Racing Mosport

No, just a generic modern car starter with reduction gears attached. If you go to a dirt track racing event, you will see all the guys using various versions of crank triggered starters(in the US and Canada anyway). Some car starters are easier to adapt than others because they spin in the right direction, most actually spin in the 'wrong' direction and you have to gear them in reverse as well.

Hey Doug! Great video.

Thassa my boy!

I've only ever seen two types of starters used on bikes at race meetings. One is based on an angle grinder driving rollers - needs mains electricity. The other is a small petrol motor driving a go-kart wheel. I saw Doug's starter in some of his videos, however I've not seen similar in Australia.
I bought the one based on an angle grinder and it works very well - most of our race circuits have mains outlets in the pits, otherwise it's the old bump start for me.
What puzzles me is how you keep the nut tight when you apply Doug's starter to the end of the crank.

When you apply a crank handle to an old car, it usually tends to tighten the nut on the end of the crank - right hand thread. On a Commando, wouldn't you need a left hand thread ?

acotrel said:

I've only ever seen two types of starters used on bikes at race meetings

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acotrel said:

What puzzles me is how you keep the nut tight when you apply Doug's starter to the end of the crank.

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The nut is not necessarily threaded onto the end of the crank but bolted to the sheave through the "puller" threaded holes.

Summit Racing offers a variety of gear reduced starters. By example, see:

https://www.summitracing.com/parts/tff-6550a

This particular starter offers 6:1 gear reduction.

acotrel said:

When you apply a crank handle to an old car, it usually tends to tighten the nut on the end of the crank - right hand thread. On a Commando, wouldn't you need a left hand thread ?

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I've used a starter similar to Doug's for about 35 years, on several Nortons and a Rotax, and now on a Yamaha single. It's pretty easy to sort out a way to lock the nut to the front pulley. When I first started using it, I just used the hex center from an alternator, which is keyed to the shaft. Later, when I started using crankshafts without the alternator snout, I used a nut with flange and a circle of holes or notches that locate on allen screws in the two threaded holes in the pulley. This is a picture of a bike set up with the alternator center. The starter motor has a large socket that engages the hex.



And this is a picture of the nut for a crankshaft without the alternator snout.



Ken

I've got a set of crankcases with a plate like that welded on. Is your drive side bearing tight in it's housing ?

Thanks Ken those pics will be of help, so Doug doesnt need to pull his cover off.
I will check summit's site
Regards Mike

Have done turn 2 . You must hit the brakes. Many factors.

That's cool that you can buy a starter ready made with a gear reduction, very interesting.

Ken, looks like you have the right idea with that setup.

I do turn 2 at Mosport in 4th gear with just a slight roll of the throttle, I never touch the brakes through there but it took a while to get that brave.

Doug MacRae said:

I do turn 2 at Mosport in 4th gear with just a slight roll of the throttle, I never touch the brakes through there but it took a while to get that brave.

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Went back and listened to the video on turn two,delicate, very delicate. Seems like you have an edge diving deep into Moss Corner. Makes my blood boil just watching

Mosport is August 12-14 John! Plenty of time for you to load up and come race...

Mosport is like Daytona, you have to do it at least once. There is a lot of new paved run off room which has made it much safer. It is a very fast track for sure, according to the lap charts, at my pace I am averaging 89 mph.

Thanks for posting Doug. Bike sounds brilliant. Please keep us updated. More videos too please

acotrel said:

I've got a set of crankcases with a plate like that welded on. Is your drive side bearing tight in it's housing ?

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Welding does tighten the fit. I've done a few cases like that, although that was years ago, before Steve Maney started supplying new heavy duty cases. After welding, I set the cases up in a mill with boring head, and machined the bearing bore back to standard. I also pinned the bearing in place to stop it from turning in the case. I should point out that even with all the reinforcement, it is still possible for the cases to fail, but it takes a lot of abuse. Years ago I broke one on a 920 cc engine racing at Daytona. And I recently had a severe crack develop in the one shown in the picture above, but it took a full bore run at Bonneville with the 920 cc motor on a good dose of nitrous oxide to do it. Still, those cases had done several years of road racing and a quite a few runs at Bonneville before failing. My last set of welded cases is still intact, and I'm using them for a short stroke 750 build, but I don't plan on welding any more like them. The Maney cases are so much sturdier, being cast in a stronger alloy with much thicker sections, that I prefer them for any serious high horsepower build. I'm still perfectly happy with stock cases for a street engine build, even with reasonable performance mods, as long as the rider doesn't think it should be revved till the valves float for every shift. Back in the '70s I raced a 750 PR with 62 rwhp for several years before cracking a case, and then welded the case and raced it some more.

Ken

Gosh, I love this web site!

Thanks Doug.

The cases I welded the plate to, came from a young guy who used to ride the Great Ocean Road in Victoria with his mates. He used to rev his old 850 Commando to 8,000 RPM with the standard balance factor. A horizontal split developed right through the centre of the drive-side bearing housing. On my bike the crank is balanced to 72% and it never gets revved above 7000RPM intentionally. I still believe it must eventually explode.

just klike this last year at Donnington park

I've cracked several cases over years of racing, but none quite so thoroughly as yours.

Ken

Ashphalt Al said:

just klike this last year at Donnington park

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A Al,
It doesn't look like you holed it.
Was that the cause of a loose or missing bottom bolt on the gearbox shell? I have seen some crack like that before for that reason. :shock:
Cheers,
Thomas
CNN

Hi Thomas , It has had many years of thrashing around circuits with a standard crank , so i think old age had a lot to do with it .