CBR4/6 seazed lump ?
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leopard_pagan
- Senior Member
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- Joined: Thu May 01, 2008 6:42 am
- Bike owned: CBR400/600 Fighter
- Location: Mildenhall-Suffolk
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CBR4/6 seazed lump ?
correct me if i have got this wrong...
i need to turn the engine by hand so that *I* know its not seazed.
1) remove spark plugs
2) removed starter motor in case it's seazed
3) put in to gear (2nd)
4) put a socket on the front sprocket nut & turn..
?
well thats what i did and i cant get anything to move! nor did the sprocket nut come undone!
starting to think the best way for this is to ditch the fitted (not) lump and get one that i know runs!
The valve stems look rusted as the carb/header ports were left exposed to the elements for what maybe a year.
i need to turn the engine by hand so that *I* know its not seazed.
1) remove spark plugs
2) removed starter motor in case it's seazed
3) put in to gear (2nd)
4) put a socket on the front sprocket nut & turn..
?
well thats what i did and i cant get anything to move! nor did the sprocket nut come undone!
starting to think the best way for this is to ditch the fitted (not) lump and get one that i know runs!
The valve stems look rusted as the carb/header ports were left exposed to the elements for what maybe a year.
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BillingCBR
- Site Supporter
- Posts: 1043
- Joined: Sat Oct 10, 2009 10:36 pm
- Bike owned: '88 NC23, NC30, '98 R1, NC35
Re: CBR4/6 seazed lump ?
leave it in neutral, if it has a timing mark cover on the right hand case, take that off and use that to turn it over.
'89 CBR400RRJ and '91 VFR400R NC30 project
Neosophist - The NC30 doesn't go very well when it's on fire
Neosophist - The NC30 doesn't go very well when it's on fire
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leopard_pagan
- Senior Member
- Posts: 1184
- Joined: Thu May 01, 2008 6:42 am
- Bike owned: CBR400/600 Fighter
- Location: Mildenhall-Suffolk
- Contact:
Re: CBR4/6 seazed lump ?
just done that and it eventually turned! its now moving as free as it gets. i cant feel any more resistance & i can now turn it on the sprocket in 2nd 
thing is, if the valves are pitted as they are covered in rust.... cost wise may have to buy another lump as each valvle is £20 x 16..... more than a working lump of same year off ebay!
thing is, if the valves are pitted as they are covered in rust.... cost wise may have to buy another lump as each valvle is £20 x 16..... more than a working lump of same year off ebay!
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BillingCBR
- Site Supporter
- Posts: 1043
- Joined: Sat Oct 10, 2009 10:36 pm
- Bike owned: '88 NC23, NC30, '98 R1, NC35
Re: CBR4/6 seazed lump ?
You might get away with having them blasted and lapped in, but if it's seized I'd definitely consider a new lump, the bores might be damaged from the rust, which could cause problems with the piston rings aswell. You won't know how good or bad it is until you get it into bits though 
'89 CBR400RRJ and '91 VFR400R NC30 project
Neosophist - The NC30 doesn't go very well when it's on fire
Neosophist - The NC30 doesn't go very well when it's on fire
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leopard_pagan
- Senior Member
- Posts: 1184
- Joined: Thu May 01, 2008 6:42 am
- Bike owned: CBR400/600 Fighter
- Location: Mildenhall-Suffolk
- Contact:
Re: CBR4/6 seazed lump ?
i know, just really didnt want to be doing that! lump is now moving/turning over freely 
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kiwi racer
- Settled in member
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- Joined: Sat Nov 15, 2008 9:10 pm
- Bike owned: CBRs
- Location: New Zealand
Re: CBR4/6 seazed lump ?
leopard_pagan wrote:just done that and it eventually turned! its now moving as free as it gets. i cant feel any more resistance & i can now turn it on the sprocket in 2nd
thing is, if the valves are pitted as they are covered in rust.... cost wise may have to buy another lump as each valvle is £20 x 16..... more than a working lump of same year off ebay!
So pull the head and check it over , that way at least you know whats wrong . If you just presume its a crook valve set etc then thats not logical. Get in there and have a good look to confirm. As was stated above you can clean them up ok .
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leopard_pagan
- Senior Member
- Posts: 1184
- Joined: Thu May 01, 2008 6:42 am
- Bike owned: CBR400/600 Fighter
- Location: Mildenhall-Suffolk
- Contact:
Re: CBR4/6 seazed lump ?
had a mechanic mate pop over the other day to take a look, due to the amount of rust inside, he said that i have probably scoured the bores when i got the pistons moving again.
yes you can clean the valves up but if pitted you still have to replace em.
the carbs are all seized up and not worth stripping & the headers are complete shite!
i am not happy with the loom so i'll get a whole one. that way if i need to cut stuff off, *I* know why.
SOOO i have decided not to use this lump at all now. getting it working will cost more than buying a 2nd working lump! i will be stripping parts off and selling to re-coop money towards buying another engine. eg side covers/rocker as they are polished, sump etc.
yes you can clean the valves up but if pitted you still have to replace em.
the carbs are all seized up and not worth stripping & the headers are complete shite!
i am not happy with the loom so i'll get a whole one. that way if i need to cut stuff off, *I* know why.
SOOO i have decided not to use this lump at all now. getting it working will cost more than buying a 2nd working lump! i will be stripping parts off and selling to re-coop money towards buying another engine. eg side covers/rocker as they are polished, sump etc.