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serious engine problems

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Jameshambleton
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serious engine problems

Post by Jameshambleton on Mon 16 May 2016, 9:28 pm

The old plug spat itself out again tonight, new spark plug has gone in spun and spun round so I think the thread is fucked, but yet it also seems to grip. When I turn the engine over and blows the plug out.
At the end of the old plug the head had bent over, i tried the new plug and it's done the exact same thing, so anyone got any suggestions?

sullivj
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Re: serious engine problems

Post by sullivj on Mon 16 May 2016, 9:41 pm

Sadly, I think the thread is definately buggered. The plug seems to be sitting too low, and seemingly gets struck by the cylinder..

Probably needs some specialist attention.
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Tricky.
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Re: serious engine problems

Post by Tricky. on Mon 16 May 2016, 9:51 pm

a helicoil insert will sort this issue out.
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wornsprokets
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Re: serious engine problems

Post by wornsprokets on Mon 16 May 2016, 9:53 pm

U could use Helicoil,( delboys garage did one last week) sounds like a mistaken wrong plug put in too , might be better go get an other engine

sullivj
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Re: serious engine problems

Post by sullivj on Mon 16 May 2016, 10:12 pm

@Tricky. wrote:a helicoil insert will sort this issue out.



Could you fit one without dropping loads of swarf into the bore?
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Jameshambleton
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Re: serious engine problems

Post by Jameshambleton on Mon 16 May 2016, 10:17 pm

Could I swap the head over from my donor bike to fix it and is the metal head gasket reusable? 

The sparkplugs that I've used are the NGK CR9EH9, it's only the left side that this has been done to, the other is fine.
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Beresford
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Re: serious engine problems

Post by Beresford on Mon 16 May 2016, 10:21 pm

@sullivj wrote:ricky.a helicoil insert will sort this issue out.
Could you fit one without dropping loads of swarf into the bore?

I was told once upon a time that this could be sorted by packing very greasy cord into the cylinder and the swarf will stick to it. Then pull it out again using a wire hook.

sullivj
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Re: serious engine problems

Post by sullivj on Mon 16 May 2016, 10:43 pm

Have a look here James:

https://youtu.be/Cqid0tfLzEg
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ANDYC
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Re: serious engine problems

Post by ANDYC on Mon 16 May 2016, 11:06 pm

You can swap the head from another engine easily enough. A new gasket would be better than taking the risk, the steel gasket would seal the cylinder well enough but not the oil and water passages.
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Jameshambleton
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Re: serious engine problems

Post by Jameshambleton on Mon 16 May 2016, 11:25 pm

I'd forgotten about the coolant passages. 

I'll be contacting the garage tomorrow to see if/when they can fit a helicoil, I know it's a 10m thread with a 1mm pitch.
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eternally_troubled
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Re: serious engine problems

Post by eternally_troubled on Tue 17 May 2016, 12:09 pm

You can do the helicoil yourself, if you are careful.  It is probably a lot easier if you have a pillar drill though (cheap from Aldi! if they still have them...), so it might be best left to someone else if you haven't got one.

Assuming you haven't overtightened the spark plug then I bet that one of the previous loving owners has done but the plug threads have been just holding and have recently given up the ghost.

I reckon that Beresfords trick would work pretty well - it would catch almost all of the swarf, so I reckon it would be fine - probably wouldn't do it on low-mileage new bike, but I can see the temptation of doing it on a well-used CB500.  Plus the swarf is aluminum, so it won't scratch the bore too much, will it ;)

More seriously, if you have the time and inclination then taking the head off, getting it fixed and putting it back on (with a new gasket, as someone said above) will fix the problem and shouldn't cause too many extra issues. While you are there you can check/sort out your valve clearances (do this after putting the head back on when you are putting the engine back together).

You can try using an old gasket but I would advise against it, unless you like taking engines apart - you will end up putting a new gasket in when it (probably) leaks in some way or the other.

If the original gasket comes off easily (it probably won't!) and you want to reuse it, despite the dire warnings ;) then I would think you'll need something like wellseal (http://www.wellseal.co.uk/) or hylomar blue to patch up the bits where the original coating as come off.

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Jameshambleton
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Re: serious engine problems

Post by Jameshambleton on Tue 17 May 2016, 12:39 pm

I sadly don't have any tools like that, I don't even have a garage or dry place to work on my bike at the moment. 

I replaced the plugs when I got the bike and it all seemed fine, as I'd put in the plug and turned it counter clockwise until it seated in the thread and then hand tightened it and then give it a 1/4 of a turn nip up. The other plug is fine and the owner before me wasn't a monkey either. 

I've put on 10k miles in 7 months, my bikes total milage is 35.5K so it's low mileage overall but quite high for such a short period of time
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Beresford
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Re: serious engine problems

Post by Beresford on Tue 17 May 2016, 4:33 pm

That clip showed the bloke using an (expensive) timesert kit. Having seen that I think it's definitely the way to go as the head is correctly cut as well for the plug seat. He seemed to have a mobile workshop so maybe you could find him, or some one with a similar business in your area , which would save having to take the head off.
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Jameshambleton
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Re: serious engine problems

Post by Jameshambleton on Wed 18 May 2016, 8:52 am

Garage is going to take the head off and then re-thread it using a helicoil, so carbs will be coming off, engine coolant drain, new head gasket, cam chain to be removed and the exhaust system. fuck this hurts right in the bank account.

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