Gas Mileage 81 Xj550 Seca?

This may be very off topic but it sounds like you have all original air box? I am currently rebuilding a 1981 550 Seca and unfortunately I am missing the air box cover. So very hesitantly I’ve decided to fiberglass one since it’s nearly impossible to find one to buy. The problem I’m having is that I have no idea what this thing looks like. I really wanted to know what the inside looks like so I can make it work with a stock filter. If you could post some pictures of it I would really appreciate it!

 

the seca cover and maxim cover are the same part
this link lists ehe bikes you can use a cover from

https://www.partzilla.com/product/y...?ref=2bf15fd226c61243fdc51998ec8be809aa681a10

 

I am so sorry I did not respond to this earlier. I will try and get to it tomorrow.

 

Thank you so much

 

So, I took the carbs out and everything actually seemed fine. Only bad part was the rust like substance collected at the bottom of the float bowls. But all the orifices were clear and what not. I put them back on, bike runs. I was nearly empty in the tank so I put 1.5 gallons of premium in there. After a couple days of riding the tank started to sputter and the odometer reads that I went thirty seven miles. Does this sound right to anyone?

 

I don't recall you mentioning, but have you serviced the petcock? Do you know if the screens are clean? I'm just thinking of stuff that would prevent you from going the 125-150 on a tank (before reserve).

On another note, I always put 87 or whatever the lower octane gas is. From what I can tell, these engines won't benefit from high octane.

 

Yes, I did actually service the petcock. Works fine. A friend of mine said you might need new clutch plates. Faulty clutch plates require more gas I guess so the engine isn't running as well. It's either that or I am running extremely rich and need to tune the carbs better.

 

You might know if the clutch is slipping. I'm not sure if there are other failure modes that degrade performance.
About running rich, I would pull the plugs, 1 at a time. If dark, adjust mixture screw 1/4 turn at a time. Less if it seems closer to the right tan/brown color. I did this a lot when I first got my carbs back in.

 

your tank holds 4.2 gallons with .9 reserve. if you are using an oem petcock and it was set to run sputtering at 37 miles is about right.

1.5 gallons into an empty tank would have given you around .6 gallon to run with petcock on run. because your reserve is .9 gallon. did you turn the petcock to reserve ?

with out knowing how much fuel was actualy in tank above statment is a rough guess.

so go to the gas station and FILL UP the tank to bottom of filler neck inside the tank. Ride 50 miles and fill the tank again. this is the only way to determine your fuel mileage.

 

Yes, I did turn to reserve and then I turned it too PRI and I still couldn't get anything. It pretty much wouldn't start after 37 miles. I walked it to the gas station and put another gallon in there and bike started instantaneously.

 

it sounds like your petcock is not working correctly

 

I think I'm getting around about 45 miles to an imperial gallon with my Radian motor'd 550 seca which is about 36/37 to a US.
Not sure how that helps but it's another reference point.

 

Joshua, are you still going to get some pictures of the air box cover?

 

Awesome thanks

 

https://postimg.cc/gallery/1tbjzd61m/

 

Sorry about that. Looks like XJ550h beat me to it.