Café Commando build thread

[T95]

Then I mated the two parts and "glued them together with vinyl ester resin and matte material.

Jean

Jean,
I am really intrigued by your approach to sealing your fiberglass tank. When you were first talking about it I thought it was out of my scope but I now have a change of heart after viewing your photos. I thought the "fix" was the vinyl ester resin coating so the secondary coating of Hirsh was a surprise. I recall you stating that after mating the two halves you would seal that seam with a slosh coat, I assumed that slosh coat would be vinyl ester.

I am having trouble visualizing one area of the repair.
Its apparent that one of the primary reasons for failure of slosh coating is the inability to ensure a complete coating. A couple of areas I see being vulnerable are the top of the tank filler and especially the petcocks where a void in coating may exist. Most of the posts on slosh systems say to thread a bolt into the petcocks or tape the bottom. I always thought that once the bolt was removed you risk the chance of creating a void between the top of the petcock neck and the liner. If you chose instead to tape off the bottom of the petcock you are then risking cutting into the liner as you thread in the petcock.
How are you eliminating voids in this area? I am hoping you can clarify this as I obviously don't understand how the petcocks are placed.
Gary

 

[Hobot]

Taping would also allow sealer/resin to fill the petcock threads : (
The way I did 2 tanks was use wood dowels worked in to cut wood threads, then light grease to run em in just proud of the stand pipe inside. Once set they twist out leaving a seal on the lips of stand pipe. I also left tank upside down a few times long enough to well surround the filler neck inside.

Vinyl resion should resist ethanol on its own, but back up sealer even better, if ya can get it on thick enough to matter over the seams.

 

[lcrken]

I failed to mention, my axle is 17mm so I didn't remove very much material to make it fit, and I removed a bit on each side.

Jean

I can't see you having a problem with a 17 mm axle. When I opened mine up for a 20 mm axle, I think that was just a bit too much metal removal. I probably should have reinforced the area around the slot, but that's ancient history now.

You're making good progress. You should have a pretty slick Commando when it's finished.

Ken

 

[Jeandr]

Gary,

I think the main reason GRP tanks fail when a sealer only is applied is that the sealer either does not adhere everywhere due to crud left behind in the cleaning stage or that the sealer did not cover a sensitive area. By painting on a layer, I make sure the inside of the tank is completely covered, the only area not covered is the seam which will be covered by sloshing. The seam being at the bottom will get a thicker layer due to pooling of the product, aside from moving the tank constantly in every direction while at the same time ventilating the tank so that it dries, I don't see how having the sealer pool at the bottom could be avoided, in my case, I want it to pool at the bottom to cover the seam. Being a belt and suspender type, I feel lining the insides with vinyl ester resing and a layer or two of material and then coating it can't hurt.

All the hardware I am bolting to the bottom is screwed in steel pieces sunk in the fiberglass to make sure the screws don't pull out. As you can see, the petcocks are not original, these should not leak. The aluminium plates will be epoxied to the bottom of the tank and they provide a good sealing surface for the petcock's rubber gaskets. With screw on petcocks, you could epoxy the two parts (there is a steel bung sunk in the fiberglass and another screwed from the outside) and do as Hobot has suggested or use an old petcock so the threads don't get all covered with sealer.

Here is my sprocket carrier lightened up a bit.

For the inquisitive minds, I had a 42 tooth sprocket, right size for a Commando, but the center hole was too big for my rear hub so I cut away the insides and kept only a "ring" with teeth, to line up the front sprocket, I had to ofset it a bit to the insides. Even buying a new sprocket would have needed a similar treatment so I saved a few bucks by using my old stuff.

Jean

 

[T95]

Jean,
Thanks for the visual. Now that I see the petcocks your using I understand how your eliminating any possibility of a void in the slosh coating.

Your really moving along on the swing arm and it looks great. That new mill is in the right hands!

 

[lcgtr]

What gearbox is that?

 

[Jeandr]

You'd better ask Jim Comstock, aka commoz, he is the wizzard who built that racer.

Jean

 

[Jeandr]

I did not want to use the "Z" plates to hold the exhaust pipes because it is kind of dumb the way Norton did it, the engine shakes, the front of the pipes shake and they have to use rubber isolators to hold the back of the pipes because the nearest fixing point is on the "Z" plates which are solidly bolted to the frame. Following Ludwig's (and others) idea, this is my way of fixing the back of the pipes to the engine cradle. So now everything that is supposed to shake will shake together, it may prevent vibrations from the pipes being fed to the frame.

Now I ahave to figure out the foot controls, I have a pretty good idea, just need to turn it into metal.

Jean

 

[Vulin]

... perhaps you could tell everyone whats wrong with using a collet chuck in a small mill thats not going to be capable of taking large heavy cuts.

I think he will say they can creep, I have seen that happening once so far and I haven't used it extensively.

Jean

Got it Ive seen alot of endmills work themselves out. Even just milling a simple slot, and oops its all of a sudden to deep. Thats bad news bears for a key slot. With a solid holder, and a nice flat, end mill stays put.

 

[grandpaul]

Jean, can you make a dozen of those pipe hangars? I think there's a market, as long as nobody has to die in testing.

hee hee

Really, I'd love a couple of sets...

 

[swooshdave]

Jean, can you make a dozen of those pipe hangars? I think there's a market, as long as nobody has to die in testing.

hee hee

Really, I'd love a couple of sets...

What did they end up weighing?

 

[grandpaul]

I'm guessing they're only fractionally heavier than the stock setup, and provide an excellent ZRV "zero relative vibration" solution.

 

[Jeandr]

This is the bracket I made, it weighs 2½ lb considering I will not be using the "Z" plates (1½ lb each) and all the rubber isolators as well as the plates holding the isolators to the mufflers and the plates holding the other end to the Z plates, I think I saved a little weight. I could go crazy and swiss cheese the metal, I may do so if I think it looks good and lose a few extra ounces.

These are my fork stops (for now). I wasted a lot of time trying to come up with a complicated solution and ended up with this. It is only weled on the top for now so if I decide to keep this solution, I will weld it on the bottom too.

Jean

 

[swooshdave]

This is the bracket I made, it weighs 2½ lb considering I will not be using the "Z" plates (1½ lb each) and all the rubber isolators as well as the plates holding the isolators to the mufflers and the plates holding the other end to the Z plates, I think I saved a little weight. I could go crazy and swiss cheese the metal, I may do so if I think it looks good and lose a few extra ounces.
Jean

The last time you came up with something brilliant you were hesitant to make more. Which I can't blame you. Would you be willing to post the making of, or how to make these?

 

[Jeandr]

The last time you came up with something brilliant you were hesitant to make more. Which I can't blame you. Would you be willing to post the making of, or how to make these?

Well, for one thing, I didn't invent anything, Ludwig had something similar years ago and I saw another forum member (can't remember who, but I have pictures) who made his own too, second, I have a hard time making stuff for myself I can't see myself being forced to make things for others and lastly I wouldn't want to upset Beng (see new-featherbed-swingarm-spindle-bushing-kits-t8910.html).

Making one is not rocket science, all you need is a grinder and a welder (a drill and a tap help too). If you want, I could send you detailed measurements, but then there is the odd chance it may not fit with the exhausts you have. I don't think Nortons and especially chassis after market parts were made with extremely close tolerances.

Jean

 

[swooshdave]

The last time you came up with something brilliant you were hesitant to make more. Which I can't blame you. Would you be willing to post the making of, or how to make these?

Well, for one thing, I didn't invent anything, Ludwig had something similar years ago and I saw another forum member (can't remember who, but I have pictures) who made his own too, second, I have a hard time making stuff for myself I can't see myself being forced to make things for others and lastly I wouldn't want to upset Beng (see new-featherbed-swingarm-spindle-bushing-kits-t8910.html).

Making one is not rocket science, all you need is a grinder and a welder (a drill and a tap help too). If you want, I could send you detailed measurements, but then there is the odd chance it may not fit with the exhausts you have. I don't think Nortons and especially chassis after market parts were made with extremely close tolerances.

Jean

No, I know you didn't invent them and that they've been done before but yours are loose, ready to be measured and fresh in your mind. Dimensions don't need to be hyper-accurate, but really you've done the hard part. I think I can draw them out with a few more pictures and some reference measurements.

I just ordered the muffler mounts from Hemmings, now I have to figure out how to put those on and make them look like they are working, but really use something like what you have. :mrgreen:

 

[slimslowslider]

This is the bracket I made, it weighs 2½ lb considering I will not be using the "Z" plates (1½ lb each) and all the rubber isolators as well as the plates holding the isolators to the mufflers and the plates holding the other end to the Z plates, I think I saved a little weight. I could go crazy and swiss cheese the metal, I may do so if I think it looks good and lose a few extra ounces.
Jean

I just did away with my Z-plates too, so had a chance to weigh.

Removed:
Z-plates 2 x 680 = 1360 gr
plates, 6 off = 800 gr
iso rubbers, 2 off = 115 gr
bolts, distance collars = 430 gr
Total 2705 gr, almost 6 pounds.

Added:
new lugs welded to frame for original Mk3 footrests rider and passenger, 800gr
exhaust brackets, 970 gr
Total 1770 gr, almost 4 pounds

Love your work, keep it going.

 

[bluto]

thanks very much for the exhaust hanger photos, think I'll try making a set myself, looks like they can be formed with fairly simple tools and I have a MIG welder to put them together...would love to ditch the stock isolator setup

 

[Jeandr]

The "kiss" principle at work, these are my new fork stops, more solid, simpler.

Jean

 

[neilt]

Just found this thread and it is very informative...great work & photos from Jean.
To control up, down, fore and aft Isolastic movement at the rear, maybe this would also work - a threaded rod from the frame to an oversized hole in the cradle at the rear of the transmission. With sturdy nylon washers and double nuts (or locking nuts) on the threaded rod end in the cradle it could be set to eliminate left to right movement while allowing up, down, fore, and aft movement. Obviously not as elegant as what Jean has done with his, but it seems to my non-machinist, non-fabricator mind that it would work.