Article [13] ST1300 - Pulls to the Right

[TerryS]

Just bringing an old thread back from the dead.

I too notice that my 1300 likes to pull to the right, even on new tyres, and with the wheel correctly installed. At 26000km I am assuming it is on original factory-installed bearings.

I do understand fully (I think) the axle procedures; effectively, one is tightening the axle to pull the axle, spacers, bearing centres and the distance collar between the bearings hard against the right leg, then tightening the clamps for the right and left leg. I understand John Heath's point about the installation order for the bearings, but if I assume they are correct then the final position of the wheel relative to the right leg is actually governed by the length of the right side spacer. Has anyone considered the option of changing this length a little e.g. by grinding the spacer down a touch? As the bike falls to the right I think the wheel needs to be shifted to the right to counteract that.

A new wheel spacer is pretty cheap so any change would be reversible. I would need to confirm that shifting the wheel sideways relative to the forks won't lead to any unforeseen contact e.g. between the disc and the caliper carrier, and the ABS sensor. I'm only thinking of a small change like 0.5 or 1.0mm. Has anyone else tried this?

I've sort of been here before, my VFR800 used to pull to one side a little, and when I replaced the forks with CBR600F4 items, my initial measurements showed the wheel was likely to be something like 0.8mm off-centre when using the original VFR axle. Being brave/foolish (and lacking a CBR axle) I took a cautious test ride, and funnily enough the bike tracked laser-straight and was better than it had ever been. I'm sure those of us with experience of chain-driven bikes have probably also experienced the effects of a misaligned rear wheel which has a very similar effect.

 

[TerryS]

Thanks John, all the parts are sitting as they should, I've had the forks out for some maintenance/changes (oil, shims in dampers and a repaint) and put them back together very carefully. I don't subscribe to the idea that if the forks are raised/lowered slightly relative to each other that that would have a material effect on wheel alignment: they are sliding components locked together by the axle/clamps. I do agree that any twist in the triple clamps needs to be considered and I will make a point of slackening the top nut and lower clamps next time I loosen the forks.

Seems to me there is plenty of evidence that the ST13 has a slight inherent bias to the right, presumably either by design (alignment or mass balance) or oversight, it doesn't affect safety or enjoyment but can be felt as a "not quite right" feeling. I was considering whether I could rectify that.

 

[Capt_Gruuvy]

I would set my throttle lock and just sit off center to ride without hands. The bike straightened out fine.

The 111 through Imperial Valley is dead straight for miles and except to pass the garlic wiggle wagons there's nothing to bother you.

 

[TerryS]

I'm not sure that I do. But it occurred to me that even a slight difference would result in one spring being compressed slightly more than the other, and therefore exerting more force between the steering (upper) part of the forks and the axle (lower) part of the forks. When you consider how very little effort it actually takes at the bar ends to counter-steer...... I don't know - but the idea seems possible to me.

If that were the case, then bikes with adjustable spring preload could be made to drift to one side or the other by differently adjusting the spring tension. There are plenty of examples of bikes with asymmetric forks (either springs, damping or both), but that does not lead to steering issues. Steering neutrality is heavily affected by the bearing, either a dented lower race adding unwanted "self-centering" or excessive bearing friction causing unwanted over-corrections (I've experienced both over the years).

My view is that a tendency to drift to the side is a very slight misalignment of the tyre centrelines back-to-front. This could be due to manufacturing tolerances or assembly (e.g. fork twist). I do like the idea that the wheel bearing installation sequence could play a part here; if the left bearing is driven home fully first, then the right bearing would be sitting proud, and when bolted into place that would cause the wheel assembly to shift to the left and cause the bike to fall to the right. It would probably be a simpler thing for me to get some new bearings installed and see whether that makes a material difference on my 1300, but I will at least relax the top nut and clamp and see what happens.

 

[Larry Fine]

Between the axle and the fender hardware, I'm sure the fork lowers move as a single unit. After all, the one-cartridge and one-damper-rod setup works.

 

[EA6BMECH]

I've only had the front wheel off a few times. But, looking at the part diagram, the spacers are different numbers. I know on the son's CBR600 the spacers are differnt lenghts and can be put in the wrong way. Does anyone know if they are different lengths?? As for the spring tension, I don't think that would play a part. On my 636 I had 2 different springs on either side and it was fine. Now if you had sloppy bearings, I could see that causing an issue. I might investigate the spacers later.

 

[Mellow]

I've only had the front wheel off a few times. But, looking at the part diagram, the spacers are different numbers. I know on the son's CBR600 the spacers are differnt lenghts and can be put in the wrong way. Does anyone know if they are different lengths?? As for the spring tension, I don't think that would play a part. On my 636 I had 2 different springs on either side and it was fine. Now if you had sloppy bearings, I could see that causing an issue. I might investigate the spacers later.

Yes, the left/right front spacers are different lengths.

 

[coolbreez1]

more food for thought; Dave Moss follows much of post #1 ; but adds the seating of the front brake calipers step; final step is pumping the front forks, w/o applying fr brakes, then final step is tightening left fork pinch bolts...…..I know every bike is different,,,,,,,edit--he didn't have a left fork spacer...

 

[EA6BMECH]

Hard to argue with Dave, but my logic says to leave the calipers slack, tighten the axle/bounce it first, then once the axle is correct, bring the calipers into play as he described. IMO, if you do the calipers first, they would somewhat have the wheel captive to they're position instead of a centered wheel. The brake pistons/pads can find they're spot and center themselves. If your pistons are clean and moving well, there shouldn't be any issues......IMO

 

[TerryS]

As I was ordering some bits from Partzilla, I added the front axle distance collar to my order. I received this last week and measured it, then proceeded to take 0.3mm off using a hand file, then I installed the spacer in my bike. I checked that I had not created any clearance issues with the brakes or fork (nope, plenty of room). Yesterday was my first ride, and the difference was apparent, the bike no longer pulls as hard to the right and only needed gentle knee pressure to keep straight. I have decided that I will take another 0.2mm off and try again.

I can imagine a scenario where the wheels on different bikes end up more or less aligned; I assume that like any manufacturing process, there is some allowable tolerance in dimensions and physical alignment as parts are welded or machined. Within the main frame there could be some variance between the swingarm and head bearings and how perpendicular those two axes are, and within the swingarm some variation between the alignment of the pivot and wheel axes, before we get on to the matter of the front wheel bearing or even the machining of the wheel bearing seats. I imagine it is entirely possible for two consecutive bikes from the same production batch to end up with their wheels either more or less aligned, and with more or less of a tendency to pull to one side or not, depending on how these expected variations accumulate or cancel out.

 

[TerryS]

You are correct that I mis-labelled the part, it was indeed the spacer that sits between the right fork leg and the wheel bearing. Sorry for any confusion.
COLLAR, R. FR. WHEEL SIDE
44311-MCS-G00

My bike only had 26000km when I bought it and I am making the assumption that it was on original wheel bearings and I haven't touched those.

By design, when you tighten the axle nut, you are pulling the axle in against the left spacer, left bearing, distance collar, right bearing, right spacer and finally the right fork leg; the left fork leg is free to move on the axle until the left axle clamp is tightened, and to be honest I don't pay any attention to the actual position of the left fork on the axle, so long as the fork has found it's natural resting position to avoid any binding. The position of the wheel in the forks is dictated by the right collar sandwiched between the fork leg and right bearing inner. By making the right collar a little smaller, I am just moving the wheel slightly to the right with respect to the rest of the fork.

I have had some prior experience of this with my previous VFR800, which had a gentle pull to the right on original forks. I changed the forks for a cocktail of CBR600F4 forks and VFR800 6th gen triples; when I did a dry assembly and measure, I determined that the wheel was sitting 0.8mm closer to the right in the new forks than the old, when using the standard VFR800 wheel and spacers. Before splashing out for the "correct" spacers I thought I would at least try the combination as-is, and was pleasantly surprised when the bike tracked much straighter than it previously had.

 

[TerryS]

Thanks for your thoughts John. I confess I hadn't looked closely at the sensor gap for the ABS until now (although I had checked for free rotation). The gap with the smaller right spacer was 0.65mm, so within the manual's spec of 0.4 to 1.2mm. Interesting that Honda allow for that variation, that does suggest some expected variation in the wheel position relative to the sensor. I have now reduced the spacer to 27.10mm (from 27.55 originally) and the ABS sensor gap is still within clearance spec. It will be interesting to ride again in the weekend if the weather is half decent (mid winter here).

 

[EA6BMECH]

One of the things I want to throw in here is, does this happen more with ABS models?? Mine is ABS, but my 3 other buddies aren't. Their bikes track straight.

 

[Mellow]

One of the things I want to throw in here is, does this happen more with ABS models?? Mine is ABS, but my 3 other buddies aren't. Their bikes track straight.

Nope... zero impact..

 

[BakerBoy]

One of the things I want to throw in here is, does this happen more with ABS models?? Mine is ABS, but my 3 other buddies aren't. Their bikes track straight.

More likely, they've more gear/tools in their left sidecase. That causes the bike to be more balanced. All heavy stuff in the left case was my trick to have mine track straight. Others have reported the same.

 

[Jambriwal]

Tried this by the Aprilla mechanic
We'll see how it works.
Won't find out till march
Going to Daytona
Only 550 miles on my 2016 and noticed slight pull to the right.
Also loosening things up some bolts were to tight, some seemed to loose. Tried to torque everything the same.

 

[mjc506]

I think I know the answer to this, but...

My 13 pulls to the right (only really notice it hands off), and I've run through 'the process' a few times with little effect. I do notice that with the front wheel in the air, it turns to the left - not all the way to the stop, but a very definite turn. Seems to be (one of?) the various hoses and harnesses pulling to that position.

Anyone else's the same? (Probably not)

 

[woodybelle]

Maybe you could try Igofar's method of checking fork alignment. Remove the front wheel and try sliding the axle through both fork legs. It should go perfectly through both side with no misalignment. If it is off he has a method to get it in alignment but I do not remember the process but it is here somewhere in the forum.

 

[mjc506]

Good shout, but I already aligned the axle a little while ago. I double checked this morning, but it's still aligned so nothing's moved.

Thanks also to Igofar who PM'd me

I get about an ounce of force on the bar end pulling the wheel left, throughout the most of range of steering motion. Enough to result in a noticeable 'pulls to the right' if riding hands off, but too much to be accounted for by the small additional weight from the SMC I think.

I'm suspecting hose routing at the moment, will have a look this afternoon hopefully. Assuming that it's not by design of course

 

[Team2010]

My 13 pulls to the right (only really notice it hands off), and I've run through 'the process' a few times with little effect.

Just a thought : I have gone through the 'process' , with good (if not perfect) success. I found my hands would not land on the handle bar grips in the same position (different arm length?). The bike pulled slightly to the right. Once I installed HeliBars with a center ball mount and moved the GPS from the master cylinder ball mount, the pull to the right diminished considerably. I think the GPS may have caught the wind, causing the 'pull' to the right (causing counter steering?). My hands now fall on the grips more evenly.

( I just bled the clutch and need to top off the MC.)