Yamaha Maxim XJ700 won't start

I have a 1985 Yamaha Maxim XJ700 that will not start. I have cleaned the carbs, yes all four, cleaned the tank, fuel lines, and petcock put in new fuel, changed the spark plugs got the coils tested, pulled out the air filter, that was slightly melted. I have fuel in all my carbs and am getting some pouring out of the overflow. I get one or two pops that sound like it is going to start every hour that I work on it but don't know where to go from here. I'm relatively new to working on motorcycles and am learning so please be patient if I ask seemingly obvious questions. Thank you in advance for all the help

 

If you have gas coming out of the overflow then you are probably flooding out. Gas coming out of the overflow would indicate non-sealing float needle valves or floats badly out of specs. Did you wet set the carb floats? Check the plugs and see if any are wet.

 

Thank you for getting back to me so quick tabaka. Like I said earlier I'm still fairly new to this what exactly do you mean by wet setting the carb floats?

 

the set of plugs that I took out were wet

 

Don't try to start the bike until you go through the carbs again, drain the oil/gas mix, put in new oil, and replace the oil filter.

In the Church of Clean

Further reading that covers all of the other things that you NEED to address before you go for your first ride.

The Information Overload Hour

Welcome to the world of classic bikes. The first step is to take care of all the years of neglect.
The second step is to enjoy riding a motorcycle that has been returned to a safe and reliable state of operation.

 

I have the same bike you have, and it took me several "cleanings" to finally get it right. I hope your bike is bone stock since that will make it easier to get right. If you do not have pods--hopefully you don't-- but have a foam Uni-filter, t hen I suggest you replace it with the stock paper filter. The foam filter flows much more air than the paper filter and will require more work in getting the carbs set. I had the foam filter and finally exchanged it for the paper filter and it made a huge difference. In my opinion, if you really want to get it tuned correctly you will need to get a colortune plug. But first you must get the carbs perfectly clean, sync'ed, and wet set the floats. Plan on taking several days to work on the carbs and follow the church of clean instructions word for word. (Trust me--and others-- on this, it will save having to do it a second or third time).

 

Thank you for the advice k-moe I will definitely go through the carbs again. does any one know what the floats are supposed to be set to? The oil was changed a few years back no more than 5 yrs. do you still suggest changing it? On another note I'm not sure how you can wet set the floats because mine hang straight down.

 

I forgot that the carbs on the 700 have fuel overflow vents. Still, check the oil level and give the crankcase a sniff. If it smells of gas then change it. Since it's sat in the crankcase for five years, change it anyway (acids form from moisture and the remaining combustion byproducts from the last time it was run, you really don't want those acids in there).

Wet setting involves putting the float bowls on, checking the fuel height, and removing the bowls to make adjustments before rechecking.

Wet Setting Fuel Levels

 

You can do it! We'll help.

Gary H.

 

Adam,

I had the exact same problem only days after bringing my xj700 home. It would not start. In fact the only thing it did really well was leave a huge puddle of fuel on the floor in my garage. I had no prior motorcycle experience and was feeling quite alone... Until I found this forum. Read, read and read some more! The folks here have literally thousands upon thousands of collective hours of experience. Listen to their advice.

My problem was two fold and it sounds like you have at least the same two.

#1. Rebuild your petcock. EVERYTHING you need to know can be found here:
http://www.xjbikes.com/forums/threads/rebuilding-the-yamaha-vacuum-fuel-valve-w-pics.25058/
Mine was allowing fuel to pass when the motor was not running... obviously, it should't do this.

#2. Do (at least) a bottom end rebuild on your carburetors. It sounds like AT LEAST one of your float needles are not seating properly. This was my problem as well.
Info on this and TONS of pictures can be found on this forum... Use the search box in the top right hand corner of the page.

Everything you could possibly need can be purchased from Len @ XJ4ever. Here's the link:
http://www.xjbikes.com/forums/forums/xj4ever-supporting-vendor.23/

For wet setting (after you clean the carbs and replace the valves and seats (again, Len will set you up with what you need), you'll need something to hold up your carb set so you can work with them. Build a holder out of PVC parts.

You can see holder that I built below. The tank has fuel in it on the shelf above. The clear tubing and PVC parts were purchased at Lowes. The four clear tubes attached to the bottoms of the bowls was for wet setting the floats. More specific info on this can be found here in the forum as well. Again, just do a search on it.

Does anyone have a .pdf of the XJ700 service manual for Adam?



Good Luck.

 

I have a .pdf copy but I'm not sure it can be copied and emailed. I'll try to send it to my office email and let you know if it works. In any case, I think you can buy on ebay for about $10.00

 

My .pdf file will not download to my email. I bought it on Ebay and here it is:

http://www.ebay.com/itm/Yamaha-XJ70...ash=item35fd6784f8:g:6BQAAOSwu1VW713r&vxp=mtr

Well worth the cost.