Cylinder head knackered.............

[andyw]

Will I ever get this bike back on the road!!!

Latest discovery is that some ham fisted tiny brained t**t has at some time broken one of the exhaust studs from the head (god knows how??!!). Then to make matters worse the culprit has drilled out the head and 'glued' a bolt in place.....surprise surprise, this bodge has failed.

I'm not sure the head is repairable, not only has a larger than necessary hole been drilled but on dremelling out the remains of the 'glue' I find that a waterway has been perforated
I'm making enquiries about repairing but seems a good idea to look for a replacement head as well!

...............(it's a good job the guy I bought the bike from is not local!!! )

........if anyone can point me in the right direction to find a replacement head I'll be very grateful

[Sourcer]

Is this what you need?

http://cgi.ebay.co.uk/SZR-660-XT-660-CLYINDER-HEAD-AND-CAM-YAMAHA_W0QQitemZ8064198944QQcategoryZ10490QQrdZ1QQcmdZViewItem

[keithcross]

Dont have a spare myself, but Steve who lives in Suffolk may have one. Or you could try to get one for a 660 Raptor as I believe they fit, no problem.

Keith

[whysub01]

I'll have a word with my mate Steve (see above) who builds race engines-he may have a spare he can sell.

Will check back later with result.

[whysub01]

I'll have a word with my mate Steve (see above) who builds race engines-he may have a spare he can sell.

Will check back later with result.

[andyw]

[whysub01]

Andy-PM Sent

[cat]

It can be fixed, but you need an expert welder and fabricator. If you were here, you could get it done. If you can see the water passage hole, the perforation, then it could almost certainly be fixed.

[andyw]

I'm waiting for a second-hand head to arrive (Many thanks to whysub01 for the lead ) but I've also got contact info for an 'expert' in aluminium welding.
I prefer to run an undamaged/repaired head so will use that when it arrives and hopefully recoup some of the costs by having the original head repaired and eBaying it.

Thanks again to everyone for the help and advice........

.......anyone got recommendations/advice for cleaning the top of the piston (removing carbon deposits) and or tips for things to watch out for on engine top end reassembly?

[cat]

[andyw]

Spent ages trawling the net but not come up with a solvent/cleaning agent for removing carbon deposits - obviously needs to be something that will not react with aluminium in any way.

Tips I've found so far:
Scraper - use a soft grade aluminium or even wooden wedge shaped scraper.
If cleaning the piston in situ (i.e. barrel not removed), tape round the edges of the piston to be absolutely sure no carbon/coke other debris can fall in to the ringland
Take great care not to mark the piston - also, DON'T polish the cleaned pistion

[keithcross]

I have used a chemical for helping to remove compond type head gaskets which loosens carbon deposits. Its not to safe and must be used in a well ventilated area. Its called MEK (shortened name - Methel ethel ketone or something like it). It used to be used in the UK printing trade, but I dont think they use it anymore.

Keith

[andyw]

IT RUNS!

..........new top end sounds quiet and smooth. So far all I've done is run it up to temp in the garage and leave it running for a few minutes more - so far so good. Will let it cool and then do the same before going for a gentle run

Cleaning combustion chamber, valves and piston crown - did use some carb cleaner but not sure it made much difference. The job was pretty easy with a bit of care using:
# An aluminium scraper (just a piece of aluminium sheet cut to 20mm wide, bend a bit of a curve at one end and then chamfer both ends to make a sharpish scraping edge)
# A small brass (NOT steel!!) wire brush
# A thin piece of plastic as a second scraper
CARE - if cleaning the piston crown in situ (i.e. barrel still on engine) mask up the edge of the piston and barrel to make sure no debris enters the waterways or ringland.
Also took the time to grind the valves/valve seats in and put new valve stem oil seals on.

[whysub01]

Did you get the head from Steve? Whatever, very glad you have it running now.

He did a motor for me whicjh is still sitting on the garage floor, and I have no time to swap them over.

Looking for a mechanic, preferably with knowledge of the Sport model or even the 660 motor to do the swap for me (nice bit of cash work) but can find anyone to do it? Can I buggery!

[andyw]