Gmann I will be at Gordon's Well

 

BillDS650,
What's up with Gordons Well? I have heard that there may be another "shootout" type event at Glamis which is why I want to be there. I usually do the family thing at buttercup and the guys only trips to glamis. This trip is guys only so glamis it is.

 

Gmann,
I also thought Kevin knew his stuff. I did't like the answer about the needing a new cable and thumb throttle, but that's not his fault. I did ask him to e-mail me the final price on it with shipping on Mon, but still no e-mail from him. Once I get this info I'll be ordering this asap.

 

Hey new ds please don't get me wrong if i were in you guy's place i would go with the lectron.man it's half the price of my miky45.and im sure if mine out preforms it.it dose not do'it by 250 dollars or more i would say dollar for dollars it sounds like the lectron is the better deal.i was just adressing what i have learned about these carbs. the secound i heard alky .capabilities i went crazy over this carb.but then i heard 38mm venturi to 44mm ports i wept'i cried 'and started looking for a new carb.but no one metioned the 50mm that may work for what i have in mind.so thanks for the ifo guy's have a nice day

 

Ref 44/38 Lectron Carbs. This is NOT the only Lectron 44 they make. They also make a 44/41. However these engine builders that use these carbs are not trying to save a few sheckles by using a smaller carb. They have tested the flow and these carbs seem work better. Fast by Gast and TC Racing use these 44/38's by preference, not financial necessity. They prefer this carb because of the velocity it creates. The high velocity waist area actually creates more negative pressure at the fuel inlet and draws more fuel into the faster air stream for a given rpm. That's why the needle length, taper selection as well as the taper flat are so critical on these units for a specific engine.

I use this carb on my old 250X/350X conversions with an extended billet aluminum port matched intake. Put it this way. The dealer who just redid my frame for me had a chance to play with it to day on their track. They are also Cannondale dealers. First impression: the old 350X (not too stock) was equal to the Cannibal on the bottom end but blew it away on the top end. This "house" Cannibal (they use it for testing) has had some of the factory fuel mapping done, and was not an "out of the box" Cannibal.

Now this was not a fair side by side comparison, but it was given by a mechanic with a fair amount of seat test time on the Cannibal. The 350X is only a 365cc version, with TC's 924 cam, valves and springs, 12:1 compression, ported for 365 cc's, cdi, Lectron 44/38, new intake manifold.

The only other change I did to this engine was add the new intake manifold. It had had the Lectron with a stock manifold before. The stock manifold was opened up to take the larger carb. (stock 350x carb was only 31 mm)This old 350 X was a pretty strong runner before, but the flowed intake has really brought out the best.
PS this engine REVS (I haven't run a tach on this one but my other one runs about 9000, and this one is MUCH higher) and pulls all the way to the top.
See Jan issue 2002 of "ATV 4 WHEEL Action" for "carb shootout" - I dont know what they did to match up intake manifolds, but changing mine made a huge difference in the performance of this carb on the bottom end.

 

hckycoach,
great post, appreciate all the info. Kevin explained that to me when I purchased mine as well.

The intake on my 01 DS is already pretty good size. I'm wondering if I need to make any adjustments? I will have it on this weekend and start the testing process.

Thanks again for all the information.

 

Thanks for your reply.

Just seat of the pants info. One of the things that I believe makes such a difference with the manifold is the section change right after the carb.
Because the Lectrons "bell out" after the 38 mm venturi waist and my new manifold is tapered from the port intake right up to the 44 mm carb outlet, there is a high pressure /low pressure effect - sort of a crude expansion chamber effect.
This can help two ways. First the low pressure area should help atomize the fuel better, and second it creates sort of a small pressure chamber for pulse air to flow into the combustion chamber at low rpm's better. At high rpms I believe only the pressure differential is helping along with the smooth transitions for better flow velocity. Because of the fairly severe angle of this "bell" created by the 38mm to 44mm transition and my relatively small port diameters (33mm on the 365cc and 36mm on the 425 cc) I believe the 38/44 Lectron is a better carb when used with this kind of intake mod - at least in my application.

With a larger engine and larger port inlet, it may be necessary to go to the 50 mm carb if Lectron makes one in the same geometry at this size (I beleive they use 4 deg taper on the inlet and 8 deg. taper on the outlet) to achieve the same effect.

I will be testing both bikes more soon - my 350/425 is set up the same way but I varied the length and taper angles a bit to better match the port angle.

 

The lectron is installed and will be tested this weekend. Install was pretty smooth and it seems to have a lot more throttle when I started it.

Can't wait to see how it works.

I will post pictures and results on Monday.