Carb adjustments for trail riding, TLR200

It seems members of this forum are able to alter the laws of physics at will.............lower air density is something that occurs like it or not at higher altitudes, which will mean overly rich mixture on bikes jetted to run properly at sea level.

Any amount of chat room BS is never ever going to alter that fact, and it seems strange none of those suggesting the BS can alter things, are capable of using Google and finding out they are wrong?

I get the feeling that anyone who suggests fitting various new parts to a 30 year old carb, whose body is almost certainly badly worn, might also suggest fitting a nice new chain to worn out sprockets is also a good idea................


The brand new Taiwan made carbs are a direct replacement for TLR OE part, and to be honest I cant really see the logic in fitting a new chain to worn sprockets?

From the look of your plug, it seems to me your fuel level is overly high, and as long as tappet clearances are correct, and ignition system is working properly, I would suggest removing carb and carefully checking for perforated float (very common on these bikes). New floats are available, and will resolve issues with high fuel level, if the original was damaged.

I have a pile of small carbs I will look and see if I have a jet for you, I do have several different sizes of carbs and wont take long to check it out for you... Ill txt you when I figure it out.
Larry

Thanks Larry!!
Did you ever get a newer trials bike?

I tore the TL down last nite so I can do some mild mods and repaint it, replace a couple of seals, thinking about putting a headlight and tail light on it and getting it street legal (I did leave the lighting coils in it when I built it!!!!) it is still really tight and just going to freshin up a bit and repaint it.
Larry

And thank you. I was wondering about the float. I really haven't done a thing to this engine, not even a checked the valves.

If your TLR was standing for any length of time before you got it, then perforated float is very likely. What tends to happen is only one side perforates, which tends to make the fuel level higher, and makes bikes run very rich.

Take the carb off, taking care not to invert it so fuel flows out, then remove float bowl, and take off the floats. If the floats are leaking you will be able to hear the fuel inside when you shake the floats.

Also well worth checking tappet clearances (2 thou inlet and exhaust), cleaning out centrifugal crank sludge trap, gauze oil strainer (behind drain plug), and refilling with fresh oil.

A float that doesn't float wouldn't be worth much, eh?

Yeah, I've got to set aside some time to lay hands on this motor. The fact that it runs and is quite rideable has forestalled the urgency.

All things in good time. I'm trying to finish a deck rail right now. And for me "good time" might mean months. When I blew up the engine on my KLR it took 18 months before it was back on the road. Not that I'm boasting about that.

I like how your so stuck on the facts of air density to fuel ratio that you can't get over the fact that your correctness doesn't take into consideration what others have also called out as facts around air density as it relates to the way the fuel circuits and jetting are also affected by that same low air density.

Just because your right about the facts of air density to fuel ratio doesn't change the simple fact that fuel ratio isn't the only thing your working with... get of your high horse and consider the bigger picture... :huh

Truth: (weather you like it or not...!)

Please feel free to provide a link to any serious technical information, which suggests carb jets need to be increased in size to compensate for lower air density at higher altitudes.

It seems astonishing that anyone would choose to make themselves look like a total idiot, by suggesting the laws of physics are subject to change, merely to excuse the fact they have made a silly mistake, by claiming jet sizes need to be increased, rather than decreased when running at higher altitudes!

One more time. By failing to consider the starting point for a specific engine, you miss the big picture. Say you start with an EPA-lean engine at 3000 ft ASL. You take that engine to 4000 feet ASL. The altitude change has made that bike run richer than it was, but it was EPA-lean to begin with, so further richening may be called for to obtain proper mixture. Nothing has changed about the laws of physics, but the baseline conditions determine the course of action, not a textbook.

As RideNM correctly states - Initial conditions are very important for any calculation whether Physical, Chemical or Comical...

Folks, Twin-Shocker is a very opinionated and very inflexible forum poster. Don't ever try to change his mind. But to be honest, I kinda like that about him. He does bring up some valid points, is helpful at times, and just because he could care less about what we have to say, and won't consider alternatives to his way of thinking - ever, doesn't make him a villain - just a character.

Side story: I remember when working in the disk drive industry, that we had to come up with an air bearing design that would maintain nearly constant physical/magnetic spacing as the transducer was "flown" across the surface of the rotating disk. Knowing that the relative velocity at the outer diameter of the disk was much higher than at the ID, I commented that it was like keeping a boat tied to the dock floating at the same height as the tides changed. Everyone knows you cant do that right? I was sure it couldn't be done.... well guess what.

I would agree entirely that any motor which is jetted very lean in the first place, may not need compensatory changes for use at higher altitudes. However not sure that many TLR's are still likely to be fitted with OE jetting, or worn out OE carbs for that matter?

I think you'd be surprised at how often low-use TLRs pop up in the US. I've probably seen 5-8 in the last couple of years turn up with ~1,000 miles or less. And I'm not looking for them...

I think most TLRs sold in the US ended up stuffed in the back corner of garages.

So, twinshocker what is the greatest elevation you tuned a bike at and what fine bike might that be?














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Hmmn, did you ever take into account the carb on the usa version of the tlr200 had no pilot jets available?

I am not disagreeing that the bike needs less fuel, just that the concept of a smaller jet being the correct direction to get there on every carburetor. Not all carburetors are designed equal...

I would hope that everyone would agree that a pilot circuits requires air pressure to work correctly and if the air pressure drops it would then affect the flow of the fuel/fluid in that circuit.

Considering the drop in pressure from sea level to 6000 feet is 20.1kPa (2.9psi) and sea level to 9000 is 28.6kPa (4.15psi), it is quite possible that a circuit designed to operate at sea level could be to restrictive at that pressure and require a larger jet to get the proper mixture.

Pressure chart: http://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html

Hope this clears up my stance a bit...