Topic: Honda 550 throttle hang

[Deltarider]

But... read closely: I've always checked afterwards by connecting an underpressure meter and, as said: always within 2cm Hg. If, after a bench sync, if, afterwards, my doublecheck had shown a difference of > 3 cm Hg, I would have known, there is something wrong and it's probably not the carbs...
Here's a question: wouldn't a too big difference in compression show in the vacuum reading? It's a question.

[dave500]

yes it would,so does one set of points way out of adjustment fool the vacuum,thats why its done last of all.

[Deltarider]

yes it would ... thats why its done last of all.

Do I understand, you perform a compression test prior to each time you check the carbs are in sync?

[dave500]

off course not,and dont quote my posts modified,YOU DIG!!

[Deltarider]

off course not,and dont quote my posts modified,YOU DIG!!

FYI ... [three dots] is the common and generally accepted way to indicate, one has left some part of the quote out. Even in science it is. You would have been right to protest, if I had edited your post without the three dots. But I didn't.
Back to my question. I mean, we all know that checking the sync comes last. Let me rephrase my question then. Is it true, what the late racer Rob Bron once told me, that - once the rest of the maintenance routine is done correctly - and you then still need to dynamically 'balance' already perfectly bench synced carbs, you're only trying to correct a - in his words - 'rotten engine'? That was and is the core of my question.

[RAFster122s]

So you do it like this?

off course not,and dont quote my posts modified,YOU DIG!!

FYI ... [three dots] is the common and generally accepted way to indicate, one has left some part of the quote out. Even in science it is. You would have been right to protest, if I had edited your post without the three dots. But I didn't.
Back to my question. I mean, we all know that checking the sync comes last. Let me rephrase my question then. I m...rotten...? That was and is the core of my question.

Just having a little fun Delta...don't get bent out of shape...

[dave500]

just to bring everyone up to speed,Deltas bike was built by Mr Honda himself,at midnight on a wednesday under a full moon,the frame is made from the steel of fallen warriours swords,it has the power to repair itself and never go out of tune,it has a soul and provides a cloak of safety for who ever owns it.

[Rosinante]

just to bring everyone up to speed,Deltas bike was built by Mr Honda himself,at midnight on a wednesday under a full moon,the frame is made from the steel of fallen warriours swords,it has the power to repair itself and never go out of tune,it has a soul and provides a cloak of safety for who ever owns it.

Nice upgrades!

[caluser2000]

just to bring everyone up to speed,Deltas bike was built by Mr Honda himself,at midnight on a wednesday under a full moon,the frame is made from the steel of fallen warriours swords,it has the power to repair itself and never go out of tune,it has a soul and provides a cloak of safety for who ever owns it.

Don't forget it has a self filling. self charging battery

That one is very important to Deltarider and his other self.

[Deltarider]

... Is it true, what the late racer Rob Bron once told me, that - once the rest of the maintenance routine is done correctly - and you then still need to dynamically 'balance' already perfectly bench synced carbs, you're only trying to correct a - in his words - 'rotten engine'?

Anyone?

[StockRider]

If variability between cylinder performance in a vintage, diecast engine makes it "rotten," then yes, I think that is what we are doing with dynamic balancing/syncing of the carbs to compensate.

[caluser2000]

Good to see Deltarider and his other self Stockrider can chime in.

[bryanj]

Even with the Honda fanaticism on qc there will be very minor manufacturing and tolerance differences making it 4 single cylinder engines on one crank that will mean minor alterations in running sync from bench sync

[StockRider]

Even with the Honda fanaticism on qc there will be very minor manufacturing and tolerance differences making it 4 single cylinder engines on one crank that will mean minor alterations in running sync from bench sync

+1

[dave500]

the only thing rotten is a flat beer reading this stuff,its cool ill grab another,50 years on the bench to bike sync is a fluke even if its close at all,as i said one point set a little out will throw a vacuum reading out,in the factory so many years ago it may have been the norm,but if you dont actually sync your carbs on your bike your just kidding yourself,they wont be spot on full stop,in the day with brand new tec points etc any worker wouldve fallen on his sword if something went wrong now matter how minor?

[Deltarider]

If variability between cylinder performance in a vintage, diecast engine makes it "rotten," then yes, I think that is what we are doing with dynamic balancing/syncing of the carbs to compensate.

Thanks, Stockrider.
More than once I've performed a bench sync my way and was pleased wih the result.
With the other variabilities within spec (tappets and ignition), after I had hung in the carbs again, bike idled and 'picked-up'* fine. Nevertheless, I doublechecked by reading the underpressure, and differences proved to be within 2 cm Hg. Am I right to conclude that at that moment a compression test is redundant?
Now to another case. Let's call it B. Imagine you have just acquired a 50 years old CB500 and you don't know in what condition it is, let alone what PO's have done and what not. Again you have the ignition and tappets within spec. The difference is: you have no intention to benchsync the carbs. Instead you connect the vac gauges rightaway and adjust the slides till you have the underpressures within 2 cm Hg. My question is: does the owner in example B now know as much as the owner in example A does and is a compression test equally redundant?
*Sorry, maybe I don't know the correct word in English.

[StockRider]

If variability between cylinder performance in a vintage, diecast engine makes it "rotten," then yes, I think that is what we are doing with dynamic balancing/syncing of the carbs to compensate.

Thanks, Stockrider.
More than once I've performed a bench sync my way and was pleased wih the result.
With the other variabilities within spec (tappets and ignition), after I had hung in the carbs again, bike idled and 'picked-up'* fine. Nevertheless, I doublechecked by reading the underpressure, and differences proved to be within 2 cm Hg. Am I right to conclude that at that moment a compression test is redundant?
Now to another case. Let's call it B. Imagine you have just acquired a 50 years old CB500 and you don't know in what condition it is, let alone what PO's have done and what not. Again you have the ignition and tappets within spec. The difference is: you have no intention to benchsync the carbs. Instead you connect the vac gauges rightaway and adjust the slides till you have the underpressures within 2 cm Hg. My question is: does the owner in example B now know as much as the owner in example A does and is a compression test equally redundant?
*Sorry, maybe I don't know the correct word in English.

I do not see a compression test as redundant in either case. As bryanj said, there is going to be variability due to the manufacturing/engineering. A compression test, tracked year-over-year, reveals the condition and wear that is happening to valves, seats, and rings.

[StockRider]

the only thing rotten is a flat beer reading this stuff,its cool ill grab another,50 years on the bench to bike sync is a fluke even if its close at all,as i said one point set a little out will throw a vacuum reading out,in the factory so many years ago it may have been the norm,but if you dont actually sync your carbs on your bike your just kidding yourself,they wont be spot on full stop,in the day with brand new tec points etc any worker wouldve fallen on his sword if something went wrong now matter how minor?

+1, agreed

[Deltarider]

I do not see a compression test as redundant in either case.

I am not sure about this. But let me confess that I have given up on doing compression tests. I am not good at it. Moreover: as long as the engine starts rightaway and performs well, no strange sounds, no smoke from the exhausts, no oil consumption, why would I do it?

As bryanj said, there is going to be variability due to the manufacturing/engineering. A compression test, tracked year-over-year, reveals the condition and wear that is happening to valves, seats, and rings.

Personally I have no desire to track 'year-over-year'. I'd rather wait till I have indication (see above) it is needed and have it then done by someone who is better at it than me .
So you don't think 'the condition and wear and what is happening to valves, seats, and rings' will show in the vac readings? Anyone else that can share a view on this?