ermm ho humm!!!

[Interpol2471]

This may be a silly question and of course I am writing this as a concept and obviously not stating anything other than that as of course I ride well within the legal limits but I had a strange thought the other day.Has anyone experienced or have any ideas on hard acceleration with a pillion two up when hitting the higher gears on an IP2 when passing just over 100mph that the bike appears to gas up and loose a bit of momentum requiring you to back off and then hit the gas again? Please remember this was two up with Krausers fitted, would I be asking too much from the old girl or is this an issue when on full open throttle in top gear?I am very interested in any thoughts on this as the bike runs perfectly, idles and starts really well and the plugs look perfect toasty? When hitting 100mh plus should I have hung on to fourth a bit longer or is this another wonderful foible I have just found

[Malc]

Do they really go that fast then!Well if they do, the 'gassing up' bit is probably correct.The trouble is that if it runs right, ticks over and accelerates cleanly, it is possibly set up a bit rich, ie needle jet slightly lower than standard . This means that it will also run a bit richer at the top end (compounded by the fact that the faster moving air through the venturi loses density while the fuel does not) and gives rise to said problem.To check, raise needle jets by 1 full turn (probably spoiling that nice running a bit) and try same high speed acceleration.Otherwise, hang on until its almost on rev limiter before changing up as this will help.If it was a real problem for everyday riding andweakening spoilt the nice running then another needle could be tried to tune out the problem but from a personal point of view, I would accept its there and try and ride around it.If you let it rev out towards maximum rpm, even though the twistgrip/throttle butterfly may be at max position, the carb slide may not be as it only gives the engine what it wants and consequently may give a slightly weaker mixture. Change up too soon at full throttle and the slide will top out giving the needle max lift and a temporary too rich mixture giving the problem you describe which is cured as you say by throttling off and then opening up again giving chance for carb slide to match engine speed.So next time your doing a track day two up with panniers fitted you can put it to the test.

[Interpol2471]

Malc as usual what you say makes perfect sense and matches exactly what I thought/had, but I hope not to be doing too many track days two up etc. especially with some idiot with his Civic with added dustbin underneath needed to be taught a lesson Tut Tut I think I may tweek the mixture slightly to lean it off but maybe only by a quarter turn to see if there is any difference but I would rather keep the good bottom end than clean up the top end which is obviously not as regularly used And yes in track conditions my IP2 has often seen in excess of 70mph