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Thermostat replacement - hope to never do this again

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Bought this awesome ‘98 49-state model with a weeping thermostat hose. Level in the reservoir drops about 1/4” every 1k miles or so. Just enough to make a stench every ride but not enough to drip on the ground. 
 

Major chore getting the airbox and all the connectors and hoses off. That little hose attached to the bypass control solenoid gave me the fits! I also needed a 4 foot piece of wood to dislodge the throttle bodies from the intake boots. 

9A244412-A65D-47BB-8CEE-AE6E8F8D5EF1.thumb.jpeg.181dbf577614dd91f69d6f0b176bc6b4.jpeg

 

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I found one screw, a collar and and two washers in the V crevice. Hope to never see this part of the bike once I’m done.

 

Replacing 10 coolant hoses, 5 o-rings, a thermostat and a new radiator cap for good measure.

 

Between rebuilding calipers and bleeding the linked braking system and replacing the thermostat on a VFR, I think most other bikes will be much simpler to work on. 

 

Anyone ever clean, balance and calibrate injectors? Can I remove the fuel rail without disconnecting the fuel lines from the gas tank?

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It is a pesky devil, isn't it? :rolleyes:  That's long been the knock on the V-4 - two of everything - 2 cylinder heads, 2 sets of cams and covers to remove for a valve adjustment, and then all that stuff crammed down in there where it's hard to get at.  But the result is V-4 magic!   Be sure all your hoses are tight - 1/2 turn too loose and you'll be chasing another coolant leak with all that to do over.  :mad:    If you're having the injectors cleaned (good idea BTW), RC Injector service is in SoCal and would be a quick turnaround for you.  $25 per plus shipping.   I just sent mine to WitchHunter Performance in Duval, WA which was cheaper, but he has a 3 week backlog.   Removing them has a set procedure that includes removing the TPS - too long to describe, would recommend reviewing that in the FSM before going further.  Also, be kind to the throttle body boots.  They are no longer available so if they get borked you'll have to find them used.  Maybe a PITA for now, but you'll be glad to did this and have the satisfaction of doing it yourself.  It's a nice looking ride and deserves the service.

 

Cheers

 

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Is it the same procedure for gen3 bikes? Yeesh. I sure hope my cooling system is in good shape...

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Good job being thorough, doing all the related hoses and O-rings.

 

In case you ever need to remove the throttle body assembly again, an easier/gentler method is the "cargo strap" approach.  First use a hair dryer or heat gun (on low heat) to warm up the boots and make them more pliable, then loop the cargo strap through the rear corner of the throttle body and loop it over your own shoulders/back, then use your hands on the frame rails for direct upward leverage.  This way you can be gentle and firm at the same time.

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7 hours ago, Gebruiker said:

Is it the same procedure for gen3 bikes? Yeesh. I sure hope my cooling system is in good shape...

Yup.  Same concept except you'll be removing carbs vs FI throttle body.  The thermostat and pipes coming out of each cylinder head that feed the thermostat all live in the same general location - down in the "V".   Hoses can be weird - some give no trouble for decades while others don't last more than 5 or 6 years - but all oxidize and eventually weaken. Plus the thermostat has been submersed in coolant for years and and can get stuck just from age.  With the  newest of the 3rd gens now nearing the end of their 3rd decade, if I had one that I knew had never had the coolant hoses (or rad cap) replaced I wouldn't take it out for more than a day ride not too far from home.   A re-fresh of the cooling system would definitely upgrade the long term reliability of such a bike particularly for long haul touring.  

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On 2/19/2020 at 8:03 PM, Cogswell said:

A re-fresh of the cooling system would definitely upgrade the long term reliability of such a bike particularly for long haul touring.  

...Words I don't want to read. I was happy in my bubble of ignorance...that might serve until I'm sitting at the side of the road with a green puddle under the bike. 8200rpm reports replacing all 10 hoses. Ten? More words I don't want to read.

 

This is going to be one of those projects I won't jump into feet first. I don't think OEM hoses are available but v4Dreams shows part of the job on his website using generic hoses.  http://v4dreams.com/maintenance.html 

 

For that day I begin to have problems, I'll hope for a small leak that doesn't leave me completely stranded. And I'll make sure there's duct tape in my tank bag.

 

Thanks for the heads up. I've been warned. 🙂

 

 

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On 2/22/2020 at 4:24 AM, Gebruiker said:

8200rpm reports replacing all 10 hoses. Ten? More words I don't want to read.

 

Thanks for the heads up. I've been warned. 

🙂


There are actually 14 hoses total. 😵

 

The upper middle radiator hose that you can see from the front of the bike is NLA. This one is easy to access, doesn’t have any significant bends and probably can be replaced using generic bulk automotive hose from the neighborhood parts store.

 

I overlooked the skinny "radiator breather hose" (19508-MGB-000) that goes from the starboard side radiator to the thermostat housing.

 

I also didn’t bother replacing the 5.5mm overflow hoses from the radiator cap to the reservoir (800mm length) and the hose from the top of the reservoir to waste (500mm length). EACH of these hoses are $22 (partzilla). Ridiculous price for bulk hoses that are not even molded, pre-shaped. 
 

Oh also, the puddle under the bike will be blue if you’re using Pro Honda HP Coolant. 

 

 

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21 hours ago, 8200rpm said:

There are actually 14 hoses total. 😵


…now you’re just tryin to bug me. Ya know, as I think on it, I’m pretty sure when I bought my bike two years ago, the previous owner mentioned he’d just replaced the thermostat and all the hoses as part of his maintenance routine. Yeah. Yeah, that’s it. Pretty sure… 😉

 

(I don’t suppose there’s any way to actually read the age of hoses? I mean, no manufacturing dates printed on them…nothing like that?)

 

21 hours ago, 8200rpm said:

Oh also, the puddle under the bike will be blue if you’re using Pro Honda HP Coolant. 

 
Uh huh. Thanks for that too. Now I won’t be muddled if the puddle is blue. Or for that matter, give it a second thought if it’s a green puddle. And what exactly makes you think I know what coolant is in there? I was assuming Prestone… What I do know is it survived 0F in cold storage last winter.  🙂

 

 

 

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The crud / dirt on the hoses and any visible cracking, particularly on the ends,   will likely tell you all you need to know. 

 

Also,  absolutely do not use Prestone or any other coolant with silicates, as the new leak will be coming from the water pump seal.  

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21 hours ago, Cogswell said:

 

Also,  absolutely do not use Prestone or any other coolant with silicates, as the new leak will be coming from the water pump seal. 

 

Whew. Thanks Cogswell. Lots to learn about my cooling system. Hoses and fluids. Happily, the hoses I can see seem to be in good enough nick. Definitely no cracks or swelling or dirt.

 

And inside? Is it blue or green? I probably shouldn’t wait long to find out. They say that regular coolant should be flushed and replaced every couple years. Yeah. I'm not sure that’s gonna happen either. We'll see.

 

There are threads of discussion right here on VFRd:

 

 

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Agree with Cogswell. Your coolant must be Silicate and Borate free.

Just for info I've always used Honda Type 2 coolant, it's premixed ready to go, bluish in color. You can purchase it from any Honda car dealership.

 

image.jpeg

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55 minutes ago, Grum said:

 

Just for info I've always used Honda Type 2 coolant, it's premixed ready to go, bluish in color. You can purchase it from any Honda car dealership.

 

That's what I do, too.  Much cheaper by the gallon at the Honda car dealer. The dye color doesn't mean much as long as it meets specs.

 

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2 hours ago, Gebruiker said:

 

Whew. Thanks Cogswell. Lots to learn about my cooling system. Hoses and fluids. Happily, the hoses I can see seem to be in good enough nick. Definitely no cracks or swelling or dirt.

 

And inside? Is it blue or green? I probably shouldn’t wait long to find out. They say that regular coolant should be flushed and replaced every couple years. Yeah. I'm not sure that’s gonna happen either. We'll see.

 

There are threads of discussion right here on VFRd:

 

 

An external inspection is good,  but much of the hoses' deterioration is on the inside from electro chemical processes. Acids and other undesirable chemicals can build up,  particularly in neglected coolant and corrode the inside material and ultimately weaken the fabric mesh that gives the house its burst resistance.  What appears to be a perfectly normal house can crack open or burst without warning.  Preemptive replacement is the best way of dealing with it.  From what I've seen Honda uses very high quality hoses, but like tires, nothing made of rubber materials can be expected to last 30+ years.  Anything rubber that old is on borrowed time. 

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24 minutes ago, 8200rpm said:

The 00-01 bikes should have two more going to the throttle body assembly. 

So that’s 17 all together?

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On 2/25/2020 at 7:12 PM, Cogswell said:

Preemptive replacement is the best way of dealing with it.  From what I've seen Honda uses very high quality hoses, but like tires, nothing made of rubber materials can be expected to last 30+ years.  Anything rubber that old is on borrowed time. 


Oh I get it. Really I do. But there’s no way in hell I am diligent enough to take on that 8200rpm project for fun. I’m going to wait for the leak to develop, or at least for obvious sign of impending trouble. And keep my fingers crossed that I don’t get completely stranded. But whether it happens in my garage or on the shoulder of rte 66 outside Tucamcari, you'll all be able to say…'told ya so'. 😉

 

Take heart. I will consider flushing and replacing the fluid. I can do that much. A proper flush might give me some slightly better idea of what is hidden in there. If the flush is truly awful, like full of rusted metal chunks, I’ll reconsider my position. Bear in mind, I only have the previous owner’s testimony on the general state of affairs. He wasn’t big on cosmetics, but he really kept the mechanicals in pretty good shape.

 

And what antifreeze to use?

 

Now we’re talkin. This is a great tip from Grum. Ya gotta give Honda powersports credit. It looks like I can spend $13 a quart for their type 2 antifreeze…

 

image.jpeg

…or I can spend $15 for a gallon of the same stuff right across the parking lot at their automobile dealership…

 

$15/gal is about the same price as any third party type 2 coolant, so in this case, the genuine Honda label product it will be. 🙂 


 

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On 2/26/2020 at 1:02 PM, Thumbs said:

Samco do silicone hose kits for the bike https://www.samcosport.com/wp-content/uploads/2020/01/GBP-BIKE-HONDA-2020.pdf

 

For 98-01 bikes they list 15 hoses

 

I'm losin count here. 10, 12, 15 hoses? Last time I looked under the hood of my Accord I think it had 2 (TWO!) hoses. I also note the complete Samco pack of however many costs 106.83 GBP. Ouch. So unless the pound tanks after brexit, I'll be getting the Gates generics and making my own sections, ala v4dreams.

 

But none of that will be necessary for many years yet... many many years. 🙂 Thanks for the Samco source Thumbs. 🙂 

 

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I made my own silicone hoses for the yellow bike in California.  Per Mohawk's pioneering efforts several years ago, which he detailed here some time ago (there's a link to his thread in my "Yellow Peril" build thread).

 

You could, of course, do the same with quality rubber hoses--for a lot fewer bones...

 

Ciao,

 

JZH

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1 hour ago, Gebruiker said:

 

I'm losin count here. 10, 12, 15 hoses? Last time I looked at my Accord I think it had 2. Two. hoses. I also note the complete pack of however many costs 106.83 GBP. Ouch. So unless the pound tanks after brexit, I'll be getting the Gates generics and making my own sections, ala v4dreams.

 

But none of that will be necessary for many years yet... many many years. 🙂 Thanks for the Samco source Thumbs. 🙂 

 

It's not so onerous on a 3rd gen.  The 5/6 side rad bikes are much more complex.  For the 3/4 gens with a single front rad,  there is 1 from the water pump to the block/ heads,  2 from the heads to the thermostat (down  in the V), 1 from the thermostat to the rad,  and finally 1 return hose from the rad back to the water pump, for a total of 5.   Getting the carbs off / on from the boots can be a pain,  but otherwise it's pretty straightforward and shouldn't break the bank. 

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On 2/26/2020 at 7:19 PM, Cogswell said:

It's not so onerous on a 3rd gen. 

 

Okay, let’s take this from the top. I checked the manual last night. Something I should have done before wading in here in the first place. You are correct Cogswell. There are only five hoses for third generation bikes. Five hoses is less daunting than 10. Half as daunting. 

 

V4Dreams spells out the replacement job on his site. https://v4dreams.com/index.html  He had the expensive Samco kit and has a picture of it with four, not five, hoses.

 

1632397820_Smacohoseset1367729_1.jpg.9a05fc5a3b2b129283627381330c69c4.jpg

(v4dreams pic)

 

There is the upper radiator hose, lower radiator hose, and two jumper hoses for between the heads. The kit apparently does not include a little hose connected to the water pump. Too much to ask for only 100GBP. 😛 It also looks like you do get a key ring! I think the Samco hoses are rubber. Not sure about that.
 

V4dreams then found he could use Gates hose #19746 for the two jumper hoses…again, the hoses nestled between the heads. He was able to cut the Gates into sections, using the elbows. The Gates costs $14.79. But what of the two longer radiator hoses? It’s unclear from his page if he could use other bits of the same Gates hose, which is pretty long, or if he needed additional source hoses.

 

Near as I can tell, you really want to try to find hose that already has most all the twists and bends of the OEM hose. Presumably any generic straight section can be muscled into position, but only to a certain degree. I can see myself, old OEM hoses in hand, perusing racks of Gates hoses at the local automart, trying to match the twists and turns with something intended for a chevy. 🙂

 

And what of that water pump hose? Hose number 5? For that, v4dreams used a short section of generic 22mm hose. A different diameter, requiring another source hose. Thanks for that Honda. Curiously, Honda seems to have these OEM hoses available. I wonder how long they’ve been sitting in their warehouse?
 

Now, moving on, JZH used fancy blue silicone hose 🙂 Nice.

 

 

Following his links I got a 404 and a dead source (APMotorstore) but Flextechnologies (Siliconehose.com) is still there.

 

And they are kind enough to explain to me the difference between silicone and rubber: https://www.siliconehose.com/blog/silicone-vs-rubber-hose/ A nice explanation, but I doubt I'll be getting their expensive hoses any more than I’ll be buying from Samco.

 

The next source is from raYzerman

 

On 2/27/2020 at 12:38 PM, raYzerman said:

 

Also nice. Silicone hoses, many colors(!) and maybe for a bit less than Samco, but nothing there for the old third generation bikes.
 

(Ed. Nope, raYzerman is right. The 3rd gen hoses are there, just not on the main menu. See BCAI link, next entry)

 

And I think that’s about it for now. For me, all this remains academic. Allow me to say again, I am really not doing this job now. No foolin. I’m only preparing my head for some future event. 🙂 But for that time, thank you all for the guidance!

 

Edited by Gebruiker
corrected information

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https://www.as3performance.co.uk/honda-vfr-750-1990-1993-high-performance-silicone-radiator-hoses-red/

AS3 makes silicone hoses for the third gen bikes in red blue or black.

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19 hours ago, BCAl said:

https://www.as3performance.co.uk/honda-vfr-750-1990-1993-high-performance-silicone-radiator-hoses-red/

AS3 makes silicone hoses for the third gen bikes in red blue or black.

 

I couldn’t find the hoses through the main menu of ASPerformance, but your link works just fine. And all five hoses to boot. The set would cost $93. Also available through an ASPerformance link at eBay for $90. Thanks.

 

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It’s coming together now...

 

For anyone replacing hoses, please remember to replace the o-rings in the water joints to the head in between the V and the two on the port side.


Inside channels look great!

B3866ED0-715E-4169-861A-A64FBE38DB27.thumb.jpeg.638d3d021c788e0bfe1fe67187423877.jpeg


O rings were FLAT and hoses were swollen. 

5DC0C4D7-C6B4-4A95-B552-BB9430EF6DEC.thumb.jpeg.b54ffe676400ef5cfe57b4fe3ffc1c9e.jpeg
 

This is the condition of the o-rings in the water joints in the V.

4C7207B1-07A3-4E6C-AB27-489BE03C42E8.thumb.jpeg.f528e8914137538abce4232b2500a43c.jpeg


Fresh o-ring

E9740635-FA59-4D45-9B15-CC69FF4A1AA5.thumb.jpeg.ba2b55e6efea2a9b7846e28aadb39625.jpeg

 

New thermostat and o ring for the housing

2F4B6CA7-A6D3-4824-A987-48824880EF74.thumb.jpeg.9b44830d3925f1a85244eeaab4f55259.jpeg

 

Looking better...

B481A0B2-BE5A-4D47-9556-0268083CA78A.thumb.jpeg.65a39f0d3ad7eb14449247d701e5e713.jpeg
 

I decided to replace the overflow hose into and out of the reservoir tank and also the air bleed hose from the starboard side radiator to the thermostat housing. Those are still in the mail, so the throttle bodies need to stay off the bike until then.

 

Not being able to ride sucks. 

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