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bolt stuck

johankjellgren

johankjellgren

Well-known Member
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Jul 17, 2020
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Location
Stockholm
Trying to replace top and cylinder gaskets. following the instruction loosening the bolts. however #7 in this pic is stuck and i dont dare to use more force. i can jiggle it a little but then after a half turn no more.
anyone got any idea? why this one? all the other pretty easy.
Longer shaft = more force?
i got a powerful airdriven "wheel-bolt-machine" (dont know the english word.) use that? (if it fits)
/ johan

Namnlös.png
 
I'm glad it came loose for you, but you probably got lucky. LDR has mentioned many times that those bolts can be very hard to get loose and sometimes the threads get damaged in the process.
 
ancientdad said:
I'm glad it came loose for you, but you probably got lucky. LDR has mentioned many times that those bolts can be very hard to get loose and sometimes the threads get damaged in the process.
Click to expand...


yay. weird with only one.
all good now
will inspect all moving parts during the holidays
 
johankjellgren said:
yay. weird with only one.
all good now
will inspect all moving parts during the holidays
Click to expand...
Glad it came out.
Remember a turn in either direction is positive.
If they are stuck loads of penetrant. Heat, cold, Repeat. Try to get a slight wiggle in either way. Once it starts to move. Keep repeating the same.
Alt
 
If one of these bolts is going to get stuck it's #7 followed by #5, front center bolts that are exposed to outside weather.
I suspect that this is the reasoning for the special #7 bolt that has the rubber wrap. If the bike is parked on the side stand in rain or washing that is a low point that can fill with water.
 
LongDistanceRider said:
If one of these bolts is going to get stuck it's #7 followed by #5, front center bolts that are exposed to outside weather.
I suspect that this is the reasoning for the special #7 bolt that has the rubber wrap. If the bike is parked on the side stand in rain or washing that is a low point that can fill with water.
Click to expand...


sorry I obviously can't count the valves.
When i saw your reply I just realized it was #8 that was stuck since it was in the rear :lol:
 
Now the next question. When i look on some videos these assemblies seems to come straight off.
Is there a trick to this?
rocker.jpg
 
When I removed the top 3 dowels followed it up so i assumed 1 was stuck in the cylinder, but no. Only 3 in total that can't be right,right?

anythin i should look for while the top is off? need to replace the cylinder gasket too so rings pistons?
How should I clean the inside of the top btw valves ?
 
Yeah there should have been 4 dowels between the head and cylinder. 2 of them, rear outer, have a rubber sleeve that's included in most gasket sets and has to be replaced each time.
Unless the valves have lots of build up, very rare, there's no need to clean the up. These valves cannot be reground, the hard facing is too thin for resurfacing at .0002" thickness.
I'm unclear as to why the head needed to come off the engine so advice on rings is a question mark.
 
If you had good compression beforehand then there'd be no reason for replacing the rings, spec is 185psi +/-14. Below 165 I would replace the rings. I'm hoping you ran the compression test before teardown since it's impossible now.
The valve cannot be reground so those are replacement only.
 
If there are any dowels missing, someone has been in there previously and lost one.
It was probably during first 1000/1500Km or so as the 3 valve motors did have some problems with oil weep on European models (and balance/cam chain adjustments)
I was 'inside' several of the 250 and 400's in 1978/79, the 'Eurosport' models were much better though (except CB900, major cam chain problems for years)
Make sure the copper and steel washers are in the correct positions, that is another reason you may have had a stuck nut?
I think we swapped all the head washers for copper, as it expands more than steel it kept head 'tighter' when hot (long time ago, I get various motors confused nowadays)
 
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