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Discussion Starter · #1 ·
So, I cranked up my motor to test it for leaks. Before I could start to test it for leaks (using carb cleaner), I noticed smoke coming up from my bike..not a good thing. I look to my ride side and noticed that smoke was coming from what looked like the hose from come the thermostat on the bike heading into the motor. When I looked further, I noticed that it looks like it may also be leaking...? I flushed out the radiator this weekend by draining all the mud colored crap out of it (it had sat a long time) and pouring water into the radiator into it until it ran clear. then adding 50/50 coolant to water mix.

Any ideas? Am i looking at some serious money? I don't have much more to invest in this thing, and I'm pretty sure I'm looking at having to clean the carbs and give it new boots, since when i did spray clean on the bottom ones, the rpm's shot up.

thanks to all.

j


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John
 

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i know everytime I get coolant on my engine or radiator (especially when I flush the radiator) it would smoke pretty good until it all cooked off the radiator and engine.
 

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It would help knowing what make, model, engine size and year you have.
Yeah, a lot of us put our Bike in the signature portion to let folks know what Bike we got...
 

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From all indications, it's looking like the engine isn't smoking the way we might all conclude. In other words, something is spilling onto the exterior and smoking just from the heat of the engine. Antifreeze/coolant usually smokes white when it's burned and your indication is that it's been leaking. Fix your leaks and run the engine. You can EXPECT some smoking if there's spilled coolant, oil or grease on any exhaust parts or the head. Use carburetor cleaner and a rag to clean the pipes before they get hot or the chrome may become more damaged from the residue.
 

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yea my bike does the same thing, it freaked me out when I saw the coolant cooking off the radiator and engine for the first time it should stop after a few minutes
 

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I dunno about your model/year, but, mine requires "burping" which eliminates air in the system...
Fill radiator, with the cap off, crank up, let it run 2 minutes, then "wick the throttle" several times to "burp it"...
Refill radiator > IF needed...

The manual tells all, Got a Service Manual???
 

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Discussion Starter · #12 ·
captain, i do, it talks about rocking it back and forth and front to back, but doesn't give an indication of when the radiator is topped off. the past two times after I cranked it with the radiator cap off, fluid erupted (spewed even) out of the radiator. hence my question.

thoughts?


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john

1987 honda shadow vt 700
 

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Mine requires FULL radiator, which means Full to the top, then close system...
I`m unfamiliair with your model though...
Is there anything mentioned about burping???
 

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fill the radiator with coolant and run the bike with the cap off until the bike warms up and the fluid disappears, keep the throttle turned a little (about 3 grand on the tach) and add fluid till ita topped off and put the cap on while at 3 grand and once the cap is on then let off the throttle
 

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About the smoking, it's fine "ish" but you need to pull that hose off and clean all that rust and grime off the metal neck to get a clean tight seal. Also, looks like your hose needs to be replaced since it's either swelled or the wrong size (big lip on both sides). Also, doesn't look like it's not tightened down all the way on the clamp, may be causing the leak too.

Fill your radiator till it's at the "full" line on the reservoir, start your engine with the cap off. Run it till the level stabilizes. Then shut off the bike and refill to the "full" line. If it erupts, you probably filled it too much or the thermostat is not in it or stuck open.
 

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If ANY coolant gets on the motor when refilling then it's going to smoke until it burns off. It looks like there's a drip from your bleeder screw on the thermostat housing. You might just need to tighten that up a little. But if the bikes been sitting, that thermostat might be toasted. Might be good to open that housing up and clean it out. If you do, be sure to apply some RTV to the mating surfaces.


As far as determining when its full, for me, it takes some work. Pour coolant in slowly until you can see it. Then you have to shake the bike around a bit. Tip it to one side, then the other, hold the brake and rock forward and back. A LOT of coolant will draw its way into the bike. Wash rinse repeat multiple times. If you only fill up without rocking and assume its full, you will get a lot of air in the system. I guess you could measure out the exact amount of fluid you would need but to me it isn't necessary.
 

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So...
Then you guys what own these models are familiar with the filling...
Y`all ain`t gotta "crank it to burp it?"
Like our 750s with the closed system???
 

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If this bike has sat for a while and you're resurrecting it, forget all of this advice I am about to give you and start with a new thermostat. It's an inexpensive part that can cause very expensive problems if it's stuck. It is also a very common leak point.

You can burp it several ways, but do not open the cap when hot. My guess, when coolant spewed out of the radiator, you opened it while hot? Or at least warm?

You're not going to hurt the engine with some air in the system if there is coolant flowing. Let it warm up to operating temp - the thermostat should open up and fluid will flow through the radiator. Let it cool. Refill the radiator. Do this again and again for several rounds until the level stabilizes. Once it's stabilized, ride for "a while" - like 50 miles or a half-tank of gas - and park the bike until morning, check again. Repeat this until you're confident the level isn't changing.

If it never stabilizes and continues to smoke, you have a leak. Probably, like others have mentioned, at your thermostat housing.

Boiling coolant will have a "celery" smell. If it's not coming out the exhaust, it's probably a leak.
 
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