Vibration above 3200 rpm

GrandPaul may have it, time for Heinz Kegler's swing arm rings?

And a DTHS will eliminate all side to side head movement, something the stock head steady does not control well at all?

Mick, yes a rumble that changes when leaned over, felt throught the bars.
What am I looking for ? too tight, too loose, or loose box section where it's fixed to the head, and side plates loose? Do you mean that the mounting bolts may have come loose ?
This vibration is something that I could live with, but it didn't do it before.

graeme.

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Graeme,

The head steady alignment and tension has some influence on the overall feel of the isolastics. On an 850 there should be 3 bolts in the box section fastened to the head. Beware these are fairly fine threads and must be torqued up carefully. The box section supports the side plates for the rubber buffers. These ideally should be parallel, not skewed left or right and I also found that the plates work better if they are parallel in the vertical, i.e. not pulled in or pushed out at the top at the buffer studs. To set this silly assembly of bits in line, I keep everything slightly slackened off and I use thick washers to space the side plates to get them parrallel to the buffers. I then just nip up the mounting studs on the side plates. Then I gently ease the box section so that the buffers are relaxed and at right angles to the side plates, i.e. neither to forward or too backwards. With a pencil mark lines alongside the box section and equally torque up the 3 bolts in the box section. Make sure it is even on both sides on the head and has not distorted the side plates. Then torque up the 3 nuts on each of the side plates.

I also made a noticable improvement by adding the Mark 3 spring tension kit ($30) which improves the feel of the isos and in my case the handling has a more precise feel.

Mick

Hi Graeme — some other suggestions:

1. Are you sure that the isolastics are adjusted properly? Some go by the book, set the clearance with the feeler gauge and then torque the engine bolt. This can be a mistake because the slack in the threads is taken up and the clearance is effectively reduced to zero when the nut is tightened. On mine, I have to back off the adjusting ring more, tighten up, then check, and repeat till I get the 8 thou I want when everything is nipped up. Please ignore if you already know this.

2. Slacken the isos off quite a bit. With the bike off the stand, grab hold of one header pipe and see if the engine moves in the front mount. Grab the rear wheel and you should get plenty of movement and you should even see the front of the engine moving (if you have the standard head steady). Then you know that the isos are responsive to adjustment. If you don't get any movement, then something is binding/stuck/bent, etc. and the isos are not functioning as they should. While everything is slack you might also be able to hear/feel if the engine/gearbox assembly is hitting the chassis where it shouldn't. Then, adjust them back to the 8-10 thou as per my method in 1. above.

2. Try removing the head steady, take the bike off the centre stand and rev it through the normal rev range and see if it makes a difference. You might also hear/feel if something is touching the engine, as has been suggested in previous posts. I agree that the left hand zorst can touch the frame, causing excessive noise and perhaps more vibes.

3. When you fitted the new isos, were the engine bolts a snug fit in the tubes to which the rubbers are bonded? Some of us have had unhappy experiences with sloppy fits in new iso parts. It's a long shot, though.

I am assuming that the isos have been properly assembled with the right sequence of parts in each assembly.

Please let us know what you discover so as to add to our knowledge bank!

Dave