xt600e rear linkage rebuild
 

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.
:rolleyes2:


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

http://vardzelashvili.com/imghost/images/590021.jpg

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

http://vardzelashvili.com/imghost/images/881552.jpg


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.

:smile2:

:)

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

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 :)

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.

:)

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.

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..

I dont know how many 100k km you ride on this bike but lets ask Jens how many times he needed change of these in what 150k km?

I'm just over 170.000km :innocent:

I think i replaced mine 2 times. 1st time was the linkage only, 2nd time was because the swingarmbearings got bad, and when I was already working, i replaced the linkagebearings aswell.

2nd time I did it, I installed greasezerks in all the linkages and swingarm. Some where missing and regular bolts was installed instead by the PO, and some not present from the factory (swingarm) I've since ridden 80.000km

After that the only maintenance was to give them a pump or 2 with the greasegun once in a while

I've just replaced the swingarm with a nice one from ebay, because it was cheaper than getting my current one blasted and painted, so I gave the "new" swingarm some new bearings, but the linkage was still fine.

The bike is used during winter, it has been stuck in mud/water up to the seat in more than one occasion.

So as I said earlier, i wouldnt bother to re-design the parts.

Well, few updates after a while.
: )
I had to postpone the idea of changing sleeves into the bearings, as I had lots of a trouble getting bearings with proper size and quality.

on the other hand, I had this plan to vanish any free play around the rear swingarm.

so, I found a good turner to cut new sleeves (3 pcs) and bolts, including shocker bolts (5pcs) from W1-7 / CT80 grade carbon tool steel. lube channels were also made as well as thermal treatment.
seems that they gonna last quite a while :mchappy:

I didn't touch the old bearing, which was in good shape.
by the way, if anyone will have to change this thing, this is exact name and type of the bearing:
NTN fs 7e-hvs 17x24x25-1

I've found this on ebay, seems that different brand, but the same size: Nadellager 7E-HVS17X24X25-1#01 7E-HVS17X24X25-1#01 NEEDLE BEARING NEU | eBay

despite of all of this effort, I still consider changing all sleeves with bearings as a possible future plan.
the worn condition of the old sleeves and bolts (I'll post some photos later) in contrast with good working condition of the bearing makes one more proof for this idea; as a longterm solution, if linkage needs some attention other than lube.

and that's how a worn pin and sleeve look:
http://vardzelashvili.com/imghost/images/67061sl.png
:9898:
and there was no lube option for the pin, which connects linkage and shocker.

I also upgraded this pin to bolt and nut, where the thread runouts before the shocker mount.

by the way, for lubing the linkage i used lithium molybdenum grease for it's water resistant properties. any better idea about it?

I use waterproff grease, belray or simular. It about impossible to dillute and/or remove with water. Its really good for this stuff.

Some things I've done with linkage pins is drill an 1/8"(3-4mm) hole from the hex end usually at least halfway the length of pin and then a 1/16"(2mm) cross hole and tap the end for a grease zerk. Then I can squirt grease as often as I want to the pins and bushings , greatly reduces wear and makes sure all areas are lubed good.

I like a high moly content grease as well .

Well, condition "ok" makes me to postpone this plan till the next winter.

Although, as it seems after completing other scheduled services I might have some spare time before I will be able to start riding again.

For such opportunity I've decided to think about kinda "intermediate" update of the rear linkage system - using bronze sleeves instead of current steel ones.

The idea about bronze came from it's friction resistant properties.
I was aware that bronze is used in some bearings, and how about as a sleeve in linkages?
Do I need some particular alloy or degree of this metal?
Has anyone tried something like that?
What about pros/cons?

So far, I'm thinking about one possible drawback - the future of the mating surfaces - well, if bronze is stronger, even in the case proper lubrication will it cause more than a normal wear on pin or linkage body? ..

So, quite a silence, huh?
Do I have to think that the stuff I'm asking is either very wacky or very obvious? :)

traffic is a bit slow these days here, bikes are in deep winter sleep ;)

many older bikes came with main swingarm bronze bushings (like british bikes and old honda sohc4's), if lubricated works ok, if not will wear out, hopefully without damaging shaft. looks like you have enough wall thickness to do them in bronze easily

I'm currently doing a lot of bearings and chain sliders with Ertalon 4.6 (POLYAMIDE [PA 46] - it can run dry even... never tried it for suspension bushings but might do one day.

Hippe PA 46 Nylon 46