Lectron carbs

Lonestar_399 1/31/2015 12:24pm
1/31/2015 12:24pm Edited Date/Time 1/31/2015 12:27pm
So, occasionally I tech at large events. Just remember the tech inspector is just a volunteer not necessarily a complete authority on every rule and bike under god's green earth. Sometimes you even have to pull in your nephews to keep the line moving, who by the way do a great job and have a pretty good understanding of what to look for.

The Lectron is legal according to the current 2015 AHRMA Handbook, pg 81 for Post Vintage Racing guidelines. It is NOT legal for Vintage and older bikes so just a heads up on that. The keyword here is "period" type carburetor and Lectrons were sold in this era. Now, I hope you have several hundy's ready to spend as these things are not cheap, however I am very interested in one for my troublesome 1980 YZ125. And yeah, I've had plenty of problems with the RM125 also, but that's a whole other thread.

If anyone questions you at tech they should have a rule book handy and just point them to this page. It's that simple.

Here's the rule:
CARBURETORS: Period-type carburetors are strongly encouraged. Period flatslide carbs are allowed on Historic and Grand Prix class motorcycles. Examples include Lake, Lectron, Posa and other period-type flat-slides. Active acceleratorpump-equipped carburetors are allowed only on Ultima-class motorcycles; all others must be disconnected or removed, even if OEM-equipped. Dell’Orto accelerator pump carburetors are allowed in the Historic and Gran Prix classes only if the accelerator pump mechanism is disconnected or removed. Period flat-slide Mikuni carburetors are allowed only on Ultima class motorcycles. Keihin flat-slide carburetors are not permitted. No modern D-shape-slide or similar equivalent carburetors are allowed in AHRMA Post Vintage off-road competition.

And if this turns into a vintage racing rules bashing thread I will cut my fingers off.
Mike P.
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Mike P. 1/31/2015 12:34pm
1/31/2015 12:34pm
I've used a 34mm on my 80 RM125 and 80 YZ125 & a 38mm on my 78 CR250, and they were pretty simple to jet, but be careful because you use a brass Mikuni jet for your main and I got mine lodged in the carb and can't get it out (so just be careful as they are brass). I stopped running the Lechron on the YZ because I ended up tearing the rubber intake manifold as the Lechron is not smooth on the intake side like a Mikuni and loosing/tightening the carb for jetting over time will tear it. They are AHRMA legal in historic and GP (been tech'ed a few times with the Lechron) so no worries there.



OldPro277
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OldPro277 1/31/2015 12:36pm
1/31/2015 12:36pm
That's good news Lonestar, and I was by no means busting any tech inspectors balls, lol. Just I've "heard" stories ,and it looked pretty clear in the book,just trying to avoid a 5 hour ride and not being able race. I've been thru tech at AMA nationals (back in the day) and it was pretty straight forward ,but I would assume the vintage stuff would be MUCH more difficult and time consuming to get thru. The tech guys need to know all the period correct pieces and mods from 30,40,50 years ago, very tough gig, I'm sure... So, now who can tell me if they are worth the $300- $500,and how will they work with the bikes and mods I've described ???
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OldPro277 1/31/2015 12:41pm
1/31/2015 12:41pm
Mike, I was under the impression that the Lectron used only metering rods and no typical "jets" whatsoever. My memory is kinda foggy, but the ones I used 'way back when' were jetless... Im almost positive. You just adjusted the metering rod by screwing and unscrewing ....or am I smoking crack??

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Lonestar_399 1/31/2015 12:55pm
1/31/2015 12:55pm
OldPro277 wrote:
That's good news Lonestar, and I was by no means busting any tech inspectors balls, lol. Just I've "heard" stories ,and it looked pretty clear in...
That's good news Lonestar, and I was by no means busting any tech inspectors balls, lol. Just I've "heard" stories ,and it looked pretty clear in the book,just trying to avoid a 5 hour ride and not being able race. I've been thru tech at AMA nationals (back in the day) and it was pretty straight forward ,but I would assume the vintage stuff would be MUCH more difficult and time consuming to get thru. The tech guys need to know all the period correct pieces and mods from 30,40,50 years ago, very tough gig, I'm sure... So, now who can tell me if they are worth the $300- $500,and how will they work with the bikes and mods I've described ???
LOL, I'm just gun-shy on here as people don't always read through and consume everything you are trying to say or will draw some inane conclusions.

I'm really interested though in a Lectron but I have only seen one roll through tech. I asked him about it and the comment was the best money he ever spent. The $300-$500 price tag is a little much for my cheap ass...I'll really have to be convinced as logic eventually rules my wallet.
OldPro277
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OldPro277 1/31/2015 1:08pm
1/31/2015 1:08pm
Yeah they are pricey( particularly since I need 2 !!) ,kinda why I'm looking for as much real life input as possible...and as much as I've spent already on these things already, I hate to get cheap now,especially if they work as well as they're supposed to. Just haven't found anyone that's used them on vintage bikes lately,for fresh input.
Mike P.
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Mike P. 1/31/2015 4:42pm
1/31/2015 4:42pm
they use a Mikuni pilot jet that acts as a main jet. I will send you a picture of it tomorrow. The metering rod is for the pilot to needle in a Mikuni. l spent a lot of time dialing in these carbs and decided to go back to a standard carb.
Lonestar_399 1/31/2015 4:47pm
1/31/2015 4:47pm
Wanted to let you know good choice on the ignition. I used to have a very nice 1980 RM125 (stolen Angry ) with a digital PVL that Joe hooked me up with also. Carburetion was a bitch though and I had this NOS 1982 RM125 carb sitting around which I bolted up and never looked back. It was a bigger bodied 32mm Mikuni than the stock one. I ran whatever was the stock jetting for the 82 model. Matched up the reed case ports to the cylinder as Suzuki was horribly sloppy with those, a Jemco pipe, DG head, modified airbox, 43mm DLS setup, and some Works Shocks. Really miss that bike and eventually will build another.

The PVL seemed to give the bike a very smooth power curve. It would not allow me to over rev either, but it did rev out higher than stock.

Oh, the cases on those RM's need to be lapped also. Air leaks are very common. Joe was pretty familiar with the bike as I let my nephew have it for a while to race...I'm sure he was glad to see it leave his garage eventually. I've been known to park a bike or two there to clear out space in my own...but hey, he has the garage majal and I just have a modest 2 1/2 car garage.
OldPro277
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OldPro277 1/31/2015 6:08pm
1/31/2015 6:08pm
You're right on the Suzuki port work and castings---worse than horrible !! Took a lot of time and a lot of material removal to get it decent.. Damn shame about your 125,sounded like a great bike!! I've put Simons modified to 11.5" travel and a ProFab arm using 17.5" Works Shocks in addition to the motor work. Should be a fun ,competitive bike when its done,can't wait to ride it. Of course it may be late April by the time all this snow is gone. And I agree with your assessment of Joe's garage,its a legend even up here in western Pa !!! Woohoo If I make it to Diamond Dons this year,Im staying an extra day just to sneak over and see his garage.....And Mike P, Im still not processing what you're telling me. I talked to a Lectron tech,and he assured me that the unit is completely jetless.Its tuned by metering rod adjustments and there are a few different rods available to match to different elevations. They send you the rod that works for your application( bike,engine,type of riding,elevation) and then its up to you to fine tune by adjusting your metering rod. Are you using a vintage Lectron or a modern one ? and are there even any difference between those two?. I've looked at what I thought was a modern one and the intake flange was smooth like a typical Mikuni. I guess I'll have to keep researching because one of the main advantages of the Lectron was the ease of tunability but you're saying that wasn't the case with yours...
Lonestar_399 1/31/2015 7:14pm
1/31/2015 7:14pm
OldPro277 wrote:
You're right on the Suzuki port work and castings---worse than horrible !! Took a lot of time and a lot of material removal to get it...
You're right on the Suzuki port work and castings---worse than horrible !! Took a lot of time and a lot of material removal to get it decent.. Damn shame about your 125,sounded like a great bike!! I've put Simons modified to 11.5" travel and a ProFab arm using 17.5" Works Shocks in addition to the motor work. Should be a fun ,competitive bike when its done,can't wait to ride it. Of course it may be late April by the time all this snow is gone. And I agree with your assessment of Joe's garage,its a legend even up here in western Pa !!! Woohoo If I make it to Diamond Dons this year,Im staying an extra day just to sneak over and see his garage.....And Mike P, Im still not processing what you're telling me. I talked to a Lectron tech,and he assured me that the unit is completely jetless.Its tuned by metering rod adjustments and there are a few different rods available to match to different elevations. They send you the rod that works for your application( bike,engine,type of riding,elevation) and then its up to you to fine tune by adjusting your metering rod. Are you using a vintage Lectron or a modern one ? and are there even any difference between those two?. I've looked at what I thought was a modern one and the intake flange was smooth like a typical Mikuni. I guess I'll have to keep researching because one of the main advantages of the Lectron was the ease of tunability but you're saying that wasn't the case with yours...
Get your reservations now if you are not staying at the track when you come to Diamonds.
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OldPro277 1/31/2015 7:17pm
1/31/2015 7:17pm
Reese,thanks but I read that as well. Rule books are great, but sometimes the interpretation of said rule book is the concern. Lonestar, having actually been a guy interpreting and administering the rules means more to me than reading the paragraph.
The other important part im trying to find out is if they are actually worth it. I've been told and read things,but they are all third party accounts,was hoping to hear from some actual users before I plunk $ 800-1000 on those 2,or should I just get 2 new Mikunis for $ 125 ea....
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OldPro277 1/31/2015 7:23pm
1/31/2015 7:23pm
Lonestar-- great advice. I have NEVER been to a vintage race at all, be nice to have DD's be my first ,lol... All depends on the next 4 weeks of progress on these things if I'm realistically going to be able to make it..
Lonestar_399 1/31/2015 7:37pm
1/31/2015 7:37pm
If you run short on any parts for your bike let me know. I have a ton of spares, well except for airboxes. My next N or T model 125 is going to have a DG 6 petal reed and some unknown aftermarket swingarm along with all the same parts I had before.

If Don's is your first vintage race well then you're picking the granddaddy of them all to attend. It is insane. Even if you don't race you should go.

I'm glad Reese pasted the link to the rulebook though as I'm not sure a lot of guys even realize it's on-line.

---albert
OldPro277
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OldPro277 1/31/2015 7:59pm
1/31/2015 7:59pm
Thanks for that.. I had Mossbarger dig me up a cool dual-stage reed cage for the 125, but the cases need milled slightly to accept the new reed block. Happen to have an extra DG set-up,lol ? That was my number one choice ,but couldn't find one
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Mike P. 2/1/2015 4:34pm
2/1/2015 4:34pm
As promised, here is a copy of the two Lechron carbs I own. The one is in the original box from around 1980 and it's a 34mm and I circled in RED where the Mikuni pilot jet is (it's stuck in there and can't get it out). This was a brand carb when I got it a couple of years ago so having the jet stuck in there pisses me off. The other is a 38mm and you can clearly see the jet (circled in RED), which this carb despite being dirty (I last used it back in 2006), worked great...I took the 78 CR250 I had it on apart back in 2009 and still haven't found time to put it or the 80 CR250 I have back together...one of these day...






Mike P.
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Mike P. 2/1/2015 4:37pm
2/1/2015 4:37pm
In truth, these carbs are not difficult to dial in once you get a basic understanding of them. I used my 34mm carb on a highly modified 80 RM125 and on a highly modified 80 YZ125 and it worked great on both, I just tend to play with my jetting on race day a bit more than I probably should (in the interest of not running lean)...
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OldPro277 2/1/2015 4:53pm
2/1/2015 4:53pm
Thanks Mike, appreciate the pics and info. That's just odd that the Lectron guy tells me that there are zero jets in the carb that would need played with. Hmmmm,Im thinking maybe pulling the trigger on the 34mm for the 125. If it works well then maybe I'll get the second one...

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