cylinder head

03-05-2013, 10:49 AM

Hi to everybody,never been in a forum before or posted a thread either,probably not had much to say,.....until now perhaps! I have a gorgeous M750 called Ruby,previous owner put all her docs,cd,etc into a folder with her name on it,so I cant change that now! Never got out on her last year due to health and crap weather. The new battery which I thought was only bought last year,turned out to be nearly two years old and goosed! Yesterday when taking out the old spark plugs,the bottom one came out and the new one went in fine,the top one or rear head one was only partways in and tight to come out,like i've put it in so far cross-threaded and stopped,probably from two years ago eh,plonker! I'm lucky I have a McConechy's literally two minutes from me,and the guy there is a wizard on bikes etc,I'm sure it'll all be sorted in the end but i just wondered if I did need a new head,or replacement,maybe someone here has had a similar experience and could pass on some valuable thoughts,info or anything,many thanks

slob · 03-05-2013, 11:00 AM

I'm sure a repair will be way cheaper than a new head. Almost any motor engineering shop should be able to do this for you.

utopia · 03-05-2013, 11:53 AM

Like Slob says, if the thread is stripped then a helicoil repair is a relatively common solution that any decent workshop will be familiar with, and shouldn't be too expensive.
I would think that the head will most likely have to come off to do it, but you never know, with the piston at tdc they might even be able to do it in situ and hoover out the metal chippings from recutting the thread......???

I'm glad you've kept the name.
Ordinarily, I never give my bikes a name, but I can understand it for a 750 monster .....somehow they have a particularly strong personality that requires a more personal relationship.
As such, mine seems to have acquired the name Rose (though I never call her by name, and I'm not even sure that she's female).
The name Ruby does (rather appropriately) suggest jewel-like qualities.

Hope you get her sorted without too much trouble.

03-05-2013, 01:13 PM

cheers guys,and she is red as well I suppose so. But thanx again,tell you when i'm on the road.

05-05-2013, 02:28 PM

If the badly fitted plug was not screwed in all the way, then you should be able to reclaim the threads. Acquire a longish tap to suit the plug thread, grease it well to hold the swarf that will be created, lower the piston down to give you enough room for the tap to go into the cylinder a bit, take a look down the plug hole to ensure there isn,t a valve head visible, and run the tap through it.

03-05-2013, 10:49 AM	#1
jimsilver Guest Posts: n/a	cylinder head Hi to everybody,never been in a forum before or posted a thread either,probably not had much to say,.....until now perhaps! I have a gorgeous M750 called Ruby,previous owner put all her docs,cd,etc into a folder with her name on it,so I cant change that now! Never got out on her last year due to health and crap weather. The new battery which I thought was only bought last year,turned out to be nearly two years old and goosed! Yesterday when taking out the old spark plugs,the bottom one came out and the new one went in fine,the top one or rear head one was only partways in and tight to come out,like i've put it in so far cross-threaded and stopped,probably from two years ago eh,plonker! I'm lucky I have a McConechy's literally two minutes from me,and the guy there is a wizard on bikes etc,I'm sure it'll all be sorted in the end but i just wondered if I did need a new head,or replacement,maybe someone here has had a similar experience and could pass on some valuable thoughts,info or anything,many thanks

03-05-2013, 01:13 PM	#4
jimsilver Guest Posts: n/a	cyl head cheers guys,and she is red as well I suppose so. But thanx again,tell you when i'm on the road.

03-05-2013, 11:00 AM	#2
slob . Join Date: Jul 2003 Location: East London Bike: Multiple Monsters Posts: 9,735	I'm sure a repair will be way cheaper than a new head. Almost any motor engineering shop should be able to do this for you.

03-05-2013, 11:53 AM	#3
utopia No turn left unstoned Join Date: Jun 2010 Location: leicester Bike: M750 Posts: 4,561	Like Slob says, if the thread is stripped then a helicoil repair is a relatively common solution that any decent workshop will be familiar with, and shouldn't be too expensive. I would think that the head will most likely have to come off to do it, but you never know, with the piston at tdc they might even be able to do it in situ and hoover out the metal chippings from recutting the thread......??? I'm glad you've kept the name. Ordinarily, I never give my bikes a name, but I can understand it for a 750 monster .....somehow they have a particularly strong personality that requires a more personal relationship. As such, mine seems to have acquired the name Rose (though I never call her by name, and I'm not even sure that she's female). The name Ruby does (rather appropriately) suggest jewel-like qualities. Hope you get her sorted without too much trouble.

05-05-2013, 02:28 PM	#5
Dookbob Guest Posts: n/a	If the badly fitted plug was not screwed in all the way, then you should be able to reclaim the threads. Acquire a longish tap to suit the plug thread, grease it well to hold the swarf that will be created, lower the piston down to give you enough room for the tap to go into the cylinder a bit, take a look down the plug hole to ensure there isn,t a valve head visible, and run the tap through it.