is good, try some plumbers tape with the compression tester to see if it seals better. Otherwise, re-torque the head...

 

[Blasturd]

yes the throttle was held wide openand every time I kicked until the needle stopped moving.... I gave the machine shop the piston and it was bored to the proper specs but one thing I forgot to leave out in the original post was that I found quarter ounce weight on all four valves

Did you measure the bore and piston yourself to make sure you have proper piston to cylinder wall clearance?

What was your ring end gap?

 

[Larry's Shee]

Must be big rush,hasen't been back, LOL