richierich Posted July 23, 2016 Report Share Posted July 23, 2016 Hi all privileged 4RT owners! :0) I have an 06 4RT (Repsol) which I bought about 14 months ago to see if I took to 4 strokes; I did and love it. I compete most weekends and the bike is rarely ridden between trials due to work etc and the poor machine is maintained to within an inch of it's life. I enjoy working on bikes as much as I enjoy riding them and the Montesa is an absolute pleasure to fettle with. My last trial was 2 weeks ago and towards the end of the last lap I noticed a noise, which had manifested the previous weekend, which was becoming "noticeable". After cleaning the bike off at home and restarting to try and trace the "noise" with a big screwdriver hearing aid, I found it to be coming from the cam chain side low down. Assuming it to be a worn cam chain and guides I prepared to order the parts and look forward to a big strip down. However, having chased my parts order on Friday which had not arrived nearly 2 weeks later, I found that due to a "system blip" the order had not yet been processed so I asked them to hold fire on the order as I had a free weekend to do some further investigations then get back to them on Monday with a full list of parts required. Having made up the little cam chain tensioner extraction and setting tool, I started to loosen off the tensioner housing (2 bolts) and noticed the whole housing did not seem to be under any pressure. Both bolts were about half way out by now and I pushed the tensioner back in to the cylinder housing with ease, so assumed the cam chain had stretched beyond the limit of the tensioner plunger. It was at this point that I tried out my newly made tool which slipped and suddenly the tensioner was under pressure. Removing the tensioner fully from the bike, I ran the plunger in a few times with a screwdriver and it was fine. There was no build up of contaminants in the assembly but I gave it a clean, refitted it using my beautifully crafted new tool and started her up (1st kick...naturally!). Sorted. No more cam chain noise. I have no idea how it happened but it did and thought I would share in case anyone else experiences similar. One question; do I trust that tensioner or replace with same or a manual one from H&D? 2 Quote Link to comment Share on other sites More sharing options...
2stroke4stroke Posted July 23, 2016 Report Share Posted July 23, 2016 I had the tensioner on mine out recently for similar reasons. For the benefit of others, there is no need to make up a tool. I found that if I wound the plunger in with a screwdriver then held it there by hand I could insert a hexagonal screwdriver bit and lock it on the flutes of the access tube then release it once the tensioner was bolted bsck in place. 2 Quote Link to comment Share on other sites More sharing options...
jonnyc21 Posted July 24, 2016 Report Share Posted July 24, 2016 I think if it was me I would order up new one. I would go with a manual one but even a stock would make me feel better after knowing it wasn't working as expected. I have an 07 and though I wouldn't feel bad about riding it like that with the parts on order I would want to be sure I trusted it long term for events etc. Would rather be safe than sorry. My 2 cents for what its worth. 2 Quote Link to comment Share on other sites More sharing options...
oz thumper Posted July 28, 2016 Report Share Posted July 28, 2016 Thanks for that really interesting information, particularly as there had been a previous post where most advice suggested the tensioner could not be a problem. Just goes to show there is always something new to learn on the forum. 1 Quote Link to comment Share on other sites More sharing options...
BillG Posted July 14, 2021 Report Share Posted July 14, 2021 (edited) Hi Folks, My 2017 4RT started to rattle. I remember this sound from my Honda 400 days as kid ! I took out the centre bolt screwed it tight against the spring then a 'tad" further to lock the tensioner. Took off the tensioner and cleaned in petrol, oiled and reinserted. Released the tensioner (counter clockwise) Fired her up and all sounds good. I'll keep an ear out for it recurring any time soon and if it does I'll replace Let you know how I get on... Edited July 17, 2021 by BillG Update 1 Quote Link to comment Share on other sites More sharing options...
BillG Posted July 17, 2021 Report Share Posted July 17, 2021 (edited) OK the sad news is that one ride in and the rattle is back... After some deliberating over boyhood issues with my Honda 400, I recalled I replaced the tensioner with another Auto version and the problem recurred.... Then I recalled the "coupe de grace" was replacing the Cam Chain Guide too (These wear and the "Slack" is taken up by the Tensioner) So, I'll buy a Manual Tensioner and replace the Guide this Winter..... Decision made ! Edited July 19, 2021 by BillG 1 Quote Link to comment Share on other sites More sharing options...
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