125-200cc MS-3 Metering rod lengths

There are huge differences in how a metering rod carb and standard carb work. I could write volumes here but the main thing is the metering rod and slide are tied together where a jetted carb draws fuel from three circuits two of which are totally independent of the slide (air volume). Usually when you get the Lectron so lean it could seize the motor it will run so bad you wont be riding it anyway, it will not idle and it will not pull. As the rod is fixed to the slide there is a 1-1 relationship very unlike a standard carb as it pulls gas from several orifices. On a standard carb you can have a way small main jet and still open the slide all the way and cause a way lean condition. This does not happen on a Lectron. You would have to have a really bad rod design and some obvious and serious engine running issues before any of this can get out of hand. There is a ton more to it and it is nothing like a standard carb so you need to think differently. Your last sentence it spot on. Yes you can make the Lectron very lean and blow it up but you would have major signs this is the condition before it happened. One other think is that the Lectron will not plug jets (dirt or water) and run lean as it does not have any. there are huge differences and talking about a standard carb and this carb with the same methods does not work IMHO. As i said I am not saying it was not the carb but I'd personally be looking elsewhere for issues before blowing it up again. The seeming bad machining on the modified FBF head might have a lot to do with it. Seems several factors going on here. Bad gas, messed with FBF head, maybe tight piston tolerances, possible air leaks. Very simple to richen the carb up til it is obviously rich and then back off a little. You can also richen the top end independently with the PJ. Simple.

Not sure what your asking. If the engine is running there is always a draw. Same draw the jetted carb sees. BTW many people have blown up motors going fast on straights and then chopping the throttle. 2 strokes don't seem to like that.

You are running a 9 heat range plug not a 8 right?

the best way is with the Lectron tool but this is not needed IMHO.




IMHO, just make sure the motor has no leaks, crank seals good, piston clearance good, gas good, run the Lectron fat and then move leaner.

Leak down info from Motion Pro...

Pressure testing is a test performed on a two-stroke engine to ensure that the engine has no air leaks. An air leak in a two-stroke engine can cause a lean condition in engine fuel-air mixture. This in turn can result in engine overheating, piston seizure, detonation etc.
WARNING!

Wear eye protection to prevent eye injury from escaping gas and/or flying particles. We recommend that a qualified mechanic in a properly equipped shop perform this procedure.

1. To leak test the engine: cylinder, head, reed cage, intake manifold and spark plug must all be installed and torque correctly. Exhaust pipe and carburetor must be removed.

2. Seal round exhaust ports with the correct size rubber expansion plug. For 1986-1991 Honda CR250R and 1985-2001 Honda CR500R, remove the exhaust manifold and seal the exhaust port using one of the flat metal plates with a rubber gasket. Optional plate 08-071O is available separately for 1987-1989 CR125R. The black vinyl cap and #32 hose clamp are used to seal the oval exhaust port on 1993 and later YZ250.

3. Insert the correct size carburetor adapter (#1, #2 or #3) into the intake manifold and tighten the manifold clamp. Teflon tape the thread on the quick coupler and install coupler into the carburetor adapter.

4. Push the nylon hose (from the pump/ gauge assembly) into the quick coupler. If the nylon hose leaks where installed into the coupler, push the hose into the coupler assembly while under pressure. It is important to have the system under pressure while attempting to seat the hose to coupler. To remove hose, push green (or gray) ring on quick coupler towards brass fitting while pulling and twisting hose out.

5. With all test equipment in place and the piston at bottom dead center, use the hand pump to pump 6 PSI of air pressure into engine. Never exceed 8 PSI of air pressure or damage to the seals and/or engine may occur. If loss of air pressure occurs, spray soapy water over mating surfaces to see where soap bubbles appear. Repair any leaks that may appear and redo test. A leakage rate of 1 PSI per minute is acceptable; however the lower the leakage rate the better your engine will perform.

6. By carefully listening at various points, you may be able to locate air leaks that are not easily accessible with soapy water. Crankcase seal leakage may be heard by removing the magneto cover or if on primary side may be heard through the oil filler hole. Leakage at the power valve seals and O-rings can be heard by removing the power valve linkage covers or through the transmission oil filler hole. On water-cooled engines, head gasket leakage may show up as bubbles in the radiator coolant.

7. On the Yamaha Banshee, RD 350/400, RZ350 and TZ250 (parallel twins) the center crank seal (labyrinth seal) will allow low velocity air to pass from one side to the other side. Therefore, both the left and right cylinders/ crankcases are tested together. To do so, seal both exhaust ports and one intake port. Then, install the correct carburetor adaptor into the remaining intake port. Perform steps 1 thru 6. There is no way to check the labyrinth seal; this seal will normally out last the crankshaft main bearings. On Suzuki RM motorcycles, the power valve breather hoses must be plugged off in order to pressure test the engine correctly. There is no seal in the power valve chamber.

8. Each leak down tester is tested for leaks at Motion Pro. To insure that your leak down tester remains leak-proof it should be tested periodically. To test simply connect leak down tester hose to a 1 quart leak proof container and pressurize to 6 PSI. If no leakage occurs in ten minutes the tester is leak proof. To locate leaks spray a soapy water solution over fittings and connections and look for soap bubbles. On pipe fittings, use Teflon tape or pipe sealant. Occasionally, the check valve between the hand pump and hose will leak. Clean the check valve with contact cleaner and re-grease the ball in the check valve to insure a good seal, and then retest.

As for the plug mine looks like the one in the first pic. I have hammered my personal 165 relentlessly and had 5 different Lectrons on the same bike. It has done endless mud riding, 2 ISDEs and lots of gnar trail rides. It has 1700 miles and 130 hours on it and I still cant bring myself to rebuild it as it runs fantastic. Was going to rebuild it before the Idaho City ISDE this year but was running so good I left it. Did that race (Hot and lots of huge climbs) and zero issues (Jake also did the same race on the same minute with a 125 with a Lectron) and still running it. Never touched the rod even though we went from our typical 2000 foot riding to over 8400 at the ISDE. Just did a three day thrashing with two other 165's with Lectrons up to 7400 feet with big climbs and we are "jetted" for 2500 feet tops. Zero issues. I've sold somewhere around 80 of these carbs and have not heard of any seizure issues other than this one. Not impossible it is the carb but improbable. I'm not trying to stick up for the carb I'm trying to save AUSKY any further grief. He could simply put the old carb back on if he feels it is the Lectron.

Measuring the rod length is a loose way to get it close but should not be used as a hard fast guideline. These are built and then the end cut off but not to the accuracy needed to use a measurement like this to dial it in as it is not a critical dimension. These are set at Lectron using the Dial indicator tool shown above. That is really the only way to get it perfect. It measures the taper with the slide attached and is the right method. The total length is much harder to measure and is not super consistent so is only a starting point to get you in running range. Just want to make that clear.

All that said even with the dial indicator there as many variations in fuel, motor configurations and other factors will change where YOU ultimately set YOUR rod.

I don't think they seized motors due to lean conditions did they?

I never said it was not the carb I said I thought it was not the first thing I would look into. I understand you think it is the carb, might be. Just saying make sure everything else is good so he does not have a recurring issue OK? I also said put the old carb back on. And yes, I am serious, these carbs function totally different that your standard jetted carb, It has NO jets, no needle, and works off a different principle. Just like EFI adds gas but is not a carb. Can it run lean? Sure. But in my experience with them which at this point is pretty vast when the bikes are lean you notice it and adjust. Running it so lean it would seize would mean it is not running well to begin with. IMHO.

There is more than a carb that makes a bike run lean. this is why I am suggesting he make sure other components are 100% AND adjusting the carb richer before the next round.

I'm trying to help him not defend the Lectron.

There are huge piles of rods to choose from and many are richer. Pertty much anything you might want. Also would be EZ to modify one for this.

- Sent some JD Jetting EFI tuners to Australia and they would not even work. Bike ran horrible. Fuel is so much different it was out of the range of working well. They had to be sent back to JD for reprogramming to get them in range to even work. Thats how different the fuel and air are between our countries and why we are struggling with carbs, EFI and engine kits.

Did not realize that and he said himself it was not right as the deck height was gone. Walt and I are on very good terms and I am not pointing at him. Love his work and this fantastic motor he came up with and say it all the time. But to your post, sorry Walt

I understand this. Not a problem nor do I care if you do slur the carb if you don't like it. I'm simply trying to help.

Sorry, i thought every MS-3 I sent out had at least a conversation about starting point. The Lectron instructions are old and odd and need updated. I am compiling a dirtbike instruction info sheet based on my experience to help out. I also posted this as a sticky on my portion of this site outlining some setup guidelines to try to help here.

http://www.cafehusky.com/threads/lectron-carb-tuning-guide.32064/

I also had one guy PM me and say my info sucked. Tough crowd sometimes and defeating when you try and help and people just lash out. I'm trying to provide info, I'm not 100% right, nor is this a hard fast rule just a guideline as it says in the title. It is tiring getting slapped on a forum when you are just trying to help.

I have two 2012 Husky small bores. A factory 144 and a WB165 Hi-comp head. I have both a Lectron 36mm and an APT Smartcarb 36mm. They work equally well on either bike. Start easy, lug well, pull hard, rev rev rev. My plug color looks in between your examples and I run NGK BR9EIX or BR9EG plugs. What plug are you running in the top picture with the extended nose?

I also have two KX85s my youngest son races in harescrambles and enduros. One is stock and one has a hi-comp head. We have a Lectron 30mm and an APT Smartcarb 27mm for those bikes. We had all kinds of trouble with the hi-comp engine and blamed the carbs. Three pistons later we discovered the water pump impeller was loose. By the looks of your head in the first picture, to me that is from a 'hot' engine. But, I'm no expert.

We also use race fuel in all of the engines with our oil mix at 32-1.

OK.

- Just trying to help the OP nothing more not trying to sell anything. Lectron's can be bought direct if you wish to do so. Very sorry if I came off condescending or like a salesmen. There is a reason many retailers and distributors stay away from web forums, I try to stay above all the crap but sometimes it just happens.

AUSKY, if you want any input on this stuff please PM me.

Lectron tuning guide - http://www.lectronfuelsystems.com/docs/Tuning_Instr.pdf

that's the confusing part to me, it sounds like you are right on to me. If a full turn is obviously so rich it will not even start I cant see how a 1/4 turn or even a half turn will be to lean. On my bike I can go 3/4 turns either way. It will run OK but show signs of lean or rich. 1/4th turn is hardly noticeable on my bike with our fuel. To me from half way across the world reading text it sounds like you are right on target.


I have several rods here I am more than happy to send you. Do you have just the MS-3? If so I have a 3-1 which is richer and 4-1 and 4-0. All of them are slightly richer on the bottom. The 4-0 will be a good bit richer. I also have longer PJ tubes to that adds more fuel earlier. I can send that too. I can also tell you how to modify your rod to be richer but there is no going back once you have done this.

PM me your address please.