ET: Engine (Twin) Twin e-starter options?

Dave61

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Non-VOC Member
My own experience of fitting, using and thoughts about the Grosset electric start on a Rapide:-
  1. 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.
  2. 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.)
  3. 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?)
  4. 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.
Well, that may have given you something to think about or at least some targets so you can shoot me down in flames.:cool:
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
 

Dave61

Well Known and Active Forum User
Non-VOC Member
Hi Dave,
He has a BT-H on his bike, so uses the ignition kill button.
The beauty of the automatic de-compressors is that you push the button down, and when the bike fires the pop closed. It's much easier to buy the 10mm ones, as they are used by both HD and many chainsaw makers. The 14mm ones are very expensive,.

Neil

Hi Neil,
Thanks for that, something else for me to think about.
Think I need to add a kill switch, got a suitable one just need to get my head round how it should work on the Grosse ignition.
Cheers
Dave
 

Bill Thomas

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There is not a lot of room on Twins, Not like Comets, I want to change my Honda seat for a standard one,
And have to find a place for the magic ign' box and a coil, Don't think it will be neat ?.
 

BigEd

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VOC Member
VOC Forum Moderator
Hi Ed,
All very helpful as usual. ....... 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
I don't know much about the ignition system that François makes but he is a very helpful person so if you have a query I'm sure he would respond to an email. A few years ago a group of us from the Coventry section had a week in France. François met us off the ferry and we followed him on his Comet back to his home for a bite to eat and a quick look around his workshop. I think he must have just been developing his system back then as he pulled up for a minute at one point and made a bit of an adjustment then set off again.
Re: colour blindness, my late brother-in-law was colour blind but that didn't stop him earning a living as a driving instructor. I initially thought, what about traffic lights but as he explained you just watch the sequence the colour doesn't really matter. He had always wanted to fly and eventually got his pilot's licence. He couldn't fly at night because of red \ green navigation lights.
Let us know how you get on with the Aliant battery, it is good to have an alternative make available.
Like yourself, I have a Walkernator and Mikuni carbs, very pleased with both items.
 
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Sten Jensen

Active Forum User
VOC Member
My friend Martin Jensen from Denmark has build an Egli-type Vincent with Molnar crankcase, Terry Prince bob weight Crank and Top End kits giving 1330cc, with 10.5:1 c.r. pistons (11.5:1 c.r. with 100mm stroke ??) and TP Mk5 cams. He has fitted a Bendix drive starter from a Harley 1200 Sportster driving a gear behind the Newby belt driven clutch and uses Harley electric decompressors which are triggered together with the starter. The starter is powered by a littium battery. Works very well He has not done any welding to the cases, just machined some holes and bolted it on. The starter is hanging a bit low (Godet style) to clear the chain.

His videos are on Facebook, so I believe you needs a FB acount to view them:
Pictures of Bike:
Harley Starter installation:
'First' start of engine:

The gear behind the clutch is Module 2.5, 72 teeth. Center to center distance from clutch to starter drive is 103.00 mm. If you can get a 73 teeth drive it will give a little more room and distance will be 104.25 mm.
The G2 cover needs to have a bit of material removed to make room for the gear.
The battery is a Jigawatt LBB18S with 750cca (!!) from www truecousins.dk. It will start the engine both with and without decompression valve.

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dagriise@online.no

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Non-VOC Member
Just a tip for the ones using BTH and especialy those with twin spark, an Grosset starter... I have a TP 1200 in an Egli, and have struggled with marginal starting power from the Starter, and very slim chances of getting the motor running, especially when having twin spark connected.. (seems the twin spark divides whatever output the BTH gives) Started reluctantly with one coil/plug connected.. Found these coils, with claimed double voltage output, and the same shape. Even though the starter is struggeling, the motor now starts even with twin spark wired: https://www.euroscooterparts.co.uk/...naraku-racing-ht-lead-coil-and-cap-2-pin.html Would love to find a slightly more powerful, bolt on motor for the Grosset kit though!

Just my two cents!
Dag (Norway)
 
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