Horrible Gas Mileage

[Mr Toga]

I'm experiencing fairly bad gas mileage right now on my 550. Right now I'm getting about 50 miles on one tank. Doesn't feel good. Also, the bike will not go over 6k. If it is in neutral I can get it up to about 7k. The bike will reach 6k under load at about 5/8ths throttle but will stay at 6k through the rest of the throttle range. Any ideas?

[MisterCinders]

Sounds like a rich condition. How are the valve clearances, carbs cleaned, jetting, etc.?

Check the plugs for richness.

[cowboyup3371]

How is that 50 miles (I assume you mean 50mpg?) - in town, on the highway, at what speed? I'm getting 46 to 48 mpg on the highway at 70 in good strong winds with my 550. Once I get up in the hills and drop to 55ish I can get 50+. In town, I can average around 50+ but that's rare since I live out in the sticks and the highway is posted 65mph.

As far as the rpms, I'll let someone else speak to that but what's the maintenance history like? When was the last time you checked and adjusted your valves?

[Mr Toga]

Sounds like a rich condition. How are the valve clearances, carbs cleaned, jetting, etc.?

Check the plugs for richness.

Plugs are a tad black. Valves were adjusted late last year. Carbs were cleaned and jets were checked to stock values. Running all stock here.

[Mr Toga]

How is that 50 miles (I assume you mean 50mpg?) - in town, on the highway, at what speed? I'm getting 46 to 48 mpg on the highway at 70 in good strong winds with my 550. Once I get up in the hills and drop to 55ish I can get 50+. In town, I can average around 50+ but that's rare since I live out in the sticks and the highway is posted 65mph.

As far as the rpms, I'll let someone else speak to that but what's the maintenance history like? When was the last time you checked and adjusted your valves?

No. I mean I get 50 miles on about 3 gallons of gas in city.

[cowboyup3371]

How many turns out are your idle adjustment mixture screws?

[Mr Toga]

How many turns out are your idle adjustment mixture screws?

I believe 2 but I will check when i get home

[cowboyup3371]

Did you adjust them using the highest idle method? If not, get your bike nice and warm and then start adjusting per the instructions found on Basscliff's site.

When you say the carbs were cleaned, was it done per the recommendations in Nessism's latest procedures?

[Octain]

50 miles to a tank? Holy smokes! Is there a hole in the tank?

[Mr Toga]

Did you adjust them using the highest idle method? If not, get your bike nice and warm and then start adjusting per the instructions found on Basscliff's site.

When you say the carbs were cleaned, was it done per the recommendations in Nessism's latest procedures?

I have not used the highest idle method. Will try that though and report back. I used the old carb cleaning guide to clean the carbs

[MisterCinders]

Did you vacuum synch the carbs after cleaning them?

If the plugs are black? Carbon black or oily black? Carbon black means rich. Oily black means bigger problems.

How is your compression?

[Larry D]

Check your oil level and make sure you're not losing gas into your crankcase via a faulty petcock.

[tom203]

Check your oil level and make sure you're not losing gas into your crankcase via a faulty petcock.

Yeah, and check wherever you park so you don't get hit with fuel spill fine! Any chance that you have prank playing "friends"?

[BigD_83]

Check your oil level and make sure you're not losing gas into your crankcase via a faulty petcock.

I know this doesn't solve anything, but when I brought my 650GD back from Saltspring this year I manage to only eke out about 50 miles on a single tank. It was running horribly...the oil was full of gas when I drained it. I checked the petcock and it was functioning normally. There was no question the bike was running rich though, and I also determined I had no spark on #2 and 4 when it was cold. It was so bad there was raw fuel in the combustion chamber evidenced by very wet (dripping) plugs. My air/fuel screws were at 3 1/2 turns out.

I've only bench synched so far, as Canada Post had been holding my Carbtune for the last month, but so far, at 1 1/2 turns (stock) out, the bike is running much smoother.

Just letting y'all know Mr. Toga is not alone in his experience.