125-200cc MS-3 Metering rod lengths

[Motosportz]

This is not unlike any other carb with a lean spot causing excess heat that leads to detonation or lube breakdown and seizure. All carbs work off a pressure difference but the Lectron has to luxury of one long smooth circuit via the metering rod that avoids the transitions present on other multi circuit carbs, these can cause rich/lean spots. Calling a Lectron "almost seizure proof" is misleading. If it's lean and ridden lean it will seize. If the fuel is poor quality running it richer will mask the poor fuel problem by lowering the temps that are causing the poor fuel to detonate. Raising and lowering the metering rod changes the air fuel ratio just like raising the needle, changing the pilot jet to a smaller size, changing the main jet to a smaller size or adjusting the air screw on a Mikuni or Keihn. This could very well be carb related but not likely because the carb is faulty. Most likely poor fuel set on the ragged edge of lean. Yes it could also be an air leak or other mechanical problem but consider this; My WR250 is set crisp and IMO perfect using VP110. I have 205psi of cranking compression which is enough that if something was to go wrong or I put crappy fuel in it it would not forgive me. If I turned my metering rod 1 turn leaner it would not run as good and I promise you my bike would seize by the end of a day's ride, Lectron or not. If I did this on pump gas bad things would happen even faster. The point I'm trying to make is if you find a specific spot where the bike wants to detonate then back out of the throttle and go home and fix it... Buy better fuel, lower the compression or set the carb richer because I can assure it isn't seize proof.

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.

 

[Motosportz]

Not trying to put a tire on the fire here, but does riding at a constant speed between trails make much vacuum to draw fuel/lube? .

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.

 

[Motosportz]

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

 

[Motosportz]

Kelly what is the best way to measure the MR when installed in the slide?

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.

 

[Motosportz]

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.

 

[wallybean]

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.

The FBF head is on a different bike. JFYI

 

[uranys]

Here is a not great photo of my diy leakdown tester built with stuff you can find at most hardware stores:

You can kind of see it has a gas valve with a handle and after that it terminates in a male barbed fitting which you hook a bike pump up to. Slowly pump in pressure and close the valve when you get 5psi in there and wait.

You can find expanding rubber freeze plugs in various sizes to plug the exhaust at the auto parts stores.

 

[AUSKY]

"The seeming bad machining on the modified FBF head might have a lot to do with it."
These heads were both machined by Walt. I think you owe him an apology!

The plug is a 9 and the engine was only about 4.5 hrs old.

The purpose of my post was to find out what MR lengths others are running on their bikes. I have one other measurement of Troffers of 49.25mm. You mentioned another of around 49mm. I just wanted a guide to indicate to me the general position for the MR. Therefore I knew if I was rich or lean compared to others with the MS-3 MR. Troffer would be about half a turn leaner than your bike. I am about a turn lean compared to Troffers.

The new MS-3 MR came with no setup info, ie no starting measurement for the MR length. The setup info in the Lectron manual said to set it to 1.920" -2.020" but this was for the XL-1 MR. I was about two turns from this setting when the bike started to fire up and the rest of my tuning was based around this initial setting.

My post was never intended as a slur on the carb, I think they are a fantastic bit of kit. I understand the benefits this is why I bought one. Fuel economy, perfomance and jetless were my main reasons for getting one. This bike will be fed via a Lectron in the end I just want to get the fuelling requirements correct & ride this bike.

Unfortunately I can't perform a leak down test as the cylinder is on its way back to Walt. Thanks for the guide Kelly and Uranys I will get this happening when the cylinder comes back. I will have a look for other issues tonight.
Thanks for your help.

 

[Motosportz]

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.

 

[Motosportz]

My guess is Walt nailed it when he said; "My guess is that he is ~1/2 turn lean on the rod and the steady small opening cruise eventually caused the seizure."
poor fuel would contribute to the problem

After all Tommy V, JohnnyBoy, AUSKY and TROFFER88 can't all have a badly machined FBF head, a leaking crank seal and a leaking Reed block.

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

"There are huge differences in how a metering rod carb and standard carb work."
"There is a ton more to it and it is nothing like a standard carb so you need to think differently."

Serioulsly dude?

"This does not happen on a Lectron." (It just did, lean is lean and lean hurts engines)

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.

"This does not happen on a Lectron." (It just did, lean is lean and lean hurts engines)

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.

 

[Motosportz]

After reading through the above posts it seems to me that there is a need for a new rod design that will keep the engine from going lean at extended small throttle openings. We can call it the "crap fuel rod". Or better yet the "I can't un-clinch my butt cheeks and part with the money for race fuel" rod.

For those of you that don't have race fuel available in your area I hope you aren't mad about the butt cheek remark. For you I would recommend going 1/4-1/2 turn richer on the standard rod until a custom "crap fuel" rod is produced.

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.

 

[Motosportz]

"The seeming bad machining on the modified FBF head might have a lot to do with it."
These heads were both machined by Walt. I think you owe him an apology!

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

 

[Motosportz]

My post was never intended as a slur on the carb, I think they are a fantastic bit of kit. I understand the benefits this is why I bought one. Fuel economy, perfomance and jetless were my main reasons for getting one. This bike will be fed via a Lectron in the end I just want to get the fuelling requirements correct & ride this bike.

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.

The new MS-3 MR came with no setup info, ie no starting measurement for the MR length. The setup info in the Lectron manual said to set it to 1.920" -2.020" but this was for the XL-1 MR. I was about two turns from this setting when the bike started to fire up and the rest of my tuning was based around this initial setting.

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.

 

[flyingbob]

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.

 

[Hoov165x]

They don't all have seized engines yet but they all describe a similar lean condition that could very well lead to detonation and a seized engine.

I'm one of the happy 80+ people that love my lectron carb but if I had a problem I wouldn't care to hear of the other 79+ but would rather get info to help fix it rather than a sales pitch. (they already bought the carb)

I agree that not recognizing a lean problem or fuel problem and running it until it seizes is pilot error and all the responsibility should fall on the owner/mechanic. Once again Walt has gone above and beyond his duty to help out.

By definition it is a carb, not fuel injection. Maybe some of the members have limited mechanical experience but that is not the case with me and even if it was I would not want to be told that it's just too big and complicated to worry my pretty little head about. You should "Seriously" read what you have written before you post it, you may not realize this but many of your comments come across as condescending. I need not go into my credentials as a mechanic or machinist to validate my statements, the phrase "if you can't explain it then you don't understand it" always holds true.

In an earlier post I jokingly suggested a crap fuel rod be made, from the sound of the previous fuel problems in the land down under maybe the custom rod could be named an "Aussie rules rod"

You sure are argumentative. Someone piss in your corn flakes this morning?

I think you made your point, time to let it go for the good Lord's sake.....

 

[Motosportz]

They don't all have seized engines yet but they all describe a similar lean condition that could very well lead to detonation and a seized engine.

I'm one of the happy 80+ people that love my lectron carb but if I had a problem I wouldn't care to hear of the other 79+ but would rather get info to help fix it rather than a sales pitch. (they already bought the carb)

I agree that not recognizing a lean problem or fuel problem and running it until it seizes is pilot error and all the responsibility should fall on the owner/mechanic. Once again Walt has gone above and beyond his duty to help out.

By definition it is a carb, not fuel injection. Maybe some of the members have limited mechanical experience but that is not the case with me and even if it was I would not want to be told that it's just too big and complicated to worry my pretty little head about. You should "Seriously" read what you have written before you post it, you may not realize this but many of your comments come across as condescending. I need not go into my credentials as a mechanic or machinist to validate my statements, the phrase "if you can't explain it then you don't understand it" always holds true.

In an earlier post I jokingly suggested a crap fuel rod be made, from the sound of the previous fuel problems in the land down under maybe the custom rod could be named an "Aussie rules rod"

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

 

[AUSKY]

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'm hearing you Kelly, it is a little inconsistent. I started taking measurements so I could get establish where I was with the MR, to have a datum so to speak.
In a normal carb you can record jet numbers and adjust accordingly with the Lectron I found it difficult to work out where I was some of the time. Did I screw it in or out last time? If you know what I'm saying.
Measuring the MR was the only reference I had as it is the only variable. So I thought I would put it out there, I didn't realise the end is not ground off the same on all the MR's. That will change the figures.
The feed back from the bike was good & telling me that I was in the vicinity of where I needed to be, on the lean side obviously . If I go in another full turn rich I'm not sure it will start, last time I did it was a PITA to start & very rich. I might try another half turn richer. The MR seems to have a fuelling range of about 2 turns from really lean to really rich with our fuel here. I'm already one turn into that range.
This is why I'm lost with this issue. And thanks for your help mate!

 

[AUSKY]

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

That would explain the extra base gasket needed to get the squish right. 1.1 mm.

 

[Motosportz]

I'm hearing you Kelly, it is a little inconsistent. I started taking measurements so I could get establish where I was with the MR, to have a datum so to speak.
In a normal carb you can record jet numbers and adjust accordingly with the Lectron I found it difficult to work out where I was some of the time. Did I screw it in or out last time? If you know what I'm saying.
Measuring the MR was the only reference I had as it is the only variable. So I thought I would put it out there, I didn't realise the end is not ground off the same on all the MR's. That will change the figures.
The feed back from the bike was good & telling me that I was in the vicinity of where I needed to be, on the lean side obviously . If I go in another full turn rich I'm not sure it will start, last time I did it was a PITA to start & very rich. I might try another half turn richer. The MR seems to have a fuelling range of about 2 turns from really lean to really rich with our fuel here. I'm already one turn into that range.
This is why I'm lost with this issue. And thanks for your help mate!

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.

 

[AUSKY]

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.

I'm running a BPR9IEX it has a projected electrode.