importance of additional counterbalance

[Sphere]

Can anyone comment on the importance of additional counterbalance on the Hatz 1B40? Browsing their website and parts manuals, the 1B30 doesn't have one, but the 1B40 and 1B50 can be fitted with one.

How are the vibrations with the 1B30 bikes at high end rpms? Will the 1B40 without counterbalance make for an enjoyable ride at all?

Will balancing the fly wheel have any significant impact? Are there other options to absorb vibrations from the engine, eg. dampening rubbers?

[Diesel Dave]

I'd say it was pretty important, the IB40 is a 462cc motor so the piston's going to be quite some weight.

Primary balancing will can only negate the up and down vibrations but not the forwards and backwards motion of the crankshaft counterweights, hence the need for the additional shaft rotating in the opposite direction and an excentric weight.

That said I do ride a 400cc unit all the time without a balancer shaft and that's fine.

If your going to mount the motor on resilient mountings then the gearbox will need the same treatment but be solidly connected to the engine - don't forget the exhaust too!

Cheers
Dave

[Sphere]

Did you shoot for resilient mounting, or weren't the vibrations at the handlebars bad enough?

I can find the part, I know the price (400 USD), but I can't see where it should go in the engine, or if there are extra parts, or existing parts that require machining to fit on. Likely some bearings, but I can't make them out...

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[Stuart]

I read somewhere that the KLR doesn't have a counterbalance. I did notice some vibes through the handlebars on that. But it was the first model and I guess it could only have improved over time.
They say that filling your handlebars with sand is a good way to get rid of vibes

[Diesel Dave]

It will be obvious inside the casings where the balancer shaft goes and i doubt the casings would not have been machines for the bearings.

There may well be a different balance factor applied to the motors fitted with the balancer shaft though.

Dave

[Sphere]

Or lead pellets

We'll see, if it's a 1B40T or 1B40U. I have called Hatz NL, but they are undecided if the casing for both models is identical. If it is, they can't seem to tell me what bearings to use with the balancing shaft part (155 euro). To be continued...

I read somewhere that the KLR doesn't have a counterbalance. I did notice some vibes through the handlebars on that. But it was the first model and I guess it could only have improved over time.
They say that filling your handlebars with sand is a good way to get rid of vibes

[Diesel Dave]

Back when I was missing a head steady and suffering badly from vibes a mate suggested we melt down some lead pipe and fill up the bars.

Seems a bit counter productive somehow - go to all the trouble of keeping things light and then add some lead.

I have fitted bar end weights though - they also seem to save the levers from damage when I drop the bike.

Dave

[Sphere]

Oh right, I certainly need to fit a head steady. I guess this shouldn't pose too many problems.

[oldbmw]

I have looked into the counter balancing of engines, and I have to say, the added complexity on a parllel twin is such that I really think it would be better to just add a third cylinder. That would be perfect balance and run smoother.

The 800 BMW twin uses a rocking bearing for an arm with a weight on the end which is connected to it via an extra big end and conrod... Might just as well have put a third cylinder in the middle

[Sphere]

I have inquired about adding a counterbalance to a 1B40T ('T' = without counterbalance). Sadly I was told by the sales person it's not possible. So if you are in the market for a 1B40, be sure to ask if it is 1B40U or 1B40T. Most likely it is possible, but you probably have to swap case plates or something for the 1B40U model, which will make it expensive.