End Gap... Uh-Oh

[viggen]

Hey All,

Finally buttoning up my gs500 piston ring replacement project.  Weather looks good for the weekend and I may finally get to ride.

However.....

I torqued down the head and was thinking I was ready to start her up tonight.  And I realized.. I never measured the ring end gap for the new rings.  Cylinders were honed, no rebore, stock pistons... I used the rings from Bikebandit, and they looked like stock replacement parts.. 

Do I have to take this *&%^ thing apart and measure them or do the come set 'close enough'?

I would have to order a new set of head washers from bike bandit if I have to check these. 

[sledge]

There are two reasons for the endgap

#1 To allow the rings to compress enough to allow them to fit into the bore before springing out against the cylinder wall
#2 To allow for thermal expansion by giving the rings some space to swell into as they heat up and expand

There has to be a gap between the ring ends but it is not too critical so long as it is not excessively large which will reduce compression or not too tight which will increase cylinder wear or cause them to break. If the pistons slid home nice and smooth........... If the rings are spaced out correctly I wouldnt worry too much about it 

[the mole]

I agree with sledge, but if your motor blows up this post will self destruct.



Also, I believe that as the rest of the motor is already run in, the best way to run in your new rings is to start off gently for a short while, but then use them hard to bed them in well. Anyone?

[viggen]

Thanks guys.

Well, I realized I was not sure if the piston rings were right side up.  I knew I needed to check that but on the drive home it occurred to me that I hadnt.  So I pulled everything apart again anyways. 

Checked the end gaps, plenty of space but definately less than the 0.7 mm that Haynes says is a problem. 

I went to put the cylinder block back on... And one of the dowels is missing.  Can't find it anywhere in the garage.  Makes me think there is only one place it could be... So I ordered an oil pan gasket, and the consumeables that were probably messed up from the initial torquing of head gasket. 

I hope the summer sticks around until november....

[jeremy_nash]

I hope the summer sticks around until november....

good luck on that one,  but on the bright side, I bet you'll never make that mistake again!

[viggen]

It's always a learning experience, for sure! 
 

Yeah, good old new england is unlikely to stay warm in November...

[gregvhen]

next your gonna forget whether not you remembered to make sure the ring gaps werent all in a line

[ohgood]

next your gonna forget whether not you remembered to make sure the ring gaps werent all in a line

rip the head off a 80's vintage japoneesian pickup. slug the pistons up through the holes. slap in new rings. slug em down again. toss the head on with permatex. top off the fluids if you care.

DON"T CLEAN A DAMNED THING and run it another 1-200,000 miles. works for me.

[viggen]

next your gonna forget whether not you remembered to make sure the ring gaps werent all in a line

Yeah, that would be brutal.  Those were all correct.  There was one piston ring on upside down.  End gaps were fine.  All in all worth taking it apart again.  I'm awesome at it now.

I ran it last night finally, and it sounds much better now that it's using both cylinders.  Now I travel until thursday... Finally get to run her in this weekend.

Any suggestions on how to break in the rings?  I looked at the suzi and haynes manuals and they say max of 5krpm for the first 500 miles.  Light on the throttle, vary RPM.  Any further suggestion?

Lots of disagreement on that.

Thanks for the help so far!

[romulux]

Any suggestions on how to break in the rings?  I looked at the suzi and haynes manuals and they say max of 5krpm for the first 500 miles.  Light on the throttle, vary RPM.  Any further suggestion?

Lots of disagreement on that.

Thanks for the help so far!

It's like asking what oil to use.  I think it's hard to mess it up as long as you don't go to extremes.  Vary rpm, don't go nuts and I can't imaging you'll do it wrong.