VHB setup

Laverdalothar said:
well - to my defence (not that I feel I have to...  :D): it was my first answer on this thread; had it been checked, we would have missed 3 pages of entertainingly searching for other faults...

My other Posts were only posted as Paul did not check what I recommended at that time and described other symptoms, which led into the wrong corner of the labyrinth...

Anyway - Bike is running, problem is solved, Paul is happy - that are the key points.    :-*

(oh - and thanks for saying I COVERD a lot of issues, instead of I would HAVE a lot of them (joker) :LOL:)
Click to expand...

Glad you enjoyed it Lothar but I've been chasing problems on this bike continuously since May 2019.
And during all that time, there were several problems with the carbs linked to storage with fuel in for 25 years and putting the wrong needles in when I renewed all the brass bits.
So when everything was nearly right but a small problem persisted, I thought "carbs".

But this time, it wasn't. It was an IEF, Intermittent Electrical Fault.

If in May 2019, I had started by looking for an electrical fault, which I did, changing coils and half the wiring loom, wrong half though, I'd still be searching.

Aber jetzt kan Ich gut schlafen Herr Professor.

Paul
 
Hi Paul,

I've been watching this thread with interest but didn't see anything I could add. I think your bike and my early SF  (the one I bought through Frederic Arger in Albi) have a lot in common. Wouldn't they have the same small ports and same cams? I finally went back to running it with open bellmouths on the VHBs, as it was intended. I tried for quite a while to make it run acceptably with an air filter. I'm surprised at your comment about it not running so well at lower rpm. Mine feels quite grunty but does not seem to want to rev much beyond 5000 rpm but it appears to me that the tach may be the problem. I need to test it with an electronic meter. I did a full rewiring job on mine a few years back, when I finally acquired the correct headlight shell and put in a brand new ignition box. You'll be proud to know that I'm still running points, but maybe that's why it doesn't seem to want to rev!

Eric
 
eabergman said:
Hi Paul,

I've been watching this thread with interest but didn't see anything I could add. I think your bike and my early SF  (the one I bought through Frederic Arger in Albi) have a lot in common. Wouldn't they have the same small ports and same cams? I finally went back to running it with open bellmouths on the VHBs, as it was intended. I tried for quite a while to make it run acceptably with an air filter. I'm surprised at your comment about it not running so well at lower rpm. Mine feels quite grunty but does not seem to want to rev much beyond 5000 rpm but it appears to me that the tach may be the problem. I need to test it with an electronic meter. I did a full rewiring job on mine a few years back, when I finally acquired the correct headlight shell and put in a brand new ignition box. You'll be proud to know that I'm still running points, but maybe that's why it doesn't seem to want to rev!

Eric
Click to expand...

Hi Eric,

Yes, same head, same cam as your SF. I opened out the intake ports to match the inlet stubs.
Carbs on the S still need fine tuning but I was so pleased that everything was ok, that I just parked the bike. Will look later. It runs well at lower revs and is quite tractable though not as much as the big valve engines. I feel it's a bit like the C cams, comes into its own as the revs rise. Thre is quite a lot of overlap on that cam.

It is a big heavy crank so it doesn't really want to rev. My SF2 with the lighter crank, and points, revs much more easily.
They do prefer bellmouths.

Paul
 
Paul Marx said:
Glad you enjoyed it Lothar but I've been chasing problems on this bike continuously since May 2019.
And during all that time, there were several problems with the carbs linked to storage with fuel in for 25 years and putting the wrong needles in when I renewed all the brass bits.
So when everything was nearly right but a small problem persisted, I thought "carbs".

But this time, it wasn't. It was an IEF, Intermittent Electrical Fault.

If in May 2019, I had started by looking for an electrical fault, which I did, changing coils and half the wiring loom, wrong half though, I'd still be searching.

Aber jetzt kan Ich gut schlafen Herr Professor.

Paul
Click to expand...

Hi Paul,

first of all - this was not meant to criticize you, it was more meant as a description of the chronology of this threat, please. For sure, my guess was an educated one as I had a similar bike with almost the same issues (SF0). And it wasn't the first bike where I - just like you - looked for carb issues for ages just to find a bad earthing connection, a battery with an intermitted fault or similar.

However, it could have been any of the other faults that others commented about (and me, too), it was just pure luck I was right (at least this one time  ;) ) So - I fully understand your pain and sorry if my comment came across different than just with a smile and a twinkle in the eye, glad you found the cure for the issue and have fun with the bike. With "I enjoyed it" I meant the journey to find the fault and the comments on the way, not your stress and anger about not finding it, please. I know exactly how it feels if you can't find a fault... Have sold my sons scooter because we could not fix it and make it reliable (but then, even a professional mechanic could not find the fault...). Currently, I am working on my dad's 1953 Triumph, which has done less than 200km in 28 years, had a complete engine overhaul but still only rides 4 km or so until the engine blocks up. I thought it was a to lean mixture and tried everything on the carbs until I gave up on the carbs and pulled the cylinder, measured everything and found that the company overhauling the engine did not adjust the piston rings  and installed the pistons in the wrong cylinders...  :o A hint I got 2 years ago but did not believe...

so - no, I am not enjoying your pain, I enjoyed you found it, please.  :-*
 
Some of us have spent years trying to fix issues, the definition of Insanity is repeating acts and expecting a different result. There should be on old motorbikes added to that. But it's so great when after all that time of banging your head on hard objects you finally crack the code. How many bikes just get pushed into a corner when the frustration gets to be too much. Bloody old Motobikes strike again.
 
Oh so true, Vince... fixing up my dad's bike he owned for long but never had the chance to really enjoy it. Wished I had taken it more serious years ago when he asked me for help on the bike and I was to busy with other things. Time lost I can not give him back...  :-[
 
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