Bought the bike (79 spada, no fairing) a year ago, sorted a few issues out over the months, and am very happy to be back riding a guzzi. Love the bike.
However, shortly after purchase, began to notice the above, and have been trying to eradicate it since.
The sensation is as if the front calipers are dragging/catching on a part of the disc as it rotates. The effect is particularly noticeable when dragging the brake during low speed manoeuvres.
So in order of approach, Iā¦
Tried cleaning up the discs
Replacing discs
Stripping all calipers, and fully refurbishing.
Replacing wheel bearings
Adjusting steering head bearings
Pestered people more knowledgeable than me
To no avail, hence this post. Wheels appear true, new tyres.
Discs are new, and true. In fact the ones they replaced were pretty good, but getting a little thin, hence the replacement. I really thought that would be the end of it!
OK just wasnāt sure if that was part of the list. Sorry! Hereās another aft angle. Have you had the headstock out or worked on at all? Trying to imagine if this would even have that effect but how confident are you that your forks are completely aligned?
Donāt want to insult you but these links cover another couple of maybes?
Hey Aj49 - this is a bit āoff centreā from your perceived problem, but.. I got a ānakedā ā79 Spada, too, and it too had oddities from the front end. Long story short, took it to a ātraditional motorcycle blokesā garage for a couple of jobs. Collected it. Rode it home - transformed. I went back the next day with packets of biscuits - what did you do to my bike? They looked puzzled.
Well, we did balance the front wheel. And we put in more air than you had, it seemed low to us.
Just a thought, mate. Good luck.
edit: oh - and it was running some āblockyā Bridgestones, as I recall. They just didnāt seem to suit it. Went with rounder profile tyres (lack the terminology here, sorry) and it was a different bike.
Yes, I know about the shims Barry, and have read a few posts on their fitment. Iāve got to the point where Iām re-checking everything, and these will be part of that.
No insult taken, chances are Iāve missed something, and need to go over things. My initial belief, following reading up on the problem, was that since the bike had been standing for some time, that the pads had compromised the discs in specific locationsā¦which the symptoms seemed to fit. New discs scuppered that theory!
Ha! Good luck! I feel for ya following a couple of weeks of serial redos and tearing my hair out! Weāve all been there with sumthinā or other I guess. Hang in!
My old Spada had a front brake pulsation. I got rid of it by taking the wheel out and then moving the offending disc round through the 6 bolting positions until I found the best position. I concluded that the machined location on the alloy wheel was not true to the spindle axis.
On my loop-frame bike (drum brake) the front starts to wander about a bit when front tyre pressure is low, particularly when the tyre is cold and slowing down for a junction etc. I run Avon Roadrider 2 tyres and have them about 0.5 bar above the book figures. Most people I know run modern tyres above the values given in original literature.
You know Ranton, this is where my thoughts keep going, I say this, because when I had my old discs on, and I was noticing the āpulsing ā, I took the discs off to give them a really good clean with brake cleaner and acetone, and perhaps foolishly without noting their placement on the wheel. When I put them back on, the pulsing became more pronounced, at which point I bought new discs. I did wonder whether by putting them on in a different orientation, I had compounded the original problem and simply muddied the water, although looking back, perhaps given a clue as to the real issue. Saying that, I had my dti out the other night, and everything seems to run pretty true. I will have a think about this.
Could it be the brake lines. I have a SP2 and had similar issues (pulse through the front brake) and ended up changing disk and brake pipes all round which solved the issue.
Not sure if it is the same thing, but a similar problem shows up on some older Brembo-braked KTMs. If the disk runout is fine, and the disks and pads are in good condition, two things can be tried:
if the disks are two part floating with bobbins holding them together, rotate the bobbins while applying plenty of brake cleaner spray. The bobbins can and do get stuck when their moving parts get clogged with dirt and/or brake dust. Some use an Allen bolt and nut through the bobbin to rotate them if they are stuck fast.
Some Brembo disk and pad combos end up with a very fine smear of the pad material on the diskās active swept surfaces, leading to the effects noted. This can be alleviated by repeated heavy braking, or aggressive manual cleaning of the disk with something like scotchbrite pads. If this is the case the longer term solution is to change to more abrasive brake pads
I remember getting a mild chastisement from local MOT tester I used to use when I lived in Essex, literally over the road, so the bike (Spada or LM1, canāt remember which), canāt be described as being ridden to the test station, unless you count literally just 100 yards, ergo rust patches on front discs, which occur where the pads were āparkedā, caused slight pulsing on the test machine, he said I should have ridden around for a couple of miles first. The old Tonti discs always were prone to this kind of thing, you can have pad rust patches literally develop overnight.
Thanks fellasā¦.discs arenāt floating, but have been replaced with new from stein dense, hoses are braided and seem ok. Much cleaning was carried out on the original discs with disappointingly zero effectā
