Topic: Ring end gap tolerance

[Trav-i]

I'm getting ready to assemble my motor and was wonder what the ring end gap tolerance should be.  I gapped them last night and got some tight readings (Clymer manual only gives max no minimum) on cyl 4.  On clyinders 1, 2, and 3 I got .013 end gap and on 4 i got .012 on one ring and .015 on the other.  I have honed the cylinders with a bottle brush (dingle berry brush) and need to know if i need to do a little more or possibly file the ring ends if there to tight.

If anyone has any info I would really appreciate it, as i would like to have my motor back in this weekend.

Thanks  

Travis

Forgot...  The rings are new and the motor is a 73 750.

[MCRider]

Rules of thumb: http://www.aa1car.com/library/ring_end_gap.htm

This yields about 10thou. for a CB750 (63mm bore = about 2.5 in x 4thou = 10thou)  A little tight by my memory.

I'd always heard 12 to 15 thou is a good starting point.  I think you are there for a tight set up. If you're going to drag race right off the trailer you might want it a little looser.

wait for confirm from a real engine builder.

[City Boy]

Hi.Factory specs. are as follows.End gap for top and second is .0079-.016''[0.2-0.4mm],service limit is.028''[0.7mm].End gap for oil ring is.004-.012''[0.1-0.3mm],service limit is .028''[0.7mm].  My factory manual shows 1 decimal point too many to add to the fun of rebuilding.Eg..0004'' is shown as minimum,a little tight I tink!  Rock On

[Trav-i]

Thanks guys that's the info I needed.  My motor will be a little tight by those numbers, but it might help since some of the cylinders showed a little rust damage from sitting.  Looks like I'm ok to finish his weeked.