125-200cc MS-3 Metering rod lengths

A question For those of you running the 36mm lectrons with a 165 kit & the MS-3 MR & short PJ tube.
What length are you guys running on your MS-3 metering rods and how many turns out on the PJ's?
I had the MR set at 49.63mm/1.953" on my 165 & seized mine again last week and I would love to get it right this time. Ive got the PJ at 2.25 turns out.
I'm just wondering what is the working around the world.

As far as i know, the rod length only effects idle.

If your seizing you should richen the top end by turning out the power jet

You should explain how the seizure occurred. The rod length affects from closed to ~3/4 throttle. The shorter PJ tube, leaner bottom grind and the richer large opening grind of the MS-3 rod allows you to richen up the rod and still have the bottom good while requiring less use of the PJ which doesn't atomize as well. It would be good to get some comparisons from guys using the MS-3 both in the US and in Australia.

Kelly,

He was running it at a steady cruise speed/small throttle opening on the road. Plug was white at and around the electrode. He had to have the PJ out 2+ turns to get a slight tan color at high rpm chops. Bike ran fine for a number of hours but seized after some extended steady state road cruising. Pictures show a heat seizure. My guess is that he can go ~1 turn richer on the rod and then back up until bottom end is crisp. My guess is that he is ~1/2 turn lean on the rod and the steady small opening cruise eventually caused the seizure. Regardless I am fixing him up with a new top end.

Walt, I think I'm in the same boat with my jetting. Bike is running great, awesome power no complaints while in the woods but yesterday my throttle cable broke and we had to take the street back about 8 miles. I noticed while cruising at low rpm the motor started sounding strange. Maybe some slight detonation so I kept giving it a bit of throttle every few seconds so it had enough gas/oil. My main concern is that the cylinder and radiators were pretty hot after getting back. It didn't boil over but maybe because I'm running Evans coolant. I think I have a lean spot just off idle. Will the MS-3 fix this?

Not sure if it helps any but my 165 with the supplied metering rod would at a steady 30 / 35mph ish would start to detonate a fair bit but if I opened the throttle then went back to say a 1/8 open it would go away but return soon after , With the rod I modded there is no detonation at all but if I go a 1/2 turn richer it will very slightly 4 stroke and if I go 1/2 a turn leaner it will start to detonate again so it would seem to be a very sensitve area with the lectron in that particular area of throttle opening with the 165.

PS My 36mm Lectron also had the exact same traights

Yes Kelly I have been in contact with Walt. Thanks for outlining the seizure for me Walt. The first time this was due to bad oil, this time leaning out at constant low throttle cruising, which would indicate the PJ was not being used. The bike was going great and just locked up without warning.
I think it may be a too lean a MR at idle and just off idle for the crap Aussie fuel we have here. Walt has already supplied the new "Super Roo" Aussie head with the reshaped CC dome, which helps alleviate the detonation issues we have been experiencing here in the land of Oz, again from poor quality fuel.
Walt has been outstanding with advice and warranty work but seizing this engine is getting painful and I need to sort it out or go to a Keihin which I don't particularly want to.
I don't want to seize this thing again!!!

I agree with you Kelly. I don't think it's is totally carb related more so fuel problems.
I'm just trying to find out what sort of settings others are running. I read people saying " I'm half a turn in from stock but what is stock and what length is the MR?
What settings are you working with over there in the States? For the MS-3 MR?
I have not discounted air leaks out of the equation. I did spray WD spray all over the Reeds and manifold to see if there was any change in running but there was none. I will check the crank seal.

49.25

My eye ball measurement says that one turn is ~.5mm. Depending on how close these rods are from one to another it appears that Damo's setting is ~1 turn leaner than yours Tim. I think that one of the things about the lectron is it will allow the motor to run at both fairly rich and fairly lean conditions. The larger the opening/larger the demand the more it compensates for a lean condition with vacuum. The problem arises when you are at very small openings/demand for a long static period. That slightly lean condition builds heat steadily until either detonation/pre-ignition or seizure results. Usually the seizure is a result of the detonation/pre-ignition. I worry that even with the new head that unless your jetting is spot on or slightly rich your gas may cause some detonation. Doesn't mean that there aren't other issues like an air leak that would cause the very lean burning condition that your plug was showing. Definitely need to eliminate all other possibilities and start rich with the rod when you get your top end back.

Beat me to it Kelly.

Tom, I am worried about your FBF head. As I was telling you, they milled so much material off the deck of the head that I was limited in how much I could reduce compression with the bowl. If you aren't able to run with a 50:50 mix of race gas/pump premium, then you will probably need to use pure race gas or I can replace your head with one that will work with the pump premium. Your head was milled very similarly to the head on Actm7's head and he is having good results with pure race gas. Drop me a pm if you want to change heads.

Walt , I will mail that head back this week. Totally forgot until I was reading this. I changed to a lower compression head and .8 base gasket on my 165 , as it was pinging if it wasn't running race gas. When i use constant low throttle openings I still get some pinging and think it might be the MS-3 rod. I switched my Ktm 200 back to the 3-1xl , it isnt as crisp on the bottom but has way more midrange.

I think that you are both right!! it needs to be richer & search for an air leak.
If Troffers MR was set at 49.5 & mine was at 49.63 it would be about one turn difference leaner, as Walt said.
Kelly what is the best way to measure the MR when installed in the slide?
What is needed for a leak down test.?
This is the plug after the engine seized the second time.


this is the plug the first time it seized

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? .