Different Transmission Ratios on EC300 ?

D

Die Tante T.

New member
I?m confused about my 2011/12er Nambo. According to all technical data sheets, sparepart lists, etc. the Nambo must have the same transmission ratios like the Ec300 or the Ec300 racing..but I think thats not possible. Because of the "much to short feeling" of the gearbox, I rode a freinds bike to compare this (the Nambo its my fist GG EC) a 2009er EC300 (same transmission ratios acc. to Datasheets) and this bike is completely differnet. The Nambo has so much shorter gears and will be in the 6th gear if you can ride the normal EC300 on the 4th or 5th. The Nambo has 13/48 sprockets, the other bike i rode has 13/51 !!!! So this is not the reason. Now I ask you if anybody knows something about a similar chase ??? Or if Gasgas has assembled different Gearsets ??
 
You could maybe be onto something. Nambo Trev has stated that his 2010 Nambotin is much more aggressive than any other 300 he has thrown a leg over too. We had considered jetting and gearing, and he was going to have a peek internally next top end to see if anything different stood out. Gear ratios would make sense though.
 
I don't know about the recent bikes, but checking the parts manual a few years ago showed the same identical ratios in the gearbox whether the bike was a 200 or 250 or 300. I would be surprised if this has changed.

I would love to have a taller 5th and a much taller 6th. I expect the Nambos get the engines with better tolerances. Good squish, high compression and a different pipe could do it. Maybe the stainless pipe adds some performance.
 
We thought that too Neil. I have never had the luxury of throwing a leg over a Nambo to know if they have much more go or not. Trev hadn't measured his squish and I'm not sure which base gasket stack they use. The S3 head only comes with the silver insert (which leads me to believe it would be a significant squish band still) and all the inserts are the same volume as the stock head. I doubt that it has much more compression than a stock 300 and probably less than one thats seen an RB mod.

I thought maybe they have a different crankcase volume? Trev said his definately has the reed block spacer installed though which supposidly softens bottom end snap, which is what they're reporting the Nambo has a lot of.
 
thanks for your reply. I cant sleep after I rode an "normal" EC..so yesterday I checked all again. First I made a Road speedtest with 13/48...feels not so fast but 140 km/h (app.87 mph) on top revs as result will confirm that the Nambo has the same transmission ratios. So I ride again both bikes, the normal EC an the Nambo. You feel faster on the normal EC an with less "stress" while riding. The normal EC revs much smoother an feel more like a 4-stroke. The Nambo has less torque on the bottom but then the Bike pull your arms as quick as you have have the feeling that you must shift 3 times mores than with the normal EC. But all this seems to be only a feeling..and you feel slower with the Nambo because you?r so stressed with fast shifting, breaking etc. more than a 125ccm. lesson learned: I have to tune the engine more softer. I will change the insert of the S3...maybe thicker cylinder footsealing (sorry if the translation is wrong don?t know the english word for it)..o.k. let?s start working :-).
 
So you are saying you have now rode 2 x 300's with 13/48 gearing and both have the same top speed?

Are both bikes running the same jetting? Don't be mistaken on how much difference a needle can make to the power delivery. If you were super keen you could use the same carb in both bikes just to rule out one more variable.

Like I said earlier the S3 head (Silver insert - stock Nambo) and the Stock head are the exact same volume. I doubt this would make much difference in the grand scheme of things. The Nambo may have been built with tighter tolerances and a better squish. My suspicion is that the Nambo get the best parts from the bin.

The other thing to check is the base gasket stack, and port timing. If you pop the pipe off and rotate the engine to BDC how far above the port does the piston edge sit. I think the later models only run 1 x 0.5 gasket which sets the piston a bit above boosting the bottom - mid grunt. If you time it level you end up with more of the power delivery you described the Nambo having. Weaker off the bottom with a more noticable mid to top end pulll.

I have run my EC300 with port timing flush and S3 black insert which ran like a big bad angry 250 albeit a bit slower revving. I then changed to a custom volume S3 insert and 250 cylinder and changed the port timing to boost bottom mid some and it feels not too different in power delivery. The 250 being just a bit more managable and quicker to spool up.

I'd really love for someone to chime in who's had a Nambo apart to confirm if there are any differences internally.
 
That seems like a really linear power curve for a 2 stroke.
It says 125ccm at the bottom? Surely thats not a curve for a 125.

Picture is too large to post on here.
 
Agree noobi. It doesn't look right to me either. Especially for a 125cc and not really sure how it relates to this thread.

Stolen from my other thread below is a simulated dyno run for the EC250
GG250powercurve.jpg


BLACK is the S3 cylinder with a 1.3mm base gasket stack
RED is the S3 cylinder with a 0.5mm base gasket stack
GREEN is the stock EC250 cylinder with a 0.5mm base gasket stack (how the last stock bike that i worked on was set up from the factory)

I also just saw the OPS also using the N1EG needle which I think lends itself to be rich off the bottom and then snaps hard as it cleans out. Nambo trev is using the JD kit in his. I'd like to see back to back testing using the same carb and jets.
 
It say?s down on the paper Motorcycle "over" 125cc!

That?s my 300cc Nambotin....and my own DYNO!
Yes, a lot of test to get this curve like this linear.
 
I'm thinking the simulation would be engine power output and the dyno would be rear wheel power? Thats one nice linear power curve.
 
Also noticed the speed, I'm not sure what gear you did the test in but mybike does well over 130 with 13/50 gearing.
 
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