XJ700 Running Cold

Greetings all,

I've got a 1985 Maxim X 700 that was supposed to be a winter project but has become my daily driver since my Honda CX500 blew its stator last week. I've put a reasonable amount of time into getting the Maxim up and running happily. If I leave it sit and idle, it warms up nicely, the electric fan kicks in and out as needed and everything is happy. If I ride the bike around the garage (~60F ambient), the needle on the temp gague drop to about 1/4 up. If I take it for a ride outside (~30F ambient), the temp gague bottoms out and the non-idling, lousy performance that comes along with being cold shows up.

I figured the thermostat was either missing or stuck open,. I popped open the housing and took out a perfectly functional 89C thermostat. It was fully closed as it should be and had a good amount of pressure keeping it that way. Just for good measure, I put in a new 91C thermostat that I had on the shelf. I put it all back together and it acts exactly the same.

Anyone have any good ideas as per why this thing would act like it doesn't have a thermostat?

Thanks in advance...

 

Thanks for the quick reply. I'll check out the cold spark when I get some time. It'll probably be a while as finals are next week. At least the bike lives in a heated garage. Thanks again --

 

Well, it's finally getting warm enough outside to start playing with the bikes again. The Honda is looking like $$ to get it back on the road, so I'm turning my attention back to the Maxim.

The issues are still about the same. Basically, it acts like it doesn't have a thermostat even though it does. It starts just fine cold so long as it is choked. It does the normal "carbs out of balance" dance where it won't really idle, but it'll happily spin up to 2000+ rpm. If I leave it sit, eventually it warms up, I can take off the choke, and it idles ok. Not great, but ok. If I take it for a ride, the temperature gauge drops and it won't idle anymore without the choke.

In December, I tried replacing what appeared to be a perfectly functional thermostat with another apparently perfectly functional thermostat. The one I took out was an 80C. The one I put in was a 91C. Does anyone know what the rating is supposed to be?

Thanks --

 

The proper thermostat is 82 deg.C (180F.)
At what temp or gauge setting is the fan kicking on and off?
Maybe kicking in to soon?
I'm pretty new to the xj's, and know nothing of the water cooled models.

 

When watching it idle in the garage, the fan kicks on at the top of the "normal" range and kicks off when it gets near the bottom of "normal". The fan seems to do a good job of maintaining temperature while the bike is idling. I can't tell you what the fan's doing while I'm driving as I don't notice it.

 

I think you are getting enough convection cooling from your aluminum block to bring the temperature of the motor down into the cold zone without the radiator. I would put a wind break in front of the rad and see if it helps. I know diesel pickups are a PITA to get any heat out of in a prairie winter, and that's with a cast-iron block and bodywork around it. My brother's Magna would barely register out of the cold zone even in summer back in the 80's. Look at it this way, the only cooling the bike gets is with the cooling system and forced convection from the windblast. Take the cooling system out of the equation and see what happens.

 

I'm thinking you're right. I fashioned a piece of cardboard over 95% of the radiator. Now, around town, it almost gets to the normal region. On the highway, it's a little colder, but still reasonable. We'll see how it goes as the weather warms up.