nelly1 Posted June 23, 2013 Report Share Posted June 23, 2013 just bought one in decent condition just a few questions why the plastic tube over the chain can i bin this and use a tensioner i have seen one on in motion site are the swingarm bushes easy to do mine are shot also rear wheel bearings anything unusual or just knock out type oil change ? two different types what amount and what type thanks for your help neil Quote Link to comment Share on other sites More sharing options...
cleanorbust Posted June 23, 2013 Report Share Posted June 23, 2013 The plastic tubes were an innovation on a production bike when the 348 appeared. They formed a neat set-up which acted as tensioner as well as protection for (and from) the chain and worked pretty well although the popular mod was to cut the bottom tube ahead of the rear sprocket to avoid fouling. The bushes between the tube brackets and the alloy holder at the rear wheel could wear so the whole set-up became a bit sloppy. Also the tubes make chain replacement a more fiddly job, threading the chain through each one. I used to tie a piece of string to the end of the chain before removing it so it could be pulled back through the tube fairly easily. I know the tubes are still available from In-Motion but not sure about brackets or bushes. A conventional tensioner is an option some have used but you'd need to weld a mounting bracket on the swinging arm and preferably rig up a chain guard on the top run if you're doing away with the tubes altogether.The majority of 348s I have seen which are still running seem to have had the tubes ditched but no tensioner fitted, which obviously leads to a rather snatchy power delivery and more stress on the chain. Quote Link to comment Share on other sites More sharing options...
dadof2 Posted June 23, 2013 Report Share Posted June 23, 2013 (edited) I had a couple of 348s, one for 8 years. I like the chain tubes as especially combined with a drip chain oiler the chain and sprocket life is near indefinite. Gearbox oil is EP90 and I think it is 600cc but double check that if you can. Primary drive oil is 10w 30 castrolite but I used to use universal tractor oil with no problems. Capacity 300 to 350cc, but double check this if you can Wheel bearings usual type Swing are bearings are bronze bushes and can take a bit of pushing out. Edited June 23, 2013 by dadof2 Quote Link to comment Share on other sites More sharing options...
nelly1 Posted June 23, 2013 Author Report Share Posted June 23, 2013 thankyou both for the info Quote Link to comment Share on other sites More sharing options...
toofasttim Posted June 24, 2013 Report Share Posted June 24, 2013 I know the tubes are still available from In-Motion but not sure about brackets or bushes. The bracket is available: http://www.inmotiontrials.com/product/montesa-cota-chain-tube-alloy-bracket/ Quote Link to comment Share on other sites More sharing options...
bigshineybike Posted July 8, 2013 Report Share Posted July 8, 2013 Even rotten tubes seem to sell for a lot on ebay so do not chuck them away. Quote Link to comment Share on other sites More sharing options...
sparkieb Posted February 8, 2020 Report Share Posted February 8, 2020 Just re-fitting mine and have no idea if anything goes at the gearbox sprocket end of the tubes, there are little arms with a couple of holes in !! Quote Link to comment Share on other sites More sharing options...
turbofurball Posted February 8, 2020 Report Share Posted February 8, 2020 According to the parts list for the 348 there's nothing on the front of the tubes 1 Quote Link to comment Share on other sites More sharing options...
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