Cylinder repair

[MitchB]

Right to the point - While re-assembling the top-end of my 350 - after a major cleaning and a re-ring - one side of the exhaust flange cracked (then broke) on the right cylinder, as I was snugging up the exhaust nuts.

I only know of two solutions, well three...
1) New cylinder - I've never seen them listed for sale. I'm supposing the are made of un-obtanium, or are very expensive.
2) Have the damage repaired. I do not know of a US-based outfit that can do this, but I've seen reference to a shop that can nikasil plate the cylinders. Perhaps they can? Are they still in business / does someone have their contact info?
3) Have the good fortune to find a a used one (or pair) that are in good shape (don't need work)

I'm soliciting any other solution(s) or suggestions...

Thx,
Mitch

[slawsonb]

Mitch, I have used Millennium Technologies in Plymouth WI (Google them for info) to repair some things that I initially didn't think were repairable. If you send them pics of the damage they can give you a quick go/no go call and an estimated cost. There are probably other shops that can do this as well, but I have had good luck with Millennium.
There are no new cylinders available (unless someone has a NOS one or two stashed). Most that you will find on ebay are in need of repair and plating (with Nicasil these days) typically about $300 each depending on the amount of welding and machining needed prior to plating. Millennium can estimate this as well.
Good luck.
...bert

[BS Mechanic]

There's a right side 350 cylinder on ebay, might be worth a look: http://www.ebay.com/itm/161743781044?_trksid=p2060353.m1438.l2650&ssPageName=STRK%3AMEBIDX%3AIT

[old smokey]

I also used Millennium Technologies in Plymouth WI to replate my 350 cylinders.
Until 6 weeks ago I lived in Plymouth and got a quick shop tour when I dropped them off.
The GTR isn't reassembled yet, but the cylinders look good. Think I paid about $520 for both which included some welding repairs on the interior walls around the exhaust ports.

[MitchB]

Follow up...

Sent both cylinders to Millennium Technologies... They repaired the exhaust port area, and I had them re-plate both cylinders. I also had them mill the cylinder head and top of cylinders to get a smooth sealing surface. Total removed was 0.5 mm. Very happy with their work, although it wasn't cheap. All back together now with cleaned pistons and new rings, and went for a brief shake down ride yesterday. All seems well.

During re-assembly I noticed - and it's worth noting - that the exhaust studs do not all bottom out at the end of the threaded area of the stud. A couple will thread all the way to and bottom at the cylinder fin. Noteworthy because if the stud trys to turn while tightening the nut(s) it will push out against the flange.. I think this may be why mine broke. I used a file to trim mine a little before fitting up the exhaust...

I'm keeping revs to 4K, with occasional blips to 5K to break in the rings. I've read that the Nikasil cylinders don't need as lengthy break in - how long do you guys use to break in rings? I've got a little extra oil in the gas tank, and running 130 main jets now... Thoughts..?

 

[slawsonb]

I would keep running premix on a fresh engine for 500 miles or so. That is just my rule of thumb from the past when I used my GTR as daily transportation. It may take a while to accumulate that many miles on these old toys, so use your discretion. If you assure the oil pump is working (you see adequate oil consumption) then you may be able to cut the premix period short. I have personally never used Nicasil plated cylinders as my first are ready to go on my in process motor rebuild. Some other members may have experience that would allow comparison of chrome to Nicasil bore/ring break-in period. Keep blipping. Constant revs are not your friend.
...bert

There is a break-in procedure in the 350 owners manual at this link:
http://bridgestonemotorcycleparts.com/index.php?action=downloads;sa=view;down=85

[OldSwartout]

I've read that the Nikasil cylinders don't need as lengthy break in - how long do you guys use to break in rings?
 

On the 175 racer, they got 1 or two practice sessions (maybe 25 miles) with a couple easy laps to start with, then on to full bore racing.  Probably not recommended for a street bike, tho.   

[MitchB]

I have read the break-in notes in the manual.

500 miles seems excessive even for stock cylinders, more so given that we have the benefit of synthetic oils. The injector system is working fine, and the engine seems willing to rev past 5K.

I've done about 80 miles so far. I think I'll check the plugs for condition, re-torque the head(s), and do another 50 miles or so, then pull the heads and take a peek at the piston tops. If good - re-torque the heads and call it done.

[slawsonb]

I've always been a conservative sort when it comes to break-in (you only get one chance to do it right), but the owners manual does recommend significantly less than 500 miles. Good luck!
...bert