How many times have you fought to get a flywheel bearing collar off a Lambretta or Vespa crankshaft and thought ‘There must be an easier way’. Well it turns out, there is…
The Universe Provides
Just as I start looking for new tips for the 4th version of The Complete Spanner’s Manual for Lambretta Scooters, I discover a post on Facebook from Paul Slaney showing a method of bearing collar removal that I’d never seen before.
The old ways are the worst ways
There are a few methods of getting off old bearing tracks but none of them are ideal.
- The Lambretta bearing puller tool struggles to grip GP-style flywheel bearing tracks (NU2205) because the chamfer is so small and most of the tools for sale are of poor quality. Very few dealers find success with them
- Grinding through the track or cutting slots into it is a skilled and risky job, and the crank must be taped up to prevent any grinding grit from entering the big end
The KTM tool method
The method in the video is based on the KTM factory tool used for fitting and removing NJ205 bearings; which are used in the Casa Performance CasaCase. The collars (‘tracks’ ‘races’ ‘sleeves’) of these bearings are the same 31.5mm dimension as the NU2205 (Lambretta GP) and NU205 (Lambretta LI/SX and Vespa T5/GS160/SS180 and Femsa Rally 200), so this tool works for those models as well.
The tool works by providing localised heat. Simply heat the main part of the tool to over 125C clamp it onto the collar and after a few seconds, it should expand enough to pull the collar off. During our testing, the success rate was higher with higher temperatures up to 190C.
Success Rate
We successfully removed three out of four collars with this method. One on the GT crank remains firmly stuck and will need to be ground off.
The trick to it is that you get a short window of opportunity where the ring expands sufficiently to remove it. If you leave it too long then heat transfers to the crankshaft and it all locks again.
This tool is better for the removal of collars than fitting. If you use it for fitting then keep the temperature below 125 Celsius.
Can I fit it?
Yes you can. This method may be employed to heat and fit a bearing collar to a crank but I don’t recommend it. If you heat much beyond 125C then you can affect the hardness of the bearing. As such I think the optimum method is to heat to 100C in oil and fit, or alternatively, just tap the collar onto the crank with a drift as most people do.
Where Can I get This Tool?
Although it originates in America, SLUK are stocking them. The tool costs £36.50 and is available here.
Tell me about Spanner’s Manual #4
Why, certainly. The plan is to get this ready for 2025 and to update and add to the tips compendium that Lambretta riders and builders have always found so useful. The current version is still available here and you can also buy the Complete Spanner’s Lambretta Kit book here.
