Proper tools for cylinder bore measurement?

[bmt]

I'm getting ready to re-ring my pistons and have all of the tools required to do the job except something to measure the cylinder bore and a cylinder hone.

Would a set of telescoping gauges and a micrometer be accurate enough to do the job? I have a mic with .001" accuracy but was worried this type of gauge might have some play in it:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=5649

I can't find a real dial/digital bore gauge available to rent locally or buy for less then $130 (which is a lot for me to spend for a tool I'll likely use very rarely).

As for the hone I was just going to get this one:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=97164

I'd prefer to spend some money on tools if I need to and DIY rather than pay a machine shop to do the work. Also, I know not everyone likes HF, but locally they have great customer service compared to the auto parts stores.

Thanks for any advice.

 

[almarconi]

The tool you listed from HF should be adequate for the job.

 

[tkent02]

I'm getting ready to re-ring my pistons and have all of the tools required to do the job except something to measure the cylinder bore and a cylinder hone.

Would a set of telescoping gauges and a micrometer be accurate enough to do the job? I have a mic with .001" accuracy but was worried this type of gauge might have some play in it:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=5649

I can't find a real dial/digital bore gauge available to rent locally or buy for less then $130 (which is a lot for me to spend for a tool I'll likely use very rarely).

As for the hone I was just going to get this one:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=97164

I'd prefer to spend some money on tools if I need to and DIY rather than pay a machine shop to do the work. Also, I know not everyone likes HF, but locally they have great customer service compared to the auto parts stores.

Thanks for any advice.

That hone will work, but if the cylinder is worn much, the stones won't touch the cylinder walls where the most wear is. Right up towards the top of the ring's travel, the cylinder could be just a hair larger in diameter, so the place where the honing needs to be the best it is actually the worst.

The ball hones do a much better job of honing very uniformly on older cylinders, it only takes a few seconds to get a good surface, and so it won't enlarge the bore as much as using the type from harbor freight.

If you are honing a new or freshly bored cylinder, it won't matter.

 

[almarconi]

I was referring to the telescoping gauges.

 

[gearman]

Telescoping gages aren't really very accurate. A dial bore gage is more suited for cylinder measurement. Here's an inexpensive one:

http://cgi.ebay.com/2-6-BEST-CYLINDER-BORE-GAGE-DIAL-0005-GAGES-GAUGE_W0QQitemZ260353681282QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item260353681282&_trksid=p3286.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50

 

[BlackStar]

You can use the telescoping gauges but you have to make a lot of repetative measurements and average them after throwing out the whacked out readings, which you will get. Your readings are very sensitive to technique. After a little practice, I was able to get reasonably consistent readings with tolerable variation.
The dial bore gauge seems a little less sensitive to technique. I think it is due to the dual rollers on the fixed end. I have this one and like it
http://www.use-enco.com/CGI/INSRIT?PMAKA=890-9842&PMPXNO=5284472&PARTPG=INLMK32

 

[SqDancerLynn1]

You can get some idea of wear by using one of the piston rings. Square it in the bore with a piston Measure the ring gap with your feeler gauges at several places Starting at very bottom where it wears the least amount up to the top where it wears the most

 

[Nessism]

Easiest way to check is to stick your piston in the bore up side down and try to cut in a feeler gauge at the bottom of the skirt. First do this at the very top and very bottom of the cylinder to get a feel of what the clearance should be with no wear, then do it at various places in the bore. As Tkent stated, max wear will be up near the top.

The standard clearance is about .0025. If you can get a .004 feeler gauge in there, you are quite a bit of wear and should consider a bore job.

 

[bmt]

The ball hones do a much better job of honing very uniformly on older cylinders, it only takes a few seconds to get a good surface, and so it won't enlarge the bore as much as using the type from harbor freight.

I think I will go with the ball hone for this given that I don't expect the cylinder to be very uniform. The POs put this bike through a lot. Thanks for the insight on how the stone type functions. I didn't realize there was much of a difference.

Easiest way to check is to stick your piston in the bore up side down and try to cut in a feeler gauge at the bottom of the skirt. First do this at the very top and very bottom of the cylinder to get a feel of what the clearance should be with no wear, then do it at various places in the bore. As Tkent stated, max wear will be up near the top.

The standard clearance is about .0025. If you can get a .004 feeler gauge in there, you are quite a bit of wear and should consider a bore job.

I think I'll give this a try first, afterall it's free! If I'm not too close to the service limit I'll feel confident enough.

Thanks for the tool links btw. I can't believe I missed that one on Ebay, I was just searching for one before I posted.

 

[tkent02]

Loose pistons, if it's a touch out of spec, it will still work.
Hone it, run it hard, you're good.
Maybe not for a high buck racer, maybe not if you need it to go another 100,000 miles, but it will run for a while.
Done a few old cars that were a little loose in the cylinder department,
(like way too fvcking loose), they ran a long time.

Donning flame retardant underwear now.

 

[silverhorse47]

You can use the telescoping gauges but you have to make a lot of repetative measurements and average them after throwing out the whacked out readings, which you will get. Your readings are very sensitive to technique. After a little practice, I was able to get reasonably consistent readings with tolerable variation.
The dial bore gauge seems a little less sensitive to technique. I think it is due to the dual rollers on the fixed end. I have this one and like it
http://www.use-enco.com/CGI/INSRIT?PMAKA=890-9842&PMPXNO=5284472&PARTPG=INLMK32

I really agree with this. It is very difficult to get consistent readings with this type of gauge. The springs are very coarse, and so feel is not a dependable acquired skill in this area. Repetition will lead you eventually to an acceptable average......but measuring is about being sure....not relatively certain. I like this link. It might make you think a bit about what tool you want.

I have never trusted myself to measure critical dimensions...but I always do. Then I take them to my machinist and compare my results with his.

Also......honing is only appropriate within certain specs. I likely didn't read closely enough to notice if yours are there or not, and I hope they are. But many a person, me for sure, has put in new rings having measured and honed their first four cylinders, only to find the result wasn't quite what they expected. It's great fun and there is no other way to learn, really, but for me, that humbling trip to the machine shop (and back) has been what has really taught me what to look for when measuring for machining.

S.



S.

http://www.realclassic.co.uk/techfiles/tech05031600.html

 

[bmt]

Also......honing is only appropriate within certain specs. I likely didn't read closely enough to notice if yours are there or not, and I hope they are. But many a person, me for sure, has put in new rings having measured and honed their first four cylinders, only to find the result wasn't quite what they expected. It's great fun and there is no other way to learn, really, but for me, that humbling trip to the machine shop (and back) has been what has really taught me what to look for when measuring for machining.

S.

http://www.realclassic.co.uk/techfiles/tech05031600.html

yeah, I am looking at this as a learning experience. If I hone them and they end up out of spec, so be it, I'll just have to hunt for a used cylinder in better condition (A rebore with oversized pistons just seems cost prohibitive for a 550).

The bike has an 'L' head on it right now and I'm just about done refurbishing the original 'M' head so I figured when I do the swap I should take care of my compression issues too.

Engine at running temp, WOT dry test: 110, 100, 115, 135 (this is after 6-7 cranks to reach full pressure). The fact that I got the highest reading on #4 even though the battery was down a bit by then says bad news. I repeated the test another time and got similar readings. Engine only has 19K on it so it really shouldn't be this low but this bike has a pretty sorry past so I'm not too surprised.

Also getting crankcase blow by and drinking oil. Wet test comes up quite a bit. Service limit is 100psi on an 82, 550 with 28psi differential. So while it runs, it just doesn't run well, and I feel like I can't make it much worse!

thanks for the link btw. good read. I'm planning to pull the cylinder, hone, then measure before I order any parts as this could take some time to resolve if either the sleeves or pistons are too worn.