Hi all Newbie alert! Just bought my 1st vfr 800, I'm very pleased with it but there seems to be a cold running issue. The bike starts ok and pulls well up to about 4500 revs, after that it's dog rough, missing and hesitating, as the engine warms up the symptoms improve, at normal temp it runs fine. It feels like there's not enough choke. Has anyone experienced this or can offer some advice. Great site btw, I've already learnt a lot, I do all my own servicing and repairs, hopefully when I've got to know my bike a bit better I'll be able to offer help too Thanks
Any mods on the bike? I'd always suspect those first. How many miles? I assume you've checked oil, coolant and noted engine temps when on the road, should be under 225ish. Was the bike running like this when you test drove it?
Tested the bike from warm so i didnt notice any problems, bike is all in standard trim, regularly serviced, 18k miles on clock, all fluids are ok, temp is normal. Ive given it some more thought, is there a sensor that tells the ecu to run in "choke" mode, could this be the problem, if so where is it ......any ideas?
you answered your own question, mike, so check the temp sensor, etc. and read the service manual to answer all your other questions......
The '00 has a automatic choke ( Fast Idle Wax Unit ) unit instead of the manual fast idle lever my '99 has, when first started what rev's when idling ?
Fast idle is working ok tho it settles to normal tickover a bit too quickly (compared to my mates blackbird) so I think that might need a bit of tweaking too. I'm going to check the coolant sensor and the air intake temp sensor to see if they are withing specifications. I will post my findings when this is done, I'm feeling confident about it being one of those that's the culprit.
Had the same issue on my 2000. Checked into the suggestions listed above but it turned out to be a left front cylinder pick-up which was dirty and likely sending lousy info to the ECU. Appeared as though the left front may allow for more dirt than the others. Cleaned it up, reconnected, and haven't had the issue since. If that fails you may also want to check the throttle position sensor. Hope this helps!
