Archived Posts

[Admin]

Paul, I have often wondered about that, since a couple of mine appear to be headed towards failure. My thought was to clean the M/C thoroughly, and plug the hole with (are you ready???) JB Weld. If you cut a small groove on the inside of the hole, it will stay in place, and it can handle the fluid.

It's not really difficult to take the top off the M/C to check the level, and if it's not leaking, it hasn't changed amyway.


Lane

[Admin]

Reiner's rebuild kits are pretty good, if you haven't tried one of those.


Lane

[Admin]

Has anyone found a sutiible replacement for the fan sending unit/switch? mine wont turn the fan on , and from what I am told they are discontinued and realy hard to find.

How did you test it? It won't turn on the fan unless it's exposed to hot enough coolant. I rode a Buffalo here in Phoenix for a few years, including riding in 110 degree weather, and the fan never came on. The temp gauge never showed any unusually high temperatures, either. To test the circuit, just watch the fan blades as you turn on the ignition key. The blade should turn a few degrees and stop.

Stu

[Admin]

Let me see a pic of that style of M/C i might have a solution for you.

[Admin]

Let me see a pic of that style of M/C i might have a solution for you.

Cool, thanks.

I'll take some pics when I get home from work this afternoon. As you'll see, it's only the (plastic) sight-glass which is jiggered. Surely there's a solution, I mean the manufacturer had to stick it in there somehow.
Not sure if this particular M/C is common to any other bike in Yamaha's range from that era. It's possible I may be able to find one second-hand in reasonable nick somewhere.

BTW, the Laverda Club is holding it's Concours this Sunday at park under the Story Bridge, for those in QLD who weren't aware.
Some bloody nice stuff comes out of the woodwork for this show of all persuasions, so if you can get along, it's well worth it.
I'm putting my GT750 on the VJMC stand, and I'll be there most of the day . If any Forum'ers (is that the right collective noun?) are going to the show, come say g'day!


Cheers
Paul

[Admin]

Has anyone found a sutiible replacement for the fan sending unit/switch? mine wont turn the fan on , and from what I am told they are discontinued and realy hard to find.

How did you test it? It won't turn on the fan unless it's exposed to hot enough coolant. I rode a Buffalo here in Phoenix for a few years, including riding in 110 degree weather, and the fan never came on. The temp gauge never showed any unusually high temperatures, either. To test the circuit, just watch the fan blades as you turn on the ignition key. The blade should turn a few degrees and stop.

Stu

unplug the wire from the sensor and wala it comes on
thats how you tell if the sensor is bad . Mine got real hot and te fan never came on.too hot for my tastes.

[Admin]

Just out of sheer curiosity...

Does anyone know what temperature the fan is supposed to cut in?

I fitted a fan to my L and apart from testing it as per the book and the small movement when the ignition is first switched on, I've not had mine cut in.

I was lucky, I found my fan sensor/switch amongst a pile of old heads and paraphernalia when I was putting it back together, but I've never been too sure if it actually works.
I guess it would be difficult to test off the bike as getting water that hot (assume just over 100C) might be problematic?


Cheers
Paul

[Admin]

the sensor turns the fan on at 221 F and off at 212 acording to the book
I am gonna take mine out when I flush the cooling sys and boil it just to see if it will free up.
to test the fan just unplug the sensor lead and the fan should start spinnin

Just out of sheer curiosity...

Does anyone know what temperature the fan is supposed to cut in?

I fitted a fan to my L and apart from testing it as per the book and the small movement when the ignition is first switched on, I've not had mine cut in.

I was lucky, I found my fan sensor/switch amongst a pile of old heads and paraphernalia when I was putting it back together, but I've never been too sure if it actually works.
I guess it would be difficult to test off the bike as getting water that hot (assume just over 100C) might be problematic?


Cheers
Paul

[Admin]

TZ375


Thanks for the help. You said it might be at the kill switch, would the starter still engage, and spin if that were the issue? I checked the spark plugs for spark, nothing.

You mentioned that if I could see sparks at the points that the condensers might be going bad. When I bought it I changed out the points and as I was setting the timing I could see small blue/white sparks at each point with the motor running.

Also, after taking another look at it, only the black/white wire on the voltage regulator is visibly melted. I pulled the battery box and looked at the back of the electrical panel to see if it was fried on the other side of the connector, and it seems to be fine on that side.
I looked at all the wires going to the coils, they seem fine, and the wires running from the points up looked good too.

thanks again!

[Admin]

I have a couple questions about my '75 185.

First...where can a person get a repair manual for this bike? I have been looking and I don't see anything on the internet for a fair price. Short of going to the dealer....I am at a loss??

Second. I am stuck with only first and second gear right now. I have the left hand cover off and I am quite confused on how this thing shifts. Looks to me like some sort of seesaw apparatus there but I am unsure. How do you check to make sure things are adjusted correctly?

Thanks again. I did a search but came up empty handed.

[Admin]

Something is broken or burned out, so the only logical thing to do is to follow the money (power).

The battery has a ground lead and red lead to the starter relay. From there the red lead goes to the fuse and to the rectifier.

Let's stick with the ignition circuit first. That red lead goes to the main switch/ignition switch between the gauges. You can use a multimeter or test light to see if the power gets that far.

From the ignition switch it comes out as Orange (switched power) and goes to the kill/run switch. and form there it goes to the starter button and then on to the starter relay.

In theory, if the run/kill switch has no connection through it, then the starter won't work either, but that assumes the wiring is stock and OK.

Ok, so the orange lead goes to the coils, so if you lift the tank and pull the coil connector, you should have 12v at the orange leads. The coils then connect to the points & condensors through the connection plate under the left side cover. If you pull the points wiring connector out of its socket in the side panel you should have 12v switched at the panel.

From there the 12v goes down those 3 leads (White, blue and black/white) under the motor to the points. Use a test light to see if you have power at the points when you turn the motor over slowly.

If you have power all the way through the system, test the primary and secondary resistance of each coil in turn with the wiring unplugged. I don't have the specs in front of me, but the primary side is probably about 5 ohms and secondary is probably 20k-40k ohms.

[Admin]

TZ is quite accurate. The secondary on the coils should be about 20K. The engine stop switches were known for burning up. My first Buffalo had that problem before I got it, and the wiring was fried back to the ignition switch from the right handlebar. It would have been better if they had run the ground through the stop switch instead of the hot.


One more thing. I had a dying battery on mine once that would "charge" but couldn't handle much current. When that happened, I couldn't use the electric starter. It would turn over, but the spark was terribly weak. I was able to kick-start it, but no electric.

FrankT should remember that day; we were at Tellico Plains when it happened. I turned off the headlight to make it back to the Gap.

Turn off the headlight and kick it over.


Lane

[Admin]

unplug the wire from the sensor and wala it comes on
thats how you tell if the sensor is bad . Mine got real hot and te fan never came on.too hot for my tastes.

No, that's not how you tell that the sensor is bad. That's how you tell that the circuit is good. The only way to test the sensor is to test its continuity when cold, and again when immersed in fluid hot enough to trigger it. Your temp gauge may have indicated a high temperature. But if it wasn't high enough to trigger the sensor, the fan still would not come on.

Stu

[Admin]

unplug the wire from the sensor and wala it comes on
thats how you tell if the sensor is bad . Mine got real hot and te fan never came on.too hot for my tastes.

No, that's not how you tell that the sensor is bad. That's how you tell that the circuit is good. The only way to test the sensor is to test its continuity when cold, and again when immersed in fluid hot enough to trigger it. Your temp gauge may have indicated a high temperature. But if it wasn't high enough to trigger the sensor, the fan still would not come on.

Stu

Your right , but if the fan isnt comming on and the the circut checks good It's a better than good chance the sensor is toasted .

all of my preveous buffalos had the fan come on between the half and 3/4 mark on the gauge . this gauge has tested accurate and the thermostat is working as it should , So I am going with a bad sensor .
I plan on heating it in a pot of hot water when i flush the cooling sys .
Maybe it it break it free if it gets hot enough. If not it's new sensor time

[Admin]

You could always put a manual switch on the handlebars, then you would be in control.


Lane