Technical Flywheel weight(s)

[Bleeding Knuckles]

Greetings,
can any of the guru's out there tell me the individual weights of the following
flywheels -

500
126 1st series (600cc)
126 2nd series (650cc)
126 BIS

Am I right in thinking that they are all interchangeable????

Ian.

 

[Alfons1972]

hello,
I hope those weights are correct:

500 ---> about 5.9kg
126 earlyer ---> about 7.5 up to 7.7kg
126 later ---> about 6.5kg (but do not know from when on...)
126 BIS ---> completely different because of the "lying" cilinders...

the flywheels of the 126s differ from those of the 500s in the width of the flywheel too...

 

[Damon500]

Hi Ian,
I have been down this route with my Giardiniera although can't help with weights on the vertical engine flywheels they will all interchange from 500F onwards.

However there is an exception of the 126 Bis which is differently balanced for the horizontal engine and will cause serious vibration issues if used in a vertical motor- it is also by far the heaviest- I had one in my Giardiniera (650cc) and ended up swapping it for a rebalanced 500F flywheel to get better standing acceleration and throttle response, it was definitely smoother with the heavier flywheel though.

 

[Toshi 975]

I am running 500 flywheels in both my engines as it was an easy way to lighten without being too extreme. However I am looking at trying a 2.8 kgs flywheel on a 795 engine which will need balancing I think. I have a mate who has done quite a lot in this field and he told me recently that the crankshaft goes out of balance by 60grams when full of oil so something to be taken into consideration.

 

[Bleeding Knuckles]

Greetings,

Thanks for the replies - appreciated, looks like I may obtain a 500 item to reduce the weight or get a modified (lighter) one. will check on cost and get back.

Ian.

 

[the hobbler]

Hi Ian;
Sorry for the slow response to your question---had to go to the wedding of the son of a friend of Ann down in Beaconsfield (aargh!!). I have a standard Fiat 500 flywheel on my (tuned) 652cc engine---I wouldn't go much lighter on an engine to be used primarily on the road. Yes, a lighter flywheel will allow the engine to 'pick-up' quicker, but you can also run into balance problems--a bit of mass is required to help balance out the inherent imbalance of a vertical twin with both the pistons going up/down together.

 

[AndrewHarvey]

I have a balanced and lightened 500 reduced to 4kg