Starting point for isos

Status
Not open for further replies.
Joined
Dec 20, 2008
Messages
379
Country flag
Bike passed it's MOT on Tues ... no problems at all really pleased as it's always a daunting procedure, now for the process of setting everything up on the road, although the engine seemed to be running fine, the clutch and gearbox too, the tester even commented on it's tickover and it's feel through the rev range, oops by saying that I hope I just haven't put the hex on it!
One thing I did notice was I was getting a fair bit of vibration, (mirrors totally blurred), lower down the rev range, but easing off as the revs rose although not smoothing out completely, I am not too sure at what revs exactly as my tacho cable decided to keep popping out of the tacho, (cable seemed to be a bit short so I'll look at that too).
I set the isos before I fitted my Taylor headsteady as per manual, "push to the right etc" and they seemed ok, but with this vibration I am starting to wonder about the gap, so some questions...

It's a MK3

What would be the best way to set them as with the Taylor fitted I would or should not be able to push the engine to the side?

Would it be off stand, slacken off through bolt, turn adjuster right in and back off, if so by how much, then retighten?, I noticed Norvil site mentioning back off 1/2 turn, I take it that's a full 180 degrees? That might sound obvious but just want to make sure!

If setting it with feelers, what would be a good starting gap?, and should the gap be the same on either side of the adjuster or will it settle in equal once set?, for example .010" total on side of the adjuster or .005 each side of mounting.
The headsteady spring is set as recommended but again might need some adjustment

I know no matter which gaps I set it to will be a compromise but I'd like to get it as smooth as possible.
Thanks
 
Joined
Nov 10, 2006
Messages
1,417
Country flag
The mirror blur thing at low rpm is pretty normal. It can be improved or even eliminated by taking care over ignition timing, carb ballance, ISO gaps and the Mk3 suspensory ( is that how you spell it ?) spring. Generally on Mk3 ISOs the fixed side has no clearance, the gap is set on the other side. I set mine 0.010" won't, go 0.005" will.

Cash
 
Joined
Dec 20, 2008
Messages
379
Country flag
cash said:
The mirror blur thing at low rpm is pretty normal. It can be improved or even eliminated by taking care over ignition timing, carb ballance, ISO gaps and the Mk3 suspensory ( is that how you spell it ?) spring. Generally on Mk3 ISOs the fixed side has no clearance, the gap is set on the other side. I set mine 0.010" won't, go 0.005" will.

Cash

Hi Cash, cheers, I take it with the Taylor fitted you adjust without trying to lever engine over to the side?

Thanks
Robert
 

maylar

VIP MEMBER
Joined
May 13, 2007
Messages
4,198
Country flag
You judge the amount of adjustment by counting the number of "holes" that you move the adjustable collar. Most of the advice I received on the subject said it's more a matter of personal preference than exact science, the compromise being vibration v.s. handling.

What I did when I installed my new vernier isos is to back them off until the vibration was very low, which amounted to 2 "holes" in the rear and 2-1/2 holes in front. Then after some miles I slowly turned them in until the vibration started comming back.

Having owned and ridden my MKII for 34 years gives me a baseline to compare against. The original isos shimmed for .010" clearance buzzed badly at low rpm then magically smoothed out at 3000 and even better above that. I have not been able to attain the same characteristics with the new verniers. What I have now is a sweet spot at about 40 mph where there's no vibes at all and higher speeds are tolerable.

My mirrors have always been blurry. It is what it is.
 
Joined
Jan 2, 2009
Messages
280
0.008" is a good gap to aim for. Measure from 1 side...lever over.
Norvil Les says 1/2 a turn....by the pitch of the thread that works out about 0.020 or more!
 
Joined
Nov 10, 2006
Messages
1,417
Country flag
I always check the ISO clearance after setting because the backlash in the through bolt thread once tight will close up the gap.

I take it with the Taylor fitted you adjust without trying to lever engine over to the side?

I never found levering any benefit while using the Mk3 type adjusters, I just make sure the steady isn't loaded up.

Cash
 
Joined
Jan 22, 2008
Messages
954
Country flag
Robert — I second Cash on checking the iso clearance after the through bolt has been tightened. You might have to set the clearance larger than 0.008" (or the clearance you choose), then tighten the through bolt and measure again. You will get there after a few goes at this. After you've set your iso clearances, with the bike vertical and off the stand, you should check that the rose joints on the head steady are free to move, again with the bike upright and off the stand. To support the bike, I use tie downs hooked to each side of the garage and the top of the fork legs or bars. My Taylor head steady does not give quite as smooth a ride as the original head steady but I can live with that. The Mark 3 spring device helps a bit at low revs.

Dave
 
Joined
Dec 20, 2008
Messages
379
Country flag
daveh said:
Robert — I second Cash on checking the iso clearance after the through bolt has been tightened. You might have to set the clearance larger than 0.008" (or the clearance you choose), then tighten the through bolt and measure again. You will get there after a few goes at this. After you've set your iso clearances, with the bike vertical and off the stand, you should check that the rose joints on the head steady are free to move, again with the bike upright and off the stand. To support the bike, I use tie downs hooked to each side of the garage and the top of the fork legs or bars. My Taylor head steady does not give quite as smooth a ride as the original head steady but I can live with that. The Mark 3 spring device helps a bit at low revs.

Dave

Hi Dave , thanks for that, all help gratefully accepted!, I had done the isos before on other bikes, and I thought I'd managed ok, and probably had!, but since reading posts on the internet there seemed to be 101 ways of doing it, and I wondered what would be the best way to do it. Also with me changing to a Taylor steady, which is meant eliminate side movement , was it neccessary to try and lever it over? the general opinion is do it without levering, which I'll do. At first I thought do I disconnect the Taylor then do the isos and connect up again? or do it with it in situ?
So for me it's; "Taylor stays connected without levering, adjust isos, and then check iso gap and Taylor for free movement after I've tightened up the through bolts!"..... then it will be a smooth as glass right through the rev range!!!!!!!!!!! :roll:

Thanks to all
 
Joined
Nov 10, 2006
Messages
1,417
Country flag
then it will be a smooth as glass right through the rev range!!!!!!!!!!!

I've had my old Mk3 running like for years, then I decided the rear ISO rubber might need changing. Oh boy did it, it just fell out in dust and bits. Since fitting the new set she's gone a little buzzy low down, nothing drastic. Strange why she was so smooth and handled so well with a knackered rear ISO? The only thing I did different was put the adjusters on the same side.

Shouldn't take long to sort it.

Cash
 
Joined
Dec 20, 2008
Messages
379
Country flag
nomadwarmachine said:
Any tips on supporting the engine while adjusting the rear iso for a guy with no centerstand? MKII 850.

What I did was I got a bit of 4" x 2" wood I screwed a piece onto the end, then measured just over the width of the frame rail under the seat and screwed on another piece so it looked like an "F", I put a piece of rubber in between the bits I'd screwed on so it wouldn't damage the frame paint, it looks like an 'F' on it's side, if that makes sense! The "top" part of the 'F' goes over the top of the frame rail horizontaly and the other end can be fixed to a workbench or something immovable, this can hold the bike upright without using any stands leaving you free to do any work that needs to be done off stand without you trying to be a contortionist and balance with one hand whilst trying to work with the other. I suppose you could use axle stands under the foot rests too.
 
Joined
Oct 12, 2007
Messages
2,983
Country flag
I have a 12" plank about 4 feet long. An eye bolt at each end. I roll front wheel up on the plank (perpendicular) and use tie-down straps to hold the bike upright. Just like tying it down on the trailer. You may want to chock the wheel. So far, I haven't had to.
 

maylar

VIP MEMBER
Joined
May 13, 2007
Messages
4,198
Country flag
My Craftsman mtorcycle lift is one of my favorite shop helpers. I have the yellow one, $199.
 
Joined
May 19, 2009
Messages
644
I got a great tip about living with Iso's a while back. When the rubbers in the Iso age they glue themselves to the inside of the tube. It doesn't exactly lock the cradle laterally, but it just about always loads the thing in one direction or the other. You can wind up chasing clearances trying achieve that theoretical balance between vibration and handling. If the things are over ten years old you can bet they're stuck. If they're twenty years old they are shot anyway. Mileage has something to do with it but just as much as anything it's aging. The point of the tip was to pull it apart, clean the rust and crapola, and put in new rubbers slathered in silicone grease.
 
Joined
Apr 15, 2009
Messages
11,415
Country flag
bpatton said:
I got a great tip about living with Iso's a while back. When the rubbers in the Iso age they glue themselves to the inside of the tube. It doesn't exactly lock the cradle laterally, but it just about always loads the thing in one direction or the other. You can wind up chasing clearances trying achieve that theoretical balance between vibration and handling. If the things are over ten years old you can bet they're stuck. If they're twenty years old they are shot anyway. Mileage has something to do with it but just as much as anything it's aging. The point of the tip was to pull it apart, clean the rust and crapola, and put in new rubbers slathered in silicone grease.

I gave the iso tube a light honing, then silicone grease. That should work.
 
Status
Not open for further replies.
Top