This is very good information, only one of my bolts has the shoulder - I understand why it needs one and will endevour to find a replacement in my box of bits - otherwise will order one from spares...
Thanks...
Thanks...
petrol tank removal
- Thread starter Joe Vincent
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TouringGodet
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For me, a drag bike or a land speed bike.
The threads in the steering column where the F81 bolts are often stripped. Sometimes a longer (but incorrect) bolt is fitted to engage sound thread further down the hole. It is a relatively simple operation to restore the thread in situ by fitting a helicoil. The standard shouldered F81 can then be re-fitted.
i have said this before but as this might be the first time you have revmoved the tank.
when you put it back,
make sure the rubber pad under the rear of the tank is thick enough to stop the tie cross bolt assembly fouling on the rear valve cap,
as it will bend the rear tank flange down when you do up the two rear bolts and crack the weld causing a leak.
yes i did?????
OSSIE
when you put it back,
make sure the rubber pad under the rear of the tank is thick enough to stop the tie cross bolt assembly fouling on the rear valve cap,
as it will bend the rear tank flange down when you do up the two rear bolts and crack the weld causing a leak.
yes i did?????
OSSIE
I had an expensive sounding rattle on my Rap at 70+, it wasnt until I had the tank off and noticed 2 faint marks on the top of the crash bar that the penny dropped. the front tank rubbers were a bit tired and let the tank settle, as it vibrated a bit at 70 it hit the crash bar. new front rubbers and a slightly thicker rubber at the back, was a cheap fix.
sorry edd,
but I am afraid you are wrong. if the tank bosses have had a helicoil repair carried out, then I would not advise using a standard tank bolt, for when you tighten the bolt down, instead of butting down on to the boss of the upper frame member, it will be butting down on to the helicoil insert, causing damage to the insert. what you need is a tank bolt that has a larger dia on the plain portion, so that it buts down onto the upper frame member, and not the insert. you will allso have to enlarge the hole size in the rubber. a dremel will do this .
regards norman.
but I am afraid you are wrong. if the tank bosses have had a helicoil repair carried out, then I would not advise using a standard tank bolt, for when you tighten the bolt down, instead of butting down on to the boss of the upper frame member, it will be butting down on to the helicoil insert, causing damage to the insert. what you need is a tank bolt that has a larger dia on the plain portion, so that it buts down onto the upper frame member, and not the insert. you will allso have to enlarge the hole size in the rubber. a dremel will do this .
regards norman.
norman
what about using a thin washer that is larger than the helicoil and is a good fit on the threaded part of the bolt.
but abutts against the frame boss.you can then use a standard bolt.
as long as you don,t over tighten the bolt and try to extract the helicoil it should stay put gripped by the rubber tank boss.
at least mine do.
OSSIE
what about using a thin washer that is larger than the helicoil and is a good fit on the threaded part of the bolt.
but abutts against the frame boss.you can then use a standard bolt.
as long as you don,t over tighten the bolt and try to extract the helicoil it should stay put gripped by the rubber tank boss.
at least mine do.
OSSIE
Dear Norman,
You have raised some interesting points here which highlights that you have to look carefully at any modification to see if there is are are repercussions "further down the line". In this instance I have had no problems with this method of repair in the last 20,000 miles. I take care when fitting and tightening the F81 bolts so that the rubber is just compressed a little and the bolt just "nipped". The slight compression of the rubber stops the F81 coming loose.
You have raised some interesting points here which highlights that you have to look carefully at any modification to see if there is are are repercussions "further down the line". In this instance I have had no problems with this method of repair in the last 20,000 miles. I take care when fitting and tightening the F81 bolts so that the rubber is just compressed a little and the bolt just "nipped". The slight compression of the rubber stops the F81 coming loose.
VincentHRD
It was hardly a cost saving exercise. The "D" tank was a vastly different design due to the top frame member being only a tube. The latter tank did not need any stiffening aids to withstand normal use. I have heard of many "C" tanks that split when the stiffening tube was omitted, but never any such occurrence on a "D" tank.
It was hardly a cost saving exercise. The "D" tank was a vastly different design due to the top frame member being only a tube. The latter tank did not need any stiffening aids to withstand normal use. I have heard of many "C" tanks that split when the stiffening tube was omitted, but never any such occurrence on a "D" tank.