LCGB Forums

I think I have a problem.

But enough of my personal issues, here's a scooter related niggle that maybe someone could help with.

At cruising speed, I get a rhythmic vibration through the bars. It vibrates for less than a second, stops for the same length of time, and then repeats ad infinitum.

I'm sure its getting a bit worse, but there is nothing obvious I can see. Ideas/suggestions gratefully received.

(series 2 LI150, btw)

On a side note, I run an Aventi 225 kit witha 30mm Del Orto as supplied by Mr Moss, with a TSR pipe. It has been dynoed and runs really nice, cruising at 60 is not a struggle (No hills to impede me in the flat lands of Norfolk! ) I am getting about 7.5 miles to a litre, and a lot of spitback (Not much of a problem, just messy). Should I be getting more miles to a litre? My old mate Soullad has a TS1 witha Makuni carb off a jet fighter and seems to get better MPG, and its a bloody rocket ship! I've got a 3.5 litre V6 thats cheaper to run than the scooter!!

sounds like like harmonious vibration Rob where 2 or more things vibrating coincide at certain frequencies. Have you checked the onbvious like engine mounts and headstock bearings?

As for Avanti fuel consumption, mine was about the same and way worse than Range Rover Good idea to check your float height

Its due to go on the ramp in the near future to have a thorough check over. i was curious if anyone else had had similar problems to give me a pointer and save some time, and possibly cash!

Im positive the engine mounts are okay, as it had a bit of a fettle during lockdown (unless they have come loose! )

Headstock bearings will be next port of call then!

robbbee wrote:Its due to go on the ramp in the near future to have a thorough check over. i was curious if anyone else had had similar problems to give me a pointer and save some time, and possibly cash!

Im positive the engine mounts are okay, as it had a bit of a fettle during lockdown (unless they have come loose! )

Headstock bearings will be next port of call then!

Couls also be tyre or whel related, I gused to get it bad on my Marcos at motorway speeds but the problem went away when I had new whels and tires fited. SIP Aloys can deform just bt hiting a pot hole, I just had to change one of mine which had a masive dent in one side but was stil holding presure

coaster wrote:

robbbee wrote:Its due to go on the ramp in the near future to have a thorough check over. i was curious if anyone else had had similar problems to give me a pointer and save some time, and possibly cash!

Im positive the engine mounts are okay, as it had a bit of a fettle during lockdown (unless they have come loose! )

Headstock bearings will be next port of call then!

Couls also be tyre or whel related, I gused to get it bad on my Marcos at motorway speeds but the problem went away when I had new whels and tires fited. SIP Aloys can deform just bt hiting a pot hole, I just had to change one of mine which had a masive dent in one side but was stil holding presure

Good point. I run Conti Twists, and have noticed the tread can 'lift' on those. I've had this on a car. Run your hand around them in one direction and they are smooth, but in the other its like a saw blade. Maybe a new front boot is called for?

I also suggest that you check your wheels. Pressure, tyres & rims.

Regarding the comparison of fuel consumption, a reed valve engine doesn't spit fuel out like a piston ported set up.

One way around that is to fit a reed valve, but I would try an easier cheaper option of fitting an adequate air filter set up. If you can fit a large enough elbow to which you have added an adequate filter, you will not waste all of the spit-back you are suffering & not really suffer any loss in performance.

The down side is that you might have a PH Dell'Orto which tend to flood making hot staring difficult.