1985 maxim 750 problems

hey everyone, new to the site so I fiqured I'd give it a try ! I'm working on a buddies '85 yamaha 750 maxim water cooled. Ist problem is it sputters and coughs when ridden in the rain or moisture, I've heard there is an electrical componinent prone to cracking on this model, but not sure which part.
second problem, oil keeps going "malted milk color and frothy " after short distance. I've done numerous oil changes, flushed the system. Pvc tube cleaned and no signs of any water whatsover being lost in the radiator. I just cant figure it out. The engine oil just keeps going bad after very short runs ? Any help on these issues greatly appreciated !
Just a note, I believe this is a Canadaian model , and the US model was considered a Maxim 700.
Thanks for any help. Al

 

Sounds awfully like a Coolant introduction to Lube Gallery or Head Gasket Problem.

Inspect pressure release function of Radiator Cap? ??

There is only one good reason that the Oil to be contaminated like that.
Coolant is being introduced to the Oil from somewhere in the water jacket.

Check the coolant level with the Engine Dead-Cold.
Measure, mark or top-off the coolant in the radiator -- Dead Cold.
Run for 1/2 Hr.
Recheck level -- Dead Cold.

 

On my way to bed but known problem are the coils. recommended replacement are Dynacoils:

http://www.skylinc.net/~hap/maxim-x/dyna_coils.html

don´t know about the oilproblem (sure others will chime in)

regards,

 

By the way, welcome to the site

 

Fuse wet.
Kill switch moisture.
Pods? Wet or allowing moisture intake?
Moisture in left side Crank Cover?

Grounds, dirty connections and loose connections?

Test the resistance at the Primary and Secondary Coils. If your within specs ... You'll need to troubleshoot the Ignition Circuit with a Multi-meter Festival.

Check the obvious places that would act-up wet. Switches and exposed ignition connectors. WD-40 'em.

 

Thanks for the replies, acouple questions back though, Redliner, how does the rad cap affect the oil, would the release act like a breather in a way ?
Also, 2nd Gear, what are the problems with the stock coils ?
Thanks again fellas

 

I haven't been able to research that cooling system yet ... later on I'll get to reading-up and see if there's something you need to do with regard to pressure.

My bikes are air-cooled.

 

Blown head gasket? I'd do a compression test before I did anything else.

 

The compression test is always a good idea. But, there's a chance that the gasket surrounding the combustion chambers is OK. On an Air-cooled bike a leaking gasket would be easier to diagnose.

Liquid cooled engines present their own problems if the inner water jacket seal is seeping-by into an oil gallery and the gasket material around the combustion chambers isn't the problem.

The standard test for a water jacket leak is to drain all the oil until the sump is emptied.
Leave the Oil Drain Plug -- OUT.
Fill the Radiator and pressurize the system.
If there is a leak in the water jacket; the pressurized coolant will eventually drip from the Oil Drain Hole.

Buy a PVC Cap just large enough to fit over the Radiator fill neck.
Drill it for inserting a an air valve stem.
Duct tape it on air tight.
Bicycle pump some pressure in there.
Wait.

 

You´re quite welcome.

From what I´ve read (mainly in the XJowners maillist, of which I am also a member) the stock coils are, if not weak, then not working very well with low voltage. Also, they (like aftemarket coils, of course) can crack, the inner windings go bad etc.

Problem with the stock coils also is that the ignition wires can´t easily be replaced; if you have to cut off too many 1/4" at the spark plug cap end of the wire (due to corrosion), you have to cut/dremel the coils open to change the wires - and seal them afterwards.

But Rickomatic is right, of course. You should measure the primary and secondary resistance to determine, whether the coils are faulty.

By the way: "Biker Wannabee", "1st, 2nd etc. gear" and "Redliner" are all
"Rank titles" based on the number of posts in the forum: http://xjbikes.com/Forums/viewtopic/t=89.html - use the usernames above the rank titles (or the "quote" function) if you want to adress someone specific (you could easily have more than one "2nd gear" in the replies in your thread.. :wink: