RM 400T swingarm

[maxi81]

I recently replaced the thrust washers and the dust covers on the swingarm. I looked the parts diagram on the alpha sports  and got the parts from suzuki. I noticed when I put the swingarm back on there is a gap betwen the dust cover and the frame. Its like there needs to be another washer either side to close the gap. Have I missed something?

[LWC82PE]

How big is the gap?

[maxi81]

Maybe 3-5mm.

[LWC82PE]

3mm is typical suzuki sloppy tolerances, i have seen it before, 1.5mm each side is non unheard of, 5mm i think is a lot to ask to clamp up to. Personally i aim for less than .5mm fitting clearance each side, for custom apps anyway. I would check the length of the inner spacer tubes. I suspect they are worn but they are a hard item and i would not expect mm of wear off those either..... Was this swingarm all loose and sloppy when you got the bike? If it had been neglected maybe the sides of the frame have worn a bit?. Also check the press in bushes in the swingarm. Flange should be 3mm thick on those. I have seen horrible stuff. I was recently sold a swingarm that has been in use and the needle bearings and pivot tube were trashed. Totally dry and rusted Never seen grease since 1978 it looked like, with deep roller marks on the tube. And people ride around like this

[Oldfart]

Have you got thrust washers insde of dust deals ...if dust seals are replaced you need to do the shims also.
Common mistake
1mm would be acceptable , anything more and l would be looking at whats not right.l

[maxi81]

The bike was my dad's and he bought it brand new. I have been slowly restoring it over the past 6 years. I suspect that the swingarm bearing/bushes etc are still original so I will get those all replaced and see how it looks then. Anyone recommend anyone in Brisbane to replace swingarm bearings?

Thanks for the replies.

[John Smith]

Sorry to deviate off topic a bit but still swing arm related. Has anyone had experience in welding an 81 (or similar vintage) swing arm up near the front bushing area? Looking at it from side on its cracked across the outer surface facing the engine where the front bushes go in.

Any suggestions ?

Thanks
JS

[rocketfrog]

Yes the suzuki swinger extrusions split at the front facing the engine in the thin area of the extrusion.

Can be welded and line bored. I think I recall reading in VMX mag that Anthony Gunter had this prob with the RM400N he restored and I have also found the same issue on PE250/400 T.

Definitely a known prob and can be fixed by competent skilled welder/machinist.

[John Smith]

Thanks rocketfrog and excuse my ignorance but what is line boring? Do you mean having the centres re drilled/bored after the welding process?

Cheers
JS

[tony27]

Lineboring is where something is clamped down & all holes that are in line with each other a bored to size in 1 pass, it makes sure that there is no misalignment. Commonly used in crankcase which are then marked as a pair, over head cam cylinder heads as 2 examples

[KTM47]

With CNC machine centres the same thing can be done with them, using a rotary table or if the cutter head rotates.  What is probably better than welding up the original pivot tube is cutting it out and getting a new larger diameter one weld in and then machined.  That way you could also investigate roller bearings instead of bronze bushes.

[John Smith]

Thanks guys.

[LWC82PE]

They use needle roller bearings as standard fitment already.

[Tomas]

With CNC machine centres the same thing can be done with them, using a rotary table or if the cutter head rotates.  What is probably better than welding up the original pivot tube is cutting it out and getting a new larger diameter one weld in and then machined.  That way you could also investigate roller bearings instead of bronze bushes.

This maybe a silly qestion but do you have to reheatreat the swing arm after a major repair like this? I had one for rm 125 repaired. Just one weld(about 50mm long) was worn off by dropped chain and I am allways bit worried that the swing arm may break where it was repaired since it was not heat treated after repair. The weld was done profesionaly(TIG) and is probably beter than original MIG weld.

[Davey Crocket]

We repair them by cutting off the old tubing and welding a bigger new one in place. Welding the old one never seems to last and distorts the bearing hole.