Massive fuel consumption & smoke

[Oilydub]

Hi, first post on here but have been reading for a while.
2015 EC300 Racing all standard (as far as I know) apart from 52 rear sprocket
Quite low hours & decent condition.
50:1 ratio using Putoline MX7 fully synthetic.
Was racing an Enduro at the weekend, dropped her on a slow corner & stalled.
When I picked her up she was difficult to start at first & then wouldn't tick over.
Continued the race but she used nearly twice as much fuel as usual.
One of my m8s said she had been badly smoking the whole race.
Filter was well clogged with dust so I put my spare on but she stills smokes like a chimney but revs reasonably well.
When i tapped the carb fuel came out the overflow.
Any ideas?
Steve

 

[Oilydub]

After talking through with a m8 the higher fuel consumption may be down to the 52 rear sprocket which had been put on for the race (originally had 48).
Course was tight twisty with no real areas to open up for long.
Race day was very hot & dusty & first time I had used in these conditions (only used it four times before in damp & dull conditions).
Would the mixture screw cause over fueling & excess smoke if turned in to far, as the plastic head looks pretty messed up?

 

[memphis2857]

Sounds like the float level is way too high and most of your fuel is running out in the ground. A 52 vs. 48 sprocket is barely going to show a noticeable difference in fuel consumption


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[swazi_matt]

Sounds like the float level is way too high and most of your fuel is running out in the ground. A 52 vs. 48 sprocket is barely going to show a noticeable difference in fuel consumption


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Try looping the ov rflow pipe to see if it improves

 

[(F5)]

Read threads on setting float height. Then the ones on throwing away the stock needle. Then be prepared for a much better running bike.
Repack your muffler once you're done as it will be full of goop.

 

[Oilydub]

Read threads on setting float height. Then the ones on throwing away the stock needle. Then be prepared for a much better running bike.
Repack your muffler once you're done as it will be full of goop.

Just drained the crankcase & fuel came out so at least I know for sure its over fueling.
Carb is now off so about to clean & check it to see whats in it.
Will read up on the float height, needle etc. Looks a minefield though

 

[swazi_matt]

I did 110km on the weekend and didn’t go onto reserve. Single track and forest switchback roads, but before setting the float height and looping the overflow I would battle to get 70km

 

[(F5)]

So there will always be some residue, maybe a tablespoon of clean oily goop.

More than than then its not over fueling; it's leaking in. Check needle valve and hairs that can cause leaks. Drain tank, check tap. Remove tap. A mate had same thing happen and was lots of rubbish in bottom of tank.

It dumped 1/2 A tank in the back of my van and then blew through the next tank scary quick on the track. How could I forget That? Had to strip carpet out.

 

[Oilydub]

Carb apart, it has the N1EF needle with the clip second from top.
Main jet 175
Pilot 40 but the pilot is blocked !!!!!
Will clean the pilot & the tank as suggested & set the float height.
Don't want to change parts for the sake of it but what needle would be suitable for the future.
Bike only used for racing enduro's, altitide sea level to about 300 metres.
Swazi matt what exactly do you mean by looping the overflow?
Sorry about all the questions, new to Gasgas I usually race a 1980 KDX175 (nice & simple).

 

[Neil E.]

Your fuel consumption will be bad until you get rid of the N1EF.

 

[(F5)]

A mate is running NEDJ (ex RM250) in his 15, 2nd from top and is excellent but our fuel may require slight changes to position, pilot main, from yours.

Float level procedure seems weird until you do it then kinda get a feel for where the float sits , carb on an angle. I cut some cardboard with a slot out of it to set measurement top of float to base of carb. Mine was seriously the other way.

 

[Oilydub]

A mate is running NEDJ (ex RM250) in his 15, 2nd from top and is excellent but our fuel may require slight changes to position, pilot main, from yours.

Float level procedure seems weird until you do it then kinda get a feel for where the float sits , carb on an angle. I cut some cardboard with a slot out of it to set measurement top of float to base of carb. Mine was seriously the other way.

I only had to do a minimum adjustment to the float height. There seems to be no measurements to be had on mine just align the float with the carb body.
The slow jet is blocked & doesn't want to clear (only using nylon to try to clear it as I don't want to damage it). Might just have to get another.
Thanks for the tip on the needle, will probably change it in the future but just need to make sure it runs as well as it did only a couple of weeks ago.
I run it on BP Ultimate (97-99 octane I think).

 

[(F5)]

Check the tank. Only a bit of grit or a hair can prop the float jet open.

 

[swazi_matt]

Carb apart, it has the N1EF needle with the clip second from top.
Main jet 175
Pilot 40 but the pilot is blocked !!!!!
Will clean the pilot & the tank as suggested & set the float height.
Don't want to change parts for the sake of it but what needle would be suitable for the future.
Bike only used for racing enduro's, altitide sea level to about 300 metres.
Swazi matt what exactly do you mean by looping the overflow?
Sorry about all the questions, new to Gasgas I usually race a 1980 KDX175 (nice & simple).

have a look at this picture:

https://thumpertalk.com/forums/topic/1226261-2017-ktm-300-xcw-mpg/

 

[Oilydub]

have a look at this picture:

https://thumpertalk.com/forums/topic/1226261-2017-ktm-300-xcw-mpg/

Cheers Matt, see what you mean now

 

[Neil E.]

Soak the pilot jet in carb cleaner/lacquer thinner/acetone overnight, then blow through with compressed air.

 

[Oilydub]

Update:
The whole carb was meticulously cleaned as well as the fuel tank/tap/filter.
The bike now has a new pilot jet as the original wouldn't unblock.
The float is set 10 degrees from parallel & doeesn't overflow until about 45 degrees lean (as per the post "float bowl height on 2010 300???").
Looped the overflow "just in case".
All new screws in the carb & a new idle screw that's easier to use.
The air screw is 3.5 turns out & she now rips on part throttle.
I know that is too far out & she will require a new needle & re-jetting in the future but just needed her running properly.
Still a bit smokey but might just be down to the mess in the silencer.
Need to get out on a practice track this weekend then will repack the silencer next week.
Thanks guys for all your advice, its appreciated.

 

[memphis2857]

Update:

The whole carb was meticulously cleaned as well as the fuel tank/tap/filter.

The bike now has a new pilot jet as the original wouldn't unblock.

The float is set 10 degrees from parallel & doeesn't overflow until about 45 degrees lean (as per the post "float bowl height on 2010 300???").

Looped the overflow "just in case".

All new screws in the carb & a new idle screw that's easier to use.

The air screw is 3.5 turns out & she now rips on part throttle.

I know that is too far out & she will require a new needle & re-jetting in the future but just needed her running properly.

Still a bit smokey but might just be down to the mess in the silencer.

Need to get out on a practice track this weekend then will repack the silencer next week.

Thanks guys for all your advice, its appreciated.

The air screw is not affected by the needle. You need a smaller pilot jet




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[Oilydub]

The general consensus on here is that the standard needle is rubbish.
Will completely upgrade the carb in one hit as I know it would benefit from the smaller pilot jet as well.
Just needed to get it running as I have a race in 2 weeks & need to get some practice in first.
Don't want to get bogged down with loads of alterations at the moment.