Honing cylinders

[KA1J]

I have two cylinders to choose from. One set has a slight ring as seen at the very top in the photo below which is on all the cylinders, after a light honing and the other has none. The cylinders with no ring have some broken fins.

I can't feel the ring at all and with more honing it would come out. I can take more off & still be within standard specs.

Should I leave the ring alone?

Hone it more?

Use the other cylinder?

Thanks!

[motoman]

Must of had a ridge from metal being pushed up at the ring top..........if it was that bad, should of used a ridge reamer first before honing. With an inside mic check the cyl. taper from the ridge bottom down. Hopefully taper(has to be one as rings work in and out slightly with taper) is constant and within specs. Should be alright as your not building a hypo motor anyways.......but again may NOT be.......you won't know untill you mic the taper.

[crazy steve]

It's been mentioned here by someone that if you heat the cylinders to about 450F, the liners come right out... you might be able to do a swap...

[cywelchjr]

It's also possible that is just discoloration and not anything else. But do check it, cause you want to be sure.

[KA1J]

Well... this has been a most confusing series of issues for me to deal with. If it weren't for the help & various parts I've found through here & the net, I'd have been lost long ago, this bike really was treated terribly in its earlier life.

That said, I measured the newer cylinders and the bores are consistently a bit wider than the ones that came off the bike. The concentric rings on the top of the original cylinders that I was told were the results of a near seizure, hone away nicely in really short order leaving no impressions or indentations.

Seems like the original jugs were the mechanically better of the two so I looked at the characteristics of different epoxies and the JB weld industrial was pretty close to right and good to 600F. Loctite epoxy was the same aluminum color but only good to 300F. So I just epoxied the broken edges of the fins with the JB and tapped the chunks back into place. I'll have to fill in one of the broken pieces with epoxy & I'll do that by making a tape base held underneath on the lower sides & form an outer edge & fill it with epoxy so it'll be fin thick when it's done. None of the pieces were large enough to be any kind of problem other than looks. Once it's cured I'll paint it with PJ-1 and it'll look and function just fine.

Next will be to see which of the 8 pistons are the best, clean the ring races out, put the new rings in & then figure out how to best get the pistons in the cylinders, use the anaerobic gasket maker & well, get it back together.

I'm ready!

[KA1J]

Motoman, I'd never heard of a ridge reamer before this issue came up. Thanks for a new lead of info to check into. There was no palpable ridge but at the speed pistons are moving I wouldn't want to take chances of doing it all over again.

Steve, I looked that up and it sounded like a neat idea & then thought it might become an issue as I don't know if I could get the swap done without some issue coming up that might mean things were assembled out of line somehow. Probably too much thinking into it but the pieces of fin that were broken off were relatively small.

Last night I put on the old fin chips with JB weld on the broken edges & tapped them into place where they stayed, made a small thin layer of JB on top & bottom of the crack for strength & will file them flatter once cured for a couple of days. I made a dam of tape around the lowermost fin where 1.5 x 1/3" of fin was missing around the front corner and filled that with the JB. I'll shape that when the JB is totally cured.

I called the company & they said the industro version of JB I'm using will hold under sustained 500F temps and will remain good to 600F under intermittent conditions. That ought to be fine for the fins, I did a bunch of searching for the temps of the fins but saw answers that were conflicting but only a couple that came close to 500F. While the JB isn't nearly the conductor aluminum is, the surface area missing is very, very tiny and with the replacement of the parts (cept for the lower thin strip) I can't imagine it'll make a negative difference in the least.

I think it's pure reassembly from here on. Maybe...

[crazy steve]

If you can't feel the 'edge' of the ridge, you should be ok; a fingernail across that is a surprisingly accurate 'tool'.

As to the JB Weld fin fix, I'll be real curious as to how that works out. Those fins vibrate quite a bit when the motor is running (at pretty high frequencies, so it's not something you can see), which is one of the reason Yammy put those rubber dampers between some of them...

[motoman]

KA, U can use the leading edge of an old ring to clean majority of any carbon or otherwise out of ring lands. Do NOT use a wire wheel as it will leave minute particals of steel imbedded in aluminum! Steve's 'rule of thumb'(fingernail) works good. As Cy said, discoloration looks like what's left anyways. Idea of a ridge reamer is to remove that ridge, which is pushed up metal from liner. With scoot engines, that amount if any is not common. Leaving any of that ridge and using new rings can and most likely cause top ring to break as new ring specs. are different than the used one obviously. Your cyl. looks fine with a good cross-hatch pattern to trap oil for lubrication. Another little hot-rod secret is to take those cyls.....sit down with a bucket of hot water, toilet brush and a bar of Lava soap and scrub those cyl. after honing and cleaning with solvent. You'll be surprised at how that brush will look!......eeeekkkk.

[KA1J]

Minor update on the epoxied fins. Almost all of them are looking great. The one where I had to build up a fin piece from the JB weld was a FAIL because after two days, it did not harden and was still bendy epoxy. The other jobs were individually mixed and they came out fine. I must have not had 50/50 mix of resin & hardener. Removed it with the dremmel and am trying again.