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Good weather/New exhaust responsible for fuel economy?

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As some of you may have read I've just upgraded my exhaust system. It's great very noticable power gain... and so has the weather been over here for the past couple of weeks.

Anyhow, I keep a very detailed log of my distance travelled versus fuel consumption. I've noticed since the change in pipe the economy has gone up first by 4mpg on the first tank, and now >5mpg on the second tank from the original ~64mpg... . First tank was 68mpg and second 69.9mpg

I not sure if it's due to the beautiful weather or souly due to the pipe... or a bit of both. I'm trying to get the economy in the mid 70s or above... so it's all good.

Anyone with any insite please let me know.

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I couldn't tell you what I get for mileage because I am always ham fisting the throttle! Whoooooooo! :)

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In the States where I live we have winter gas and summer gas... not sure if the UK does or not... but it do notice a small difference here when they change out the blends.

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Regalman not that I know of... we either get super 95 or super 98 petrol from the petrol station and it costs a fortune. 2/3 of it is tax.

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Did you rejet for the pipe?

I'm jealous for your good weather. We're quite the opposite here.

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They don't even tell us when it switches from summer to winter bend. It all comes out of the same tap. The average consumer doesn't even know the difference.

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Yeah, they always bump up the price during the switch over... they always blame it on the refineries having to switch over and it affecting general supplies. However, just recently around here the winter blend was quite a bit cheaper since they had too much and were dumping it into the market.

Its not a huge change by any means, you need to be really on top of the system to know about it.

We just had about a .30 increase per gallon here, the winter blend is gone and the summer blend costs a bit more to make and wholesale gas prices went up because of it. Not huge, but its just part of the game.

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Did you rejet for the pipe?

I'm jealous for your good weather. We're quite the opposite here.

No rejet, just replace stock for a Scorpion system.

I'm out riding in my jeans at the moment, although it's bitterly cold at night.

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im just about to put a system on mine once its had its 600 mile service, wasnt sure what to buy system wise. got any pics of the scorpion system

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im just about to put a system on mine once its had its 600 mile service, wasnt sure what to buy system wise. got any pics of the scorpion system

Good point, not yet. I'll take a picture and post it tomorrow. I think it's a nice looking bit of kit, stainless pipe and titanium silencer. Too dark at present to photograph it.

I bought the cheapest exhaust system I could find. If you're after pimping gear I'd go for the next model up, looked a lot nicer and is about £60 more than mine.... Or obviously look at other brands.

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i've been looking, but just cannot make my mind up, would prefer a full system and dont wish to spend more than £350. dont want anything too loud either as i head off for work early and dont want to upset my neighbours

( note the correct spelling yanks )

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Lee, my set cost me £280 or something like that delivered. It's under 94dB as legal stuff goes, and I've taken it to the MOT centre to see if it offended the tester, he said it would pass no problem in his centre... obviously this is not going to apply to yours just yet.

As for loudness, I wheel it out down the road before I crank her up, I feel guilty about the old dears that live nearby when I leave before 8am. As said before, photo tomorrow.

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Depends on what type of riding you do, but goint +1 on the front sprocket or -2 on the rear might be enough to bump you up into the 70's. Made a noticeable difference on mine.....as did removing the giant radiator shrouds/air brakes.

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Note that those UK fuel grade figures are RON & I believe they use MON in the USA, 95RON is approx 87MON & 97/98RON is approx 91MON. In case anyone thought we were getting avgas at the pumps :thumbsup:

The annual temperature differential in the UK is not sufficient to need winter & summer blends of Petrol. The average maximum temperature here is only 25C & the average low is 4C. This varies across from the most northerly parts of Scotland where the average is a bit colder, to the balmy South & South east areas of England where its a bit warmer.

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I used to get almost 160 klms { 100 miles } to a full tank in standard trim . After the 3x3 , rejet and a full free flowing exhaust , I am doing about 20 klms less per tank . I think this is partly due to my right wrist , as it is so much fun to ride now . We have had a lot of rain in the top end of australia lately , and this has slowed me down quite a lot , enough so , that I got 140 klms for 7.5 litres just last week . So that puts me back up there again near the 160 mark . I think wrist = fuel economy on these bikes , plus performance means more fuel burnt , greg

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As some of you may have read I've just upgraded my exhaust system. It's great very noticable power gain... and so has the weather been over here for the past couple of weeks.

Anyhow, I keep a very detailed log of my distance travelled versus fuel consumption. I've noticed since the change in pipe the economy has gone up first by 4mpg on the first tank, and now >5mpg on the second tank from the original ~64mpg... . First tank was 68mpg and second 69.9mpg

I not sure if it's due to the beautiful weather or souly due to the pipe... or a bit of both. I'm trying to get the economy in the mid 70s or above... so it's all good.

Anyone with any insite please let me know.

Hi crawler, :lol:

Yes... better mileage is at least partly due to a higher ambient tempratures. Hot weather riding bumps it up just as cold weather keeps it down. hot days are the best, because if you tank up in the morning with cold fuel, it heats up and expands. And since your carb dispenses the mixture by volume, the gas goes farther as you're running leaner.

As long as you don't modify the airbox or change the jetting, you'll retain the mileage gains with your new exhaust. If you do the 3x3 and rejet, you'll give up the mileage gain in exchange for more performance.

The overall mileage on my SM does stay consistently above 70mpg which includes both winter and wummer riding. The best 500 mile record average is77.1 mpg in hot Summer weather. I think that's about the best the bike can reasonably do under ideal conditions without making some really drastic and expensive modifications... but I'm happy to average 70+ and that was my goal. :usa:

There's usually warnings from the good folk here about damaging the engine from running it lean, and since I have been doing exactly that for 21,000+ miles now, a while ago I got curious and so had the oil analysed by Blackstone Laboratories at 15,000 miles and the report was a completely clean bill of health... ( and of course no fuel dilution of the oil. :lol: ) If there was any damage, the very first subtle sign would be a slight drop off in gas mileage due to the engine becoming less efficient. Since that has yet to happen, I see no reason why the engine won't run for another 20,000 miles with reasonable maintenance.

My trusty reliable SM has made me thousands and thousands of dollars as a useful daily work vehicle for these 2 1/2 years...

IMG_1807.jpg

...which pleases me to no end, being the cheap b'tard that I am. :thumbsup:

Take Care,

Greg

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I noticed a big difference after I swapped out my stock exhaust for the full exhaust in fuel mileage. With the stock pipe (w/ 3x3 mod and jet kit) it would usually always run out and have to switch over to the reserve at about 85-90miles. After putting the full system on an upping the mainjet, I can go right up to 135-140 miles before having switching over to reserve on the stock tank.

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