Bleed screw on thermostat housing?

I just noticed there is a bleed screw on the thermostat housing on my '84 700. It looks exactly like the bleed screws on the brake calipers. There is no mention of it in the Honda service manual or owners manual. However it does show in a few pics in the service manual so it is original.

My question is it for exactly what you would think? Get the engine up to temp and crack it open to release any trapped air? My '69 Miura has a bleed screw on the radiator for that purpose.

 

thoughtful engineeriing back in the day? They used to give you "zerk" fittings on the swing arms and steering heads. Some tractors/HDs still have the steering head "zerk" why I dont know, all the grease is just gona slither down the neck :loco:

Plastic necks are common, have seen a few busted too. Ass-hole bean counter engineering.

 

I'd guess it's main use is for eliminating air pockets when refilling a drained cooling system.

 

That's my guess also, what the heck else would it be for? But being that it's the bike it is I wanted to be sure. Strange there is no mention of it in the service manual. Next time I ride it I'll crack it and see if any air comes out.....probably all that will happen is that it will break off or strip or just plain never seat again and leak all the time.

 

One of those sceneros (sic) "if it aint broke, don't fix it." Remember the old ZX11 of yore had a bleeder nipple on the t-stat and the lower swing arm. Like I said, thoughtful touches are gone now, its all mass produced shtuff. :sad:

 

Definetly not. Opening it while hot is like opening a hot rad cap. It will blow hot water all over you.

When it's cold, open it up and see if any air comes out followed by water. Maybe tilt the bike to the right. Once water comes out tighten it and your good to go.

It's possible the bleeder was added due to the thermostat not having a bleed hole in it. Some t-stats might have the hole, some might not, so they added an external bleeder.

I love Muiras. Jay leno has a video on youtube talking all about the specific bleeding procedure for those cars.

 

I don't own a Miura, I just put that in there to see if anyone would notice. :biggrin-new: I had just watched the Jay Leno vid you are referencing when I noticed the bleed screw on the thermostat housing.

I did see a Miura when I was a kid....my grandmother lived in Houston and once when I was visiting she took me around to the exotic car dealers because I wanted to see a Lamborghini. We went to one place and I remember they actually drove this car out for me to see but it wasn't a Lamborghini....not to a 9yr old boy anyways. It was a Miura! I had no idea what it was at the time and was not impressed because I was looking for a Countach. Now 25 yrs later I realize what it was!

We went to a few more places and eventually found a very strange looking white one with no wing? That's what I remember thinking at the time and being disappointed. (I should have been smacked!) I now realize that it was a 25th anniversary version! Can you imagine! A bran new 25th anniversary sitting on the show room floor in 1988 or 1989. Wow!

But my 9yr old self was disappointed because I wanted to see one like my poster....red and with the wing!

What I would give for a pic of me with the Miura and the Countach back then.



BTW...Jason...its damn beautiful out today, why are you working on your carbs! You should be riding this week! Get that thing back together ASAP! It's gonna get super hot and nasty soon. 187deg and 300% humidity is just around the corner!

 

I'm riding right now!

I just dropped a K&N filter (I got for $26) into the bike and I'm out testing the top end of the rpm range. So far, no popping or sputtering. Maybe my 118 main jets are the bigger Dynojet ones and not the Keihin 118's. The darn thing wants to pop a wheelie as I go through the gears getting up to the speed limit. Cool.

 

A lot of my 80s Honda V4s had bleed screws too, but all the newer ones don't. The thermostat housing is higher than the rad neck (especially when it's on the sidestand), so it's more or less required. I also prefer open bearings & ball joints with zerks myself. I've 'upgraded' a few car parts myself from sealed to unsealed. The open parts cost less and last longer, if you check them once or twice a year. Every oil change they get a little squirt of grease. What could be easier? I prefer open bearings & ball joints with zerks myself. I've 'upgraded' a few car parts from sealed to unsealed. The unsealed parts cost less and last longer, if you check them once or twice a year. Every oil change they get a little squirt of grease. What could be easier? I've seen a few newer vehicles that don't even have engine oil dipsticks, and claim they've developed miraculous "lifetime" lubes for their transmissions. Thus, the bean-counters have deleted the tranny drain plugs. Seems a little overconfident, doesn't it?

+1 on the open only when cold! Don't open it when the motor is good and hot. Not only do you run the risk of scalding yourself, but you'll also flash the coolant to steam inside the thermostat housing, and you'll siphon more coolant out of the motor. You'll be worse off than when you started. they operated just like they should. It's at the highest point...crack it open with the motor turning over to bleed off collected air.

 

I was half thinking of asking to ride over to check it out if you were around Houston. Ah well.

I think the Miura's are more sophisticated looking than the Countach, but they are both beautiful in their own way.

I had a die cast Miura as a kid. It had working doors and pop up headlights. It was awesome. Then I think about Phil Collins on Miami Vice driving that White Countach. Phil the Shill was the character I think. Ha ha. Good times.

 

Ya, no kidding....I would have asked to come see it also! I'm sure there are at least a few Miuras in Houston, just gotta find 'em. Problem is that they are most likely tucked away in a climate controlled garage and never see the light of day.

I would like to see that bike of yours someday. I live an hour south of Houston, due south on 288. Maybe someday we can meet up on a ride in the area.

 

The miura is a beautiful car. It is the only Lamborghini I have had a love affair with, which started around the age of seven or eight...along with several other exotics.