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I sold my K7 Wee and bought an L4 Wee back in April. One major disappointment has been that the L4 Wee has been very viby, much more so than the K7. When I first got the bike it was viby right around 5200 RPM which turned out to be a loose lower throttle-body boot clamp. Once that was fixed it was still more viby than my K7 with a noticeable shudder right around 2-3K RPM and buzziness that starts around 7K and peaks around 8K RPM.

Anyway, one Rx for excessive vibes is to check the motor mounts and to reseat the thrust adjusters and re-torque everything to spec so I wanted to perform that procedure to rule it out as a cause. One catch is that the manual assumes you can lift the motor from the bottom which is not possible unless you remove the exhaust pipes (the cat is in the way). I developed this procedure to do a full realignment per the manual without removing the exhaust pipe and muffler.

Here are (roughly) the steps that I used;

  1. Loosen the rear axle and chain adjusters and move the tire forward to put slack in the chain.
  2. Remove the L/R foot pegs brackets and bungie everything out of the way
  3. Loosen the front & rear header clamps and muffler mount bolts (see notes)
  4. Remove the front upper motor mount through-bolt (you'll need two 17mm sockets, I had one and now have two)
  5. Remove the rear lower mount through-bolt (14mm socket + 14mm box wrench)
  6. Remove the front upper and rear lower thrust adjuster lock-nuts (you'll need a special castle socket tool).
  7. Loosen the rear lower thrust adjuster (19mm or 3/4" 6pt hex socket)
  8. Loosen the front upper thrust adjuster (see notes)
  9. Loosen the upper rear motor mount bolt and pinch bolt.
  10. Remove the upper V engine brackets and clean the mating surfaces. (optional)
  11. Install the V engine brackets and tighten bolts to spec (16.5 ft-lbs, see notes)
  12. Align the lower rear motor mount through-hole. (see notes)
  13. Install the lower rear motor mount through bolt and nut but leave it loose.
  14. Tighten the lower rear thrust adjuster to spec (8.5 ft-lbs)
  15. Install the lower rear thrust adjuster locknut and tighten to spec. (32.5 ft-lbs, castle socket)
  16. Align the front upper motor mount through-hole.
  17. Tighten the front upper motor mount thrust adjuster to spec. (8.5 ft-lbs)
  18. Install the thrust adjuster locknut and tighten to spec. (32.5 ft-lbs, castle socket)
  19. Install the front upper motor mount through bolt and nut but just snug tight.
  20. Tighten the lower rear motor mount through bolt to spec. (40 ft-lbs)
  21. Tighten the front upper motor mount through bolt to spec. (67.5 ft-lbs)
  22. Tighten the upper rear motor mount bolt to spec. (40 ft-lbs, see notes)
  23. Tighten the upper rear motor mount pinch bolt to spec. (18 ft-lbs)
  24. Reverse steps 1, 2 and 3 and go for a test ride.
Notes:

Step2: If your bike has a lot of miles you may want to leave the header clamps alone. The bolt/nut tend weld together due to heat over time and if you have a lot of miles then when you try to loosen them they may just break off, something to avoid. My bike only has 7500 miles and the bolts came out but were screeching the whole way. I cleaned them up with a wire brush and reinstalled them with anti-seize compound. The down side is that some mechanics claim that loosening the pipes so they can realign with the new position of the motor is crucial to keeping them from transmitting vibrations. Your call.

Step6: The special castle socket is available much cheaper from sellers not named Suzuki. Its the same size as the GSXRs.

Step7/8: Both thrust adjusters need 6pt or hex sockets, a 12pt socket won't fit. The upper mount thrust adjuster is some odd-ball size like 23mm 6pt hex socket that is difficult to find. I was not even able to find or confirm that that size would work so I just ground down the thruster and used a 13/16" hex sparkplug socket. A 3/4" 6pt hex socket worked fine on the lower rear thrust adjuster.

Step10: The mating surfaces of my V-Brackets were a mess with old loctite, uneven paint and raised bosses around the bolt holes on the frame. I sanded everything down for a clean tight fit just to be sure a poor fit would not cause any vibration issues. If you don't clean them just make sure they are torqued to spec in the next step. I also lightly sanded the thrusters and engine mount points to remove old witness marks to give a clean surface for re-installation.

Step11: According to GW, the manual spec of 25.5 ft-lbs is wrong and too high for this size bolt. I went with his recommendation of 16.5 ft-lbs.

[Aside: At this point in the procedure the motor is only hanging from the upper rear motor mount bolt and rotates around that point]

Step12: Aligning the through-holes properly is really what this is all about. The witness marks on my upper and lower engine frame and thrust adjusters seemed to indicate that my motor was not square within the frame so I was hopeful this would fix my problem. Aligning is pretty easy if you look into each side of the bolt hole and adjust the motor position until everything is concentric. I also shone a line through the other way to confirm. Getting it spot-on was a bit tedious but doable with a little patience.

Step22: Be sure to check that the bushing that the upper rear motor mount bolts screws into is seated in its slot on the motor case. You can see it just behind the pinch bolt mechanism that traps it. One time I got everything set and had to redo this because the bushing was not in its slot.

I took some pics: First pic is the witness mark on the motor from the right side. Second pic is the witness mark on the motor from the left (circled in red). These are the tell-tales that the motor was not squarely in the frame. The lower thruster was even more out of alignment. Note the yellow circles in the second picture which highlight that the ignition coil was rubbing on my radiator hose, I'm guessing a few thousand more miles and I would be walking home. I am glad I caught that and rigged a rubber hose to give it more clearance. Pic three is the upper thrust adjuster that I ground down to fit in an 13/16" 6pt hex socket aka spark-plug socket. The last two pics are how I jimmied the motor around to align the motor mount through holes. There is hardly any pressure on the jack under the front cylinder and lightly tapping the wooden shims moved the alignment quite a bit but I got everything aligned and locked down.

So what was the result? After a fairly brief ride (just under an hour) I can say the bike is much smoother and less viby. On the freeway I especially notice how calm everything was right away. The mirrors were rock solid which wasn't the case before (but they weren't bad either). However, the 2-3K shudder and 7-8K buzziness remain but a little less noticeable so my search for a fix continues. One final comment, if you do this please verify my torque numbers, I could have them wrong and I don't want someone to break a bolt.
 

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Discussion Starter #2
Here is a picture of how I installed a piece of fuel hose with a zip tie on the upper engine V-bracket to prevent the radiator hose from rubbing on the ignition coil.
 

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I've seen a few 650s with the radiator hose in contact with the coil. I did the same thing and used a spacer until I was able to adjust the hose during the valve adjustment job.

Sent from my SM-G930V using Tapatalk
 

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Just went out to have a look at my bike. The hose was in contact with the coil and slightly abraided. I will be working on this as soon as things warm up a bit. Thanks so much for starting this thread and the follow up posts!!
 

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I'll try this procedure soon, but I have one question.

When removing all of these engine mount bolts, will the engine just hang in the fuel hoses, etc? Do I need to be afraid of it falling to the ground?

I see that you have a support in front of the exhaust, but am not sure if that is just used for the alignment procedure?

It will be interesting to see if I will get rid of some of the vibrations on my bike as well! :)
 

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Hi Staffan,

Sorry I missed your post, I wasn't alerted by the bot.

I'll try this procedure soon, but I have one question.
When removing all of these engine mount bolts, will the engine just hang in the fuel hoses, etc?
Do I need to be afraid of it falling to the ground?[
There are three mount points -- Upper Front between cylinders and Upper and Lower Rear of the engine case. If the Upper Front and Lower Rear mounts are removed then the engine rotates around the Upper Rear mount which is never removed. The alignment really is about rotating the engine about the Upper Rear mount.

I see that you have a support in front of the exhaust, but am not sure if that is just used for the alignment procedure?
Only for alignment. Viewing from the left side of the bike, raising the jack would rotate the engine clockwise around the Upper Rear mount. There is almost no pressure on the jack and the tiniest adjustment would cause a big movement in the rotation but it was good enough to get the motor centered in the other two mounts.

It will be interesting to see if I will get rid of some of the vibrations on my bike as well! :)
It made a noticeable difference on my bike, especially on the freeway.
 

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Addendum

There seems to be some confusion on why my procedure is so complicated (discussed in other threads) so I'm adding some clarifying comments;

I know my procedure seems overly complicated but there is some rhyme to my reason. When mounting the motor it has to be properly aligned in two directions; up and down and left and right. At the factory Suzuki probably has a jig/lift that holds the engine in the proper orientation (i.e. rotation) so that its just lifted up/down into the cradle till all the holes line up and everything tightened to spec. I have no such jig/lift in my garage and it would require removing the exhaust since the cat is in the way of jacking up the motor from the bottom so I had to improvise.

There are three engine mount (through) bolts; Upper Front (between the cylinders) and Upper and Lower Rear. You need loosen all these bolts so the engine is free to move about in its cradle so you can reposition the motor then retighten them. Its okay to remove one bolt at a time (for cleaning, inspection and lube) but never remove all three or the motor will drop and you will have a hell of a time getting it back in its cradle. The basic idea of the procedure is to loosen the Upper Rear mount bolt and release its pinch bolt then remove the Upper Front and the Lower Rear through-bolts and thrust-adjusters so you can see and align the holes. The engine is now only mounted at the Upper Rear mount and rotates around that point. The jack and wooden shims are used to rotate the motor until the Upper and Lower through-holes are concentric and aligned. You then install and tighten the thrust-adjusters. The term "thrust adjusters" seems to confuse people but all that means is that their purpose is to transmit lateral (i.e. side-to-side) loads or forces, like a thrust bearing. So the thrust-adjuster is just holding the lateral (i.e. left/right) position of the engine until the main mount bolts can be installed and tightened which is why they only have to be tightened to 8.5 ft-lbs (11.5 N-m). Once the holes are aligned and thrust-adjusters tightened then you reinstall the Upper Front and Lower Rear engine mount through-bolts and tighten to spec and finally tighten the Upper Rear bolt and its pinch bolt.

Some people have had success just loosening and retightening the bolts and thrusters to spec (which is a much simpler procedure). But that may or may not fix a motor that is crooked in the cradle. The non-concentric witness marks shown in my pics indicate that my motor was crooked in the frame and I wanted to be sure everything was aligned to rule this out as a cause of the vibrations. I also didn't want to do it twice.
 
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