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vorhese 09-15-2015 05:25 PM

Ball hone grit for Triumph?

I started honing some cylinders and read up on it. According to this page scan, they should be honed at a much rougher grit than most machine shops do. Can anyone weigh in? I'll have to buy a new $50 hone if so.

And John Healey had this to say:

"Most technicians who work exclusively on modern automotive/motorcycle engines, would consider using a 150 grit surface finish on a cylinder bore ludicrous. They are used to preparing cylinders to be used with Steel or Ductile Iron piston rings. Bores that use ductile iron or steel rings require the cylinder be prepared to a much higher standard and finished to a 300 to 600 grit surface - almost a mirror surface. "...

Also correct break in?

"My Guru uses 120 grit stones. The logic being that the rougher surface seats the rings properly. After honing thouroughly clean the bores, spritz one time with WD 40 and install the pistons. Use only the minimal amount of lube required to get the piston to go into the bore (the cylinder should be nearly dry) and install the rings dry. After starting the bike for the first time immediatly rev it to full throttle and hold it for 30 seconds, then ride the bike hard around the block, reving to full throttle and banging the clutch around. The rings seat within the first one or two minutes, if you have an issue after that then it's tear down time again. After a year and some change of having done this myself I have clean and dry exhaust pipes, so my Guru seems to know what he is talking about.

I used to do it the "conventional" way. For the last 30 years I've super lubed the pistons, gave it easy starts and slow gentle runs until the mileage was past 500 or so. I've had leaky cylinders, blow by and oil leaks for a lot of miles doing it that way, and from time to time during an engine tear down I would still see cross hatching on the walls indicating the rings never seated properly.

My Guru said do it his way. After the almost dry tube start with sandpaper grit honing (make sure you have oil pressure first!), and dogging the bike straight away on start up, I changed the oil, adjusted the usual bits, and the bike was good to ride as one normally would a fully broken in bike. It took me about 10 min to break in the bike, after almost 2 years it runs and rides perfectly with no evidence of blowby or compression issues. I would have to say his method works."

geezer 09-15-2015 10:58 PM

Re: Ball hone grit for Triumph?

I use whatever grit the ring manufacturer recommends. They know more about the product than I do. I bore/hone to size,allow to cool and measure again. If all is good next step. I used to finish under light pressure with super soft stones to break the peaks and remove torn metal from the bore. Sunnen stopped making the stones a long time ago. I used the brush type stones for the same purpose for a bit and quit when I found they do nothing other than appearance..

After honing the cylinder I clean with very hot soapy water and a large stiff cylindrical brush and dry quickly with air. Then using WD-40 and lint free cloth I wipe the bore down until the rags show no color from honing debris. The another thin film as rust prevention is applied.

I prep the piston by lightly polishing all the sharp edges on the dome and inspect for burrs which are removed when found. Then I measure end gap,adjust if needed (rare if the bore size is right) and install on the piston. I NEVER INSTALL RINGS W/O RING PLIERS. I dip my finger in clean oil and wipe a thin film on the rings as they're installed. This avoids heat related fretting in the ring land on start up. Then install the assembled piston/rings on the rod. I install one clip in the pin bore then press a lightly oiled pin into the bore and install the other clip. I dip my finger in clean oil and wipe a thin film of oil on the skirt and install the cylinder.

For start up I fire it up and raise the RPM to 2500-3000 as soon as I'm sure nothing hideous is going on in there. Allow it to become fairly warm while looking for oil leaks,ect. If all seems good I'll let it cool and re-torque if the engine design allows it. Then I just take the bike for a 10-20 mile shakedown cruise. I'll let it see some RPM in lower gears but avoid heavy load high RPM in upper gears. Back to the shop for a final inspection. If all is good call the customer and give him the good news.

I tell him not to beat it up for a hundred miles or so but don't be afraid to give 'er the juice. Just don't beat the shit out of it. Leave an autograph at every stop sign and it'll repay you with a short life. Abuse and hard running are different things.

That's been my routine since the late '80s and it's worked well. I had the good fortune of working for some good builders and that's what I was taught.

richbob 09-16-2015 01:44 AM

Re: Ball hone grit for Triumph?

i have just done this twice
and ran first bike yesterday
using instructions as per your text "my Guru.......
i saw lots of cast cylinders in the shop i used (car,agriculture machines,bikes etc)
he said he does all around 120 or less (he couldn't say its exactly 120) he could not do 150
Assembled dry with a touch of oil on skirt of piston
Theres some pics on my 49 thread.

jhays79 09-16-2015 04:11 AM

Re: Ball hone grit for Triumph?

I used a 120 grit three finger spring hone on my B50. As far as break in goes when I got it fired up I rode it pretty hard, it was too much fun not to. Haven't had any issues, and it doesn't burn oil.

vorhese 09-16-2015 12:53 PM

Re: Ball hone grit for Triumph?

You guys convinced me on the 120g hone, dry cylinders on assembly, and The Guru break in procedure. THANK YOU

richbob 09-16-2015 01:54 PM

Re: Ball hone grit for Triumph?

I think part of the problem is new build you fire up your checking oil return and stuff/jetting etc.pampering bike(normal you want to know its ok)
then maybe you have not a "perfect" seal.
my green bike i just done, i knew it was good so checked nothing kicked it and gave it a good blast around for 20 mins.

old.wrench 09-16-2015 02:36 PM

Re: Ball hone grit for Triumph?

It all depends on your rings.

Every reputable ring manufacturer supplies detailed information regarding the type of cylinder finish that works best for their rings. The ring manufacturer will tell you what grit finish and what type of cross-hatch pattern to apply to the cylinder to get the best results for their own particular rings. The way I see it, they know what the make-up of the ring is (style, material, alloy content, etc.) and they have done the research and have to stand behind their product.

All of the old motors I have run alloy pistons in iron cylinders, and I use Hastings rings - either iron or moly, whenever I can, because I know what kind of results I'll get from them. If I recall correctly, Hastings recommends a 240 grit finish with a 45 degree cross-hatch pattern for those type of rings and cylinders, and I follow their recommendation. I don't believe in using any secret voo-doo procedure for this step in a rebuild; I just do what has worked well for myself and others in the past.

I use the 240 grit silicone carbide Flex-hones for the combination of iron cylinders and Hastings iron or moly rings. In order to get a nice 45 degree cross-hatch you need to correctly match up your r.p.m. and your stroke speed.

I was just thinking about one of the old Triumph "guru" break-in tips, . . . .
don't dump any Bon-Ami or Ajax scouring powder in your intake :).


vorhese 09-16-2015 02:45 PM

Re: Ball hone grit for Triumph?

The set of pistons/rings I got this time are old Hap Jones made in Japan .060 over. No instructions of course. Last time I had Hastings, and it was a fresh bore, and I didn't deal with it. They had probably 500 miles on them before I blew a piston. Walls looked pretty glazed.

I have no idea how to get the correct cross hatch using a ball hone on a drill.

rustybill 09-16-2015 02:51 PM

Re: Ball hone grit for Triumph?

I assembled the top end on my T100 both ways... Oil on the cylinder walls and pistons led to glazed bores.

Assembling the top end with the cylinders dry after a 120 grit hone led to a good ring seat on the cylinders. I was also told not to run it unloaded for the first few heat cycles. Start it and immediately ride it and vary the engine rpm.

joe49 09-16-2015 03:56 PM

Re: Ball hone grit for Triumph?


Originally Posted by vorhese (Post 1734793)
I have no idea how to get the correct cross hatch using a ball hone on a drill.

Cross hatch is just stroking the hone up and down the cylinder. How quickly is dependent on drill speed, slower the drill rpm slower the stroking. It is just a trial and error thing, do a little and check, you will catch on quickly. Stroking to slow and cross hatch will be less than 45 to fast it will be greater than 45.

vorhese 09-16-2015 07:50 PM

Re: Ball hone grit for Triumph?

I was hoping to find a 3-arm hone in 120 or 150 grit but I'm not having any luck. Suggestions? Trying to save some money vs the $50 ball hone.

beaverbikes 09-16-2015 08:20 PM

Re: Ball hone grit for Triumph?

My NAPA store always has one. And I buy the roughest stones they got for these bikes. Last ones I got just said "course", with no real numbers on the package. But they feel just like some 150s I bought elsewhere.

I'm with the others, put her together dry. Start her up and idle only long enough to check oil return, make sure timing seems close. Then I got a pretty steep hill on road out front of my shop. I run up this almost WFO in third, rings are seated by the time I get to top of hill.

geezer 09-16-2015 08:39 PM

Re: Ball hone grit for Triumph?

Use the ball hone if you're just prepping for new rings. I'd lend ya one but I don't have anything as course as you want.

richbob 09-17-2015 01:26 AM

Re: Ball hone grit for Triumph?

I spent a long time looking for a 120grit (i contacted flexhone in uk)
in the end took to shop.(still cheaper than buying ball hone and i did 2 pairs of cylinders)

'59 09-17-2015 02:18 AM

Re: Ball hone grit for Triumph?

for what it's worth my 650 rebuild ( pre JJ knowledge base access )I used too much oil on bore and rings and it smokes.

0n 500 rebuild (post JJ knowledge base access ) 150 three finger cross hatch hone on a hand drill, you get a feel for it, minimal assembly lube and is a smoke free motor.

I appreciate the idea of running hard from the off but think you are lucky if you have everything dialled in just right from the get go so just don't keep it spluttering at low revs for too long too often.

vorhese 09-17-2015 11:33 AM

Re: Ball hone grit for Triumph?

After some more discussion I'm getting a BRM Flex-hone 4" ball hone 120G. There are no close by machine shops, at least ones that do motorcycles. Thanks everyone, I'll update this thread after I get it all together.

bp131 09-17-2015 01:04 PM

Re: Ball hone grit for Triumph?

Don't know how much honing you're gonna do in the future. If it's a one time deal save your money and call Mike at Engine Dynamics. An hour drive is pretty local.

Truckedup 09-17-2015 01:07 PM

Re: Ball hone grit for Triumph?

I use a 180 hone and then 220 to flatten the "peaks".. I lube the pistons with motor oil during installation...Never had an oil usage or blowby problem...

Try this on that fresh honed cylinder ...Run a bore gauge through it to make sure it's round...Then torque the head on the cylinder ..then flip over the head/cylinder and check it gain with your bore gauge...You'll find about .001 or more bore distortion around head bolts....
Kinda makes all that fussing around a lot less important if you're not using some sort of torque plate...

richbob 09-17-2015 01:21 PM

Re: Ball hone grit for Triumph?

"The proof is in the pudding"

old.wrench 09-17-2015 01:25 PM

Re: Ball hone grit for Triumph?


Hold up a minute before you hit the buy it now button on the 4" hone!!

BRM sizes it's ball hones by cylinder diameter. They do the figuring for you, so if you are honing a Harley cylinder with an approximate 3.5" bore you buy a 3.5" ball hone. Their hones are already over-sized so you'll have the proper tension on the individual spring wires and correct pressure of the abrasive balls against the cylinder walls.

If you are working on a 650cc and honing those .060" over cylinders that you are talking about, they are probably bored to somewhere around 2.85" or so, no? If so, you need a 3" hone, not a 4". I'm not sure that you could even crowd a 4" ball hone into a 650 Triumph cylinder.


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