xt600e rear linkage rebuild

[N67]

Hi guys
: )
as the weather in Georgia gets shittier and riskier to ride, I've started my wintry improvements and that one seems to be most important:
time after time rear swingarm on my '02 xt has gained quite a free play in almost all links of rear linkage (so far not on the swingarm's bearings).


so I've bought used linkage kit on ebay, but instead of direct replacing, I've decided to improve the "new" one in this way:
all but one links are made with just sleeves and I'd like to replace them with bearings.

I will have to ask you guys some questions about this stuff.
also, if you've done something similar, than sharing your experience would be great.



well, as you see (or just already know without these pics) only in #3 is a bearing and other links are made with sleeves.



as far as I know there's quite similar configuration on all xt's of other years as well.




the reason why I do this is simple - more durability. sleeve or bearing, they obviously depend on lubrication and I suppose, bearings should last much longer.

so my plan is to change sleeves with bearings in the link #2 and #4.
and probably I will also have to change/reshape one or more center axis or outer hole diameter according to the size of the bearing.

and now I start with questions:

1. is there any chance to place a bearing in the link #1 (coilover's end) as well?
2. which will be more durable in the links 2 and 4 - needle roller bearings or couple of ball bearings on the both sides?
3. do I have to stick to the special grade of bearing or any new bearing will anyway be better than sleeve?


that's it so far. I'm gonna update this topic according to the progress as well.

[Jens Eskildsen]

I see no nead for a bearing. Use the greasegun once in a while, and youre golden.

[turboguzzi]

i actually can see the improvement, I have bikes with both solutions and the ones with needle bearing always showed more wear resistance and less need for maintenance, so you have a point IMHO. problem is that you will need to enlarge the holes to install a bearing as it has a larger OD than the bushing and i cant see enough "meat" there to do so, it will weaken the link noticeably.

the only real solution is to design and produce by CNC new aluminum links with more "meat" around the bearings, that's what i did in one of my road race bikes. the play in the links was upsetting my cornering and it also saved quite bit of weight compared to the steel piece.

not rocket science, but not a piece of cake either. best/easiest if you can do the CAD by yourself and have friends in a CNC shop

[N67]

thanks guys
: )


actually yes, I think that all this stuff is worth to the effort.

well, now I've got 2 general options and so far both of them seem to be feasible:

1. using existing linkage and find appropriate OR almost appropriate bearings. about "almost" - outer side of some bearing (especially if there will be coupled ball bearings) could be trimed to fit. also grinding a new center axis with a bit smaller diameter and stronger material might be option as well.

2. CNC. CAD is easier then it might seem - only a distance between links, some (not even all) inner diameters and angle matter. so, precise measurements could be done easily.
a challenge here might be to get proper raw materials. I'm not an expert in this but I think that it should be not pure but some alloy of aluminum. There're few decent CNC shops in Tbilisi and hopefully they will be affordable, in the case if I will have to stick to this option.


I'm gonna dig through the details of the both options and hopefully it won't take a long time.

[turboguzzi]

go with option two... if you are worried about the alluminium strength, oversize it quite bit over the bearing areas. rigidity and strength go up by the power of two, i.e. 140% = 200% stronger.

another option that i tried once was to build a wooden link and then give it to casting. again, oversize by a good 3-4 mm compared to the steel part.

[N67]

Well, as it appears I have to stop thinking about CNC option.

everything is clear about the material - it's duraluminum; maybe the most common and easy to get alloy of aluminum, which is strong enough and there's no need to oversize it.

The main reason is that for cutting such shape normally 5-axis machine is required. it's almost the same as 6-axis machine, intended for cutting spatial shapes.

And the bad thing is that there's none of such CNC machines in the whole Georgia. Sucks but it true.

I tried to figure out how it's possible to simplify the shape to make it feasible to be cut by the existing "flat" machines (and then find a good turner to complete the shape).
but unfortunately as it appears this will cost too much - probably even more than buying brand new linkage. - the thing is that pricing is calculated according CNC working time (not including the material) and for simple machines it takes too much time to cut even plain spatial thing.


So, I'm gonna take my time to find a good way to renovate and improve my existing linkage..