Replacement battery for Baghira 660

[Hockers]

New battery in situ

New battery type

Hi everyone this is my first post and I'm hoping to make it a useful one . I've just swapped out the battery on my old Baghira, and the replacement battery type is A12.6Ah AGM .

It was a tight fit but the cables reached the new terminals and the bike spins over much quicker now

[Hockers]

You can also see a general lack of air filter in the photo - this is because I have removed it, and cut up a metal flour sieve to cover the intake. The cut edges needed to be taped up to stop the mesh falling apart. the additional trick is to spray the mesh with fine oil or wd40, so dust is captured. This really improves the air flow, and makes it easy to spray carb cleaner into the inlet, which I've found gets rid or that annoying engine splutter when carb 2 tries to join in at about 60mph .

[Puffs]

Hi Hockers!

Surprised to hear that battery was a tight fit, as AGM's often are slightly smaller & lighter than their conventional lead-acid counterpart. Does the one you fitted have a higher capacity?

Yes, something like a flour sieve (with holes of typically 1x1 mm) is sometimes used in road racing, then aimed at preventing big particles to enter the engine. Then the conscious focus is on performance, rather than longevity of the engine. It is understood that, if you ride in a dusty environment with only such a sieve, you'll get more rapid wear on valve stems/guides/seals/seats, piston, bore, ...

For filtering the air properly, I do not recommend the air filter you describe:
- The last thing you want to happen is that your filter looses strands of stainless steel into the intake air stream. Filters are there to avoid that sort of thing to enter the engine. The glue on the duct tape is likely to dissolve due to the presence of some petrol, at least over time. At any rate, not a risk I'd like to take. I'd suggest to immobilise the edges by placing them in a rim of epoxy.
- What you describe is not an effective air filter (1x1 holes are too big), or it will actually give a higher pressure drop than a common paper filter (if the holes are much smaller than the flour sieve I looked at, but then the surface area is much smaller than that of a paper filter, which has many folds).
- A thin oil, or WD40, might indeed catch the occasional very fine particle, but the oil being thin means it has a very low viscosity and no significant gel strength, and is not very sticky at all. Under the prolonged flow caused by the engine, a particle that has somehow become stuck in the (very thin) oil layer, will move to the leeward side of the sieve, and then over time just un-stick & continue its journey into the engine - which is exactly what you wanted to prevent happening. Note that oils commonly used to oil foam filters (as used in MX) are actually very thick & sticky oils, with a high gel strength, dissolved in a special solvent that evaporates after application.

I know there are so-called 'high flow' filters from companies like K&N, made from cotton between a course mesh, and that they are oiled with an oil spray, but I sincerely have my doubts if they filter effectively. IMHO the only way to increase the flow (or reduce the ΔP over the filter), while retaining the same filter efficiency, is by increasing the surface area of the filter material. And the idea of particles being caught in a layer of sticky oil requires a tortuous path through the filter, as in a foam filter.

Also, note that an engine can run well with any sort of filter, as long as the jetting is adapted to the flow (or pressure drop) from that filter. Normally: different type of filter --> adapt jetting.

[Hockers]

Hi Puff, thank you for your lengthy reply. The new battery is much more powerful than the standard fitment, I assumed those interested in the post would be aware of the standard battery specifications. I enjoyed reading your thoughts on air filtration, I'm sure many people share your worries, however I find it an excellent arrangement, that has improved mpg and performance. Also the carbs are performing more smoothly, when I bought the bike 3 years ago the carbs were pretty awful,with sliders constantly sticking and performance on motorways almost unrideable. Since the modifications it's a smooth ride throughout. The previous owner is amazed as it turns out that was the main reason the bike was sold so cheap (£800). Thank goodness it's a free country where I live and I can make my own choices on this

[Puffs]

Just politely pointing out that the customary approach is to adapt the jetting to the filter, not to adapt the filter to the jetting.

Of course everyone can always make his own choice, within a given range, only the consequences of a choice are not always clear to everyone. Yet we all live with the consequences of previous choices, which makes it worthwhile to choose wisely.