Is there a fuel filter?

Hi folks. I have an 85 XJ 700 and a couple questions. First is there a fuel filter on this bike? Inside the tank? Second where is the air/fuel mixture adj. Is that the small screw set deep into a threaded hole next to what I assume is the starter plunger (or the only thing I can see move when I move the choke leaver) Believe it or not, I have the service manual sitting in my lap at this moment. I have been through it 100 times and find no mention of a fuel filter or a fuel air mix adj.) Seriously folks, I'm really trying, just give me a little clue. Thanks. Karl

 

The only fuel filter is inside the tank, on top of the petcock. This part also deals with fuel levels so it tells you when it's time to switch on "Reserve".

It is not a very good filter. For proper filtering, put an inline fuel filter between the petcock and the carb rack. SOme prefer paper filters, some use the conic shape with a brass element.

As for the mixture screws, here they are:



These are not exactly the same carbs you have but the screws are located at the same place.

 

Wow! Thanks. Those do look like exactly the same carbs I have. I took them all apart and got them spankin clean. I'll go to the fuel filter next, it must me a mess considering what I found in the carbs and the front break system.
Thank you so much for your assistance. Very helpful!

 

It is common practice to add a fuel filter in the fuel line between the petcock and the carbs.

I dont think calling the top of the petcock a filter is accurate. More like a fuel screen.

 

Thanks for the help guys, and it is helping. I'm getting close. I determined that there is no fuel screen at the top on my petcock, so I put the inline filter as well as a little screen where I believe it was suppose to go. Now, I also believe that my # 4 carb is not getting fuel. I have already taken out and apart the carbs and got them spankin clean. I adjusted the floats as per manual. So I'm going back to the manual (such as it is) to see if I can figure out how the fuel is delivered to each carb. Also (uuuugg) I still have a small bit of fuel flowing from the petcock even though I just replaced the diaphragm and the seals. I do understand the air fuel mix, thanks, I have them at two full turns from closed. As for the synching, I did a bench sync when they were out, and I'll do the vacuum sync when I can get it to idle properly. Thanks again and feel free to toss me any advice you like.
PS Wish you were here.

 

Fuel is delivered to the carbs via a number of small tubes interconnecting the carbs. You probably have a float issue on #4.

As for adjusting the floats, have a look at this, the correct way to do it: http://www.xj4ever.com/setting%20fuel%20levels.pdf

In regard to the petcock, give this a read. Not all petcocks can be rebuilt successfully; and doing so involves more than just installing parts: http://xjbikes.com/Forums/viewtopic/t=25058.html

And more importantly; you didn't mention valve clearances. Unless your valves are in spec, you can't do a good vacuum sync.

 

Thanks, you are aces in my book.
I'm still shy about adjusting the valves. What do you think, should I just dive in and do it? The bike ran great before it sat for two years. Are there any special tools needed?

 

How to: http://xjbikes.com/Forums/viewtopic/t=14827.html

Part Deux, without the tool: http://xjbikes.com/Forums/viewtopic/t=29209.html

Valves gotta be checked (and adjusted if necessary) every 5000 miles. It's not a "one time" thing; you need to learn to do it anyway if you want to ride this bike.

 

Than that's what I'll do.
Thanks