Fuel economy....

N

n_green

New member
My gas gas lives up to its name, it's obviously off the irish factory floor thats how thirsty she is.
It's a '11 300 with the 36mm carb. The squish and compression ratio have been corrected and reed petals replaced. Power valve has also been adjusted to remove free play.
Best ever economy I have gotten is 10l per 100k's (23.5 MPG), was hitting reserve at 80-85k's which would give me roughly 95-100k's out of the 9.5l tank.

Then I went and chased a bit more top end from the 36mm carb and had it oval bored, since then I've had nothing but jetting drama's with it, but I have a whole other thread regarding that and thats not the point of this one. Nothing has changed apart from the oval bore.
Best ever economy I've gotten out of this oval bored carb is 11.5l per 100k's (19.9 MPG).

I don't think this is acceptable, but maybe it is. I know Jake gets good economy but we all know how picky he is with his jetting.

What I want to know is whats the average GG rider getting from their bikes? Am I chasing a pipe dream hoping to be able to do 100k's from the stock tank??

Side issue, I'm at 95hrs on the top end now and its due for a freshen up, could this be contributing to my poor economy?
 
I have an 09 300 and10klm's per litre is the best I have ever got in tight single track.Its the off/ on throttle ,2 /3 gear constantly that ultimately causes this sort of consumption.I have a mate who rides a 300 ktm and only gets very slightly better . I have a good idle and if anything lean jetting and a1.6 squish.I can only suggest anyone who gets better are riding on more open trails with no obstacles and are using 5/6 gear and I would guess would not be on the pipe in those gears .Its the nature of the beast but a shit load of fun.You just have to plan your rides ,have 4 by backup or carry a couple of litres
 
Just another thought.Are you losing any fuel from your carb overflow pipe due to incorrect float height or I found just riding rough terrain ,I would find fuel dripping from the overflow tube.I re-routed the tube back up over the carb then back down through the guide to the swing arm.This will still work as an overflow when the bike is on its side but prevents leakage over rough terrain.Do this then ride and see if there is any fuel in the loop of the overflow.
I do have an 38mm carb ,principles the same.Good luck
 
Good points regarding the riding style too. Almost all of my rides will have at least 10-20kms of transport sections. Usually on the morning run they'll be taken easy off the pipe, but coming home things are usually a bit more aggressive. 5th gear lifting the front end, or sliding sideways out of corners in 4th gear. You've seen the single I ride which is mostly 2nd and 3rd gear on and off the throttle with the occassional kick back to 1st to boost up a ledge or hop over a log. I base my consumption over an average ride which typically includes a bit of all the above. I'd have no hesitation getting 90kms out of the 9.5L tank and can generally get to the 90km mark before hitting reserve. I also carry 1L of fuel in the backpack, and 200ml of oil. Mostly so I have a backup, and if I get really desperate I can scab and mix of 4T mates! ;) 10-11KM/L seems about as good as it gets.. Remember my last piston also showed signs of running hot and lean so I've been dancing on the edge.
 
I get 10km per litre of fuel. I doubt you can do much better unless you are just cruising down fire roads.
 
Last year I used to get about 70-80 out of a tank. Not flash but bearable, I've since done the top end, fitted an over size power valve cover, I only fitted two gaskets instead of the standard three and now I get 45-55 a tank!
Bloody horrible.
Same jetting (180, 40, N1EF) and now I'm wondering if I should go back to what I had before and add the extra gasket.
I just did the float height which appeared to be out by a fair bit as I noticed it leaking fuel when it was on the stand on Saturday, almost vertical. So it is possible that it was leaking around every corner and across the bumpy tracks.
 
With the new cylinder I'm getting 10 GPS km per litre and about 11 on the speedo, nothing done to the motor. Same with n3cj 42/178 or NEDW 40/175.

I reckon you are pretty close to on the money.

From what ive read Nutty Proffesor blueprints, case matches, cleans up ports, spends 8 hrs on the carb alone, sets the squish and sets the comp ratio and runs longer gearing (because of increased torque) to get 6 km a litre out of a kato.

I think you've done everything reasonable for a mortal owning a gasgas wth a keihin. :)
 
I can't believe how good on gas mine is. Raced today, very fast, MX track and fast woods. Lots of heavy throttle stuff, very little low speed technical. After two hours finished with just under half a tank. Head mod and JD Blue needle. My buddy's identical bike had similar results.

I just don't understand the whining about GG tanks on the orange website, at least from a HS racing perspective.


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I'm not unhappy with it getting 10kms to the litre, its just mine won't get it. Yet.
My old '04 pumpkin and a mates '09 pumpkin 300's used to get 10-11ks per L. Mates new '11 pumpkin 300 gets 14-15ks per L. Std bike with corrected squish.
If I can achieve 10ks/L ill be able to get 90-100ks from a tank. That's fine by me as my average trail ride loop is 80-90ks. Just annoying only getting 70-80ks from a tank at the moment.
I got there once with the 36mm carb but
get close with the oval bore.
In any case you've all answered my question, it is possible to get this economy consistently so ill go back to playing with my jetting.
 
Have I done my sums rite, mpg what r u getting

Gg2012 250. They got a 10.5l tank rite?

I done 56 miles per 9.7l (incidentally hit reserve at 50miles)

So based on the above. 56x10.5 /9.7 = 60.2 miles per tank. Sound about rite to u boys.?
 
Its in the ballpark. Lots of other variables like how you ride it, load on the engine, how well toleranced your engine is.

60 miles = 96km or so. I can generally squeeze that out on a tank, and sometimes without hitting reserve. Thats on a 2010 with a 9.5L tank. In comparison with stock jetting I was hitting reserve between 60-70kms and was hardly ever riding on the pipe.

Even last weekend I rode with a mate who was on a 2011 300 running an N1EG. He was well into reserve and took about 9L to fill, where I had been riding harder and only took 7L. We both covered the exact same loop.
 
Not to bad then, I'm sure I could get another 5-10 if I rejeted and tweeked but as I'm happy with the performance I'll prolly leave it till it gets bit warmer. To bloody cold to get out there messing ATM
 
All my gassers have gotten @23mpg with stock jetting. I had RB do a full carb job and recut the head on my 07 300 and it jumped up at least 2-3mpg. We ride technical woods at a moderate pace. My friend who rides with me gets 15% better mileage than I do riding the same trails at the same pace but he is way smoother on the throttle than I am. He rides a 300 ktm.
 
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