My own experience of fitting, using and thoughts about the Grosset electric start on a Rapide:-
Well, that may have given you something to think about or at least some targets so you can shoot me down in flames.
- It is not a big deal for an average home mechanic to fit the Grosset starter. Most of it is disassembly and reassembly with new parts in the kit. The only modification that needs some machining is the part of the kickstart ratchet mechanism. There are pictures of two suggested way of doing this in the instructions. The kick start quadrant needs thining a little and this can be done with an angle grinder or a bench grinder. The gear cover modifications can be done with a hacksaw and file to make the cutout for the narrow transfer gearbox and a sander to relieve the inside of the gear cover to create a bit of extra clearance. The battery platform may need a mod to accommodate whatever battery you decide to use. The starter solenoid fits nicely out of the way under the battery platform.
- My engine as I have already mentioned elsewhere has 8:1 pistons and Mk 1 cams. The battery is a Lithium Shorai. The starter turns my engine over without using the valve lifter. If for whatever reason the battery was getting low I see no reason not to use the valve lifter to get the engine spinning first before dropping the lifter lever. Before I fitted the electric start I always held the valve lifter in and released it near the bottom of the swing so the spinning flywheel momentum did the work of getting over the compression. It almost always started first or second kick. I can never understand why people spend time listening to the inlet suck to find the long gap between compressions position and then ease it over compression, at least not on a fairly standard motor. (That might provoke a little feedback in this thread.)
- Regarding the reluctance of some people to use the original valve lifter equipment due to perceived fragility. Mine has been OK, not fallen to pieces or lost one of the little needle rollers and it has done tens of thousands of miles in my hands. How many people actually have personal experience of the standard valve lifter mechanism failing if it has been assembled correctly? (Do we need a poll?)
- Stopping the engine. The sprag clutch doesn't like attempts to make it go backwards as happens if the crankshaft turns backwards. (François stresses the importance of correct ignition timing so there is no chance of a backfire. I use a modern BT-H magneto, auto advance and never once had a backfire when starting. Maybe people with manual magnetos might be most likely to have this problem if they don't have the adv/retard lever in the right place?) If you use the valve lifter to stop the engine then there should be no chance of the crankshaft going backwards as there is no compression that a piston might bounce back from and as there is no compression there should not be any chance of a backfire. If you use a kill button there should be no spark so no chance of a backfire. There is still some compression so there is a chance that a piston coming up to TDC on the compression stroke could bounce backwards. I don't know how much force this would have or how much strain it would put the sprag clutch under. My guess is probably similar or less than the strain experienced when the engine is started without using a valve lifter.
P.S. My right knee likes the electric start and I have (bravely\foolishly?) removed the kickstart.
Hi Ed,
All very helpful as usual.
I haven't found fitting the electric start too demanding, just waiting on a new G84 Bush as I wasn't happy with how it looked after I'd machined it to not protrude past the G50 plate.
Only other thing was that the G46 cog seemed bloody hard when modifying it on my mini lathe even using Carbide tipped tools.
I'm running one of François's electronic ignitions so just need to get my head around how to add a kill switch.
I'm not too bad on wiring despite being colour blind but don't want to fry the ignition inadvertently.
I've come across Aliant batteries while looking for Lithium Iron batteries & I'm going to try one of them, was intending to make another battery tray platform from scratch as my Walkernator & Mikuni carbs already make it all a tight fit.
Cheers
Dave