B50 Street Tracker

[koncretekid]

I'm well into this new project which I'll post when I get time. I'm hoping to get it substantially completed before I leave Colorado, but other stuff (like buying an old K&N dynamometer) keeps getting in the way. Here is a sneak preview. The front and rear of the tank were damaged, so I'm reversing the original paint scheme so the center section will be polished aluminum, painted front and back. I'm open to color combination suggestions?

Tom

[beat]

big and clean workshop!

my compliments

beat

[koncretekid]

This project started with a Triumph 250 gas tank I bought about 10 years ago. A couple of years ago I scored a nearly complete B50 motor, and just last year found a frame and exhaust on Craiglist. With a notarized bill of sale on the frame, I have just 2 years to complete the project and apply for a Colorado title. A couple of ebay wheels and hubs, and I almost had a bike.

I bought a flat tracker style seat on ebay, but it sat too far back, in my opinion.

Only thing to do was shorten the frame.

Underside of shortened rear frame section with seat in place.

Which allowed the seat to be moved forward. I also extended the tank mounting tab on the top tube to allow the tank to be moved back as well and made a bracket similar to original front seat mount.


Tom

[Andy Chaos]

Looking good Tom.
I wish we had a bike to work on,
Ours is not due back until the 28th so i am earning as many garage time vouchers as i can before it all starts again.

[koncretekid]

I bought a complete set of front forks with triple clamps on ebay only to find that the damper tubes were rusted almost solid, so had to buy another set for the damper assemblies. Neither set of stanchions were useable and I had to make a tool to get the lower bolt to unscrew from the damper assembly. It is made from a piece of 1/2" diameter steel rod with all but about 3/16" ground cut away. It fits down the stanchion and traps the the damper nut against the stanchion preventing it from rotating.

I used a brake cylinder hone to remove corrosion from inside the fork lower tube, but the stanchions were beyond hope.

Upon disassembly of the damper assembly, the first thing that appears ruined is the plastic bushing that rides in the stanchion end plug. I used heat on the first one to try to remove it from the stanchion which of course ruined the bushing, but was able to take apart another one without heat only to find that it was so worn out as to be useless as the damper tube can rub directly on the plug body (aluminum) and does nothing to restrict oil flow into the damper. I made new ones from an unknown plastic, maybe nylon or delren.

The bushing is trapped into the end plug by dimpling the outer collar on the plug which was easy to remove on a lathe allowing the new bushing to be inserted and re-swaged in place with a drift.

Finished end plug - - you can buy these but they are expensive.

The damper rod assembly here shows the slot at the lower end, the two small holes near the top, and the damper valve. When the stanchion comes down, it forces oil in the lower fork leg to enter the damper assembly, first thru the slot and the two holes, as well as past the bushing in the end plug (now much more closely fitted) and thence thru the damper assembly. The top nut on the damper assembly is hollow so the oil simply flows up into the upper part of the stanchion impeded only by those holes and then the slot until it reaches the bottom where presumedly the last bit of oil is trapped to from a hydraulic stop.

When the stanchion retracts, the oil must reverse its flow but the only damping takes place as the oil trapped between the damper assembly and the stanchion must exit back into the the damper tube and it moves in thru the slot and holes and some up thru the damper valve which has a floating washer that partially blocks holes in the valve. It doesn't appear very effective.




Without any upper spring in the forks, I tried various oils from Canola (veggie oil), 10w-30w motor oil, straight 30w, Amsoil 20w-50w, Automatic transmission oil, and Belray 30 "anti foaming" oil, all with same result. After pumping the stanchion up and down about 20 times, I got this with all of them!

Is there anything that won't foam up? Also, because the damping action is poor, I think it needs to be thick. Maybe I'll try gear oil.
Tom

[hwan]

TOM - fork oil is supposed to reduce foaming .......?
Probably why i fall off after a few miles of Enduro - or is it cos i'm crap ?

Oils can have a bad effect on plastics, veggie oil is incredibly destruction - it only required a couple of weeks testing a centrifuge (with camera's inside it) before all the PVC insulation went brittle, cracked and caused all sorts of electrical problems (the G force eventually killing the cameras).

ATF is also supposed to be 'designed' to reduce frothing.

I suspect nothing will stop aeration of oil when its forced through orifices, as film strength and viscosity will always prevent the air from escaping easily ....

[skippy]

I suspect nothing will stop aeration of oil when its forced through orifices, as film strength and viscosity will always prevent the air from escaping easily ..

Which is why they add gas to shockers.

[hwan]

Pressurizing the oil in a hydraulic system is primarily to reduce/prevent cavitation (see any definition of cavitation).
Pessurization is supposed to increase the vaporisation point of the oil and hence stop the cavitation.

My Ohlins, when i rebuild them, show marked wear due to this effect - normal high velocity oil flow produce a 'wire-cutting' pattern, cavitation produce a much rougher, pitted effect.
The piston surface (anodised ali), under each reed-valve looks like a lunar landscape, with non of the 'flow' pattern you would expect.

Military MT spec Ohlins have sintered iron pistons, presumably to help wear, 'performance' versions seem to use anodised alloy pistons.

I worked a for a centrifuge company which stuck with hydraulic drive's for Ex(D)/Zone 1 applications, well into the late 90's - we quickly learned the difference between erosion and cavitation of motors and valve blocks, while trying to keep these machines running (customers would not swap over to electronic drive machines at the time).

As for removing air from oil, F1 engines tend to use a centrification type system, an alternative used in industry is vacuum de-gassification (see oil-field applications) - pressurization keeps the air in the oil - think bottle of coke when opened and the reduction in pressure.

Warming oil up to 90C will get the air out more quickly, used by Ohlins when filling the shocks in he first place.

[koncretekid]

Nigel,
Does hydraulic oil have any more resistance to foaming that could be used in our forks?
Tom

[minetymenace]

Doesn't automatic washing machine soap powder have grains of something (PTFE?) in it to break the bubbles up and/or reduce the surface tension thus reducing foaming?

[hwan]

TOM - good question, probably yes.

We purchased hydraulic oil by the barrel load, it was not expensive and not considered anything 'special'.
Hydraulic pump/motor/valve systems have lots of moving parts, all working to very close tolerances, wear other than damage due to grit, was never an issue. Foaming was keep low with large tank volumes and a series of horizontal flat plates which the returning oil flowed over. The tanks were always heated and cooled for a constant temperature

I served my apprenticeship with International Harvester tractors - particularly the Hydro-static range, the entire hydraulic drive train, gearbox and even the rear brakes, all ran in gallons of SHELL ROTELLA 40 oil.
Several years later, i was recommended this oil by the Silkolene tribologis's for my vintage racing bike engines instead of Castrol R.

ATF oil is basically a 'hydraulic' oil, because of the way automatic gearbox's work - the oil has to go through a valving and flow regulation system, causing lots of shear in the oil. I don't know how any foaming is dealt with in this case.

FORK OIL is supposed to have reduced frothing tendency's - would not be surprised if it was repackaged hydraulic oil

I suspect, what you have is not a problem and all bike suspension systems suffer from it.
i think i'd find something else to REALLY worry about - such as track markers which jump out in front of you, you lucky lucky man ......

[hwan]

MM - the sufactent in any detergent is what reduces the surface tension.

Salt (as in Sodium Chloride) is the active ingredient in non-bio detergents, hence the high quality SS used in making the drum - hence them making great BBQ's.

Not certain what PTFE would do other than give the Advertising people something to shout about?

[koncretekid]

So much for the front forks.

Preparing the hubs. First photo is front wheel bought on ebay with good hub and rim (19").

Spokes will be replaced with SS. I gave the wheel the "lightening" treatment plus new paint.

Same treatment for rear hub.

Front hub mounted on forks.

Rear hub mounted on swing arm. Shocks are vintage Cornutt which were easy to rebuild and seemed like good quality. I don't know much about them, but I'll bet Stan does??

Hubs mounted on bike with seat and tank. These cases are 250SS but bolted in to check fit.

Tom

[hwan]

looking good, like wot u hav done to the brakes

[koncretekid]

Respoking the wheels:
The front rim is an original Jones 19" which came with the hub, obviously from a 650. But the spokes are new Central Wheel S.S. from Walridges in Ontario.

I was surprised that although the original spokes had an extra kink or dogleg in the spokes for the outer spokes, C.W. didn't think these bends were necessary. This is the result:

When I questioned Mike at Walridges, he said there was no point in even asking C.W. about the result, as they would just say "let someone who knows how to re-spoke wheels do the job." I solved the problem with a rubber hammer by smacking each outer spoke after they were tensioned to give them the appropriate bend. Has anyone else had this problem?

The rear wheel was respoked with spokes from Buchanans, which had four bags of 10 spokes, each with a different bend. The outer ones had the appropriate dogleg, and the inner ones actually had slightly different bends depending on whether they fit the outer or the inner hole in the hub. The inner ones were slightly longer before the bend because the hub is thicker at that location. And Buchanans provide anti-seize oil to ensure that the nipples don't gall.

Tires and wheels mounted on frame:

Close-up of extended levers at the front brake plate: By the way, I think the 19" front wheel with a 3.25 - 19 tire fits fine with an original front fender, even better than with the 3.50-18

Tom

[HPbyStan]

Looking good my son.

[koncretekid]

Thanks, Dad!

[koncretekid]

After disassembling the motor, I sealed it up and bead blasted the cases.


Motor cleaned up nicely. I had Ed.V. rebuild the crank for me with a 6" Carrillo rod and new bearings.

Meanwhile, I decided to open up the intake port to 32mm and the exhaust port to 1-5/8" to match the pipe I had bought along with the frame. I borrowed an adjustable mounting jig and bored it out with my Rung Fu RF 25 mill-drill.

Bored out to 32mm. I later finished out the porting with a die grinder.

Motor mounted in the frame showing the fit of the carb and the exhaust pipe. It might be a bit loud.

I picked up a Sifton HT cam on ebay but had to make a new gear. I turned off the shoulder on the lobe side to ensure the tappets don't hang up if I miss a shift.

I decided to try retarding the gear by one tooth (12º) which puts the timing "straight up" at about 108º lobe centers on both intake and exhaust. Stan says these cams never worked out well on the B25 flat trackers, but it might just work with the bigger motor. Valve timing is almost identical to the Megacycle X4, but has less lift.

New plus .020" JE piston fitted to bored cylinder.

More to come.
Tom
P.S. (Sunday morning): I reviewed my notes on the Sifton cam and I find that with the cam retarded one tooth, the lobe centers will be 110º on the intake and 104º, exhaust, and not 108º as indicated above. However, the cam gear I am using is different from the one I tested with only a single dash, not the V and the dash, so I'm not sure what I've got now. Hopefully, I checked that when I built the motor last spring!

[hwan]

Nice use of G clamps TOM

As for cams ...... its when you measure them up one evening, then repeat and get something completely different the next evening ...........

[koncretekid]

Here's a photo taken of the ported intake port.

I decided to add a 2nd sparkplug while mucking around on the mill. This photo is of the trial drilling using the "rust bucket" motor head, which obviously needs some work. After drilling, I chamfered the hole using a shallow chamfering tool.

Top of head looks like this. The sparkplug seat has to be spotfaced for a good seat and to allow clearance for the socket wrench. I wasn't able to save all the fins, as the end mill broke them off.

With the rocker box on, the question is how do you replace the spark plug?

Luckily, I had a spare 5/8" deep socket which I turned down to a minimum OD, and with the help of a wobble extension, it just clears the compression release.

Good head installed on the motor in the frame. Because I helicoiled the threaded holes and countersunk the rocker box for Allen head bolts, I could more easily install the motor. In fact, I laid the motor down on my lift and lowered the frame over it with the help of my wife. We still managed to ding the paint in one place fitting the motor.

It took a while to figure out how to get the rocker box on over the pushrods. The answer is, you rotate the rocker box 180º to the right side so you can get it over the pushrods, then rotate it back around under the frame. Some of the bolts need to be in the rocker box when you do this because you can't get them in afterwards.

I wanted to see if I could mount an oil filter on the motor mount plates, similar to the Norton Commando. I started with a flat plate motor mount plate from an SS250 but had to ground a bit of clearance into it as I put it on the opposite side.

Another view from above.

Final fitting looks like this. I should have started with a slightly larger plate, because I had to modify the left motor mount flange for clearance. I added the hose clamp so I can safety wire the filter to keep it from coming loose.

In the electrical department, I shortened and moved the battery box over to the left side to allow a straight shot from the carburetor to the air filter. I mounted the voltage regulator (Tynpanium) on the bottom of the battery box.

On the right side, I added a tray where I can mount the Boyer box as well as a fuse block.

Enough for tonight!
Tom

[Jack Gifford]

... I wasn't able to save all the fins, as the end mill broke them off...
... Enough for tonight!...

Watching your persistent progress is enjoyable. Please keep sharing with us.

To avoid breaking those fins, you need to add a small/cheap (less than $60) electric downfeed to your little mill, as I did. Thanks to an $8 pulse-width-modulation circuit board, I can dial it down to less than .001"/second. I included an adjustable down-limit microswitch, so I can walk away while it finishes its s..l..o..w cut. With 5 minutes work it can be moved to the X or Y table feed, also (although no limit switches- yet). It's been invaluable- couldn't live without it now.

[koncretekid]

... I wasn't able to save all the fins, as the end mill broke them off...
... Enough for tonight!...

Watching your persistent progress is enjoyable. Please keep sharing with us.

To avoid breaking those fins, you need to add a small/cheap (less than $60) electric downfeed to your little mill, as I did. Thanks to an $8 pulse-width-modulation circuit board, I can dial it down to less than .001"/second. I included an adjustable down-limit microswitch, so I can walk away while it finishes its s..l..o..w cut. With 5 minutes work it can be moved to the X or Y table feed, also (although no limit switches- yet). It's been invaluable- couldn't live without it now.

Thanks, Jack. I was beginning to wonder if anyone was still out there! And please send me details about your mill-drill electric feed system. As you know, there are people out there converting these mill-drills to full computer controlled complete with ball screws and programming, but they are a little out of my league.

Meanwhile, back in the shop.
Coil bracket:

Taillight bracket from underside:

Taillight from behind:

After the complete dry build, the bike is disassembled and stripped. Here it is after 3 applications of paint stripper, scrapers, and coarse Scotchbrite pads:
And after sandblasting. I use a Harbor Freight blaster with screened "play sand", allthough double ought (00) grade blasting sand is best. You need an air compressor with about 10CFM capacity to keep up with the blaster.

And after painting. My paint booth is a temporary 3 walled plastic covered affair in the doorway of my shop. Lighting is the biggest problem.

Frame with forks and swingarm. I subsequently had to remove the forks and swingarm in order to set the frame down over the motor.

I had no suggestions on color combinations, so I had to choose it myself!
And the right side:
Finally, it sees the light of day.

Still to do: Headlight, ignition switch mounting, finish wiring, fuel system, and seat cushion. But I'm leaving to go back to Nova Scotia on Sunday so these finishing touches will have to wait until Spring.

[beat]

[skippy]

It looks really good. The seat looks a bit hard thou.

[HPbyStan]

I'm liking it Tom !!

[Jack Gifford]

Looking good!

Although I spent my career in electronics- I'm left with some questions. Such as- if two spark plugs are both connected to the same coil, would they ever both spark? Seems likely that the first one to begin an arc would drop the voltage too low for the other plug to spark? Are two coils required to have them both consistently spark?

[johnq]

The reversed colour scheme works great

[koncretekid]

Thanks for the thumbs up Beat. You know how much work it is to complete a project!

It looks really good. The seat looks a bit hard thou.

Yes, a cushion on there would help. But the wife told me last night how much I had already spent so that seat will continually remind me.

I'm liking it Tom !!

Stan, we're still looking forward to your next build and I hope your new "Indian made" new parts have a good warranty!

Looking good!

Although I spent my career in electronics- I'm left with some questions. Such as- if two spark plugs are both connected to the same coil, would they ever both spark? Seems likely that the first one to begin an arc would drop the voltage too low for the other plug to spark? Are two coils required to have them both consistently spark?

Jack, I'm using two 6v coils in series which is what Boyer recommends, or a dual output coil. But I can't tell you the question about the electronics. But think about all the 4 cylinder bikes out there. They usually have just two dual output coils and spark 2 cylinders at the same time (wasted spark on the one on the exhaust stroke).

The reversed colour scheme works great

Thanks, John, and the reversed color scheme works really well when the front and the back of the tank were "modified" by the previous owner.
Tom

[Jack Gifford]

So... apparently a "dual output coil" has two discreet secondary windings, as opposed to merely having two "outputs" of a single winding? [Do me a favor and put an ohmmeter across the two outputs?]

[skippy]

So... apparently a "dual output coil" has two discreet secondary windings, as opposed to merely having two "outputs" of a single winding? [Do me a favor and put an ohmmeter across the two outputs?]

That's how they work.

[Jack Gifford]

Thanks Skippy. Can we also trust that the design is correctly altered (from the single output version) to provide twice the spark energy (more primary current, and/or higher turns ratio, or whatever)?

[hwan]

Re; twin output coils -

Currently running a twin output coil + Wassel on the B25 - i discovered while trying to find a coil with the required ohm's, that 6V twin output coils are more 'correct' than the 12V ones - which figures as they are usually paralleled up for four-cylinder bikes.

So it may be worth looking @ 6V double output coils - to provide the required current draw/resistance.


I always was told and have read in books, that a twin output coil is basically a single coil with one plug connected to the 'earth' end and the other to the 'live' end - thus forming a circuit.
I am probably remembering it wrong and the 'single' coil had a center-tapped feed - producing two separate coils i guess.
As i know one plug will spark, with the other unconnected (and probably buggering up the coil) on the coil i have had.

[stew79]

hi hawn, in the normal 4 cylinder set up its 2 sets of points, 2 double ended coils, just like a 180 deg twin but x 2.(nothing in parallel or series) the coils are normally 12 volt of a higher res if its using points. or a lower res if its transistor. you have just found the best type of coil for your needs, but there are lots of similar coils around. (H*nda cd175 6 volt coil has the right res and works perfect on an 800 beamer with trans ignition) as for the output, the secondary isnt earthed, one lead is positive the other negative.(one plug has reverse polarity and will fail first, leads should be swapped over occasionally if you can to get even plug where. thats why on a modern car with twin lead coil packs the spark plugs have odd earthing tangs so the one thats sparking the wrong way round, works better. (there is a small time factor between the 2 plugs firing which is why on high revving 2 stroke twin or four race bikes they have individual coils, with individual timing circuits)
stew

[koncretekid]

Update on the Tracker - I'm now struggling to get the bike titled in Colorado. The Department of Motor Vehicles here has an idiot rule for old motorcycles that had matching numbers frame and motor. If the motor has been changed and no longer matches, I have to fill out another 5 forms, supply photos and a Bill of Sale for both the frame and the motor, and then the Department will issue a new VIN number complete with a tag which they will permanently attach to my frame (I don't know how they plan to do that with oil-in-frame), and destroy the old numbers! Here are some new photos: Note - the plate is off my other B50.

left side

right side

right side - motor

one for Stan!

[Barry Creary]

Very nice work Koncretekid thumb

[whitedog1]

Hey Koncretekid - don't know if this will help you with your specific case, but if the Colorado hoops are too big/costly/etc you can always go with what I call the "Vermont Route". Here's the beauty of it in a nutshell and its all perfectly legal and cheap. First, you do not need to be a resident or live there to do this, they do it for anyone, anywhere. Vermont does not issue titles for cars/trucks/motorcycles over 15yrs. old. Your registration is your proof of ownership. Once you register it with Vermont, they send you a plate in the mail and with that...you can walk into ANY DMV in any state and they have to issue you a title against your Vermont registration. There is a set of DMV reference books that each state has and if they are unfamiliar with the law regarding this/Vermont, they look it up, but the net is they have to issue you a title against your Vermont registration. I was given my BSA B50 with no title and I went this route. YOu can download the form off their website. Any motorcycle under 500cc (B50 is 499cc) does not require a VIN inspection of any sort. You simply put your ViN# on the form, send along a bill of sale (regardless of how "old" that may be...), compute the tax and add to the rego fee. Note, they would not accept that I was "given" the bike and use $500 as the minimum purchase price for taxation purposes. I live in New Mexico and it worked just fine to help me title it here with no drama (otherwise, I would have had to put up a stupid amount as a bond for two years...!). The DMV here did not even blink or check the engine number for that matter, just the frame VIN.

Again, I realize in your case this may not prevent them from scrutinizing engine vs. frame VIN's but you could easily find this out by calling their 800# and ask if a VIN inspection is required for bringing in an out of state *titled'*motorcycle. If its not, go the Vermont route. If it is, go the Vermont route and don't bother re-registering it in your state (if you ever get pulled over, tell them its normally kept at your second home in Vermont)

[koncretekid]

Good information, Whitedog. I finally got a return call from the State Police who claim they have not yet got my new registration tag, but they do have the paperwork (my paperwork that I filed 6 weeks ago.) I've heard they will want to drill holes somewhere on my frame to mount that tag but I will be walking away quickly if they bring the drills anywhere near an inappropriate spot. So far the costs have been minimal, so I may try your idea, or just ride the bike using the tag off my other B50SS.

[koncretekid]

This is just a notice to all that I (we) are being blackmailed by Photobucket. All the photos that I have hosted on Photobucket have been disallowed and they are demanding $399 to allow 3rd party hosting. Because we were not advised this when we started using the service, it seems we have no alternative than to pay their BLACKMAIL request or, too bad, they will no longer post our photos!

Please spread the word. I for one, will not pay so all my posted photos (from Photobucket) will now be invisible!

Tom