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Discussion Starter · #1 ·
Hello,

First, let me introduce myself. I'm Jay, and the bike under discussion is Dad's '89 FXR that he bought almost new (bought from the first owner in 1989 with maybe a thousand miles on it). This bike currently has about 76,000 miles on it. A far cry from the 8000 miles I've got on my Sportster!

Dad's '89 FXR has developed a bad vibration at around 40-50 MPH (no tach so I'm not sure what RPM). This is an RPM-dependent vibration, since it will do it by revving the engine in Neutral sitting in the garage; if you get it vibrating while riding and downshift, the vibration goes away. It's bad enough that it's breaking parts like the heat shields on the exhaust. Outside of a small RPM band, there is no abnormal vibration.

Some back history -- A couple of years ago the rotor let go in a spectacular way, while on a trip. Dad managed to ride it home (about 250 miles) but without it charging, it was a chore. We managed to swap batteries around the various bikes on the trip to keep one charged, but it sure didn't do it any good and at some points the bike was running on one cylinder (which sure gave the engine/drivetrain a beating). We pulled the primary, cleaned everything up and replaced the alternator. The vibration started shortly thereafter and has steadily gotten worse. It's almost like the engine vibration resonates with something at a narrow RPM range and sets up the vibration.

We haven't been able to find the problem and unfortunately have resorted to swapping parts. We've replaced a LOT of parts in the hopes that the vibration is due to the bike running on one cylinder beating something to failure. The engine mounts and both stabilizer links are new. The driveline alignment is spot-on. The primary chain is new. The clutch hub bearing is new. We even were worried that it might be something in the engine bottom end, and since we don't have the tools to deal with truing flywheels, Dad sprung for a new engine from H-D (not aftermarket, not rebuilt). The new engine certainly runs stronger than the old one, but the vibration remains. We have examined the frame for cracks and haven't found any. As an aside, the new engine came with a new alternator, so it's not a problem of an out-of-balance replacement rotor.

I keep telling myself that it has to be in the primary somewhere since the vibration is there sitting still in the garage, and is even there with the clutch pulled in. The only parts in the primary that are original are the clutch assembly and the compensating sproket. The compensating sprocket is working and the spring is not broken -- I've heard one with a broken spring and it's an obvious noise. I've wondered if the spring may be weak but I don't know if that would cause this problem. Since it does it with the clutch pulled in, I doubt it's the transmission main shaft or any of those bearings.

We've removed and inspected the swingarm pivot bolt, rubber bushings, etc. and they look fine. We may replace them anyway (at 76k miles it's not a bad idea anyway).

The ONLY thing that looks even partially goofy to me is the pivot bolt fit into the transmission. I'm not sure what the spec. is, but if I insert the pivot bolt in the transmission without the swingarm installed, I can wiggle it (just a bit, but enough to notice that it's not a perfect slip fit or an interference fit). Considering the transmission is captured in the swingarm between nylon washers, does that matter?

I HATE throwing parts at a problem but we're lost. Everything seems fine by examination. I'm open to any ideas. Thanks.

Jay Vessels
2003 Sportster 1200S
Lexington, KY
 

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seeing how you have covered the basics and then some here is somthing to try with the front rubber mount first loosen all three bolts alittle so they turn and the mount can move fire the bike up with dad sitting on it holding it up no brakes on bring the rpm up to the vibration point tighten the frame to mount bolts first then the center bolt and take it for a ride and see if it helps
 

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I'd suspect the compensating sprocket given everything else you've replaced.
I'd double check that front motor mount even being new,a little loose can make for a lot of bad vibes.
Keep us posted on what you come up with.
 

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jwvess00 said:
....... The engine mounts and both stabilizer links are new. The driveline alignment is spot-on. ......
Welcome to the Forum.

What about the engine stabilizer under the gas tank?

How was that stabilizer adjusted?

Who did the drive line alignment? Did they follow the Service Manual EXACTLY?

That top engine stabilizer should NOT be under any stress.

As an experiment - remove the gas tank and with the bike upright - remove the vertical bolt on the stabilizer link to the engine.

Does the bolt just EASILY lift out or do you have to twist and pull to get it out?

If the bolt will not just lift out and "drop" into position (from the stabilizer link to the attachment hole) the top link is not adjusted properly.

If the top stabilizer bolt was not exactly in line, then start the bike WITHOUT the bolt in place (bike should be upright - no side-to-side stress on the motor).

Is the vibration gone? If so you need to adjust the top stabilizer linkage per the Service Manual. If you need to do this post back and I'll give you some suggestions.

Good luck - sounds like a quite a puzzle.
 

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man am i glad ya'll brought this up as i am bout ready to be installin my motor, good thing is i kept the old stab links and never had much prob in the vibe area. i like to know these things like the bolt to top motor mount and dad sittin on the bike and all.
 

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Discussion Starter · #6 ·
Hello,

We're planning on swapping out the compensating sprocket assembly Real Soon Now. The complete assembly (sold by the piece -- the sprocket, cover, sliding cam, nut, and shaft extension) is in the $150 range from Zanotti's. That's about the same price as the kit from a local indy. We'll also swap out the rubber swingarm bushings, too, since the rest of the mounts are new. Some of this may be overkill and not strictly necesary, but a few hundred in parts to freshen up this bike after 76k+ miles of good service sure beats buying another bike!

84FXRP, Dad and I did a full driveline alignment including the stabilizer under the tank, using the genuine H-D shop manual as a guide. The top bolt falls in place with no stress. The top and bottom stabilizer links are both new, as is the front rubber mount.
 

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1989 Motor Problem

Hi, I also have a 1989 HD.
I hate to be the bearer of bad news, but. I have found the 1989 BT was a transsission year. That is a year Harley changes some part, or model. Harley used a 5 piece crank assembly in all BT motors from 1988 and earlier. A crank pin, 2 flywheels, and 2 pinions. The 2 pinions were case hardened In 1989, they went to a 3 piece crank. The pinion was cast into the flywheel. They were surface hardened. HD didn't take into account for the difference in the depth of the hardening and bearing size. This caused the crank or bearings to fail. I had my crank to break while I was going down I-40 outside of Jackson Tennessee. HD didn't put out a recal. Only a service bulletin. That way they only had to fix those that came into the shop within a set time/mileage limit. I was lucky. When the dealer tried to not repair my motor under warranty, I knew and called Wille G. He and I had met and gotten to be friends at a Love Ride in California.
I only hope that this is not your problem, but from what you say, it appears to be the only thing left.

Ride Safe :chopper:
 

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Discussion Starter · #8 ·
Hi there!

An update:

We have replaced the comensating sprocket and the rear swingarm bushings. The rear swingarm bushings seemed to help some, but the vibration is still there. The compensating sproket didn't help.

The only mounts left in the system are the Clevebloc bushings in the swingarm. There is no play in the swingarm and no undue tire wear so we think they're fine. We will probably replace them this winter since they have close to 80k miles on them.

The only other rotating part in the system is the clutch basket, which we've considered replacing.

We don't suspect anything in the transmission since the vibration is there with the bike sitting still and the clutch pulled in. The vibration seems to depend only on engine RPM.

Ultra89Rider, the engine is new from H-D (not rebuilt) and the vibration is still there; we too suspected the crank assembly but the new engine pretty much rules that out. Thanks for that information on what changed, though -- it's good to document that stuff here.
 

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vibration

Hi I had a similar problem on my 91 fxrp, turned out the previous owner put forward controls on the bike that had a master cyl. on them. At a certain rpm the front pipe was hitting the plunger for the master cyl.. The bike would do it sitting still when revving the motor or while riding at about 2500 rpm a real pronounced vibration.

I hope this helps
 

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Hi there!

An update:

We have replaced the comensating sprocket and the rear swingarm bushings. The rear swingarm bushings seemed to help some, but the vibration is still there. The compensating sproket didn't help.

The only mounts left in the system are the Clevebloc bushings in the swingarm. There is no play in the swingarm and no undue tire wear so we think they're fine. We will probably replace them this winter since they have close to 80k miles on them.

The only other rotating part in the system is the clutch basket, which we've considered replacing.

We don't suspect anything in the transmission since the vibration is there with the bike sitting still and the clutch pulled in. The vibration seems to depend only on engine RPM.

Ultra89Rider, the engine is new from H-D (not rebuilt) and the vibration is still there; we too suspected the crank assembly but the new engine pretty much rules that out. Thanks for that information on what changed, though -- it's good to document that stuff here.
Hello,

First, let me introduce myself. I'm Jay, and the bike under discussion is Dad's '89 FXR that he bought almost new (bought from the first owner in 1989 with maybe a thousand miles on it). This bike currently has about 76,000 miles on it. A far cry from the 8000 miles I've got on my Sportster!

Dad's '89 FXR has developed a bad vibration at around 40-50 MPH (no tach so I'm not sure what RPM). This is an RPM-dependent vibration, since it will do it by revving the engine in Neutral sitting in the garage; if you get it vibrating while riding and downshift, the vibration goes away. It's bad enough that it's breaking parts like the heat shields on the exhaust. Outside of a small RPM band, there is no abnormal vibration.

Some back history -- A couple of years ago the rotor let go in a spectacular way, while on a trip. Dad managed to ride it home (about 250 miles) but without it charging, it was a chore. We managed to swap batteries around the various bikes on the trip to keep one charged, but it sure didn't do it any good and at some points the bike was running on one cylinder (which sure gave the engine/drivetrain a beating). We pulled the primary, cleaned everything up and replaced the alternator. The vibration started shortly thereafter and has steadily gotten worse. It's almost like the engine vibration resonates with something at a narrow RPM range and sets up the vibration.

We haven't been able to find the problem and unfortunately have resorted to swapping parts. We've replaced a LOT of parts in the hopes that the vibration is due to the bike running on one cylinder beating something to failure. The engine mounts and both stabilizer links are new. The driveline alignment is spot-on. The primary chain is new. The clutch hub bearing is new. We even were worried that it might be something in the engine bottom end, and since we don't have the tools to deal with truing flywheels, Dad sprung for a new engine from H-D (not aftermarket, not rebuilt). The new engine certainly runs stronger than the old one, but the vibration remains. We have examined the frame for cracks and haven't found any. As an aside, the new engine came with a new alternator, so it's not a problem of an out-of-balance replacement rotor.

I keep telling myself that it has to be in the primary somewhere since the vibration is there sitting still in the garage, and is even there with the clutch pulled in. The only parts in the primary that are original are the clutch assembly and the compensating sproket. The compensating sprocket is working and the spring is not broken -- I've heard one with a broken spring and it's an obvious noise. I've wondered if the spring may be weak but I don't know if that would cause this problem. Since it does it with the clutch pulled in, I doubt it's the transmission main shaft or any of those bearings.

We've removed and inspected the swingarm pivot bolt, rubber bushings, etc. and they look fine. We may replace them anyway (at 76k miles it's not a bad idea anyway).

The ONLY thing that looks even partially goofy to me is the pivot bolt fit into the transmission. I'm not sure what the spec. is, but if I insert the pivot bolt in the transmission without the swingarm installed, I can wiggle it (just a bit, but enough to notice that it's not a perfect slip fit or an interference fit). Considering the transmission is captured in the swingarm between nylon washers, does that matter?

I HATE throwing parts at a problem but we're lost. Everything seems fine by examination. I'm open to any ideas. Thanks.

Jay Vessels
2003 Sportster 1200S
Lexington, KY
So ive been having the same issue and ive realized when putting the new motor mount in it caused the motor to sit too high and the top of my motor was resting on the frame... so i had the motor mount on top of bracket its bolted too between the frame switched it to underneath the bracket and had good clearnce but at about 1200rpms tends to vibrate but way better then the 3500rpm vibrations thats for sure and the mount is technically incorrect being underneath the bracket
Hello,

First, let me introduce myself. I'm Jay, and the bike under discussion is Dad's '89 FXR that he bought almost new (bought from the first owner in 1989 with maybe a thousand miles on it). This bike currently has about 76,000 miles on it. A far cry from the 8000 miles I've got on my Sportster!

Dad's '89 FXR has developed a bad vibration at around 40-50 MPH (no tach so I'm not sure what RPM). This is an RPM-dependent vibration, since it will do it by revving the engine in Neutral sitting in the garage; if you get it vibrating while riding and downshift, the vibration goes away. It's bad enough that it's breaking parts like the heat shields on the exhaust. Outside of a small RPM band, there is no abnormal vibration.

Some back history -- A couple of years ago the rotor let go in a spectacular way, while on a trip. Dad managed to ride it home (about 250 miles) but without it charging, it was a chore. We managed to swap batteries around the various bikes on the trip to keep one charged, but it sure didn't do it any good and at some points the bike was running on one cylinder (which sure gave the engine/drivetrain a beating). We pulled the primary, cleaned everything up and replaced the alternator. The vibration started shortly thereafter and has steadily gotten worse. It's almost like the engine vibration resonates with something at a narrow RPM range and sets up the vibration.

We haven't been able to find the problem and unfortunately have resorted to swapping parts. We've replaced a LOT of parts in the hopes that the vibration is due to the bike running on one cylinder beating something to failure. The engine mounts and both stabilizer links are new. The driveline alignment is spot-on. The primary chain is new. The clutch hub bearing is new. We even were worried that it might be something in the engine bottom end, and since we don't have the tools to deal with truing flywheels, Dad sprung for a new engine from H-D (not aftermarket, not rebuilt). The new engine certainly runs stronger than the old one, but the vibration remains. We have examined the frame for cracks and haven't found any. As an aside, the new engine came with a new alternator, so it's not a problem of an out-of-balance replacement rotor.

I keep telling myself that it has to be in the primary somewhere since the vibration is there sitting still in the garage, and is even there with the clutch pulled in. The only parts in the primary that are original are the clutch assembly and the compensating sproket. The compensating sprocket is working and the spring is not broken -- I've heard one with a broken spring and it's an obvious noise. I've wondered if the spring may be weak but I don't know if that would cause this problem. Since it does it with the clutch pulled in, I doubt it's the transmission main shaft or any of those bearings.

We've removed and inspected the swingarm pivot bolt, rubber bushings, etc. and they look fine. We may replace them anyway (at 76k miles it's not a bad idea anyway).

The ONLY thing that looks even partially goofy to me is the pivot bolt fit into the transmission. I'm not sure what the spec. is, but if I insert the pivot bolt in the transmission without the swingarm installed, I can wiggle it (just a bit, but enough to notice that it's not a perfect slip fit or an interference fit). Considering the transmission is captured in the swingarm between nylon washers, does that matter?

I HATE throwing parts at a problem but we're lost. Everything seems fine by examination. I'm open to any ideas. Thanks.

Jay Vessels
2003 Sportster 1200S
Lexington, KY
1989 Motor Problem

Hi, I also have a 1989 HD.
I hate to be the bearer of bad news, but. I have found the 1989 BT was a transsission year. That is a year Harley changes some part, or model. Harley used a 5 piece crank assembly in all BT motors from 1988 and earlier. A crank pin, 2 flywheels, and 2 pinions. The 2 pinions were case hardened In 1989, they went to a 3 piece crank. The pinion was cast into the flywheel. They were surface hardened. HD didn't take into account for the difference in the depth of the hardening and bearing size. This caused the crank or bearings to fail. I had my crank to break while I was going down I-40 outside of Jackson Tennessee. HD didn't put out a recal. Only a service bulletin. That way they only had to fix those that came into the shop within a set time/mileage limit. I was lucky. When the dealer tried to not repair my motor under warranty, I knew and called Wille G. He and I had met and gotten to be friends at a Love Ride in California.
I only hope that this is not your problem, but from what you say, it appears to be the only thing left.

Ride Safe :chopper:
Chack to see if the top of your motor is hitting the frame..mine was switched the mount to bottom side of the bracket fixed the 3500 rpm vibrations
 
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