Snatchy throttle at low engine revs

We have 2 of these bikes and both are the same. They have DNA air filters and the CAT's removed from the standard silencers, both now have about 5000 miles on them and are running in nicely with a steady improvement as the miles go on. They are very economical achieving 80 + mpg with Sue getting 98 mpg at one point and perform as expected most of the time however both suffer from this very snatchy running at low engine rpm the throttle almost being an on off switch when you want to run slowly, as soon as load goes on they improve as long as you drop a gear but when doing slow turns or difficult terrain in first and second it's a real pain. The valve clearances were checked at 600 miles and although on the lower limits were within tolerance, oil and filters changed 4 times so far. The engines have always idled erratically on cold start up smoothing out after a few minutes warm up. Hope advise is out there.

 

Interesting. I haven't done any modifications to the air box, filter or Cat and mine is butter smooth. Do you think it could be the filter starving the engine for oxygen? I know on other bikes you can remove the Cat and add a resistor to balance out the fuel/air mixture and keep it running smoothly, maybe that would cause it to run/idle rough?

 

Thanks Mike, The bikes were no different before the mods, when the Cats came out the mid range and mpg improved but the problem was still there, seems funny both bikes are the same. The engines run really well and are very smooth when warmed up but when standing up running at 7-8 mph in second or a little faster in third they hunt on and off the throttle unless load is applied which is very annoying. I thought it would improve with mileage and I guess at only 5000 miles they will need another 3000 odd before they get to their best but this is not changing. We recently did 800 miles in 6 days going to Mull and back with luggage and on the road you hardly ever notice this problem but on slow back roads and off road it is very pronounced, sometimes to the point where you have to tap the clutch lever to settle them down, having always run bigger capacity engines maybe its a lack of cc's and they are normal. I think if we keep them a trip to Aberdeen next spring to put them on Honda's diagnostic devise may be in order.

 

My 16 is the same, I also have a ST1300 V4 engine that is fuel injected it acted the same until I got use to the throttle .at 93,000 miles I don't notice it anymore, but it was a big complaint from most people that went from Carb bikes to FI ones. Some went to a throttle tamer to fix the problem and some went to a differnt fuel pressure regulator both seemed to fix the jerkiness, don't know about the little 250 though.

 

Thanks for your reply Daniel. We have had a number of fuel injected bikes but have never had this problem, I think it may be the small displacement or the fact that it is sports bike derived, it is most pronounced when running off road in low gears where you need smooth torque at low speed. Although we have had great fun with these bikes this problem has been a nuisance coupled with the fact that we need to be able to do a good 300 mile day we have changed them for KTM 690 Enduro's and that seems to have solved the problem. First time for 25 years that I have not had an every day Honda but still have a CB 750 K6 tucked away.

 

/thread moved to tech-tech