Not exactly sure what this hose does..

I was out riding yesterday, got home and realized there was fluid all over my boots and pant leg. It had also sprayed all over the inside right fairing. I knew right away it was coming from the radiator and was quickly able to figure out which hose was leaking. However, it appears that nothing in the manual or anywhere I can find on VFRworld actually mentions this hose. I haven't had a chance to pull the tank and everything off yet, just did a temporary fix with some duct tape and a zip tie to seal it back on. Does anybody know what this hose is/ where it goes to? I'm going to replace it tomorrow, I was just trying to find some part specs so I know what to go pick up before I pull everything apart. I included the OEM radiator parts picture here. The hose I am talking about connects with the clamp that is indicated as #32. Any help would be appreciated!

The hose seats just below the radiator cap.

 

It is the line to the over flow tank, it should not have much to leak unless your over heating or the radiator cap is leaking/failed though.

 

That doesn't sound good then. The hose was basically splintered at the attachment point, meaning it essentially wasn't even attached anymore. It isn't vacuum sealed or anything like that is it? Definitely wasn't overheating, only rode for about half an hour and the temp gauge was just getting to normal. Didn't check the seal on the cap because it was still hot from running. Is it possible to be spraying out if the hose isn't attached?

 

The thank is open to atmosphere on the other side so I would suggest inspecting the radiator cap........very likely original so leaking is not oot of the norm given the age.

 

Yep, overflow hose. When your engine heats up, water expands, and a little water is dumped into your overflow. When engine cools down, water contracts, and vacuum pulls water from overflow back into radiator. Check your fluid level at the radiator - it is most likely a little low. Replace the rotted out hose. Adjust coolant level at overflow tank, and you are good to go.

I had same problem the very first time I rode mine, right after I bought it from my bud who insisted it was ride ready.

 

Alright, cap has been replaced. I checked the coolant reservoir and it seems to be all the way up at the top, and I don't mean at the line. It's at the top of the bottle. Should I be able to see fluid in the radiator? I can see it at the bottom, if I shine a flashlight in there. When I start it up and rev the engine, coolant comes rushing in as I'm assuming it is supposed to. 4a15- What do you mean by adjusting the coolant level at overflow tank?

 

All your water (coolant) blew into your overflow bottle. Adjust your coolant in your overflow to the high line, and top your radiator to the very top.

 

Didn't see anything in the manual about adjusting the coolant in the overflow. Just to be sure, you are saying to drain the coolant overflow until it reaches the top line and then put that coolant or perhaps fresh coolant into the radiator?

 

Yep. Level at radiator should always b at top. overflow will fluctuate during operation but try to keep it near the top line.

 

Yes, checking when the engine is cold.

The overflow bottle will puke out any excess and show any future coolant loss if you check it often when cold.

 

VT, not sure if I'm reading this right. Did you replace the hose between the radiator and the overflow tank? If not do this first. Next, with engine cold, fill radiator full with 50/50 mix of coolant and water. Now fill the overflow with the same 50/50 mixture anywhere between the low and high lines on the tank. Put the cap back on the radiator. Start the bike and warm it up. You have to get it hot enough to open the thermostat and make sure the coolant is flowing. This will force any remaining air to the top of the radiator. As the coolant expands, as va15 said, it will force some air out of the radiator and into the bottom of the overflow bottle. You may be able to see it bubble in to the bottom of the overflow bottle.

Turn the bike off and let it cool until the radiator cap is cold. When the coolant cools down it will contract and draw liquid back from the overflow to replace the air that was forced out of the radiator.

When you are sure that the whole system is cold check the radiator again. Add coolant mix again until it is full. The system may have to cycle a few times to get all the air out of the engine. Once the radiator remains full you will notice the coolant level going up and down in the overflow bottle. Now you can fill to the top line when the engine is hot. When the engine cools down the fluid will go down to somewhere between the lines. This will be your normal levels. Just make sure the level does not go below the lower line when it is cold and not above the upper line when it is hot.

 

All I've done so far is replace the radiator cap. I haven't ridden it since the coolant issue. Bad weather mainly. I'm going to be replacing the hose this weekend as long as it's nice out and changing the coolant as the manual suggests, which is pretty much what you suggested there. I think as 4a15 and Squirrel said the faulty cap blew all the fluid into the overflow and now the radiator is low.

 

Once you get this all done still check for a leak.

When a leak develops, each time the bike cools down it will draw more coolant from the overflow to replace what is lost. At some point in time there will be no more coolant left in the overflow. If this situation is ignored the coolant in the radiator will slowly get lower and lower. At some point the coolant in the radiator wiil become too hot to cool due to low volume. At this point the coolant will boil over and blow itself out of the radiator and fill the overflow completely. This situation does not guarantee you have a bad radiator cap, but that could still be true. Some leaks will not leave a puddle under the bike, they are pressure leaks that only leak when the coolant is hot and pressure in the system is high.

This is my best guess as to what has happened to your bike. But again it is just a guess.

 

I replaced the overflow line with a slightly thicker, carbon braided line. Drained the overflow and replaced what was lost in the radiator. It appears that all is well now. Ran it for about 10 minutes and got it up to temp and no leak from the overflow line or the cap. Level in the overflow didn't change either. Thanks for all the input! Glad this resource is here!! :thumbsup:

 

Well, it seems that's wasn't the issue. It's still coming from somewhere out the right side of the radiator. It's raining now so I'll be waiting for the next sunny day to hunt for the problem. It doesn't to happen at idle, Only when I start riding and get the rpms up. I'm thinking that a possible block in the radiator could be causing a build up of pressure.

Edit: I posted from the phone earlier, so I'm going to try and explain better. The coolant issue only happens when I get the rpms up. When it's idling in the driveway, and giving it a little throttle, there is no problem. It didn't seem to be spraying this time but leaking out from the upper radiator hose. When I parked it back on the side stand, I noticed a fair amount also came spilling down from the overflow. It seems to me that pressure is backing up in the system somewhere and then blowing out through a hose. If I'm not mistaken, coolant shouldn't be regularly flowing into the overflow container. I think the reason coolant came out around the overflow is because the hose I just replaced may be slightly larger in diameter and allowing some coolant by. I'm going to check the radiator tomorrow to see the coolant level in it.

Maggot- you mentioned a leak but the only place I can find coolant coming from is the radiator hose and cap area. Is there a way to check other than visually? I don't have a garage so tearing everything down is a hassle.

 

I think I solved the problem. It all had to do with the overflow hose. The new hose I put on was too big so I was still getting the same problem. Coolant spraying onto the right lower fairing. And an added one, coolant dribbling out around the hose where it connected to the overflow tank. After flushing the system and putting fresh fluid in, I swapped back to the old hose. Instead of putting the slightly shredded side onto the radiator, I swapped it around so that the good side attached to the radiator. My best guess is that when I was rolling on the throttle the radiator was trying to pull coolant and it was just spraying out the hose instead of actually going into the radiator. Then dumping back into the overflow instead. Which explains why the radiator was so low and the overflow so full. I'm hoping it's a temporary fix but what I really need is the proper size hose for the overflow. I can't find any measurement for diameter anywhere and the local auto parts store apparently can't match it up. Any of you 2nd gen geniuses know about this?

 

Any stock Rubber Vacum hose should do. Go to the parts store with the old hose and get one that fits over the nipple of the radiator or the overflow tank. Buy it longer than you need and cut it to length when you fit it to the bike. You can even clamp it to the nipples with tiny hose clamps. If your original hose is long enough you can cut the shredded end off and still use it.