Repair by main dealer failing

[kramdra]

Would like some advice, 2 years ago 7 exhaust studs snapped off my CBR6 when changing rotten downpipes. I paid the main dealer £800 to remove the head, and put everything back together (they subcontracted the stud removal/repair). This has lasted two years. Now the 3rd cylinder studs appear to be pulling out of the head - the nuts are tight, but the flange is loose, and blowing very badly.

In my opinion, this repair should last a very long time, certainly longer than two years. I took it in for them to have a look. They say it had a years warranty for the work, and quoted £250 to "fix it" - this is with no guarantees that they would not snap a stud making it £800+ Do I have any options here?

When they repaired it, I wanted them to fit M8 stainless studs, but they refused and instead fitted OEM studs that reduce M8-M6 making them highly likely to snap.

*IF* the current studs could be easily removed, I would prefer it to be drilled and tapped for M10 stainless studs. I have no problem DIY'ing this if the current ones are out.

[lihp]

You're moaning that a main dealer used OEM stuff?
____________________
covent.gardens: lihp is my most favourite member ever

[Rogerborg]

[kramdra]

[DrDonnyBrago]

Have you tried turning one of the loose studs?, it's probably just undone a little, hardly the end of the world.

If they were out 2 years ago, assuming the dealer used copper grease they should still be pretty free moving. I fitted st/st headers using m8 stainless threaded bar about 2 years ago. One of them backed out about a year afterwards as I went copper grease crazy on the install, the repair was simply a matter of screwing it back in.

£250 quote is amusing.

[evoboy]

Did a job similar to that for around half the price including having 6 out of the 8 ( Thundercat ) studs removed, re tapped and with new studs. ( Thats doing the job properly by taking the head off and setup on a mill to remove the studs, including all the parts to build the top end back up )

4 years later, they are still perfectly fine to be removed.
____________________
Suzuki GT250 x7------- Fazer 600------CB250RS------Aprilia Rally 70----- Bandit 600

APT Motorcycles

[MattEMulsion]

Two years down the line I think you are unlikely to have much comeback against the dealer unless they make a gesture of goodwill. How many miles has the bike covered in that time?

Have the work done elsewhere & sue the arse off the dealer - You'll need a lot of luck to win by my reckoning. Anything over 12 months you are on rocky ground, whether you think that it is reasonable or not.
____________________
Yamaha YZF-R6

[Teflon-Mike]

You don't put stainless into blind holes if you have any sense.

Stainless is more brittle than mild, due to the nickel content; & being more brittle, it is actually more likely to shear, than mild.

Then you have the rather un-nice scenario of having to try and drill out the harder stainless stud, corroded into an alloy head, without the drill running off into the soft and expensive metal you want to save.

Honda 'stepped' head-studs holes used to be the ucommon M7x1 thread size.... this MAY be why Dealer used OEM studs; M7 is not a standard bolt size.

However, it IS convenient that the M7x1 thread size is exactly the helicoil thread for an M6 stud..... which would be tempting, to make upgrade out of a repair, but have't ever had any issue with stepped studs shearing at the step.

As for the dealer? You paid frachise dealer price for 'Honda' approved repairs, using Honda approved parts, got a 12 month warranty, that has lapsed. I don't think there's any come-back on the dealer doing what the manufacturers recommended they should, rather than what you might have suggested they do instead; or for a bolt they did up two years ago now working loose.
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[kramdra]

I have no problems drilling stainless, carbide drills dont give a shit

Provided the studs are going to last forever, I would have no issue with them being stuck in the head. If they wont ever snap under normal use and wont suffer significant corrosion, they are ideal.

Metal properties are very complex, so please correct me if Im wrong - I believe 304 grades have very good creep and high temperature resistance without significant embrittlement.

I dont know what grade the OEM studs were made of, but they were extremely weak and sheared if breathed on. Mild steel is not known for its great high temperature properties.