Suzuki 2 Strokes

I removed the coolant bypass line and plugged the cylinder and case. I measured the lower pipe nipple (on the case) to be 14mm x 12mm with an extra fine pitch of 20 threads per inch. I purchased the plug number 3082M (pipe plug Japanese) but it threads all the way down to the bottom of the hole and does not seal. I expected that a Japanese thread would be a metric pipe but sure doesnt seem to be the case.

Does anyone know the exact description (size) of the lower threaded hole on the bypass line (that enters the case) so I can order the correct part. Thanks

http://www.magneticdrainplugs.com/pipe_ ... panese.htm

kevin,

it's probably a silly question, but did you wrap it with teflon tape?

if that doesn't work I'd try the dreaded JB weld on the threads after you clean them of course.

Hi Richard,

I thought the plug had thread sealant on it. I will try some paste in the morning and see if that doesnt do it. Otherwise, JB, here I come.

Thanks,
Kevin

Kevin,
I was out in the garage checking on something completely different and there in front of me was a lower pipe fitting. It looks just like a 14mm spark plug, because that is the size. You could screw in any B series plug and it would seal OK.

Or just cut a stock fitting short and weld up the top of it.

Kevin, I am interested in knowing why you are plugging up the bypass and what the net effect of doing that will be.

There is a reason I would like to know:

In 2007 I completely rebuilt from the frame up the 76 Buffalo in my avatar. When I got it running, it would puke water out the overflow as if it were getting hot before the water ever even got warm to the touch. I had a NOS water pump, but I pulled it out and put another NOS water pump in its place, same thing. I changed the radiator twice thinking that something might be plugged up that I could not see, same thing. Changed the thermostat a couple of times, same thing. I then pulled the thermostat out, problem solved. Bike does not get hot and I have ridden it as much as 300 miles in a day with no problem.

Relationship to what you are doing is that when the thermostat opens up, it closes off the bypass hose, but in my case it was almost as if the thermostat was blocking the bypass when it was still closed, forcing water pressure from the pump to push water out the overflow.

Just wondering if you have removed the thermostat as well.

Wayne

Richard,

The band of teflon supplied on the plug from the factory (according to them) is provided for lubrication and they advise that addition teflon tape be added for sealing. I took care of that this morning and the system is holding with no leaks. However, the plug I installed is a straight thread and I believe the bypass holes require metric taper pipe thread.

What I learned is that "Japanese Plugs" are straight thread and "Metric Plugs" a tapered pipe. Very different from each other.

The bypass nipple on the cylinder head is clearly a 16mm x 1.25 extra fine pitch pipe thread. The bypass nipple on the case is 14mm x 1.25 extra fine pitch pipe thread.

I'll need to change out both plugs in the near future....lesson learned.

Wayne,

Though I had a bypass line installed last year, I didn't install the thermostat. The only reason I wanted to remove the bypass was due to clearance issues after I milled the back of the block and installed that carb adapter plate to change the intake angle. The adapter plate made it impossible to route the stock bypass hose so I made one up and had to loop it around the middle carb. But for dragracing, it would almost be better to keep the bypass, add a pressure relief and get rid of the radiator...saves a ton of weight.

I think Dave and Lane explained to me that you couldnt remove the bypass line without removing the thermostat since all coolant would flow through the bypass until the thermostat opened.

On the stock setup, the pump intake (suction) is coming from the lower radiator. The radiator would make up what ever the pump needed above and beyond what the bypass line is supplying. If the thermostat is closed, all flow goes back to the pump suction side through the bypass and the weight of the water in the radiator is keeping a constant pressure on the inlet of the pump keeping it primed and keeping that part of the system full. Cold, the fluid should have circulated through the block and returned to the pump via the bypass.

My immediate thought is that the bypass nipples are corroded on the inside and the pump is drawing mostly from the radiator when cold instead of from the bypass. As a result, more coolant is entering the system via the radiator until pressure increase to a level that forces it past the thermostat and pressurizes your radiator. I need to think about this one for a day or so...I will get back to you Wayne. Its a very interesting problem and I suspect that if you did a frame up restoration, you probably removed or cleaned both bypass nipples. Do you remember what condition they were in?

Kevin

Kevin, the entire cooling system was in pristine condition. Obviously, I could not see deep into the radiator, but what I could see looked great, and it was the same radiator I was running before the rebuild and did not have this problem. I cleaned up everything to like new before reinstalling everything. The engine was rebuilt from the crank up with everything new, Crank was sent to Bill Bune. Cylinder bored and new pistons fitted by Eric 2-Cycle in Penn.
EVERYTHING was rebuilt or replaced.
The only thing that I did not use from the stock engine was the cylinder itself, and the only reason I did not use the original cylinder was that it was stuck and I had not gotten it off, so, just to save some time, I sent a spare I had to be bored and pistons fitted while I worked on getting the old one off.

Wayne