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Discussion Starter #1
My son and I have been dealing with problems resulting from a bad tank of gas in his '86 VFR700. After identifying the problem, flushing the tank and removing and cleaning the carbs, it was still not running right and dying on the road. I replaced the fuel pump with a universal low pressure pump and hopefully that's the end of it.

My daughter's bike, an '85 VF500 which we just bought, has just developed a mysterious engine noise. We were going on a short ride to get the bike inspected, she pulled up next to me and I could hear a knocking noise. Ultimately when we got back and I had a chance to inspect it a little closer I found that it was overheating (she hadn't noticed the little temp gauge) and the knocking noise sounds pretty ominous. I suspect I'm about to learn more than I really wanted to know about that little V4.

And in the middle of all this, my buddy out in S.F. called me to let me know that his once pristine '97 VFR750 that he bought brand new in '97 and put 30,000 miles on before he was pushed off the road by a cell-phone distracted driver is now making it's way back to the east coast and I have the first option to buy it, for well under it's book value. The damage from the accident was minor and mostly cosmetic.

I've been ready for a change from my '97 GSF1200 Bandit, so the timing on the VFR750 is good....I just hope it's as reliable as the Bandit has been for the last 5 years that I've owned it.

FR
 

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quote:[
My daughter's bike, an '85 VF500 which we just bought, has just developed a mysterious engine noise. We were going on a short ride to get the bike inspected, she pulled up next to me and I could hear a knocking noise. Ultimately when we got back and I had a chance to inspect it a little closer I found that it was overheating (she hadn't noticed the little temp gauge) and the knocking noise sounds pretty ominous. I suspect I'm about to learn more than I really wanted to know about that little V4.
i don't know shit, but...perhaps detonation? pre-ignition maybe? that'd make for some funny knocks and a lot of damn heat.
 

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Discussion Starter #3
Yeah, I'll get into it and see. Have to start with the basics, pressure test the cooling system, compression test etc. I don't suspect the noise will go away without mechanical intervention though. I'm guessing blown head gasket...


FR
 

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FR,
500 interceptors would lose a rod bearing due to questionable oiling to the crank. There was a recall on some of the 85s to replace the entire engine. I don't remember what the identifier was for that recall having been done. Check the engine number and if it is way off numerically from the frame, then it may have been changed already. The 86 had the best motor if you are looking to do an engine swap.

Ken
 

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The early VF500s had cam oil problems. So did the Magnas. The cams didn't get enough oil and started pitting, and would eventually fail.

My first bike as a 85 VF500F. Great bike.
 

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Discussion Starter #6
Thanks Ken. After we got the bike I did notice that the engine number was way different than the frame number but I didn't know whether to attribute that to some PO doing an engine swap or just freaky production. I think if this engine needs a teardown I'll be looking for a swap candidate. I hadn't planned on spending the money for even a cheap rebuild, the bike's not worth it.
The guy I got it from had installed an oil pressure gauge to replace the idiot light in the cluster. When I checked that on the ride it was OK, 30 psi or so, except at idle which was alarmingly low...

FR
 

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Discussion Starter #7
Soooo, 4 months later. I'd decided to pull the engine and take it apart. I should've done a leak-down test but I didn't have the right equipment to do that anyway. I did do a hot and cold compression test, found one bank had really weak cold numbers, both banks were ok hot. Head gasket maybe, could explain the knocking noise and overheating.
Didn't find a smoking gun, other than one piston that looked much cleaner than the others. I called the local Honda store, they assured me they could get rod bearings, so I went ahead and split the cases.
Walked in with the bearing codes I needed, the parts dude looked 'em up and said naw, those numbers are no good, intergalactic back order. Same for the gasket sets. Faack!
So I call Cometic, the dude says "yeah, we have the head gasket pattern, we can send you a pair next week". Great. $55 each. Great.
Well that project sat for a few months till a couple weekends ago, when I decided to put it all back together. Slow progress at first, had to have one head resurfaced, probably the cause of the problem to begin with. Got the head back, and this Sunday spent the best part of the day on it, heads on, cams in, timing chains and tensioners in, oil pump in. Look in the box and see a part I don't remember.
Look through the factory manual, page by page. Found it. It's a guide for one of the timing chain tensioners. Have to split the cases to install it. The factory manual never mentions it, but I had to remove it to separate the cases, I'd just forgotten that last step. Must've put the guide in with the oil pump parts.
Which means another complete teardown.
I don't want to get another pair of head gaskets at $55 each, but I'm scared to put it back together with the new ones that have been torqued.
I'm so sick of this engine.
 

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kinda makes you want to play white rabbit 50 times and throw the toaster in the bath tub.

beers on me next time bro. cheers, b.
 

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Since the engine hasn't been run yet, I would go ahead and pull the heads and re use the gaskets without too much worry.

Ken
 

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I'm with Ken on this one. Shouldn't be a problem. Been there done that. I've also reused cometic head gaskets after they've been run for quite a while with no problems.

Craig
 

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Discussion Starter #12
I'm going to reuse 'em. I just spent a couple hours trying to sneak the guide in place, almost got the hammer out but thought better of it.
Good thing too, it was close, but not close enough.
Anyway, it's all coming back apart. Good thing it's November, hunters are in the woods, crappy day, nothing better to do. Oh yeah, except work on all the other bikes that need my time.
(Now I'm just bitchin' about my own dumbass mistake.)
 

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Too bad I found this thread too late to save you from a rebuild. That knocking noise sounds a lot like the knocking noise my 84 made before it threw a rod through the front of the block. This happend to me at 80mph on the interstate, but luckily I pulled the clutch in immediately and it didn't lock the rear wheel and send me off into the weeds.
You get the VFR? That was my last bike, which was preceeded by a VF1000R, which was preceeded by a VFR700, which was preceeded by a pair of VF500s (one 84, one 86.) What color is the round side cover on the motor? Black or bare aluminum?
 

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Discussion Starter #14
quote:Originally posted by buckandaquarter

Too bad I found this thread too late to save you from a rebuild. That knocking noise sounds a lot like the knocking noise my 84 made before it threw a rod through the front of the block. This happend to me at 80mph on the interstate, but luckily I pulled the clutch in immediately and it didn't lock the rear wheel and send me off into the weeds.
You get the VFR? That was my last bike, which was preceeded by a VF1000R, which was preceeded by a VFR700, which was preceeded by a pair of VF500s (one 84, one 86.) What color is the round side cover on the motor? Black or bare aluminum?
When I checked the rod bearings they were just barely out of spec, like .0002, and that was only one, the others were right on the max allowable.
I didn't wind up getting my friend's VFR750, I still have the option on it.
The VF that I'm working on is an '85, with black side covers.
 

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Discussion Starter #15
quote:Originally posted by buckandaquarter

Too bad I found this thread too late to save you from a rebuild. That knocking noise sounds a lot like the knocking noise my 84 made before it threw a rod through the front of the block. This happend to me at 80mph on the interstate, but luckily I pulled the clutch in immediately and it didn't lock the rear wheel and send me off into the weeds.
You get the VFR? That was my last bike, which was preceeded by a VF1000R, which was preceeded by a VFR700, which was preceeded by a pair of VF500s (one 84, one 86.) What color is the round side cover on the motor? Black or bare aluminum?
When I checked the rod bearings they were just barely out of spec, like .0002, and that was only one, the others were right on the max allowable.
I didn't wind up getting my friend's VFR750, I still have the option on it.
The VF that I'm working on is an '85, with black side covers.
 

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IIRC, the black covers are a good sign meaning that it was a late 85 or already has an 86 motor in it. With max tolerance bearings, I would run really good oil of a slightly higher viscosity than normal. You may be OK there, and at least you didn't spend a fortune on parts.
As for the 97 VFR, I liked the bike, but never really fell in love with it. It does everything pretty well, but in the end it is a compromise bike. Not fast or sharp enough to be a sportbike. Not comfortable enough for touring. Could be either if you buy the right bits, but is neither in stock form.
 

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IIRC, the black covers are a good sign meaning that it was a late 85 or already has an 86 motor in it. With max tolerance bearings, I would run really good oil of a slightly higher viscosity than normal. You may be OK there, and at least you didn't spend a fortune on parts.
As for the 97 VFR, I liked the bike, but never really fell in love with it. It does everything pretty well, but in the end it is a compromise bike. Not fast or sharp enough to be a sportbike. Not comfortable enough for touring. Could be either if you buy the right bits, but is neither in stock form.
 
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