Loud Knockin on my VFR700. Transmission?

I've got an 86 VFR700 with 44K miles on it. I've had it about 10 months. Carbs were synched and valves adjusted about 6 months ago. I've been having occasional issues with it not fully engaging 2nd gear and sometimes wondering between 3rd and 4th when shifting really aggressively. Normal riding and shifting is fine, so I think my left and center shift forks are worn. I had planned to pull the engine and split the cases to replace whatever trans parts I need, when I started hearing a faint knocking.


I kept riding another 20-30 miles and it stayed faint. Then I made a 30 mile trip and it got really loud and I felt lucky to get back home. The sound is not from the top end, valve area, it's more from the bottom and right behind the crank. I'm thinking the mainshaft that has the clutch mounted to it. It's hard to pinpoint, equally loud on left and right side, might be the rods or crank. It could also be worn spacers between the trans gears and the dogs are making contact. Makes same sound hot or cold.

Here's a video:
VFR700 1986 knocking sound - YouTube

I'm gonna pull the oil pan and clutch cover soon and do a visual inspection. Maybe I can spot a simple fix. If not, I'm open to ideas, sell it whole for parts, part it out, swap in used motor, etc...

It's a shame as I just installed new steering bearings and completed body work on the cowl and fairings. I was gonna paint them up and the bike would look great.


Thanks

 

Yikes. That sucks but it should be easy to figure oot what it is when you dig into it.

 

rod knock, one has spun a bearing.

 

Is it that obvious? I want to live in denial, say it ain't so. :sad:

I've got some days off soon, so I'll confirm it.

What are these bikes worth? I paid $550 for it in rough shape and not running. I cleaned and fixed a lot of stuff putting $400 into it. Should I just put it on craigslist as is for $500?

I'm leaning towards getting rid of it for a faster, newer bike, but I need to get as much money out of this one to do that.

 

Part it out.... Body panels alone can get you a decent price I would verify that you spun a bearing first...

 

I'm wondering if a rod bearing can be replaced (assuming it needs it) from the bottom without pulling the engine? They do it all the time on big rigs. If I can fix the knock, I'm selling this thing.

 

Shoot you replace the bearings you might as well keep it and ride the piss out of it

 

What if another bearing is on it's way out? Plus it needs stiffer front springs, a rear shock rebuild and revalve, 17" wheel swap, cartrige emulators, paint, new tires plus the transmission work which might be extensive.

If i can fix the knock and the next owner is not as picky as I am, I think it needs to be sold. Even though I love the sound of these V4's, I'm used to it's power and it feels weak. I need more power, 150+HP. I think this is a good time to cut my losses.

Maybe a 90's Kawa ZX-11 sport tourer?

 

That bike looks really nice, I would fix it. Hopefully the crank is ok, but even if it is not I know you can get used engines. Shoot me an email and I can give you the contact of someone who has a good running engine for your bike. Should be fairly cheap.

 

I got the pan off and am trying to get the oil pump out of the way to see the left side cylinders. The 2 rods on the right side look "OK" just by turning the crank back and forth and looking closely. Swaping a bearing from the bottom looks pretty iffy, I need to get the pump off to be sure.

Anyway, I cleaned the magnet on the drain plug less than 300 miles ago when I changed the oil and it had only a little fine powder which is normal considering it may not have ever been cleaned in the past. Now it has metal flakes, reminds me of bearing material.

 

That kind of failure is rare, so you wonder WHY ?? The bikes are usually more reliable than the riders, and maybe some abuse, neglect like low oil or excessive rider habits exceeded mechanical limits somehow.

You probably shouldn't try a repair unless you're prepared to replace ALL the crank and rod bearings since they ran at reduced oil flow while the one bearing tore up and they're likely damaged. Without that, low oil pressure on the "rebuild." Crank could also be damaged. If those metal flakes circulated through the pump, it needs replacement.

I know a rider in town (Dave) with a useless '86 bike and motor (condition unknown) in his basement, and i could hook you up so you could replace rather than "rebuild" if you'd like.

 

I'm betting it was abused. The previous owner was supposedly a motorcycle drag racer that used this VFR as a daily driver. The fluids were not maintained and it had been scraped up on both sides. Still, it ran smoothly for the 1500-2000 miles I had it. Maybe I bought a "timebomb".

 

That sounds like what I was thinking myself, Jason. Most of these VFR's get ragged out by guys that live for speed, stunt the bikes and Street Fighter them out. Once they screw them up good enough, they'll drop them for whatever they can get.

I met a guy here in Mesa that bought an '86 750 and paid a good price for it because it had all the plastics in-tact. What he didn't know what the guy had taken them all off and put on a crap tank, stunted it, dropped it several times, ragged it out, and then put em all back on and sold it looking great.

If the guy sold it to you for $500 then he knew already that it was on it's way out. I got mine for $1000 in non-running condition, but that was because the lady was a family friend of a guy I was going to school with that also happened to be dating my cousin. She wasn't going to sell it, but because he put in a good word for me, she let it go on the condition that I not part it out, Street Fighter it, and that I never sell it unless I absolutely had to. My point is that these things are worth much more than what you or I paid. I see 2nd Gen's go for well over $2000 around here in the condition yours is in.

I'd look into what Squirrel suggested and get yourself a good used engine to swap parts with. In the end, the 2nd Gen's are only going to increase in value so it's worth the investment, IMO.

 

Hey, Jason, i bought a really good replacement 700 engine a few years ago from a place in Houston called "Sam's," so give that place a try. No shipping charges !

 

Just an update, I decided not to sell the bike for parts and instead get a replacement motor. I found what looks like a good one in Florida. Only 20k miles, no leaks, 180 psi compression on all cylinders from a bike that hit a car and had front end damage. The insurance totaled the bike. I got it for $350 plus $135 shipping.

After a valve adjustment and applying silicone to both sides of the valve cover seal I'm going paint the whole motor gloss black like the 87's. That sandcast finish just isn't my cup of tea. The all black 87 motors look great in the all white bikes. :redface:

 

I regret to say I'm not familiar with Sams. I tried all the big established places around and after hours and hours of searching these places, no one seems to have an 86 or 87. I'll give Sams a call and see if they have any of these bikes. I could sure use a few knick knack parts that are missing on my bike.

 

Well, it's been a month. I got my replacement engine shipped in and I just finished the install. It's running like a champ now.




On a side note, once I had the old engine out I noticed the numbers don't match. Aren't the engine serial numbers supposed to match the bikes vin number?

 

Good to see you opted for repair. I dont think the motors matches the frame numbers.

 

Yeah, after some research I found they never match.

I'm wondering if the new engine needs to be noted on the title or some other paperwork. I don't think Texas is anal about that stuff, but I've never come across this situation before.

 

Keep the receipt you got for the replacement engine to answer any questions should they ever come up. That should do it. Here in NY there is no need to inform DMV and no place on the title for any notation like that - only a place for listing lien holders. Nice job! BTW, we had another inch of snow last night - Last year at this time we got out and rode to a local place for the St. Patrick's Day big too do. Not this year. :frown: