OIF Cdo

Has anyone ever converted the top spine tube to OIF?

If so, was it successful?

How much oil can it realistically hold?

I'm inspired by the open / naked look of cNw's cafe racer. I know Matt used his own frame design, but I'm wondering if a similar effect could be attained by us amateurs?

From my perspective as a former N-V engineer with significant involvement with the Commando, I wouldn't risk drilling holes in the top tube , even close to its neutral axis, but particularly not at either the top or the bottom of the circumference. Stress cracking would be a major risk, even on the bikes with the secondary reinforcing tube.

I had an interesting experience with the AJS moto-cross bike, which had a very similar frame design, though with the top tube attached at the bottom of the headstock rather than the top. We had done very well at one particular race meeting. Dave Bickers asked if he could try out the bike after the races were over. He did a number of very fast laps and was very complementary about the handling. Back at the factory, we started our usual post-race strip down. When we took the gas tank off, the frame fell apart. The top tube had broken into two pieces just aft of the headstock.

The frame was redesigned by separating the top tube along its length into two halves, then welding in a long skinny triangular steel filler. This made the tube obround at the headstock end and circular at the back of the seat. We had no more problems with the frame during my time at N-V. I suggested to the folks at Plumstead Road that the same fix would solve the Commando issue, but they said it was too much trouble and went with the secondary tube design. As far as I know, all the production AJS Stormers were built with that redesigned frame.

Yes I've seen a few feature bikes in magazines etc over the years, you can plate in the top tube to the bracing tube for extra capacity, from memory I think I read the top tube itself can hold 4 pints?? , Obviously don't just drill holes in the top tube ,they need a decent boss welded in to maintain integrity,the top tube on my commando is drilled this way as I was going to use it for a reserve tank that never reach fruition, never heard of one breaking because using it as an oil tank, cheers

Yes I did this many years ago, I dont think I have pics, it was successful
Don

I believe HOBOT's latest bike is OIF. I could be wrong, because I don't actually speak swahili... 8)

Jean DR has an oil in frame modification that boxes in the space between the top tube and lower tube if I remember his build thread. If I was going to modify the frame , I would be looking at the strength of it rather than making it into an oil tank. These frames are weak to start with. Have a look at Metal Malarkey for a decent frame, though I don't think their frames are Isolastic. I could be wrong.

gripper said:

Jean DR has an oil in frame modification that boxes in the space between the top tube and lower tube if I remember his build thread. If I was going to modify the frame , I would be looking at the strength of it rather than making it into an oil tank. These frames are weak to start with. Have a look at Metal Malarkey for a decent frame, though I don't think their frames are Isolastic. I could be wrong.

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Why strengthen a frame that's got rubber hinges in the middle?

Apart for the early 'widow makers' are there any strength issues with the Commando frame?

Fast Eddie said:

Apart for the early 'widow makers' are there any strength issues with the Commando frame?

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frame-blueprinting-t1294.html#p8979

frankdamp said:

Although the Commando frame is light, it's not because it's weak. For a structural design that pre-dated finite element analysis, it's quite a remarkable piece of work. I personally tested both bending strength in the vertical plane (between front and rear suspensions) and torsional strength between the headstock and the swing-arm axis (trying to twist the front wheel out of alignment with the back wheel).

The tests were done on bare frames (no engine/transmission or Isolastics installed) and compared to the same tests on an Atlas Featherbed frame. From memory, the torsional strength was about 8 times better and the bending strength about 5 times better.

The only real weakness on the Commando is that the two downtubes can get splayed apart by braking forces. With the original Italian (Campagnolo?) TLS front brake that was never a problem!

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With the front Iso. fitted and also with the frame cross member in the forward position (from '71) then "braking forces" don't seem to have been a problem.

Several of Kenny Dreer's VR880s with OIF had to be re-done due to various warranty issues.

That was one of the biggest reasons he finally shut down VR.

"Widow-makers' ? - wash your mouth out ! What does 10 thou of an inch at the ISO adjusters, translate to at the handle bars ? Peter Williams built a racer which had an open frame below the motor and I think he said 5 times the movement at the handle-bars was answer. Isn't that about a millimetre a side ?

acotrel said:

"Widow-makers' ? -........... What does 10 thou of an inch at the ISO adjusters, translate to at the handle bars ? !,,...... Isn't that about a millimetre a side ?

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The early commando frames used to break at the stearing head. ISO adjusters are a seperate issue.

Proper silver soldered fittings or threaded bungs for fittings, placed with some thot strengthens the thin spinal tube. Arc welding mild match book thick steel tends to weaken. Some of Mz Peel fittings and frame sealing gaps from missing or incomplete factory welds rely on JBW and Iron Putty, especially where under tube merges with spine gusset and mid down tubes, inside the junction, hidden from welding reach. Must provide for sufficient heat reserve capacity so most scab in clunky boxy reservoirs and plumb with clunky ugly garden hoses routed from one end of their Commando up to other, sheeze. Oil tank weighs over 5 lb and the battery tray a bit over 3 lb so about 9+ lbs can be removed, if battery remounted, especially if smaller lighter size to carry on the main reason for OIF. Filler hole size and capping as well as pressure venting takes some thot to avoid hunky clunky style/rider intrusion or tank fouling. Garden size hose length nullifies a few lb gained so Peel cycles oil via 3 JBW on steel tubes a few inches long and each side of frame loop tubes for up to a gallon of oil volume though 2.5 qts is enough to feed oil pump in any position from vertical at either end or horizontal. Peel's OIF vents through exhaust sucker. Peel will need a funnel to add oil w/o removing tank or seat and the filler bung in spine doubles as post mount for Scott damper some events require. Oh yeah rear end plate of spinal tube has bung welded in to mount temperature sensor and clean out - inspection access. Drainage port placing and access to solve. Also a check valve to prevent wet sump back through oil pump exit port, which feeds into over head spine OIF. A fail safe shut off to oil feed needed too as common to all Cdo's.

No one seems to mention frame's interior condition or protection over time from corrosive moisture laden hot oil. Its a total raw rough finish with light rust patina until O2 used up but once exposed to more the paper thin frame life time is ticking away unseen. No way to coat inside with tank sealer to get everywhere and not also clog up passages and no way will paint adhere over years to flake off into flow leaving exposed frame again. Peel's insides are chemically pickled by some Strominum zinc phosphate juice. Turns out to be the best ever brazing flux - even carbonized rusted cracks in fire place box a foot long each - had all other fluxes fail like hot wax rolling off polished marble, till my chemistry flashed back and splashed pickled that cracks to find braze stuck like acid soder on clean copper. Amazing results for novice, encouraged more by wife shock at $500 extra propane winter bill d/t me too busy to harvest wood last year. Chem Preserve brand - if can find it. If not be pensive for those after you.

I would worry about JBWeld for oil fittings on a Commando.

"Whole lotta shakin' goin' on!"

Why not just cut out the stock top tube and replace it with a sturdier with cleaned interior tube with all oil line fittings properly welded?

If you are going through all the effort why not do a proper job?

Overall would it not simply be easier to cut out the tube and weld in
a complete well sorted new section?
I cannot see that the cost would be much.

In 1990 a crafty and highly skilled friend of mine did an OIF conversion to his 74 Roadster. It was a flawless job and looked and performed as if it was OEM. About 2 years later he converted back to the standard oil tank. He said that he never liked the feeling of the additional weight. He then cut an access port on the rear blanking plate of the main frame tube and used it to store extra cables and other small parts. He moved away about 2006 and the storage in frame mod had not caused him any problems in about 45,000 miles of use. I've considered this modification myself except that I don't posses the skill set that my buddy Karl has.

Have to ask. What does TLS stand for in regards to the post mentioning Campagnolo as a supplier for the front brake. Is it "twin leading shoe" ? I know I risk scorn trying to guess. But just had to.

Joe Schlaberdowski said:

Have to ask. What does TLS stand for in regards to the post mentioning Campagnolo as a supplier for the front brake. Is it "twin leading shoe" ?

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Yes. Although the TLS front brake fitted to the production models wasn't made by Campagnolo as far as I'm aware.

Bob Z. said:

Why not just cut out the stock top tube and replace it with a sturdier with cleaned interior tube with all oil line fittings properly welded?

If you are going through all the effort why not do a proper job?

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May as well build a new frame.

grandpaul said:

Bob Z. said:

Why not just cut out the stock top tube and replace it with a sturdier with cleaned interior tube with all oil line fittings properly welded?

If you are going through all the effort why not do a proper job?

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May as well build a new frame.

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Quite...

Which isn't very high on my list of things to do. I'll put this one back in the ideas box!