Normal to be bounced off the seat? VFR700 '86

Jamie built me a shock for my VFR (1986 VFR700) this summer. trying to get it installed, but the stars haven't been lining up for that. While his website doesn't show it, he does build them.

 

The stock 86 VFR shock is very stiff, around 950lb spring and too much rebound damping, also contrary to popular opinion these shocks dont seem to wear out however they are rebuildable. I have an 86 and 89 shocks and they are far from worn out.

From my 27years owning an 86 its probably the rear tyre, what tyre are you using?
Crossplies give a very hash ride and will have you out of the seat, radials are much better but hard to find anything for the 18" rim.

 

Dicky, the stock 86 units are a sealed Showa here in the states and are only rebuildable if you perform surgery on them, and good luck finding any replacement seals or shims in case anything internal is shot. Unfortunately these rear shocks suffer the same price point design engineering as the stock Showa shocks on my CB750- they don't last that long and are basically designed to be chucked after 10k or 20K miles.

 

Hi Dukie,
I agree the Cb750 shocks are wank and dont last long but the VFR showa's dont seam to wear out, they do come apart if you can get the nut undone on the bottom.

This is on an 84000mile 1988 shock

 

I was just rereading this thread and I do need to replace my tires. I have Macadams on it front and rear which is bias ply.

I've seen some radials in 140/60/18 and 140/70/18 so I might give a radial a try. My question is whether you can safely run a radial rear and bias front? I remember something way back in my youth about not mixing them, but that might have been cars, not bikes.

 

I believe our wheels are not safe for mounting radials, bias-ply only. (they don't have the extra retention rib for the bead??)

 

I've never heard anything about the rims being different. I assumed the only difference was in the tires internal construction. I'll have to look into it.

 

Bounced off the seat? You are wearing the seat belt right! The previous owner may have taken it off.

Bite the bullet and give Jamie a call... well worth it. Made my old bike fun to ride instead of a literal pain in the ass. Getting bounced off the seat is an understatement - was more like being kicked in the ass with a sledge hammer!

 

I do plan to have Jamie revalve my stock shock for about $150. I can't afford anything more.

I've done a lot of research on fitting radials to these bikes. The narrow 2.5x16" and 3x18" just don't meet the requirements that most radials have. There is a reason radials are lower in profile than bias ply tires. It's because they have to be. The softer sidewalls would allow s radial to flex too much side to side in the stick sizes.

Avon makes the radial tire Azaro in 120/80/16, but requires a 2.75-3" rim which might work, but it's iffy. In the back all the 130 radials require a 3.5-4" rim. A 120 radial would fit, but it will be a front tire. Those can be mounted backward, but you might have that narrow tread shape so many front tires have. So the only real options are to run wider rims.

The cbr600 hurricane front rim is interesting as it's still a narrow 2.5x17, but the Azaro is available in 110/90/17 that is recommended for 2.5" wide rims. It's a direct bolt on, but the downside is there's only the one tire available. If they discontinue it, your back to bias ply.

One another side note, it is okay to mix a bias and radial on the same bike. Lots of people do it and there are even some bikes that came that way from the factory.

 

I was riding on the freeway just last night and it felt really unstable and kind of scary. It doesn't want to follow a straight line. Just horrible. It makes me want to get rid of this bike.

Then again everyone says these bikes have great potential so I'm gonna stick some new bias ply tires on it, probably Pirelli Demon Sports, and add an steering stabilizer. Maybe that will calm it down. Then get the rear shock revalved and some stiffer springs up front. If that can't fix it, then it's time to get rid of it.

 

Stiffer springs up front and adding a fork brace will go a long way to helping out sketchy lines- I had problems with both of my bikes before those upgrades.
You may want to look to changing out the steering head bearings to tapered bearings before adding a stabilizer.

 

are you being bounced on rebound or compression, IE, when the road dips you float, or are you being spring boarded on rebound.

spring boarding, no rebound dampening, shock is toast. Floating to much rebound dampening, unlikely on a stock shock.

Spring is probably OK, has to be the shock/dampener.

 

I've got new tapered bearings and a fork brace. It felt exactly the same with the old bearings. They had a flat spot on center and I ran them just loose enough that I didn't feel it. I could hear and feel the looseness in bumps, but it was no big deal. The new bearings got rid of the play and bumps went directly into the forks which is better, but had no effect on the unstable straight line tracking of the bike.

 

When the road drops, the bike drops instantly leaving me up in the air then I drop down onto the seat. I think it's got too much rebound damping. Jamie said he knows how to revalve these shocks. I'm gonna let him redo it when I get the money.

 

I got a line on a whole front end for $200. Actually a whole bunch of parts, including a matching rear rim. Trouble is I can't tell for sure what it's from. The guy says it's late 90's cbr600. (After more research, I think it is 99-00 early F4 parts where the rims have been chromed and a brace welded to the swingarm.)

 

Adjust the bearings per the manual, you need enough torque on the locking nut or you can get some serious tank slappers.

How many miles on the bike? I'd say check everything at this point. Wheel bearings, axles, linkage, shock, but the squirreliness I think is the tires. Buy the best tires you can get; I had BT45's on mine and they were fine and rated very high by many classic cycle mags. I never had stability issues at speeds.

Now with the upgraded wheels and new radials its more like a later model vfr, 3rd gen or even 4th gen. Tires make all the difference, IMHO. Really, for less than 500.00 I can show how to upgrade the wheels to the f2 setup.

 

The manual talks about torqueing the ball bearing style bearings, but not the tapered type. I tried cranking down on the adjuster nut, but the steering resistance never increased. It was weird.

After the bearing change, but before my motor went out, I did have a pretty good tank slapper on the freeway. (see, this bikes trying to kill me! :redface
I hit a smallish rough spot that I did not see and I think it pushed the steering to the side and bam, instant shake. Notice the 45* angle in the pic below? I stayed cool, though. I tightened my grip, but relaxed my arms and got off the gas and it came back under control. A good reason to get that steering damper.

Should I try tightening those bearings even more, until the steering develops the drag that the manual recommends?

 

Supposedly 44K miles. Wheel bearing front and rear are good, linkage is good I recently checked it and added extra grease. The rear shock is stock junk. It works, but the valving is way off.

When you say check the axles, do you mean their tightness or pull them out and roll them on glass to make sure they are straight? I haven't checked their straightness, but I guess I will next chance I get.

My rear tire is worn flat across the middle. The last of the tread just recently dissappeared. I bet that would make it act funny, right?

My front tire still has tread all over, but the sides are feathered/scalloped. I don't think that would effect straight line stability, just turning. I'm guessing though.

This bike has always had a wierd quirk. If you take both hands off the bars it would start shaking very tiny amount and it would build up into a big shake. It's annoying, but I usually hold on with both hands and might use one hand rarely, so it was never an issue, just something that bugged me. I was hoping the new steering bearings would fix it, but they had no effect.

Screw it, I'm gonna buy those parts and make them work or else sell them and buy a F2 or F3 front end.

 

don't mix tire types.... and the shocks on these suck... I have the BT 45 on my 86 there are great ... they astick to the road really well even if I can't keep the bike on the wheels

 

Tires. tires, tires, get rid of those worn out tires. I used to get the same shake your talking about on a almost new 86' and it is 100% the crummy old tech tires. Do the F2 wheel swap, and don't run your tires down so far, replace the rear when you still have some tread left or you will bite the dust hard one day, trust me on that.