Oh-oh. Consider letting it just idle up to temp and view what is going on. If you are losing coolant you should see it smoke off the engine etc. If not, you are burning it in the cylinders which is a bad thing.

 

Wouldn't a head gasket leak produce volumes of steam out the muffler? I've seen that sometimes from beater cars.

 

It depends how fast it is getting consumed in the cylinders. Have actually heard stories of a car gaining power when it is leaking coolant into the cylinders; it is like water injection. But if it is leaking that quick; I would tend to agree with you. If it were me, I would remove the thermostat to avoid the burping issue while you work on it and then I would idle it up to temp to see if you experience any leaking and then try some shorter rides to see if you lose coolant. Was the overflow empty too?

 

Yes it was empty also. I did a couple short rides since and will check the level.
I did some reading on the subject and yes it can be a slow leak. The suggestion was to use some radiator stop leak.
I looked for a new head gasket. Amazing none are available in the USA!!! I have to order one from Britain, aftermarket brand Athena.

 

I would not use stop leak. It can block cooling passages. Check the bolts on these two coolant pipes. I saw some fluid coming from one of mine after disturbing it. I loosed and re-tightened and it seemed to go away. I am new to this Honda CBR thing, but threads I have read say a head gasket failure is very rare on these engines; so I definitely think pursuing a possible leak is the way to go.

 

FYI: after doing the stick coil mod yesterday I went for a 5-6 mile trip and I could barely get the gauge to move. Thought I might have disturbed the gauge wiring; still not sure. But I noticed it did move just a touch. Pretty sure this bike is missing the thermostat.

 

Wire was loose. Part of the risk of doing major re-wiring in tight spaces during stick coil mod.

 

After topping off the coolant a couple days ago I racked up 30 miles. Checked the level and lost some ounces.
I added 2oz of stop leak, that's in proportion to what they recommended for a 4 engine car [6.8 quarts]. Stop leak has gotten more refined than back in the 80s when I had my beater cars.
Topped off the gas and calculated I'm getting 48 mpg!!!

PS: What is and why do; the stick coil mod?

 

Stick coil mod converts the old CBR to a modern one per spark plug coil from the modern CBR bikes. So only low voltage is traveling and you don't deal with the losses across the spark plug wire and get trapped buying used wires and/or coils if you have an issue. I bought a set of stick coils (4) from an 06 CBR (since my son owns one, I was able to check fit and proper coil resistance before I ordered) that came with a wiring hardness that you need for the connectors. I found them on ebay for 25 dollars. I then followed instructions on this thread ...
https://cbrforum.com/forum/showthrea...43#post1324543
I added some pictures and info from my mod. Bike is definitely a bit smoother, although my coils and wires were working after some repair to the wires. The stick coils are easier to insert and remove than the wires since they are solid. You get a lot of extra room below the carbs due to the lack of coils and wires. I did find that the #3 cylinder stick coil touches the fan and I added a MM of spacers to the lower radiator bracket to compensate and avoid pressure on the coil. Try to make sure you get the shorter coils (127MM and not 140MM), since the 140 will definitely not fit without interference from the radiator.

 

That's interesting, I remember now the conversion to that type of ignition in cars.
Something my bike sorely needs is new front brake lines. Kinda spongy after even after bleeding.
OEM is not available so I'm looking at DIY pieces and a ready to install kit from Britain.