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Lectron clone -- sort of

24K views 117 replies 14 participants last post by  ArcticJeff 
#1 ·
After reading some old threads I remembered why I lost interest in my Keihin pumper carb. -- mainly it has a broken pilot jet with a piece stuck in the carb. body.

Moving on I looked on the shelf and found a cheap Chy-knees sort of a Lectron clone carb. I had forgotten about.


I checked out the cheapy and it fits the TW200 intake manifold and an air filter I have that goes directly on the carb. looks like it will fit between the engine and the air box. The only thing to do is hook up a single line throttle cable and the fuel line and it should be ready to go. I hope this works well......

Auto part Carburetor Automotive engine part


Auto part Carburetor Automotive engine part
 
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#2 ·
Tony, you've mentioned this carb a couple times now. I don't know why, but I feel there is great promise in that thing... haha seriously. It looks very interesting. I went to that site a couple times and read up on it too. I am very interested in your results. Thanks for checking this out, I've been curious for a long time about this one. 🧐 (y)

*and I don't even have a TW... 😊
 
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#4 ·
Tony's pretty good at fab and mod work, I'll bet you 5 cents he gets it on. ;)
 
#9 ·
The throttle cable just arrived. It must have been sent by sail boat from China. It is a new TW twin push/pull cable of which I plan to use only one cable -- i.e. I will destroy it as a twin cable setup. I have to grind down the thing on the end of the cable to a little nub so it will work with the carb. The other end should work with the stock TW twist grip.

Looking down the centers of the carbs the replacement carb's passageway (venturi) is much larger. This could be a cheap performance upgrade! (Stock on left.)

One picture with slide down and the other with slide up.
Auto part Automotive engine part Engine Carburetor Automotive super charger part


Auto part Automotive engine part Carburetor Engine Automotive super charger part
 
#10 ·
I bought a cheap from China throttle cable for a TW. With it I was able to use the TW twist grip but I had to modify the other end of one of the cables to work with the new carb. (The second cable in the two cable TW throttle cable system does nothing but sit there.) Naturally with two ends to choose from I chose the wrong one to modify and ended up doing it twice.

Screw Fastener Auto part Fuel line Tire


For the other end of the cable I took a short piece of aluminum tubing and bent it to "sort of" hold the end of the cable in line with the carburetor.

Auto part Vehicle Tire Fuel line Pipe


The boot from the air box aligns very nicely with the carburetor and I bet if it were new and soft and supple it could be stretched over the end intake flange and clamped down.

Auto part Fuel line Pipe Vehicle Suspension part


Overall view.

Engine Auto part Vehicle Motor vehicle Fuel line


It started right up but wouldn't idle below 2800 rpm. I think the cable is a touch to short and holding the slide thing open a little bit. I jumped on and rode down the street and back -- a very short ride and I can tell ya it will need some tuning to get it right. The original carb was working very well so I can put that back on if necessary and still be happy.

More reports to follow either until I get it right or give up and toss it. Tony
 
#16 ·
The boot from the air box aligns very nicely with the carburetor and I bet if it were new and soft and supple it could be stretched over the end intake flange and clamped down.
Soak the boot in a 50/50 mix of Pine Sol and water over night, and it will be soft, pliable and supple when you take it out.
 
#11 ·
It seems I have T2 running reasonably well with the new carburetor. It zips right up to 65 mph with zero problems and if I hold it wide open for a little while 75 mph is easily obtained. I bet in a tuck it would do 80.

Acceleration seems very brisk according to the butt accelerator-o-meter. I wish I had a bone stock TW to compare it to.

Low speed torque seems very good. No bogging or lack of power. If I snap the throttle open it will die as there is no accelerator pump but if I "roll on the throttle" the power comes on very nicely and strong.

The downside is the cable system is on the "Mickey Mouse" side of things. I don't have a high degree of confidence in it.

Getting it to idle seems to be getting better with use. Rev it up and shut the throttle and it takes its time slowing down. At first I couldn't get it below 1800 rpm and now it is down to 1300 to 1400. Maybe its the cable hanging up or maybe its something else.

I will take a longer ride and see if I keep it. I like the increase in performance. I really think I could beat a 225cc if it was using a stock carburetor.

The engine sounds very different, not so much like a TW.

It is fun have a little more power to play with.
 
#14 · (Edited)
Its not really a Lectron carb. Its kind of a clone. As for jets, the carb came with 3 sets of jets, one already installed which is the one I am using. I did lower the clip on the needle to get rid of a slight bog in the middle of the rpm range. There aren't any numbers on the jets so its a little hard telling which one is rich or which one is lean.

To me it sure seems like a substantial improvement in performance.
 
#17 ·
What size clone Lectron carb did you get?
30mm carb. The intake port in the head is about 30 mm so it matches well.

Soak the boot in a 50/50 mix of Pine Sol and water over night, and it will be soft, pliable and supple when you take it out.
Thanks. I will give it a try.
 
#24 ·
I went for about a 45 mile ride today with the new carburetor. Overall, it seems to be working well with the exception of the idle. When I pull up to a stop sign the idle is fast but slows down. Then it slows some more to the point where it stops running. Its not that big a problem to keep revving it a little to keep it running and if it stops it starts right back up. It actually seems to slowly be getting better.....I adjusted the idle speed screw and it helps but the problem is still there.

It will easily get up to and cruise at 60 mph (approx 7600 rpm) to 65mph (approx 8200 rpm) and not only maintain that speed going up slight up hills but actually accelerate. I am not sure if the mixture at WOT is as good as it can be because it seems to have better acceleration at almost WOT than it does at WOT. I guess I will have to start playing with jets and the clip on the needle to find out.

In terms of performance I have to say it is better than a stock carburetor, at least that is what I am experiencing.

BTW, for the locals, it was smoking and hazy as could be. Dang forest fires sure mess up the air quality.
 
#28 ·
I am not sure if the mixture at WOT is as good as it can be because it seems to have better acceleration at almost WOT than it does at WOT. I guess I will have to start playing with jets and the clip on the needle to find out.
Can you adjust this screw on the top of the power jet? It is supposed to control the amount of fuel being delivered from 1/2 throttle to WOT.

207545


This is how the powerjet is described to work, not sure if it works the same on this carb?

The power jet is used to fine tune your top end and works like a faucet. If you turn it to the left, it opens the valve and richens it. If you turn it to the right, it closes the valve and leans it out. Tuning this has nothing to do with your idle or low to mid-range throttle response. NEVER ride with a closed power jet. If you are riding dunes, deep sand, outdoor motocross, or snow where you are wide open for extended periods, we recommend going ¼ turn richer to keep your motor cool. The fuel level in the line will be even with the level in your float bowl until the power jet is activated.
 
#25 ·
elime; about your idle anomaly; did you try adjusting the idle air screw once you rode it a bit and these symptoms showed up? My idle was also doing the same, even if I bumped idle adjustment up. So I next tried adjusting that idle air screw. It wanted to go IN! As I turned it in 1/4 turn at a time, my idle speed picked up. I had to adjust the throttle idle screw to bring it back down. Kept going between those two adjustments until I was get a max idle speed with the air screw at an Idle RPM I felt was correct, around 1200rpm.
Just something you may want to diddle with next ride out. It helps I have one of those cable style remote adjustments for my air screw. Makes it easy and I don't burn myself. I ended up at just a hair under 2 turns out. Had started at a hair over 2 1/2 turns out.
I have no idea if your clone is anything like the factory carb for adjustments, so none of this may even apply.
 
#26 ·
Ski Pro 3 -- I did play with the idle mixture air screw a little. I adjusted it to the highest idle speed and had the idle speed adjustment screw all the way out -- that is the slide was all the way down. I am thinking air is leaking around the slide but as the slide goes up and down the surfaces wear together and makes a better seal hence seems to be getting better by itself. At least I hope something like that is happening.

The idle mixture screw is on the side of the carburetor so access couldn't be any easier. I will try adjusting it some more and see what happens.
 
#27 ·
Ski Pro 3 -- I did play with the idle mixture air screw a little. I adjusted it to the highest idle speed and had the idle speed adjustment screw all the way out -- that is the slide was all the way down. I am thinking air is leaking around the slide but as the slide goes up and down the surfaces wear together and makes a better seal hence seems to be getting better by itself. At least I hope something like that is happening.

The idle mixture screw is on the side of the carburetor so access couldn't be any easier. I will try adjusting it some more and see what happens.
Don't be surprised if it changes due to air temps and elevation. Most well tuned carbs will be sensitive enough that you can dink with the air screw as you're riding higher or lower during the day or as the air heats up.
 
#29 ·
I removed that screw and it looks like a jet is under it. I don't know if that is the same as a power jet. That screw on top seems more like a plug than an adjustment screw. I could be wrong.......

T will try to get some pictures later today.
 
#30 ·
I removed that screw and it looks like a jet is under it. I don't know if that is the same as a power jet. That screw on top seems more like a plug than an adjustment screw. I could be wrong.......
Its design is the same as a power jet. I bet that screw adjusts the fuel flow for that power jet (1/2 to WOT).
 
#32 ·
The rubber gasket from inside the pod filter makes a perfect adapter mating up the stock TW rubber boot from the air box / filter to the new carburetor.

Pod filter rubber gasket.
Auto part Metal Wheel Steel


Pod filter rubber gasket next to a stock TW air box to carburetor connector.
Tire Auto part Automotive wheel system Rim Automotive tire


The end of the connector inside the rubber gasket from pod filter.
Auto part Tire Automotive tire Wheel Rim


And looking into the carburetor end of the connector with the adapter in place.
Tire Automotive tire Auto part Automotive wheel system Synthetic rubber



I think it looks remarkably good, almost like it was made for it. Bottom line is I can use the stock air filter and air box. That is perfect!
 
#37 ·
Carb enthusiasts like us! I'm following closely. My XT350 is exhibiting some of the same characteristics as you are describing. I have adjusted the (new) float once already and have been adjusting the "airscrew" as you're calling it. I think you'll know which one I'm talking about (not the pilot jet or main jet or idle speed). Starts and idles fine but one I get riding I have a hanging idle. Thought I had it fixed but back at it again.
 
#39 ·
Hanging idle appears to be a common problem with flat slide carbs. I've read folks using flat slides complaining of erratic idle, many of times. FWIW, I have a snowmobile with flat slide carbs (twin) and it has hanging idle problems too. I wouldn't say I've been able to fix it, but I have it at a place where its 'tolerable' and can work with it.
 
#40 ·
I lowered the float today and went for a test ride. It ran worse. I came home and spent much of the afternoon getting it back to where it was before I changed the float level and now I think it idles a bit better than before but it seems to have lost a little of its "zip" -- or maybe I am just getting used to it or maybe the placebo effect is wearing off.

I checked the pilot jet and it is the lean one in it now. Ditto the main jet. I did lower the clip on the needle to get rid of a mid range stumble. I am thinking maybe I should try a richer main jet to see how it reacts at WOT high RPM. Or move the clip on the needle down one more step and see what that does.

gammer73 -- interesting you say the flat side carbs have idle troubles. That actually makes me feel better in that I was getting very frustrated trying different things without positive results.

I still have a PZ30 accelerator pump sitting on the shelf. Cornelius in South Africa states he has gotten very good results with it. If this flat side carb overwhelms me I may give it a try.
 
#42 ·
I lowered the float today and went for a test ride. It ran worse. I came home and spent much of the afternoon getting it back to where it was before I changed the float level and now I think it idles a bit better than before but it seems to have lost a little of its "zip" -- or maybe I am just getting used to it or maybe the placebo effect is wearing off.
What about moving the floats up 1mm from base setting? I'm thinking if it ran worse when you lowered it 1mm (leaner), then maybe try richening it by going up 1mm from original setting. This also make it a tad richer at WOT too.
 
#41 ·
Thank you Tony for the lectron-clone sort of thread. The conversation has helped me on my XT350 carb.
I too did some carb adjusting today. I may, might, could've dialed in my XT350 Carb. I've thought that before so time will tell.
30-year-old carbs may have issues. Since I bought it last year I've been dealing with a hanging idle. I've been thinking it was running lean to cause this.
Last fall I bought and replaced the missing spark arrestor. This helped calm down the hang.
The problem this year it started leaking fuel out of the overflow tubes. After several adjustments on the float, I replaced the float, float needle, and seat. The float was set to high so I did have to make one adjustment to lower the fuel level. That seemed to stop the overflow leaking problem completely.
However, on a ride yesterday, at 1/2 to 3/4 throttle in 6th, I would get a stutter/hesitation. To compound the issue, at very slow speed (1st & 2nd) riding at low rpm, it would start to blubber.

Thinking back what you suggested a few years ago with the XT200 carb doing something similar, today I put in a 122 main jet. A 125 or 126 (can't read it clearly) was in it and I believe stock.

Test ride today. No more stutter/hesitation and any throttle position and the bonus, no more blubbering at low speed/rpm...so far.

I almost forgot. I also adjusted the idle mixture while it was running at operating temperature. Adjusting this helped stop the hanging idle. Probably should have spent more time doing this in the past instead of adjustments when the engine was cold and off. To get it right I think you're actually supposed to adjust this when it's warmed up and running.
 
#43 ·
Admiral -- We are definitely playing the same game. Much of which you wrote I touched on today especially adjusting the idle mixture while the engine was running. So easy with the screw on the side of the carb and you can hear the results as you turn the screw.

gammer73 -- The float is about as high as it will go. When I was trying to put it back to the way it was before I started I over adjusted and the float hit the top of the float chamber and wouldn't stop the flow of fuel. I adjusted a little bit down and now it works like it supposed to.

I think I will just ride it for a little while before I do anything else. About the only thing I can easily do is change the clip on the needle and put in a richer main jet and richer pilot jet and I don't think it needs a richer pilot jet. Not sure about the other two. They may help at WOT.
 
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