Lightend Tappets/Cam followers

Gday all,
has anyone had experience with lightening their Commando's tappets(ludwig?). Jim Schmidt reccomends drilling a hole in for some lightness, but below is a pic from Dominator Engineering with quite radical machining gone on or are they their own build/design! I know Jim also supplies BSA followers but more money of course and have to have cam to suit. Thoughts??

Rgds Foxy

Hi there, unless going to Bsa design and then Jim Schmidt solution, you had better to leave them as they are , more trouble than any gain...........

I've thought about lightening the valve train. I got titanium collars and stopped there. It seems the next steps would be lightened rockers, titanium valves, then lightened followers. Paul Dunstall advised against going too far lightening the followers. It seems that the only benefit would be in being able to spin the engine faster and running a radical cam grind, which are worthwhile but it gets pricey because the rest of the motor needs mods to get the most out of it, and then there's all the things you'd have to do to make it stay in one piece. Having said that, there aren't many things that are more fun than making a bike go faster.
P.S. There are benefits beyond higher redline and radical cams. You can use lighter springs and have less wear. Also, I read the actual valve timing and cam profile can be two different things due to flex in the valve train and float by the valves, even at moderate rpm.

Foxy said:

Gday all,
has anyone had experience with lightening their Commando's tappets(ludwig?). Jim Schmidt reccomends drilling a hole in for some lightness, but below is a pic from Dominator Engineering with quite radical machining gone on or are they their own build/design! I know Jim also supplies BSA followers but more money of course and have to have cam to suit. Thoughts??

Rgds Foxy

Click to expand...

Those lifters are their own design, not modified Stock lifters.

I've used conservatively lightened stock lifters in race Commando engines for decades with no issues. I did have one lifter where the brazed on base fell off and trashed an engine, but it had nothing to do with the lightening cuts. Stock lifters occasionally do that, fortunately not too often.

I've had really good experiences with the BSA lifters in adapter blocks like the ones Jim Schmidt sells. It's a conversion the factory used on some of their flat track bikes back in the '70s, and Jim has done a lot of recent research and work to apply it to more cam choices.

Ken Canaga

Foxy said:

G... but below is a pic from Dominator Engineering with quite radical machining gone on or are they their own build/design!

Click to expand...

Own design and Hartmut states on his website that he doesn't fancy the original two-piece design with the soldered on hard plate for the mating surface of the cam. If you look closely you can see the difference.


Tim

Gday All,
many thanks for the replies. Now that I've put my glases on I can see Dominator Engineerings are different. I think I still will and have a play and lighten my standard lifters per the Jim Schmidt manual. Every little bit helps to take the load of the valve train and reduce cam wear. My motor when complete I wont race(?) but its nice having something with good potential. Anyway I've been enlightened.... especially to Ken,s comment about the history as to where the BSA conversion was first utilised! Once again thanks to all.
rgds Foxy

Less mass up to reasonable reserves is both fun and profitable
for sporting use and less wear strain.

The standard factory set up seems to float valves a bit before
8000 rpm, more or less in some. Almost killed me in early
Combat days, on passing a semi with oncoming, pulled
as expected till just about to front of semi then valves
floated-noise and acceleration dropped so hit 4th to carry
some speed and slip back just enough ahead of truck grill.
When examined no evidence found on pistons but
valve edges were chipped and clipped.

With the common K/W 7mm valves and better springs and
DIY lightened factory items it may not float valves till
tach needle hits stop, so no power drop off as a rev limiter
and noise as in factory set up.

Most benefit though is gotten by grinding the valve end of rockers
down so the push rod can go in and out slick as you please,
no more random frustrating puzzling just to put head on and off.

If you want more, its still easy and fun DIY process to approach
what Dunstall shows in photo's. Note there is oil passages in
the arms which I exposed in one rocker so had to order
another for a bit less taken off. Most benefit is relieving ends.
http://rides.webshots.com/photo/1039499 ... 1179zGCIIS


Also for extra rev-ability stability, racers would toss out
factory rocker spindle spring spacers and mill brass spacers to
keep valve stem and rockers aligned.
Michael Starkey - British Toys did Ms Peels
Now that is a real machinist anal skill tedium task.

hobot

hobot said:

Also for extra rev-ability stability, racers would toss out
factory rocker spindle spring spacers and mill brass spacers to
keep valve stem and rockers aligned.
Michael Starkey - British Toys did Ms Peels
Now that is a real machinist anal skill tedium task.

hobot

Click to expand...

Bronze spacers and shim kits are available from RGM (and probably other sources) to replace the stock spindle springs. No machining required. As with the stock springs and shims, it's a good idea to make sure the rocker tip is centered side-to-side on the end of the valve stem. I find this usually requires installing some of the rockers more than once to get the shims right. I'm not sure how much benfit follows from getting rid of the stock spring's friction, but it's a cheap and easy mod, and certainly can't hurt.

Ken Canaga

Yep trick is get best fixed geometry. IF mix and matching by a RGM kit
works, great luck out on that, otherwise hand fitting is more
direct route.

Trixie Combat can still use lightened Norton lifters process,
so back to the mill with you. JIm's made to order cam kit
goes into Ms Peel though your trap door, some day.

hobot -