Scooterotica

Recently re jetted my carb on my TV bought new needle and needle jet Checked the old needle for wear, it was worn by nearly 0.02mm at the point where it should have measured 1.5mm and at the point where it should measure2.45mm it was 2.40..... Showing the wear that has impeded performance.... The new needle and my old stock New needles were at hand so I checked these as well prior to fitting one...The dimensions prior to fitting were not identical, which they should be as they are both K 5 needles new and unused... There is a 0.01mm difference at the end point one being 1.5mm the other being 1.49mm this would make a differance to the scooter, only slight but maybe its worth checking these parts prior to fitting as maybe more are incorrect and by a bigger margin.... Needle jets that these Needles run in, are only 0.01mm differance between sizes... So its the equal, at some throttle openings to an upjet... Just thought I would mention this incase anyone has replaced a needle with the same size and then had unexpected results.... I know raising or lowering the needle would compensate for this but you might not know and just run as is...

Just re-checked all measurements and ammended.... is right now..!!

Needles wearing out was not something that had really occurred to me until I was chatting to someone at Lincoln about the same thing.

Clearly running open mouthed carbs will not help, but are there any sort of guidelines as to when you should think about replacing them?

I had previously replaced the needle Jet a DQ265 which wore a little after about 8,000 miles. I then fitted another new needle jet after only about 4,000 more....(this was when I did a rebuild with new rings seals bearings and changed the crank just in case) so I thought maybe somthing else was wearing and as the scooter has always run with a filter the slide still looks new I checked the needle....I think the carbs only being mounted by the carb rubber adds to the vibration which causes accelerated wear and as the only thing that can cause this wear through use and vibration is the needle, I thought it may also have worn a bit.... But I was surprised by how much.... The performance, power wise was only a little down but a little boggy at tick over.... But the miles per gallon was down to just over 35... Having previously managed a best of nearer to 55mpg when first built in 2001... So to date 3 needle jets and 2 needles all within 13,000 miles on a Dellorto VHSA 32mm

Interesting. Almost seems a good idea to change them regardless every 7 or 8000 thousand miles. I believe the brass can also become pitted which can't be seen by the naked eye, but which does effect performance.

Slides too. With old SH dell'ortos and their plastic slides it was easy to tell when they needed replacing ie. when they became about 1/3 shiney. I run Keihins at the moment. Their chrome slides are pretty hard to tell when they are worn (and frighteningly expensive to replace).

Ah well, at it to the last of things that can and will go wrong eventually