Dickwad Posted March 7, 2012 Share Posted March 7, 2012 Just fitted some slash cut pipes to my 2000 reg. xvs 1100a, it runs fine up to about a 1/4 throttle, but if I open it up, it miss fires, back fires, pops and bangs and flames at the exhaust ends when throttling off, If I run it on choke its fine, any ideas, low back pressure perhaps? Its obviously a fuel problem, anyone know of any tricks to cure this, without re-jetting or reverting back to the stock pipes????? Link to comment Share on other sites More sharing options...
Noise Posted March 7, 2012 Share Posted March 7, 2012 Hey man, i had the exact same problem with my straight through pipes, ran great on chock but when i went to over take or open her up she lost all power popped banged and farted. Sadly you will have to re-jet her, take the spark plugs out and i grantee they will have a whitish powder on them meaning she is running week, take your carbs out and drain them and remove the float chamber covers and see what size main jet you have in there, then go onto wemoto.com and get a few sizes up. For "example" i had 90 main jets in the carbs when i started and my needle valves where set on the 1st notch, i then went up to 122.5 main jets with the needle valves set on the 4th notch, the bike ran better at the bottom end of the rev range but died as i got up to speed (running too rich) so i then down sized the main jets to 105 with the needle valve still on the 4th notch, she now runs like a dream! I also had to play about with the pilot jets, when i took the carbs out i wound them fully closed and then advanced them 2.5 turns, (this was with the 105 main jets) she was a tad lumpy at the bottom end so i then advanced the pilots another 1 turn, problem was then sorted and she is groovy! Like i say this is just an example and it will be trial and error till you get her right, the main jets are only £3 a pop on wemoto so don't panic with the price its just a bit tedious till you get it right. Word of warning tho (you might already know this tho) if you ride the bike with it running either too week or too rich you will fuck the pistons up and this will be a costly re-build so if you do ride it before you do this work take it easy and don't thrash her. Any more help just shout! Link to comment Share on other sites More sharing options...
Shep639 Posted March 8, 2012 Share Posted March 8, 2012 Re-jetting is the only way. A lot of fiddling to get it right. Well worth it. Link to comment Share on other sites More sharing options...
Dickwad Posted March 11, 2012 Author Share Posted March 11, 2012 Thanks for the replies guys, Iv ordered a new main jet (the front one which is a 112.5 will go in the back cylinder) and a new 115 for the front, It was 112.5 front and 110 back, this will increase to 115 front and 112.5 back, It runs fine on tickover and low speed, so i will leave the pilot jet and needle alone, if this fails then i will have to alter them. Im trying to minimise the amount of tampering and hopefully this will be the case, cant do anymore to it until the new jet arrives, my local bike shop has a box full of jets of every size, from 80 to 210 at £2 each, great, except the 115's are missing!. spent a whole Mo-Fo hour going through that box. Link to comment Share on other sites More sharing options...
Noise Posted March 11, 2012 Share Posted March 11, 2012 When you change the main jets over the tick over will change and she may become lumpy at the bottom end. Just take your time. Link to comment Share on other sites More sharing options...
Toutsuite Posted March 11, 2012 Share Posted March 11, 2012 Erm, anybody know why the two carbs don't have identical jet sizes? Just curious, I know next to nothing about mechanical stuff. Link to comment Share on other sites More sharing options...
Shep639 Posted March 11, 2012 Share Posted March 11, 2012 Erm, anybody know why the two carbs don't have identical jet sizes? Just curious, I know next to nothing about mechanical stuff. Cuz the front pot runs cooler than the rear due to air flow. ?? Link to comment Share on other sites More sharing options...
Noise Posted March 12, 2012 Share Posted March 12, 2012 Erm, anybody know why the two carbs don't have identical jet sizes? Just curious, I know next to nothing about mechanical stuff. I have no idea either! lol when i took my old main jets out they where both the same so i replaced them with two identical sizes in both and she runs fine. But im no mechanic and not o fey with the XVS1100 Link to comment Share on other sites More sharing options...
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