im new to 2 strokes so gime some slack if im wrong hear, but the detonation would be that constant tick on that thing right?Originally Posted by lisnup65
Power User
The day begins with 3WW
im new to 2 strokes so gime some slack if im wrong hear, but the detonation would be that constant tick on that thing right?
1985 Tri-Z-
Just Too Addicted
Arm chair racerJust too addicted
That is beyond detonation! Their is definite piston slap or rod slap going on in that motor. Detonation if my memoty is correct will be most prevaliant under load and NOT at idle.
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1985 ATC350X
1986 TRX-250R(Soon to be an 87)
2001 Polaris Scrambler 90
2004 Arctic Cat DVX400
2003 Yamaha Blaster
2005 YFZ450
Rip: To many to list........
Power User
Roostin Away
I thinks ** problem is piston slap with rod slap and why it quiets down when * add gas is it gets enough case pressure to keep it off ***** from rocking as bad, I says rip it down and do it again, if * runnin it more the sound will get louder and the bottom end might be freid, I also suggest getting a new rod also as this one could be slightly "grooved from being fired on and slapping around" thats the worst case problem, it also just could be piston slap from being broke in 2 times cause ** clearences from being takin apart and being put back together 2 times are different. i hope * have luck with this
adam
86 ATC 500R the duner..
85 ATC 500R...the not quite finished faster duner
1985 ATC 250R Bone stock!!
1985 ATC250R mx/duner
1986 TRX370R MX/Duner
94 Banshee 400PV Cheetah 105RWHP
At The Back Of The Pack
Arm chair racerFirst time rider
Dunno if this will help you or not. 86 TRX's have a higher exhaust port than there latter yrs.This is partly why so many want the motor from an 86.ANyhow,do to this higher port,if all you have done is hone the cylinder,you might be running into exhaust port slap.Mine had done this as well. What happins is as the piston wears,it starts to rock front to back,this cause the piston to just catch in the upper side of the higher exhaust port.Not a good thing. If you dont catch it soon enough you will be resleeving a good jug and possibly worse dmages if it hangs altogether. If you have to tear it down,look to see if theres any hair line cracks running off the exhaust port into the cylinder walls.You should see some flatness to the edge of the top of the port ,as well as the piston will have marks on it. HOpe this helps,hope its not the problem. Good luck.
ROOSTINS RACIN!! YOU GETTIN ANY???
Roostin' Away
Arm chair racerRoostin Away
What's up guys.
It's not detonation. You can cross that one off the list. You will know detonation when you hear it. It's a pinging noise from the cylinder when you're hard on the gas (sounds like a death rattle). 180 something in compression is not enough to cause detonation, so I wouldn't worry about that.
I've had that noise in the past:
The most common cause of that noise is piston slap. If you honed the motor, that would be my first place to start. Check your piston clearance (piston to cylinder wall clearance). Excessive rod clearance makes a knock when you're decelerating. The wear limit is .14mm or .006 inches. Normal is .06 -.08 mm or .0024-.0031 inches. (also make sure that you don't have a sticky ring)
I also had that noise come from my counterbalancer. I rebuilt my bottom end 2 years ago because my motor sounded like a time bomb. I thought it was crank bearings, but it tuned out to be a loose fit on the counterbalancer bearing. I had a new bearing pressed on it in 1997 and I guess it came loose over time.
If this means anything, you should fix that noise, but I raced my bike for 2 years like that.
Hope this helps.
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