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Triumph cylinder barrel repair advice needed #296842
01/31/10 6:44 pm
01/31/10 6:44 pm
Joined: Mar 2007
Posts: 1,156
Winona, MN
Swan Offline OP

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Winona, MN
I recently bought an incomplete 1966 Triumph Bonneville and have begun a complete restoration. The bottom end is completed with new sludge trap, bearings etc.

Recently, I measured the barrel and discovered each has a fine crack at the base of the cylinder skirt about 1 and 1.5 inches long. GRRRRR... They are standard bore, in great shape on the exterior and no scoring or significant wear inside. What are my options? Can I braze or weld the cracks and rebore? Is there someone who can repair this? Advice? Is it time to find a replacement? I really want to use this cylinder for it is original to the motor.

I'll post photos tomorrow.


1966 Triton
1962 BSA DBD34 Gold Star
1966 Triumph Bonneville
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Re: Triumph cylinder barrel repair advice needed [Re: Swan] #296921
02/01/10 2:47 am
02/01/10 2:47 am
Joined: Sep 2006
Posts: 398
hamilton on. can.
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highway Offline
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hamilton on. can.
If the cylinder is cracked, it is scrap. Make sure what you think you see isn't just a casting line. Rick

Re: Triumph cylinder barrel repair advice needed [Re: highway] #296941
02/01/10 7:44 am
02/01/10 7:44 am
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Nanaimo, B.C. Canada
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Wilfred Online content
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Seems to me that if the bike is already incomplete, replacing the barrel shouldn't be an issue. What Highway said and I wouldn't consider it either. I've found a number of spare T100 barrels so I wouldn't think another T120 barrel would be impossible to find. Cheers, Wilf.


"It's about the ride..."
Re: Triumph cylinder barrel repair advice needed [Re: Swan] #296983
02/01/10 3:59 pm
02/01/10 3:59 pm
Joined: Jun 2002
Posts: 9,972
Scotland
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Stuart Offline
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Hi,

Been there, done that, 'T'-shirt's in the wash. wink Found pretty much the same thing in my T100. Took it to the engineer doing all the other machining, he advised against brazing or welding or anything like that. He did say he could bore the whole cylinder out of the block to the o.d. of the spigot, then make a 'liner' to bring the cylinder back to size and replicate the spigot, but we were talking a similar amount of money to a brand-new barrel, so the latter's what I did.

Hth.

Regards,

Re: Triumph cylinder barrel repair advice needed [Re: Stuart] #296996
02/01/10 5:05 pm
02/01/10 5:05 pm
Joined: Mar 2007
Posts: 1,156
Winona, MN
Swan Offline OP

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Its cracked and is therefore junk. I was in denial but am now in the market for a good 1966 650 cylinder with stock to +.20 bore. If anyone has one please let me know.


1966 Triton
1962 BSA DBD34 Gold Star
1966 Triumph Bonneville
Re: Triumph cylinder barrel repair advice needed [Re: Swan] #297009
02/01/10 5:58 pm
02/01/10 5:58 pm
Joined: Dec 2006
Posts: 3,895
Massachusetts, U.S.A.
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btour Offline
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Hi Swan,

Mine was cracked on one skirt. It was welded, and bored by John. Still good so far. So it is doable.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
Re: Triumph cylinder barrel repair advice needed [Re: btour] #297045
02/01/10 8:37 pm
02/01/10 8:37 pm
Joined: Apr 2008
Posts: 230
Marblehead,Ma USA
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Woody1911a1 Offline
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hey btour , do you remember the method of welding John used ? mig , tig , oxy ?

cheers Woody

Re: Triumph cylinder barrel repair advice needed [Re: Woody1911a1] #297051
02/01/10 8:56 pm
02/01/10 8:56 pm
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Massachusetts, U.S.A.
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btour Offline
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Sorry Woody,

John had his friend, an expert welder, weld it, so I do not know what was used. I do know that a bit more had to be bored to get it smooth.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
Re: Triumph cylinder barrel repair advice needed [Re: btour] #297082
02/01/10 10:51 pm
02/01/10 10:51 pm
Joined: Aug 2001
Posts: 918
hampshire, england
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t120mike Offline
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hampshire, england
Swan,

Before you go for the expense of repair (don't forget shipping both ways, re-painting, etc), check out the NOS and re-manufacture situations on your side of the pond. I believe they are available and a bit of detective work should reveal all!

BTW, any progress on your TRITON "Patent Plates"


mike
Member #: 147
1960 T120 Bonneville
1999 H*%^a VFR 800 FI
V4 Triton Project (still keeping me sane (Ha-Ha!))
Re: Triumph cylinder barrel repair advice needed [Re: t120mike] #297217
02/02/10 6:56 pm
02/02/10 6:56 pm
Joined: Mar 2007
Posts: 1,156
Winona, MN
Swan Offline OP

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Swan  Offline OP

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Winona, MN


Crap photo, but there is only one crack, but it is a good one.

t120mike, the only NOS barrels I know are Morgo Big Bore kits and the ugly billet cylinders from MAP cycle. I have not made up the badges yet, I was sidelined with a family issue. I'll keep you in mind.

Last edited by Swan; 02/03/10 12:01 am.

1966 Triton
1962 BSA DBD34 Gold Star
1966 Triumph Bonneville
Re: Triumph cylinder barrel repair advice needed [Re: Swan] #297263
02/02/10 10:36 pm
02/02/10 10:36 pm
Joined: Mar 2005
Posts: 460
Cincinnati, Oh
Jethro Offline
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Cincinnati, Oh
That is a nasty crack, my friend. I'm with you, after all the work, all the time, all the expense of doing an engine, even if it is top end ONLY, I would NOT take a chance with that. Here is probabaly why. I don't think I would EVER forget that it was there... even if repaired, I would always remember it... always wonder if I were flirting with catastrophic failure somewhere, and then, JUST IMAGINE the worst case scenario, whether it is a seizure, with metal contamination EVERYWHERE... I think you have made the right choice here. But I await further expert opinion.

Re: Triumph cylinder barrel repair advice needed [Re: Jethro] #297857
02/06/10 6:49 am
02/06/10 6:49 am
Joined: Oct 2009
Posts: 765
Santa Barbara, Cal.
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Bodger Offline
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and then there's the question of why did it crack?


Have you checked the crank and the cases ? That indicates maybe a racing stress or a blowup...maybe since fixed, I hope so, but jeepers, that's a strange place for a crack.



And then there's the rods...

The loading would be the greatest there, fore and aft, wouldn't it, and if the dpo had run it hard and worn, there would be even higher loads, right?

Curious...

Sorry to be such a worrier...

Last edited by Bodger; 02/06/10 6:56 am. Reason: I'm an idjit.
Re: Triumph cylinder barrel repair advice needed [Re: Bodger] #297860
02/06/10 7:35 am
02/06/10 7:35 am
Joined: Apr 2005
Posts: 2,383
Bega NSW Australia
Mark Parker Offline
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Bega NSW Australia
There are these cyls advertised on this site, would be my preference when you weigh up how much you may spend anyway plus with this you get 750cc less weight and alloy:
http://www.triplesrule.com/T120SleevedIron.html


mark
Re: Triumph cylinder barrel repair advice needed [Re: Mark Parker] #297881
02/06/10 12:54 pm
02/06/10 12:54 pm
Joined: Oct 2004
Posts: 4,429
Melbourne Australia
Tiger Offline
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Look closely at the conrods, I suspect that a broken 'rod did that damage, I would be pleased to hear arguments to the contrary.

The chamfer indicates that the cylinders are std bore or very close to std and quite salvageable as the rings go nowhere near that point, although the piston skirt does.

I think perhaps you are looking at originality as the '66 did not have the square edge on the timing side forward cylinder base flange as was provided for pressure feed to the exh cams ?

Lots of new cylinders are s#it in any case as green castings are machined and offered to blokes like you and I.

With my admittedly very limited knowledge of all welding.

I would clamp the cracked skirt back in place, undergrind the bore side of the crack and weld with bronze, then remove the clamp and undergrind the external side and arc weld after pre heat etc.

I understand only enough of the above processes to make my advice possibly dangerous, there are surely blokes here who reclaim castings or know folks who do ?

Cylinder skirts are very lightly loaded and I reckon when a boring bar hits [soft] bronze it would not deflect or do other silly things ?

Those cylinders certainly do need boring but I would use them.






Last edited by Tiger; 02/06/10 1:00 pm.

1969 TR6R
7.62 x 51 is not a maths puzzle.
Re: Triumph cylinder barrel repair advice needed [Re: Tiger] #297894
02/06/10 2:34 pm
02/06/10 2:34 pm
Joined: Sep 2008
Posts: 274
Angus, Scotland
mick2 Offline
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i would have thought that could be repaired by tig. i would rout out the crack both sides and tig weld it up then blend out carefully. i dont think the rings would go anywhere near there so no danger of losing compression or burning oil because of it.
you should see some of the repairs that we do on the tornado jet engines, if the work id carried out by a competent welder then i see no reason not to try and repair?

Re: Triumph cylinder barrel repair advice needed [Re: Bodger] #297896
02/06/10 2:50 pm
02/06/10 2:50 pm
Joined: Oct 2009
Posts: 765
Santa Barbara, Cal.
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Bodger Offline
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The 750 kit is nice Mark...money money money...

Tiger, as a known Bodger I would certainly try to fix these, and as to the broken rod cause, aren't both cracked?...but if only one that seems seems most plausible..and hopefully the cases and crank are good.

If Swan's saying both are cracked, geez, maybe a blower on a drag bike or something, next the top will come off the flange or something..

But if fixing,I would do what you said, but I would grind and clamp and preheat, tack from the outside, let it cool, still preheated, then weld a little more, wait, weld a little more...(people get so crazy to weld they pour tons of heat into a part and wonder why things warp. I weld .040-.060" galvanized tubing with a MIG weld and sometimes get as good looking as with a TIG.)

After you get the whole outside welded, you could grind it clean enough, then braze the inside if you want to..you could skip it if the rings aren't going to get that far down and leak. The outside welding will probably get through almost to the inside, and get cleaned up by your dremel or the bore machine..and drill the end of the crack(s), btw.

If you have to pay to get it welded, forget all this and go buy a good used and get on with the show.

Then rebore and Bob's your uncle....I still think there is some pretty good loads there however, so if it blows up I'm not here.

But again, a good used cylinder on this pretty common part would be cheaper than all the worry and especially cheaper than a nice rorty 750 kit.

(My bets are BOTH cylinders cracked from being run crazy with a blower and nitro or something like that, yet why didn't the flange let go? Throughbolted maybe?...but both rods breaking at once? I don't think so.)

Re: Triumph cylinder barrel repair advice needed [Re: Swan] #297936
02/06/10 6:29 pm
02/06/10 6:29 pm
Joined: Jul 2009
Posts: 3,549
Vic. Australia
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Pete R - R.I.P. Offline
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Vic. Australia
If you plan to use bronze as a filler rod,grinding is not the prefered surface preparation for cast iron (the bronze won't stick,though it might look OK).There are "welders" out there,who should know better,who will try this.
Grinding is OK for preliminary shaping.The surface must then be prepared either by filing or sandblasting after grinding.

Any electric welding (arc,TIG,etc.),even with pre-heating,is likely to leave hard spots in the iron;very,very hard.The man who does the rebore will hate you for this,and you might not be pleased with the results.
I'd go for the bronze repair,with correct surface preparation.

Re: Triumph cylinder barrel repair advice needed [Re: Pete R - R.I.P.] #297944
02/06/10 7:10 pm
02/06/10 7:10 pm
Joined: Nov 2006
Posts: 112
Ottawa Ontario, Canada
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mike07 Offline
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I think i'd go with a new or good used barrel just for peace of mind as Jethro says. I'd check with Ray & Gina Spevak from Queeng( queeng327@cableone.net) or watch on eBay. I got a really good set of standard bore barrels for under $100 on eBay.


68 Bonneville
68 Daytona
68 CL450
68 CL350
Re: Triumph cylinder barrel repair advice needed [Re: Pete R - R.I.P.] #297992
02/06/10 11:03 pm
02/06/10 11:03 pm
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Santa Barbara, Cal.
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Bodger Offline
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Grrr, heh, Pete's right of course, I totally forgot this is cast iron (too much rain, I'm waterlogged) :>
There are also better choices for welding wire and gas, and at least I would have tumbled to that eventually...I hope. There's also better choices for brazing filler as well.
Grrrr.
(At least I'm honest enough to not edit my stupid :>)

All that trouble adds up to a replacing with a good used barrel.

Still curious why both are cracked.

Re: Triumph cylinder barrel repair advice needed [Re: Bodger] #297997
02/06/10 11:41 pm
02/06/10 11:41 pm
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Posts: 3,730
ca, us
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DMadigan Online content
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That crack is typical of a rod hitting the cylinder. If you want to keep the barrels, I would suggest getting a set of sleeves, boring out the cylinder and pressing in the sleeves. You could just do the one but modern cylindrically cast sleeves (such as LA Sleeve) might need different clearances. Of course, there is little load on that part of the cylinder with an intact rod. You could probably get away with brazing.
I remember that Britton had to braze a crack in the sleeve of his racer at Daytona one year. It lasted through the race (until the rectifier blew a couple laps from the end).

Re: Triumph cylinder barrel repair advice needed [Re: DMadigan] #298050
02/07/10 6:01 am
02/07/10 6:01 am
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Santa Barbara, Cal.
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Bodger Offline
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(oh man I should stop now to retain whatever credibility I might have fooled people into...)
(but...that hasn't stopped me before :> )

DMadigan, both cylinders say Swan, altho the picture doesn't clearly show the other cylinder. What could have caused that? I ruled out dropping, because the metal is displaced outward on the one we can see. Simultaneous rods breaking and...AND impacting the barrel bottoms at the same time is just statistically not possible, imo...and even breaking the other rod later and having it hit the cylinder the same way instead of the cases is low probability imo.
And that speaks to high and continuous loading from something, with the cracks NOT caused by , or the cause of, catastrophic engine failure. I'd say, and since the cases are not reported fixed, it came with rods and crank unbroken, that it was likely stopped while running, and dismantled...whether the cracks caused the dismantling is not said if known.
Another possibility is the crank breaking and the intact rods' sides hitting the barrel ends, I don't even know if that's dimensionally possible, and alloy rods might not be able to have done this. Carrillo steel rods on a broken crank may have, but I would think the cases would show damage as well, maybe in the bearing area.
But, guess what, that's what I'm doing , guessing as this still strikes me as odd.
As Mr Healy suggests might have suggested, maybe, find out why something happened before throwing more time and effort into it. So I would really go over the cases and crank and rod to make sure there isn't some hidden something there to come back and undo what you, Swan are trying to fix.

Now watch,Swan will pop up and say, "Ooops! only one cylinder cracked.", and one broken rod could do that, cause that one crack...still a good inspection is warranted anyway...beyond normal (for me ) paranoia.

I've got a nice Goldie barrel liner with the same crack, and it was a steel rod what done it...Sniff.

1. as to the sideways forces at the bottom of the liner, duh, yes, of course I was wrong there about that being the highest loading on the wall...however...what I was 'thinking' is
that this the point that the piston gets the rod inertia and thrust loading reversed...(at least at the rod end, the pin end loading would follow later, via sine curve loading profile I think).....and combined with some mental construct of the piston clacking over to the forward face (which face is the crack on anyway???), so I'm all wet there...

2. the piston and ring load on the wall would be reflected in the wear taper of the bore, measured top and bottom, right?

So..wouldn't that speak to this repaired area being lightly loaded, and technically fixable and reliable?

Yet, with all the fuss, the doubts, and the low cost of replacement, getting a good used is way better.

I just like puzzles :>

(thanks again for indulging my ramblings y'all.)

Re: Triumph cylinder barrel repair advice needed [Re: DMadigan] #298118
02/07/10 6:52 pm
02/07/10 6:52 pm
Joined: Mar 2007
Posts: 1,156
Winona, MN
Swan Offline OP

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Winona, MN
All,

Thank you all for your advice. I have carefully looked over everything I believe the barrel was cracked during shipping and have decided to replace it. Despite my pleas with sellers to wrap and package things well, they do not. This one was wrapped in newspaper when it arrived. I handle high value art and archaeological items as a profession and ship very expensive items worldwide without any problems because I package things correctly.

The crack appears to be fresh and the conrods are in pristine shape. I am still in the market for a decent 650 barrel.

Last edited by Swan; 02/09/10 10:10 pm.

1966 Triton
1962 BSA DBD34 Gold Star
1966 Triumph Bonneville
Re: Triumph cylinder barrel repair advice needed [Re: Swan] #298192
02/08/10 8:50 am
02/08/10 8:50 am
Joined: Oct 2004
Posts: 4,429
Melbourne Australia
Tiger Offline
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Melbourne Australia
Not suggesting that both skirts are cracked but if they were it would be possible for a hideous Bodger [as opposed to our Bodger] not thinking to relieve cylinder skirts after having fitted a stroked crank or wide shank conrods ?

Hideous Bodgers are very creative, I sometimes suspect that there exists a secret brotherhood of the buggers and that they gain kudos amongst their friends for knackering things and setting traps for better men.

Hmmmmmmm ! Perhaps a good topic for British Bikes in general ?


1969 TR6R
7.62 x 51 is not a maths puzzle.
Re: Triumph cylinder barrel repair advice needed [Re: Swan] #298285
02/09/10 12:12 am
02/09/10 12:12 am
Joined: Sep 2006
Posts: 398
hamilton on. can.
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highway Offline
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If it is only cracked on one side you have to option of resleeving the barrel, especioaly so, when the other barrel is std.
The resleeving of both sides is usually not worth the cost. It is a repairable barrel, so don't throw it out if you get a replacment. Rick

Re: Triumph cylinder barrel repair advice needed [Re: highway] #298316
02/09/10 5:25 am
02/09/10 5:25 am
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Posts: 3,252
arkansas
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leon bee Offline
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arkansas
Then when you find a replacement, you have to try to get the guy to package it well enough......at the risk of offending him. Its always like, "don't worry, man, I know what I'm doing." I've now had four (4) barrels shipped to me which were busted in transit.

And I've sent out a few which made it just fine cause I worried about em a little.

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