E: Engine Comet Mongrel

[davidd]

I was chatting with Maurice Candy in the paddock of Road America once and his Manx was sitting there. I noticed that his frame was not painted and asked him if it rusted. He said "no, it always seems to get plenty of oil". He said he did not paint it so he can see cracks. Not practical on a street bike, but I have found many cracked frames by cleaning them and seeing the cracks in the paint (all were racers). It is one of the reasons that I keep the bike clean. It is easier to spot cracks.

David

 

[Cyborg]

Just for the record David, I did take a stab at making an aluminum fuel tank to be used with a fibreglass cover. The first 2/3 went “ok”, but was turning out to be too labour intensive. As previously mentioned it just got to the point where I wanted a tank, so I could move on. Using a lighter gauge would have helped with the forming of compound curves, but then I’d have to up my game with the TIG welding. I seem to be able to sort out torch angle, arc length, amperage, pedal control, gas coverage, etc, but I still haven’t been able to feed the filler rod properly. Ok for short runs, but can’t advance the rod through my hand without bashing it into the tungsten.... then have to do the walk of shame over to the grinder. Tried a TIG pen, but not any better.. maybe with more practice. Often thought about a small variable speed motor to feed or help feed the rod.

As I ‘m currently indisposed and have time on my hands to post things.....
I don’t have any decent photos of my frame jig, but it is more or less a traditional setup. Some advantages and some shortcomings. I found this article from Tony Foale. The table he is using probably cost a kings ransom when new, but one could make something accurate enough for the job. Always interesting to see how someone else skins the cat.

Making a Racing Motorcycle Chassis

Making a Racing Motorcycle Chassis: In the early 1970s I built a frame for my racing motorcycle to house a 350 cc Aermacchi engine (HD sprint in the US). In 2006 after being away from the track for 30 years I started racing again in classic races in the US and I built a close replica…

www.instructables.com

 

[vibrac]

Here is a Tony Foal frame I got for a song at an auction I had for a year or so it was intended for a Honda 4 engine it has some similarities to Egli. It had no providence or V5 so not easy to put on road
Tony Foal was in US when I tried to contact him

 

[Cyborg]

 

[davidd]

I think the best way to train your hand to feed is to do it while sitting on the sofa watching tv. Keep doing it until you think you have it. Then try it with a glove on.

That is a nice article. I think the things that are important in a jig is to have everything adjustable to level. I used a table that I was able to buy. I put adjustable feet on it to level it and it is reasonably smooth.

I use the right side of the jig to make the RFM and the top to make the UFM. The 2" x6" for the UFM was squared on all sides on the milling machine and I put centerlines on almost everything. The UFM portion is bolted onto the two legs which were welded to the table square. This allowed me to level the fore and aft on the UFM portion and to also remove it from the jig.

I can remove it and set it on the welding table for easier tacking. Once it is tacked, I can toss it in the car are take it to my welder.

I have one of these on the table and one here on the UFM jig.

The stuff Tony has is tens of thousands of dollars, which is not a surprise. His fish mouthing is expensive also. I got a Balleigh, which I considered very expensive, but it really does the job and It is one of the few tools I have that did a better job than I expected.

David

 

[Cyborg]

Nice jig you have there. The Balleigh looks slick. I had a look at a couple and see they have one that uses an abrasive belt which is interesting.
Tried practicing feeding rod a couple of times while sitting in front of the tube, but keep forgetting to do it. Probably need to attach some rods to the remote. Didn’t think of practicing first without the glove, will give that a try. Main issue seems to be that although I can go through proper motions I find it difficult to do it for any length of time and also very difficult to keep the filler going straight into the puddle without stuffing it into the tungsten every once in a while. Also difficult doing everything all at once. Like a one man band.

 

[davidd]

I hope that you are using lanthanated tungsten. Grinding the thoriated tungsten is not considered a healthy habit.

I do not "grip" and move the rod in my hand. I just move my hand closer. This often causes more stops to re grip, but that is what I do. I don't think of the tungsten as being that close to the rod. It tends to melt before the rod gets too near due to the heat surrounding the tungsten. It does mean that I am moving the rod a lot more as I am poking it in and out of the weld area, but it doesn't seem to need a lot of motion to keep the rod cool.

Make sure your vision is good. I have helped several folks who have just had too hard a time seeing the weld even with my Jackson TrueSight, which helps most old guys.

David

 

[Cyborg]

I use lanthanated , but still wear a mask when grinding... on an old repurposed sewing machine motor with a diamond wheel attached. It’s set up and dedicated strictly for tungsten. The wear on the wheel reflects my somewhat spastic arc length and filler feed.
I try and move the arc back slightly and then dip the rod into the puddle to melt it, all the while trying to keep the semi molten end of the rod etc within the argon shielding. I find it slightly bizarre how little it takes to contaminate the weld. Maybe my decision to learn how to TIG on AC (aluminum) first was the wrong move. So much to deal with and the aluminum tends to be there one second and gone the next. Any oxide or crud remaining after prepping the weld will find its way into the puddle and then it starts to look like a dog turd. Even something minor on the backside will bob to the surface... seems that’s an unwritten rule. It was just this past April that I switched it over to DC to weld the flange onto the intake manifold (stainless steel). I couldn’t believe the difference in the arc. Like opium compared to crystal meth. When I ran a test pass, I kept checking the amperage to see if something was amiss. The oil tank literally had about 6 ft of welding and this is what it looks like. If I could master the filler feed, then it look better. I suppose it’s a bit of a vanity thing, because in reality, penetration is fine and there’s no hot cracking. At the end of the day it holds oil. The top of the welding table is an old range hood with two 2 speed fans. I bought a better helmet along with a cheater lens. My eyesight is actually pretty good considering, but the lens makes a world of difference.

 

[Bill Thomas]

 

[Bill Thomas]

Would this work good enough, With out a Notcher ?.