Misfire when cold, fine once up to temperature
Posted: Sat Aug 31, 2013 4:17 pm
Hello
My 400 has been sat in the garage for the last couple of months and she has developed a misfire when the engine is cold, it runs on the choke but as soon as I touch the throttle it dies.
When the engine gets some heat into it the misfire seems to go away and I can rev it up no problem, although I haven't ridden it because I'm in the final stages of getting my license. The fuel in it is not that old so I don't think that's the problem and I do get her running every few weeks and get her warmed up so the fan kicks in.
When I bought the bike there was no misfire, I decided to put a new set of plugs in so ordered exactly what was in there, gapped to the guage in the manual and torqued the plugs.
I have had the air filter out, cleaned and re oiled but apart from that I haven't done anything that should cause a misfire or to run rich.
I let the exhaust pipes heat up a little and checked but they all seemed to be hot, although I can't find my infra red thermometer gun at the moment so couldn't tell for sure if one was cooler than the others.
I then removed and checked the plugs again and cylinder 1 is running rich with sooty deposits on the plug but the other 3 cylinders were fine but with a slight bit of wetness to the plugs but they looked clean.
I checked each cylinder for a spark with the corresponding lead and all sparks seem fine.
Ok so it's obvious my problem is with cylinder 1 running too rich, but like I mentioned I haven't changed any settings or touched anything else and when I got the bike there was no misfire.
The only difference is when I got the bike the plugs were finger tight so this could have leaned out the 1st cylinder.
Ok so after a bit of brainstorming and searching the web I have come to the decision I must be having electrical problems, maybe a faulty coil??
The plug caps have seen better days and so have the leads, after a bit of searching around I've come up with a parts list worth £200 as the plug caps are like rocking horse pooh.
I have priced up the stick coil mod, parts from a cbr 600 and they come to £60 so might give that a try.
I'm just worried that won't correct the problem.
Also while I was reading around the forum I noticed somebody mentioned what way round the wires to the coil are and mine are completely opposite to what he wrote, I can't remember exactly off the top of my head but it was something like green to 2+3 red to 1+4, well mine were the exact opposite of what he wrote.
I was wondering if somebody would be good enough to post a picture showing the coils and the order of the leads so I can compare, or at least point me in the write direction
Thanks for reading
My 400 has been sat in the garage for the last couple of months and she has developed a misfire when the engine is cold, it runs on the choke but as soon as I touch the throttle it dies.
When the engine gets some heat into it the misfire seems to go away and I can rev it up no problem, although I haven't ridden it because I'm in the final stages of getting my license. The fuel in it is not that old so I don't think that's the problem and I do get her running every few weeks and get her warmed up so the fan kicks in.
When I bought the bike there was no misfire, I decided to put a new set of plugs in so ordered exactly what was in there, gapped to the guage in the manual and torqued the plugs.
I have had the air filter out, cleaned and re oiled but apart from that I haven't done anything that should cause a misfire or to run rich.
I let the exhaust pipes heat up a little and checked but they all seemed to be hot, although I can't find my infra red thermometer gun at the moment so couldn't tell for sure if one was cooler than the others.
I then removed and checked the plugs again and cylinder 1 is running rich with sooty deposits on the plug but the other 3 cylinders were fine but with a slight bit of wetness to the plugs but they looked clean.
I checked each cylinder for a spark with the corresponding lead and all sparks seem fine.
Ok so it's obvious my problem is with cylinder 1 running too rich, but like I mentioned I haven't changed any settings or touched anything else and when I got the bike there was no misfire.
The only difference is when I got the bike the plugs were finger tight so this could have leaned out the 1st cylinder.
Ok so after a bit of brainstorming and searching the web I have come to the decision I must be having electrical problems, maybe a faulty coil??
The plug caps have seen better days and so have the leads, after a bit of searching around I've come up with a parts list worth £200 as the plug caps are like rocking horse pooh.
I have priced up the stick coil mod, parts from a cbr 600 and they come to £60 so might give that a try.
I'm just worried that won't correct the problem.
Also while I was reading around the forum I noticed somebody mentioned what way round the wires to the coil are and mine are completely opposite to what he wrote, I can't remember exactly off the top of my head but it was something like green to 2+3 red to 1+4, well mine were the exact opposite of what he wrote.
I was wondering if somebody would be good enough to post a picture showing the coils and the order of the leads so I can compare, or at least point me in the write direction
Thanks for reading