VFR700... Contemplating engine rebuild

Looking for opinions. I have a feeling I have compression issues. Last night I cleaned the carbs out really good, made sure I had spark and tried to get the bike to fire off ether, no luck, just backfires. The plugs smelled like ether so I know it is getting fuel, this means the only thing left is compression. I will know for sure tonight if this is an issue, I just rented a gauge. If it is the issue, the recourse would be rebuilding the engine. Has anyone here rebuilt one of these? If so, where did you get your parts? What was the cost like? Any words of wisdom in general?

 

Did the engine overheat badly at some time ?? Compression doesn't disappear suddenly unless a headgasket is shot, so when did the bike run right last ??

Since it won't start you can't do a proppa compression test, best done on an engine warmed to operating temp, but you will get some useful data anyway if you remove all plugs b4 the test, have a well-charged battery, and hold the throttle wide open while cranking.

I'd guess that on a cold engine in good condition you should see about 150 psi and no cylinder more than 10% different from the others.

You'll need to seriously wrestle with the radiator (or remove it) to get access to front cylinders for compression testing.

 

The wet and dry compression test will tell you a few things about the rings and valves.
Let us know how the test goes.

 

Well, couldn't do the compression test, the kit that I rented did not go small enough, but there are some other symptoms that point to engine issues. When i try to start the bike, I just backfire on all cylinders, I can literally watch fire shooting out of my carbs anytime I open the throttle while starting. Additionally, I inspected my oil and it has a very milky color to it. Am I wrong to point to a head gasket issue? If so, what do you guys think about a rebuild?

 

Milky oil almost always means a headgasket replacement, not necessarily an engine rebuild. Overheated or run low on coolant recently ? Remember when you changed your coolant last ?? Was it 1999 ?

Backfires show lean fuel condition like clogged filters, bad gas, dirty carbs, etc. Is your fuel tank clean ?

You know it's not an electrical deal.

 

Coolant was replaced not too long ago, but I did have some over heating problems prior to that due to a coolant leak.

I flushed out my tank and put fresh gas in it, I guess it is entirely possible that the fuel pump had bad gas in it. I recently replaced the fuel filter, as well as cleaned the carbs. I pulled the covers off the bowls, soaked the jets in carb cleaner then sprayed the inside of the bowls with carb cleaner. That should be sufficient, right?

The only thing I could think is maybe the fuel pump isn't supplying enough fuel? It is an aftermarket fuel pump, but had the same output as OEM.

If I go down the route of replacing my head gaskets, is there anything else I should do while I am in there since I will already have the engine tore apart?

 

Soaking won't usually clear jets reliably, but a steel .012" wire will.

 

I stripped my 84000 mile 86 model after the head gasket failed, there was no water in the coolant the only symptom was pressurising the coolant syatem and blowing water out the rad cap.

Water in the oil may be the seal on the water pump as this is in the gearbox?

On closer inspection the exhaust valves were badly seating and it had compression down to 120psi on the front cylinders.