Drumming petrol tank.

Is the tank staying in place on the front mounts? The U shaped mounts on the tank on SFs are virtually horizontal and allow the tank to fall backwards, with all sorts of under tank contact. I have repositioned them to about 30deg so that they locate the tank, instead of relying on the rear rubber strap holding it forward. If the rubber mounts are very old they can be hard, new ones are much better at damping.
 
Grant said:
Not my experience.
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Agree with Paul - had to do this on my 750's - the amount is quite small - less than when you're cranked over in a corner. - Will be using remote float(s) on a 41mm PHM set at 10? more angle - Regards - Phil
 

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Being cranked over in a corner is a different thing to leaning the carbs over on the manifolds. Unless you have a sidecar, "gravity" always acts through the centreline of the bike (or near enough) whether you're leaning into a corner or not. So the liquid in the float bowls is unaffected by the lean. 
 
Dellortoman said:
Being cranked over in a corner is a different thing to leaning the carbs over on the manifolds. Unless you have a sidecar, "gravity" always acts through the centreline of the bike (or near enough) whether you're leaning into a corner or not. So the liquid in the float bowls is unaffected by the lean.
Click to expand...

There's a bloke in Melbourne renowned for pulling long wheelies on his Lavs.
I wonder what happens to the float levels while doing them?
 
Fore and aft sloshing of fuel in the float bowls is to be expected during acceleration and deceleration, so carbs should be designed to handle it. But not sideways.
Doing a wheelie is just an extreme form of acceleration.

On the subject of fuel sloshing sideways, my Kawasaki 1300 with sidecar is fuel injected, so there's no float bowls to worry about. But the fuel tap is on the left side of the tank. If the fuel level is below about half full, in a hard left-hand turn all the fuel sloshes to the right side and the injector pump sucks air. The engine cuts out immediately, like hitting the kill switch. It can be a bit disconcerting at times. I generally try to keep the tank more than half full.
 
chrisk said:
There's a bloke in Melbourne renowned for pulling long wheelies on his Lavs.
I wonder what happens to the float levels while doing them?
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..
 

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I've never been any good at sustained wheelies. I gave up practicing them after busting several rear mudguards on dirt bikes.
I can do sideways wheelies (sidecar wheel in the air) forever, but I guess they're a bit easier.
 
According to Dell'Orto manual "A guide 1.1 to the choice, setting and use of tapered-needle motorcycle carburettors". On page 5 they state that PHF can be tilted from 0 to 40 degrees forwards and on motocross and trial engines from 0 to 30 degrees forwards. Then they give just one float height setting.

I have understood the fuel level should be correct on the main circuit on all of these angles because the main circuit and the floats are positioned on the center of the bowl.

Edit: Ok you meant sideways.
 
I stand more of a chance with this new set of tank rubers received from Slaters.
The original ones are at the top.  The original rear ones may not even be Laverda, of course.
Is the lug hole towards the front or the rear of the rubber when in position?
 

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dammed if I can remember, but I seem to have logged in the brain that your lugs for the rear rubber are "ground off" or was that another 750 in recent times?
CLEM
 
The lugs are there Clem and the new rubbers fit both ways round.
They may lift the tank more if placed forwards of the lugs.
The original rubbers had no lug holes in them.
 
Hi, Simon.
Don't remember which 750 you have.
The original SF0-tank (72) has smaller recesses
for the carbs, as it was designed for the smaller
VHBs.
Later tanks had to come clear off the PHFs and have
larger indentations.
Could it be you have the early tank with big carbs?

Ernesto
 
yes wrong tank,bread loaf,. You should have this "camel" one, if it is a S or SF 

 

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Depends on the SF version.
The "camel" tank for the 71 SF.
With the 72 SF (from # 8357 approx.) the new
"bread loaf" tank was introduced. But unique
to this year with smaller "dents" underneath for
the small carbs. From SF1 on larger "dents" for
the 36 PHFs.
So, if Simon would check the number/year.....

Ernesto
 
The new set of tank mounting rubbers have completely eliminated the drumming.
Comments please on the following issues.
(1) Gear lever needs adjusting as 4th and 5th need the lever touching down before changing up.
(2) The ride is HARSH.  I cannot find any trace of the rear shocks currently fitted.  The upper spring seats are KONI castings but that does not mean that they are cndeed KONI shockers or usual fitment.
 

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OK Simon it is on JLOs Laverdamania registry  listed as in Germany, and the plus side is it is an S or an old Eagle..  ,listed in between the American Eagles, in fact frame number before yours is an Eagle in the States,Not too many about.

http://www.laverdamania.net/registre750.htm

 
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