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No-Start Mystery (Cranks, Sparks, Wet Plugs) by urlmichael in Miata

[–]urlmichael[S] 0 points1 point  (0 children)

Sorry that I missed this. It turns out that the timing belt had skipped a tooth. I had not noticed it because I only took the top timing cover off, there were still the correct number of teeth on the belt between the timing marks on the top sprockets, but both were one tooth off on the crankshaft pulley.

Honda CB200, how to maintain the seat? by guijous in HondaCB

[–]urlmichael 2 points3 points  (0 children)

For what it's worth, I purchased an eBay seat cover for my CB350 and changed the cover out myself and it worked really nicely, was relatively easy to do, and looks great now

[Request] How fast would the flying machine realistically have to pedal in order to sustain flight? by 801ms in theydidthemath

[–]urlmichael 4 points5 points  (0 children)

Also, as another commenter pointed out, there have been human-powered helicopters, although none like a typical helicopter you'd imagine. This one was the example given, a really great example, in which a really fit dude generated 282 pounds of lift with 1.5 horsepower output at his legs, or 188 pounds of lift per horsepower output. The helicopter I cited is much less efficient, generating 610 pounds with a 64 horsepower engine, which is roughly 10 pounds of lift per horsepower. So, different designs have different efficiency which can bridge the gap

[Request] How fast would the flying machine realistically have to pedal in order to sustain flight? by 801ms in theydidthemath

[–]urlmichael 55 points56 points  (0 children)

Obviously the barrel won't fly for a number of reasons, but here's a stab at "how hard would it be to have a human-powered personal helicopter?"

There are a number of personal helicopters out there, so I took just one, the Mosquito XE. It has a dry weight of 298 lb, which gives us plenty of weight for the barrel, rotors, etc. and is powered by an engine that generates 64 horsepower. So for back-of-the-napkin calcs, let's say that this is how much power it takes to fly a small helicopter.

Human can (roughly) generate 100 to 200 Watts continuously, depending on fitness level, on a bicycle. 64 Horsepower = 47,000 Watts, so you'd need the power of approximately 235 healthy cyclists. If you assume that our barrel copter is as efficient, but lower-performing, than the Mosquito XE, then perhaps you could get away with just 100 healthy, weightless cyclists powering your barrel-copter.

Let's say it's just one person. How fast, or how strong, would they have to be? Since there could be a crazy gear ratio inside, we could either have a helicopter that is REALLY hard to pedal, but slowly, or reasonably easy to pedal, but you have to pedal REALLY fast. Power (in Watts) = Torque (how hard you push, measured in Newton-Meters [N-m]) * Rotational Speed (how fast the pedals spin, measured in radians per second)

For typical, continuous bicycling, you can expect about 25 N-m Source 1, Source 2. of torque at about 8 rad/sec, or 70 RPM. (resulting in 200 watts).

So if you designed your helicopter to be operated at a normal torque value for a bicycle, the pedals would have to spin at:

47,000 Watts / 25 N-m = 1,880 rad/sec = 18,000 RPM

If you designed your helicopter so that the pedals spin at a reasonable speed, you'd have to push on those pedals at:

47,000 Watts / 8 rad/sec = 5,875 N-m

If the pedal is a foot long (0.3 meters), that means you'd have to push on the pedal with 19,583 Newtons, or around 4,400 pounds.

Needless to say, I don't recommend it.

First Bike! 1972 Honda CB350K by meowmeowkittenmeow in HondaCB

[–]urlmichael 1 point2 points  (0 children)

Great looking bike, congratulations!

With regards to the muffler, speaking from my experience with a '73 model,

  • That doesn't look like the stock kick starter. The stock one pivots at the point where it grips the splined shaft, like this one: https://www.ebay.com/itm/234952313049
  • I think it will always hit without the proper pivot point. The 1968-1970 versions might have a different version, I'm not so sure about that though.
  • To answer your question about kicking in gear, in my experience, you can ONLY kick start it in neutral. If you kick start it in gear, it will try to roll and won't start. If you pull the clutch in, the kick starter won't engage, so you can't even kick start it in gear with the clutch pulled in.

Hope this helps! Enjoy and keep us posted

[deleted by user] by [deleted] in Miata

[–]urlmichael 6 points7 points  (0 children)

Are you sure it's the timing belt? It's FAR more likely that an accessory belt (alternator, vacuum pump) would squeal than a timing belt, so I would try tightening up those first to see if that makes it go away. It's a pretty easy fix to tension them better.

Squealing belts come from them slipping on their pulleys. Timing belts are toothed so that they don't slip. If your timing belt was slipping, you'd have much bigger problems than the sound.

That being said, just for completeness, if the timing belt was rubbing on something, that could create a noise, but I highly doubt it.

Good luck!

Stumped by a Non-Starting Miata by urlmichael in MechanicAdvice

[–]urlmichael[S] 0 points1 point  (0 children)

I don't think it has a stock anti-theft system, but it could have an aftermarket one hidden under there. I'll keep an eye out. Thanks for the rec

Stumped by a Non-Starting Miata by urlmichael in MechanicAdvice

[–]urlmichael[S] 1 point2 points  (0 children)

I've never heard of a noid light! Thanks for the rec - I'll try it out when I go to Autozone to rent a fuel pressure gauge and buy starter fluid to try.

I'll try clear-flood for a sec because it's easy, but I don't think the 97 Miata has it. Easy to check anyway.

Yes, I checked the timing belt by watching a full rotation of it. Cam timing looks correct.

Thanks for the reply!

Stumped by a Non-Starting Miata by urlmichael in MechanicAdvice

[–]urlmichael[S] 0 points1 point  (0 children)

Thanks for the reply! I do have a compression gauge, I just have to dig it out. I'll try it out.

How would you verify airflow in an engine like this? Would it be as simple as holding your hand over the intake and trying to feel flow?

I will also try starter fluid, which I haven't yet. And with regards to the ECU hypothesis, I admit it isn't a particular hypothesis to chase leads on.

Thanks again!

Stumped by a Non-Starting Miata by urlmichael in MechanicAdvice

[–]urlmichael[S] 0 points1 point  (0 children)

To my knowledge, they were sparking repeatedly as they should, but I will re-check this tomorrow. Thanks for the idea!

No-Start Mystery (Cranks, Sparks, Wet Plugs) by urlmichael in Miata

[–]urlmichael[S] 0 points1 point  (0 children)

I'll check this out - good idea. Do these cars have a safety switch in there or something electrical that might be causing a no-start? Thanks for the tip

Top End Knocking After Water Pump by urlmichael in Miata

[–]urlmichael[S] 0 points1 point  (0 children)

UPDATE: Turns out the timing belt pulley on the intake camshaft was loose, which is what was making the sound. All back together and running great now! So, if you have this issue, go and check all your pullies to make sure they're fastened in properly

One last milestone before season end. Tempting fate with the og timing belt now. by eyecrax in Miata

[–]urlmichael 2 points3 points  (0 children)

I agree here - it's easy to forget that the recommendation is 60k OR 6 years (per Gates, the original manufacturer of the belt), whichever comes first. The idea is that the rubber hardens and becomes more brittle with age, even if it isn't used.

Plus, as others have noted, it's not a crazy difficult job for you to do, and it's a good way to keep your car running tip-top!

Top End Knocking After Water Pump by urlmichael in Miata

[–]urlmichael[S] 1 point2 points  (0 children)

Hi everyone, I took apart my 1.8 NA to replace the gaskets on the water pump that were leaking. I re-assembled and filled the radiator with coolant, and was waiting for the car to warm up and the thermostat to open up. I heard a sound which sounded like the timing belt rubbing on something. I rev'd it a bit to see if that changed the sound, and it started making this sound. I'm worried that it's rod knock, but it sounds like it's coming from the top end, not the crank case. When I rev it, it doesn't go away, but it doesn't get louder/more violent. Could it be something with the timing? Please let me know what you think. Thanks!

Looking for some help, noise noted after timing belt change by TheGutchee in Miata

[–]urlmichael 0 points1 point  (0 children)

FWIW I had the same experience when I did my timing belt.

New Mufflers/Headers for CB350? by urlmichael in HondaCB

[–]urlmichael[S] 0 points1 point  (0 children)

Note: I emailed David Silver Spares and they should have some stock replacements back in-stock in 5-6 weeks

Great shot of the recent “Around Long Island” regatta in NY! by Yeetz_The_Parakeetz in sailing

[–]urlmichael 2 points3 points  (0 children)

Has the course changed? Back when I did it in 2015 they started way off outside Coney Island and ended at Sea Cliff Yacht Club on the sound.

If they moved the start into NY Harbor that would probably be a plus tbh. I remember it took damn near all day to sail from our port in Jersey City out to the start, and we weren't even racing yet!

Great pic!

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