Hi,
A couple of observations during a current re-assembly of a twin.
A plunger A10 but they may apply to others.
Replacement gear box seal and circlip.
Nice new seal, snug fit but circlip would not go in to the groove as the seal did not seam to go in enough. Despite some enthusiastic efforts I could not get it to fit properly. Checked the old seal and it was the same so what was going on. Eventually I removed the rubber from the back of the old seal and 'hey presto' it all fitted properly so since 2012 and over many miles the clip may have not have been seated properly. After thinning down the new seal the new circlip fitted properly. Although this had possibly been like this for a long time with no issue there was the possibility that the seal could have become dislodged and in theory the main gear box bearing.
New crank plugs to be used with a hex key. Great for fitting and removing rather than mutilation with an impact driver. They are however about 1mm deeper than the old style ones. 1mm may not seem much but the oil way from the T/S bush/bearing journal to the crank comes through the last few threads that the plug screws in to. There is the potential for the slightly longer plug to partially obstruct this oil way. Easing the inner edge of this oil way can offset this. Very careful use of a Dremel can just take the inner edge a bit further in to ensure no restriction.
Dave.
Some very useful tips Dave. Thanks for taking the time to post them.
Hi Dean,
I suspect a bit of variation from crank to crank but worth checking. If the oil way is modified then surgical cleanliness afterwards to get rid of any debris.
Dave.
I thought i'd butchered my crank plugs but that picture shows a real masterpiece. :o
On my early A7 the replacement plugs screwed further in than the originals, so I marked the area where the oilway would be when the plug was in tight and ground it away.
It would have reduced the oil hole by half had it just been left.
Hi,
I suppose over the years crank plugs have been removed and replaced several times and paranoia usually means an over abundance of precautionary dot punching so I cannot take credit (blame) for all the 'scars'. It does not look so bad with the new one in and it will hopefully not have to removed by me again but with the new hex key ones it will be very much easier.
I wonder how many bikes left the factory with a partially obstructed oil way and how many have been rebuilt with out knowledge of this potential problem?
Dave.
ps. I wonder how professional engineers/rebuilders remove incredibly stubborn crank plugs.
Instead of punching the crank web which will eventaually weaken it. Punch the plug at the point where the factory centre pop mark is.
I also use a thread sealant (not thread lock) which also has a medium locking strength.
I've found with big journal A10 cranks and A65 cranks that you can screw the plug fully home and it won't restrict oil flow. However I seldom do that and will fit them flush to the crank web.
Hi,
Another one to ponder. Cylinder head bolts original vs replacements.
Have you ever studied your head bolts? Perhaps comparing original ones to replacements from the myriad of suppliers out there.
Torquing an iron head and one bolt did not seem to want to tighten up so before actually destroying the thread I removed the head and had a look. The bolt was not too bad and the thread in the head was just about there but would definitely not take a full torque so what to do?
Taking a closer look I could see that only about 2/3 of the thread had actually been engaged by the bolt. So after a bit of measuring of holes depths and the amount of thread that comes through the head it transpires that this applies to all the bolt holes. The threads in the head go all the way to the bottom of the holes so why are the bolts about 1/2" short. I think I may have bought these head bolts back in 1997 when I put the engine together but never thought to check the length of the bolts, trusting that they would be right - perhaps they are.
After a rummage I found a few vagrant bolts for the aluminium head which are longer so after making sure they would not bottom out I used two of them. With confidence in the tidied up thread and access to a bit more at the bottom of the hole I torqued the head down for the second time in a week.
Dave.
Unless obviously knackered I prefer original bolts anyway. At least you know the metallurgy is sound, unlike stuff knocked up on a dirt floor in some far away country..
Quote from: V500 on 21 May, 2024, 18:48
Unless obviously knackered I prefer original bolts anyway. At least you know the metallurgy is sound, unlike stuff knocked up on a dirt floor in some far away country..
That depends where you buy them from.
You'd hope and expect that trusted reputable suppliers would only supply good quality replacements, but there's been cases reported on the various bike forums that that isn't always so.
"Do you know how hard it is to get good parts made?" doesn't really hack it as a reason for supplying duff stuff, but they still do.