northumbrian Posted July 3, 2018 Report Share Posted July 3, 2018 Hi, in need of a little help, have sourced a 2nd hand ( new) 4rt front pipe ( without the cat) what do I do with the 02 sensor connection? 1 dealer told me just to disconnect and lose the wire and it would be ok ??? another knew what to do, but wouldn’t tell me, because I didn’t buy the pipe of them !..... great eh?.... they did tell me tank and air box needed to come off , but wouldn’t tell me anymore..... help please..........cheers Quote Link to comment Share on other sites More sharing options...
section swept Posted July 4, 2018 Report Share Posted July 4, 2018 15 hours ago, northumbrian said: Hi, in need of a little help, have sourced a 2nd hand ( new) 4rt front pipe ( without the cat) what do I do with the 02 sensor connection? 1 dealer told me just to disconnect and lose the wire and it would be ok ??? another knew what to do, but wouldn’t tell me, because I didn’t buy the pipe of them !..... great eh?.... they did tell me tank and air box needed to come off , but wouldn’t tell me anymore..... help please..........cheers It’s only the profit that makes things expensive, but that’s what keeps businesses going? It’s the same in most trades but some are helpful but others have manufacturers warranty and disclosure restraints imposed by their agreements. You’ll get all the help on this site though? Quote Link to comment Share on other sites More sharing options...
jonnyc21 Posted July 4, 2018 Report Share Posted July 4, 2018 20 hours ago, Nebulous said: http://inside.hondamc.com/upload/techdoc/Microdata PDF/COTA/Kit Full Power Cota 4RT 260 (YM14-Eng).pdf This link may help possibly. They remove restrictors in the inlet , in order to exploit the new un-restricted manifold. This would necessitate tank , injector and airbox removal. Remove cable , raise idle rpm back to 1,800. Enjoy. Check there is at least a 5mm gap between throttle-body and exhaust before re-assembly. edit- possibly there might not be restrictors in the uk inlets. But if there are , then it is likely that you would need a remap to achieve any true linear power benefits from your exploits. The step of disconnecting the white/green wire on pages 5 and 6 causes the ECU to use a different map to allow for the extra fuel needed. 1 Quote Link to comment Share on other sites More sharing options...
northumbrian Posted July 4, 2018 Author Report Share Posted July 4, 2018 Thank all for the info...... much appreciated ? Quote Link to comment Share on other sites More sharing options...
northumbrian Posted July 4, 2018 Author Report Share Posted July 4, 2018 Ok guys, on letting your info digest...... 1) the full power mods allow more air, ( lid mod).........more fuel white / green wire mod and the removal of the restrictor washer........then exhaust mods to get complete the flow improvements.......got it. what happens if I just want to change the front pipe to get rid of that horrible looking CAT, and not perform the remaining power up mods as above...... 2) can I fit front pipe and just disconnect the 02 sensor ( reading about 02 sensors tells me they do very little, only trying to optimse the fuel / air ratio which allows the CAT to be most effective thanks again guys !! Quote Link to comment Share on other sites More sharing options...
jonnyc21 Posted July 5, 2018 Report Share Posted July 5, 2018 (edited) Hard to say for sure but if I was going to try it I would not do the wire mod to prevent running the high fuel map. I simple terms your risk when not doing the full switch is if you run to rich or to lean. I would think it would run a bit rich maybe (best guess) and be ok... but I could be very wrong. Edited July 5, 2018 by jonnyc21 Quote Link to comment Share on other sites More sharing options...
section swept Posted July 5, 2018 Report Share Posted July 5, 2018 (edited) 11 hours ago, Nebulous said: If removing the O2 sensor cable switches the map in the ecu to a different mode - then it will “guess” the mixture needed across the rev-range from pre-programmed data - rather than O2-sensor feedback. The ECU is now relying on air-temp sensors and flow/mass readings to address injector pulse-width. All perfectly ok. Leaving restrictions in the inlet , and removing them from the manifold - will not change the ecu’s ability to present a workable mixture to the combustion. So no damage will ensue. Best to come back later , and tell us what your “seat of the pants” dyno tells you - after riding the bike with the new pipe. But you may find the difference is small , the exhaust-note richer/deeper/sexier/barkier whatever - and the placebo effect of that gives you the feeling of a meatier bike under you. Money well spent then! O2 disconnect and ecu will not be able to match output to input and vic versa. Dump the cat but keep the O2 sensor that’s what a lot of tuners use to keep exhaust gas at optimum. ?♂️? Edited July 5, 2018 by section swept Spelling Quote Link to comment Share on other sites More sharing options...
northumbrian Posted July 6, 2018 Author Report Share Posted July 6, 2018 Well got round to changing the front pipe on the 4 ride. so, tie wrapped the 02 sensor out of the way, and it fired up .... 1) engine management light cleared as normal, 2) when warm rick over as before ( seat of the pants tachometer) 3 no noisier than before 4) Runs clean through the Rev tprange, and pick up does seem a bit sharper ( might be my imagination, but front wheel does seem to lift easier) 5) and best of all that horrible looking (and heaviy) CAT is gone! thanks again guys for all your support on this one ? Quote Link to comment Share on other sites More sharing options...
Srenwick Posted December 19, 2019 Report Share Posted December 19, 2019 Is that De Cat pipe still going OK? I'm just considering it myself. Also in Rothbury. Quote Link to comment Share on other sites More sharing options...
riffraffretro Posted January 27, 2020 Report Share Posted January 27, 2020 (edited) Has anyone carried out this de-cat/power-up conversion on a standard 4-Ride? http://inside.hondamc.com/upload/techdoc/Microdata PDF/COTA/Kit Full Power Cota 4RT 260 (YM14-Eng).pdf Any recommendations for exhaust headers, or other parts? Thanks in advance. Edited January 27, 2020 by riffraffretro Quote Link to comment Share on other sites More sharing options...
woody1970 Posted March 16 Report Share Posted March 16 Just been reading all of your posts & anybody recommend any favourite front pipes ? Also by removing the o2 wire does that affect emissions on the mot ? Thanks Quote Link to comment Share on other sites More sharing options...
lemur Posted March 17 Report Share Posted March 17 My 2017 260 4RT came with all of the parts needed to make it street legal in a civilized country plus all of the parts to make it race ready plus a supplementary instruction manual on how to convert the bike to race ready. It was dirt simple and involved little more than removing parts, replacing parts that were provided. Does it affect the road worthy status, yes of course it does, invariably when you remove pollution equipment you are breaking a federal law. Quote Link to comment Share on other sites More sharing options...
lemur Posted March 17 Report Share Posted March 17 (edited) It is likely a little known fact that Montesa bikes came crated with a whole slew of parts the dealers keep for profit as part of the dealer preparation, the bikes came with 2 different sized rear sprockets plus 2 drive chains in different lengths to fit the sprocket change, 2 header pipes one with cat and one without cat, 1 intake restrictor, 2 exhaust restrictors, plus 2 tail pipes one for street with a smaller opening and one for racing along with 2 pop rivets of the correct size to change the tail piece easy, full set of street lights, horn, steering lock and key, speedometer parts, 2 headlights one with speedometer and lights the other just a small headlight and no speedo, 2 heat shields one for the cat header and one for the straight header. Near as I could tell the dealers keep all the extra parts that come in the crate and charge you for dealer prep, which is very lucrative if they can sell all the extra parts. If you need headers go to a Montesa dealer that has been around for a while, they have the parts. Edited March 17 by lemur mirrors lol it came with mirrors too Quote Link to comment Share on other sites More sharing options...
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