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Posted

in my last thread i had problems with inhaling alot of sand into my carbs and i think it may have led to a compression problem now

 

as i understand i should have around 120 compression new?

well i tested and i came up with approx 85 on left and about 105 on right

obviously thats a problem, im goign to go ask a buddy to see if he has another tester i can borrow and recheck. but even if mines reading wrong there shouldnt be a difference like that i know

 

where do i go from here guys? do i need to quit riding it or should i ride the piss outta it for now?

Posted

Im actually suprised it started with the one side being that low but recheck it and let us know what you get. If its similar, time for a rebuild.

 

rechecked a few more times, i got about 90psi on left 100psi on right

seems low to me but performace is not really that bad, i mean it should be pretty shitty running at that psi shouldnt it?

maybe im doing the test wrong?

anyone have some exact steps for me?

 

also my dad said that if i pour a small drop of oil directly into the cylinder then recheck them if the compression rises that would mean i could have bad rings because the oil was sealing it, we tryed this and no improvement? is he on the right track? also i checked my buddies banshee just down the road from my house and he had 95psi each side, both out bike run pretty decent so maybe i dont have a problem??

Posted

Are you using a "GOOD known compression gauge, or is this something that as been kicking around in a drawer some where? Even good compression gauges can miss read if the check valve is dirty or no good (I am talking about the check valve in the thread adaptor of the gauge it self)

 

Also are you holding the throttle wide open when performing the tests????

Posted (edited)

Are you using a "GOOD known compression gauge, or is this something that as been kicking around in a drawer some where? Even good compression gauges can miss read if the check valve is dirty or no good (I am talking about the check valve in the thread adaptor of the gauge it self)

 

Also are you holding the throttle wide open when performing the tests????

 

i used 2 different gauges mine and my buddies both came out relativly the same

i checked each cylinder many times with both gauges throttle open and throttle closed both came out pretty much the same, the readings of approx 90psi left and 100psi right are my best readings with the throttle wide open

 

i believe my elevation is somewhere between 600ft and 800ft

Edited by christ6
Posted

It's at least ring time...and get the piston to wall clearances measure, more like a fresh top end probably.

 

Since you mentioned sucking sand, now would probably be a good time to tear the bottom half down, get new bearings on the crank...and have it welded as well.

 

Sand has a way of kissing your crank bye bye....

 

Sure, you can ride the piss out of it...it's only going to cost you more when the motor let's go...

 

Less than 100PSI and it's rebuild time, period...(at or near sea level anyways, which...you are at.)

Posted

well whenever i do something i got the attitude like go big or go home, so if i gotta rip apart my engine then im gunna beef it up, i dont know a whole lot about this stuff so what parts am i gunna want to put into er, so i get a port, stroker? i have no idea really what these things really are so hit me with some info guys

 

so far i thinking

wiscoe piston rings, bored out a few sizes? or should i go big as i can go?

and a noss cool head

 

im mostly going to be riding mx, jumping, trails and some full throttle riding road/dirt dragging my buddies

any other ideas

 

also im thinkin of a 2-1 trinity 35mm carb setup this winter as well

Posted

only go as big as you need to on the bores, if you bore it out as big as you can the next time they get loose you either need new cylinders or resleeve them. the gain from a bigger bore is minimal compared to porting. and i like the single carb setup.

Posted

It's at least ring time...and get the piston to wall clearances measure, more like a fresh top end probably.

 

Since you mentioned sucking sand, now would probably be a good time to tear the bottom half down, get new bearings on the crank...and have it welded as well.

 

Sand has a way of kissing your crank bye bye....

 

Sure, you can ride the piss out of it...it's only going to cost you more when the motor let's go...

 

Less than 100PSI and it's rebuild time, period...(at or near sea level anyways, which...you are at.)

That is good logical advise. Our readers should heed your suggestions.

Posted

well whenever i do something i got the attitude like go big or go home, so if i gotta rip apart my engine then im gunna beef it up, i dont know a whole lot about this stuff so what parts am i gunna want to put into er, so i get a port, stroker? i have no idea really what these things really are so hit me with some info guys

 

so far i thinking

wiscoe piston rings, bored out a few sizes? or should i go big as i can go?

and a noss cool head

 

im mostly going to be riding mx, jumping, trails and some full throttle riding road/dirt dragging my buddies

any other ideas

 

also im thinkin of a 2-1 trinity 35mm carb setup this winter as well

 

Go big or go home and 2-1 carb setup don't belong in the same paragraph...:) lol

 

I think you're confused on the rings...bored out a few sizes. You MAY be able to lightly hone the cylinders and replace the rings...if the cylinder to piston clearances aren't to great.

 

If they're too big, a new piston(s) is required when you go with a bore.

 

So....if you want to go big... How much is your budget is the next question...

 

While the cylinders are out for a fresh bore job, now is the time to get them ported.

However...as said, you want to get the crank checked and possibly fixed first. That could easily cut into your porting funds....

 

All the porting in the world don't mean squat if you lockup a crank...

Posted

yea it usually starts up pretty good, minus the times when i flood it

 

what type of port is my best bet if i plan on porting it? also where should i get it done and approx how much should i be looking at? i live in canada too so if anyone knows a good builder in sw ontario let me know, mostly ride on tracks and trails and i would liek to get into some minor mx riding

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