RGS Tach Calibration

ksoholm

ksoholm

Senior member
Location
Bellingham, WA, USA
Lads,

My RGS's tach underwent surgery recently to upgrade the chip to stop it waving all over the place, which it no longer does. But, I suspect it reads about 6-800 RPM high, per gearing calculations and GPS speed. Is calibrating these junky tachs a simple matter of rotating the needle on its shaft, in this case counter-clockwise?

Thanks,

Kristian
 
ksoholm said:
Is calibrating these junky tachs a simple matter of rotating the needle on its shaft, in this case counter-clockwise?

Thanks,

Kristian
Click to expand...

Ummm, wouldn't that imply that it must be showing 600-800rpm now ... before you even start it?!!
 
Piranha Brother 2 said:
Ummm, wouldn't that imply that it must be showing 600-800rpm now ... before you even start it?!!
Click to expand...

Don't know what's going on with the tach in the resting position when off, but if it's fairly linear through the range a counterclockwise turn of the needle should do it, though I hear of a calibration pot somewhere.
 
Most Tachos have a way to adjust them. However, most of them do not show correct readings EVERYWHERE, you calibrate them to a certain rev that you feel is necessary to be accurate (either midrange with some plus or minus showing on the higher and lower revs or - for facing f.e. - you calibrate them for best accuracy at shifting revs or maximum revs.).

So - what you would need is a oscilloscope to simulate accurate revs and then adjust it to where you want it to be accurate.
 
Then again, it isn't a 60s 50cc 2 stroke racer with a powerband of a few hundred revs.
Does it really matter if the rev counter of that agricultural lump is a few hundred out?

Paul
 
Paul Marx said:
Then again, it isn't a 60s 50cc 2 stroke racer with a powerband of a few hundred revs.
Does it really matter if the rev counter of that agricultural lump is a few hundred out?

Paul
Click to expand...

Good point - I probably use my ears and 'feel' (is that 'vibes' on an SF?  :D) more with regard to revs than the tacho. If you're accelerating flat out you shift when you need to shift and if burbling along you don't labour the engine. Could easily toss the tacho without a problem.

Rode for years with a Honda tacho and no speedo, so redline became 10,500 and kph in 5th was revs x a factor of 2 (so 5000 was 100kph) and mph x 1 in 4th (so 3700 was 37mph or 60kph). Was surprisingly accurate.
 
My Guzzi LM1 tacho reads way too high. According to the tacho I'm always riding it in the red zone, and occasionally bouncing the needle off the stop. Can't be bothered fixing it as it's not really necessary for road riding.
 
Who really looks at the tacho anyway? Just set the rev limiter if you have a modern ign. Several years ago the needle broke off the SFC1k tach I have fitted to the Motodd. Still haven't got around to having it fixed but I will some day just for appearances.
But any good instrument tech should be able to calibrate it. Would annoy me if it wasn't correct.
 
Paul Marx said:
Then again, it isn't a 60s 50cc 2 stroke racer with a powerband of a few hundred revs.
Does it really matter if the rev counter of that agricultural lump is a few hundred out?

Paul
Click to expand...

800? Yes. With what I've done to this RGS - everything - it should work properly; besides, that's how I like things.
 
There's a reason for run-of-the-mill Veglia clocks being called "vague lies"....

Definitely not top notch equipment, made to a price, dictated by the industry.  For a half-accurate reading, you'll need to turn to the Veglia Competizione stuff.

Components such as these weren't built to last 30 years or more.  Even Massimo wanted you to buy a new Laverda every 3-4 years!

piet
 
Laverdalothar said:
yeah - but only while keeping the other one... ;)
Click to expand...

No Lothar.  These were also just ordinary used bikes after a couple of years, often enough run into the ground by youthful over-exuberance.  Massimo had to keep the lights on, just as any other bike manufacturer, the only way to do this was by selling bikes.  They weren't cheap back then, not very many could have afforded to keep more than one bike in the garage/under the lamp post.  I certainly couldn't !!  Only steadily rising affluence enabled me to amass my collection.

Massimo may have shown far more passion for his products than many other bike builders, but his main priority was to earn money, to pay his workforce and to keep the ball rolling.

That the big Lavs have attained classic status is testimony to their ruggedness and uniqueness.  The fact that they are still being used and worn out instead of being stored in glass cases helps to feed the cult, thankfully.


piet
 
So true. Massimo once said to me that once a new model came off the production line, he lost interest and concentrated on something new.

Marnix
 
Easy for me to say as I wasn't there or in any way involved at the time but it seemed lack of focus was an issue.
The V6 consumed many hours and money (even if reportedly it was his own) and there were many wild projects such as the 4x4, V3 2-stroke and so on.
It seems the 79 crank bearing issue and the 80 valve seat issue made the buying public wary of Laverdas, they were already a bit of an unknown quantity as the bike magazines rarely 'got' Laverdas as they weren't Japanese.
The RGS was a wonderful progression, better made, stronger, reliable but I heard it was a rush job as it should have had a new engine (not necessarily the V6).
After all the development on the V6 it would have been relatively easy to create a modular range of water-cooled 4 valve V twins, V4s, even take a bank of 3 and make an inline triple.
The biggest issue for the RGS was that the bike world had been shown the future, and that was the GPz900R.
It singlehandedly (until the first Fireblade arrived) killed off the overweight air-cooled dinosaurs from many manufacturers.
 
Grant said:
Easy for me to say as I wasn't there or in any way involved at the time but it seemed lack of focus was an issue.
The V6 consumed many hours and money (even if reportedly it was his own) and there were many wild projects such as the 4x4, V3 2-stroke and so on.
It seems the 79 crank bearing issue and the 80 valve seat issue made the buying public wary of Laverdas, they were already a bit of an unknown quantity as the bike magazines rarely 'got' Laverdas as they weren't Japanese.
The RGS was a wonderful progression, better made, stronger, reliable but I heard it was a rush job as it should have had a new engine (not necessarily the V6).
After all the development on the V6 it would have been relatively easy to create a modular range of water-cooled 4 valve V twins, V4s, even take a bank of 3 and make an inline triple.
The biggest issue for the RGS was that the bike world had been shown the future, and that was the GPz900R.
It singlehandedly (until the first Fireblade arrived) killed off the overweight air-cooled dinosaurs from many manufacturers.
Click to expand...

No, what killed off Laverda was the Honda 90.

Paul
 
sfcpiet said:
No Lothar.  These were also just ordinary used bikes after a couple of years, often enough run into the ground by youthful over-exuberance.  Massimo had to keep the lights on, just as any other bike manufacturer, the only way to do this was by selling bikes.  They weren't cheap back then, not very many could have afforded to keep more than one bike in the garage/under the lamp post.  I certainly couldn't !!  Only steadily rising affluence enabled me to amass my collection.

Massimo may have shown far more passion for his products than many other bike builders, but his main priority was to earn money, to pay his workforce and to keep the ball rolling.

That the big Lavs have attained classic status is testimony to their ruggedness and uniqueness.  The fact that they are still being used and worn out instead of being stored in glass cases helps to feed the cult, thankfully.


piet
Click to expand...

Yes Piet. I agree with you of course apart from the classic status.
Any old crap that reminds the more mature citizen of his youth has classic status.

Will disappear in the not so distant future when we've all died.

Paul
 
Paul Marx said:
No, what killed off Laverda was the Honda 90.

Paul
Click to expand...

Are you for real?
The Honda 50/70/90 was on the market since the early 60s.
I would say the glory days for Laverda were the 70s.
 
Grant said:
Are you for real?
The Honda 50/70/90 was on the market since the early 60s.
I would say the glory days for Laverda were the 70s.
Click to expand...

It's actually the Honda Super Cub 50 from 1958. That little bike was the harbinger of death for Laverda, lots of other Italian brands, the entire British MC industry, and many more, besides. It was already over for Laverda when their first 650/750 twins hit the road given that their engines were directly based on Honda's CB77 Super Hawk and by extension all the 1000s too.
 
Grant said:
Are you for real?
The Honda 50/70/90 was on the market since the early 60s.
I would say the glory days for Laverda were the 70s.
Click to expand...

I'm very serious.
A lot of people have never heard of or considered an GPZ 900. As usual, all depends where you live which is why I mentionned the worlds most successfull motorcycle, the C90.
The glory days of Laverda, competition and production wise were in the 50s.

Paul
 
If all you consider is the tiddlers. Outside of Italy how well were they known back then?
I was referring to the endurance success, not just in Italy, of the SFC and the triple in various forms, but even that was done by the mid 70s.

I still don't get your point about the Honda killing Laverda. If anything, the success of the Honda probably brought more people into bikes, more for other manufacturers to benefit from.
Areas where the target market overlapped would have been very small, even then a Jota and a CB750 were really at opposite ends of the buyer spectrum.
 
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