Blaster not Running... Need some help

[Johnston Repair]

I just bought at 1990 Yamaha Blaster 250 and it was not running. I brought it home and cleaned the carb, put fresh gas in it and it started up. I can get it to idle now but every time I touch the throttle it dies? What could be leading to this?



Also when I bought it I was told that it was put away running rough and smoking more than usual for a 2 stroke... I did a compression check and got 75psi. I have read that it should be around 100, would you agree with that? If so, would that lead to the engine not reving?

The guy I bought it from suggested honing it out or bore it out.. Whats the difference?

Thanks

 

[super noober]

I just bought at 1990 Yamaha Blaster 250 and it was not running. I brought it home and cleaned the carb, put fresh gas in it and it started up. I can get it to idle now but every time I touch the throttle it dies? What could be leading to this?



Also when I bought it I was told that it was put away running rough and smoking more than usual for a 2 stroke... I did a compression check and got 75psi. I have read that it should be around 100, would you agree with that? If so, would that lead to the engine not reving?

The guy I bought it from suggested honing it out or bore it out.. Whats the difference?

Thanks

ok we got a few issues here.. first off its not a 250cc, even with a a/m big bore cylinder and stroker it still comes in under that. your compression is ddefinately way low and it needs a rebuild.

 

[Awk08]

yep, at that low of compression, i doubt just a hone/new rings will be the cure
next size piston/new bore to fit that piston is needed

 

[PikledBeats]

I just bought at 1990 Yamaha Blaster 250 and it was not running. I brought it home and cleaned the carb, put fresh gas in it and it started up. I can get it to idle now but every time I touch the throttle it dies? What could be leading to this?



Also when I bought it I was told that it was put away running rough and smoking more than usual for a 2 stroke... I did a compression check and got 75psi. I have read that it should be around 100, would you agree with that? If so, would that lead to the engine not reving?

The guy I bought it from suggested honing it out or bore it out.. Whats the difference?

Thanks

First thing is that it is not a 250, you might be close with BBK/stroker but If they told you that when buying I would smack them.

Compression stock should be up around 135 at the low end, it sounds like it's time for a top-end.

Bore and hone??? A hone is sometimes used in reference to a crosshatch to seat new rings, a bore would encompass this as it is re-boring the cylinder for a new piston slightly larger and would include the cross-hatch. Best bet is to take off your cylinder, bring it to a well-known machinist and have them bore it for the next size piston (get the measurement from the machinist so you know your getting the right size) and voila ... top end rebuild. Also new top-end gaskets etc. You can buy a top-end rebuild kit just make sure it is right size for bore. I:I

 

[PikledBeats]

haha you guys beat me to it

 

[Johnston Repair]

So, if you say that its not a 250cc then what should it be with the stock motor and parts on it?

Thanks for all the recomemdations and help so far!

 

[TeamChaos99]

stock motor is 200cc

 

[super noober]

So, if you say that its not a 250cc then what should it be with the stock motor and parts on it?

Thanks for all the recomemdations and help so far!

a bone stock blasty is a tru 195cc's, even though they call it a 200cc. what i would be willing to bet happened is the previous owner had the cylinder bored out .050 to clean up a blow up or something and then though that 200cc +"50 over" bore makes it a 250cc wich it does not.

 

[SalM]

250cc LOL! No man its not a 250 cc and your issue like everyone else is sayin most likely bad compression and it will need a rebuild.

 

[super noober]

ok ok ok everyone calm down lol he gets its not a 250cc lol I:I I:I. sorry man but this happens A LOT and its kinda a pet peeve of everyones lol

 

[PikledBeats]

yea don't worry about the 200cc thing, people get testy when people start claiming 250cc and 265cc etc, noober is probably exactly right on what the previous owner thought/did.

But as said, you definetly have a compression problem and need a top-end rebuild. there are many threads on how to remove your cylinder and do this and I would suggest you find a reputable machinist to do the bore. If you have not rebuilt a topend two stroke before do not worry it is very straightforward. most important thing as stated is make sure you have proper clearance/right size piston/rings

 

[Awk08]

actually 195 cc, yamaha just calls it a 200
the machinist will tell you what size the piston is, and what size to get
if you don't know, or have close by, a reputable shop, call the number below in my sig pic, it will be well worth the few extra bucks shipping, to have ken do it right

 

[PikledBeats]

beat me to it again awk and noober ....... arrrggghhh

 

[Awk08]

beat me to it again awk and noober ....... arrrggghhh

us pa. boys are quick...on the track, in the trails and with the keyboard !!!!
hahahaaaa

 

[PikledBeats]

us pa. boys are quick...on the track, in the trails and with the keyboard !!!!
hahahaaaa

in the sack ......... hahahahahahahahahaI:I

 

[super noober]

in the sack ......... hahahahahahahahahaI:I

baahahahaha nice

 

[Awk08]

in the sack ......... hahahahahahahahahaI:I

damn straight, done and run !!!!!!!!!!!!!!!!
i've done my share of pleasin, these last few years are for me
aaaaaaaaaahahahaaaaa

 

[Johnston Repair]

When a motor is bored out how much of a power difference will that make between a .020" bore and say a 0.040" bore?

 

[sicivicdude]

When a motor is bored out how much of a power difference will that make between a .020" bore and say a 0.040" bore?

Nearly none at all. You're adding 1.2cc's by boring it but losing a couple of potential lives on your engine.