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Post by Moat on Oct 27, 2013 22:57:46 GMT -5
A few things stick out, to me -
1) It appears like there's a small section of the carb's attachment flange broken away beneath the lower attach screw in the lower pic - that could possibily be causing an intake leak, and the fuel stains around that area of the flange, black insulator plate and gold-ish intake manifold/reed block further point to a possible leak.
2) Rubber boots are missing from both the choke and throttle cables, where they enter the carb body. These boots could be a source of a small air leak, causing erratic idle/low-speed mixture problems.
3) Rubber intake boot from the air filter, is partially broken away and un-clamped to the carburetor - likely a source of excess (and dirty) air entry, affecting the overall mixture/driveability.
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Post by Moat on Jun 14, 2013 17:19:43 GMT -5
I'd never put all synthetic oil in an aluminum block engine! Way too expensive! We're talking ALL synthetic? That's ~$50-60/gal, compared to regular synthetic (semi-synthetic) going over the counter for $20/gal? Aluminum block engines are not worth that. Magnetic oil filter is useless on an aluminum block engine, as the majority of the particles (99% of the metallic particles) are aluminum, which is non-magnetic; and the other major pollutant in oil is carbon, which also is non-magnetic.  |
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Post by Moat on Jun 7, 2013 6:01:31 GMT -5
I wouldn't say that's true. It's easier to initiate a spark when the arm and tip are closer together, but with a wide center pin, the spark can form anywhere on the surface of the center pin. With a tiny center pin, there's a lot more heat that the pin has to endure (which is why they chose irridium), and the spark is more focused. Besides, if you look at it in slow-mo, there's not one, but several sparks that appear every time the plug ignites. It goes so fast, we barely can see it, but it are several sparks, that cause ignition. When you lengthen the gap, the bike needs more power to overcome to create a spark, and there will be fewer energy releases (or sparks) seen in slow mo. When you shorten the space between arm and center pin, the spark will be smaller, but more sparks will be fired in that millisecond. It's actually healthier for the bike to have a small spark plug gap, than a big one. But like with anything, there's a middle road you'll have to figure out what works best for your bike. On my taotao ATM50, no question, a 0.012" gap is optimal! I set that same gap for my 150cc, and it works fine. Ug. ^^ This post is so, so very filled with inane, nonsensical misinformation, I wouldn't know where to start. Do you just make this stuff up as you go?  Please consider a little research before posting authoritatively, Prodigit! |
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Post by Moat on Jun 6, 2013 14:20:12 GMT -5
It is easier to initiate a spark from a smaller tip surface - therefore the smaller electrode of an Iridium plug will provide an advantage of more consistent ignition (resistance to misfire) under worst-case conditions... all else being equal.
Also note that, as long as the ignition circuit can supply it - and all else being equal - a larger plug gap is always better than smaller. It's as simple as a matter of the spark having a greater chance of exposure to something ignitable - thus preventing mis-fire. Cold starts, lean mixtures... a wider gap is very benificial. This is why auto manufacturers developed High Energy Ignition systems (pushing the spark across wide plug gaps) in the 70's - to help cure the poor running/misfire that resulted from lean, emission-tweaked mixtures.
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Post by Moat on Jun 3, 2013 17:34:58 GMT -5
I need to figure out where to find a really small wire to open the idle jet. I've had good luck using a snipped bristle from a wire brush, if you so happen to have one floating around somewhere. Held with ViseGrips or hemostat. |
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Post by Moat on May 17, 2013 6:53:26 GMT -5
Valve adjusting nuts are not your garden-variety, hardware store nuts. They are fine-threaded, high strength steel, designed for a higher torque than standard fasteners (hence the fine thread, which facilitates torquing to those higher specs). Replace it only with another valve adjusting nut (a motorcycle shop might have one of the right size) - or else it will come loose in service, and go crunch/boom.
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Post by Moat on Apr 22, 2013 6:36:05 GMT -5
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Post by Moat on Apr 19, 2013 4:23:01 GMT -5
... there is a gizmo you can screw into the spark plug hole that keeps the motor from turning over... Contrary to seemingly popular (mis)conception, those tools are NOT intended to hold the piston/crankshaft in place for whatever tightening/loosening antics. Their true purpose is for precisely determining piston position BTDC/ATDC in order to calibrate a degree wheel, for cam/ignition timing purposes. Like the "rope trick", using one to keep the motor from turning over while loosening/tightening things is an invitation to big, big problems. Might be fine in a low-torque application on a weed whacker engine or the like - but not on something requiring this kind of force! |
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Post by Moat on Apr 19, 2013 3:52:55 GMT -5
1) Make (nice job, chindog!), borrow or buy a proper variator locking/holding tool/spanner.
2) Soak the nut's threads repeatedly over an entire day or two, with penetrating oil (PBlaster, Kroil, Mouse Milk, Liquid Wrench, etc...).
3) Get the nut good and hot with a propane or Mapp gas torch. Smoking hot... but being careful that it's not hot enough to melt any aluminum variator part(s).
4) Immediately (while still very hot), and with the locking/holding tool securely in place, crank on it with a big 'ol breaker bar (1/2" drive, minimum) with a proper fitting socket installed (preferably 6 point).
I'd bet it comes right loose.
You might want to replace the crankshaft seal while you're in there, if the heat appeared to do it any damage.
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Post by Moat on Apr 17, 2013 0:38:31 GMT -5
What could of happened is it sheared the woodruff key holding the FLYWHEEL in its position and now it is out of time. That could only have happened if he were trying to break the variator nut free while holding the flywheel stationary, on the other side of the engine - but it doesn't sound like that's what he did. Justin - you first need to do a compression check, with a proper gauge. If it's low, then - To check for bent (leaking) valves, remove the valve cover again, set to TDC of the compression stroke (like Alley's earlier posted picture), loosen both valve adjuster nuts/screws so they are waay loose, and then - while holding the crankshaft at TDC with a wrench - somehow pressurize the cylinder with compressed air through the spark plug hole (like with a firmly held rubber-tipped air gun, a leakdown tester, a homemade hose and fitting, etc...) - a bent valve will leak the pressurized air, and you will hear it hissing noticeably from either the carburetor/intake or from the exhaust/muffler. |
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Post by Moat on Apr 17, 2013 0:14:34 GMT -5
Yeah, just a little dried fuel varnish residue, looks like. Nothin' worth worrying about unless it becomes a messy nuisance - in which case you could seal it up as I mentioned above. Pretty much all carburetors (bikes, cars, boats, etc...) will start to weep a little, eventually!
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Post by Moat on Apr 16, 2013 21:55:40 GMT -5
... I had to cover about 12 miles in less then 15 miles... Hmm, odd... that should have been really easy to pull off...?!?  ;D
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Post by Moat on Apr 16, 2013 21:37:26 GMT -5
... now my top valve is really loose ... Well, that's not a good sign. I wonder if you didn't have the piston at TDC of the *compression* stroke when you did the rope trick, and ended up bending the intake valve...? |
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Post by Moat on Apr 15, 2013 23:33:23 GMT -5
Like JR said above, a somewhat mushy feel will be the result of using DOT 5 (Silicone) brake fluid. Also DOT 5 doesn't lubricate internal seals and pistons as well as DOT3/4/5.1, so things end up feeling sorta "sticky", too. So DOT 5 = mushy and sticky. Blech. If you're doing any high-speed downhill twisty mountain road racing, and your brake fluid is boiling away to a mushy lever... try some DOT 5.1.  |
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Post by Moat on Apr 15, 2013 23:14:15 GMT -5
I'd have to guess that it's just a bit of varnish residue left behind as fuel evaporates from around a slightly weepy float bowl seal. A very tiny bit of fuel-proof gasket sealant (Permatex Form a Gasket #2?) smeared on the seal would probably take care of it, if so.
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Please consider a little research before posting authoritatively, Prodigit!
