Ok guys. Done lots lots of things, but the stutters problem still happens.
What I've already done:- disassembling, dismantling carbs, cleaning with detergent and blowing with compressor, put them back, then synchronized, caps (for synchro) are in place. Inlet rubbers are fine, diaphragms are fine, and moving without problems;
I've set the idle screws 2,25 turns out.
- replaced spark plugs, spark caps, bought brand new HT coils (chinese one), replaced the ECU, replaced the alternator and pick-up coil,
- measured the resistance of TPS and adjusted it, so it's on 5K rpm,
- replaced the fuel with a new one, also added some isopropyl additive (to make sure there is no water),
- sprayed all connectors, plugs, near the ECU, the alternator and pick-up coil plugs and all plugs in the compartment just under the fuel tank with the electric cleaner:
http://www.halfords.com/webapp/wcs/stores/servlet/product_storeId_10001_catalogId_10151_productId_195717_langId_-1_categoryId_255223- checked if choke cable it's not too tight (and choke it's not enabled as a result)
- checked and cleaned the air filter,
- bypassed the fuel filter and fuel pump to test whether bike works better (no effect at all)
The problem in short:- When very cold, bike starts, on idle it runs like on 2-3 cylinders. Adding gas more than 1/10th results in bike starts stuttering. Adding full gas at this moment means that you won't hear any engine noise except the throttle: 'buuuuuu'. Reaching 30mph means really smart throttle play, if not your engine will die.
When you push a throttle very little like 1/20th or sth, there is chance that you will hear proper engine noise and bike running on 4 cylinders, but if you try to add more... unfortunately dies.
- When warmer (after about 1 mile), bike still runs on less than 3 cylinders, but the difference is that adding full gas don't kill it, it makes bike stutters and backfiring for 2 sec, then it accelerates with about 20-30% of it's power.
- When warm (after about 5 miles), same as above, but have somewhere around the 50% of power, also sometimes you can feel the vibrations like the only 1 cylinder does not work.
- Still warm (after about 10 miles). Bike most likely runs on 3 cylinders, but when you hit the gas carefully (not more than half) then you can hear sometimes 4 cylinders running. Sudden accelerations cause the backfire, struggling for a sec then accelerating with sometimes full power, sometimes somewhere around 70-80%.
- Still warm (after about 20 miles). Bike basically works on 4 cylinders (in the mid and high range). Idle is always like 3 cylinders running. Rare situation when it struggles to accelerate, most likely it means that you've suddenly pushed throttle from low range.
Some notes:- Adding choke when bike stutters makes thing better, you can add little bit more gas, and skyrocket your speed (in the first stage of stutters) from 30mph to insane 40mph,
- Bike was not used for about 2 weeks and was under cover, but noticed that there is some water around the 3rd cylinder (the cylinder that's exhaust little bit colder when bike starts),
- My method of detecting how many cylinders are running it's just noise from the exhaust combined with the vibrations that you can feel on handle bar,
- When bike stays for about week, when turning on the ignition fuel pump clicks very fast for around 2-3 sec (fuel evaporates?)
Guys do you have any ideas what could be wrong?
1. Is it something to check in the ignition system except the things I've mentioned?
2. Why my bike needs as much as about 20 miles to start running in a not acceptable, but rideable level?
3. The problem seems to affect all cylinders as I can feel when bike runs on 2 cylinders, 3 and 4.
4. What else can I check?
5. Anyone knows a good garage in the Trowbridge, Bath area?