Discussion in 'GAS POWERED BIKES' started by PeteMcP, Aug 8, 2017.
Paint looks great!
DRIVE-TRAIN OPTIONS & DECISIONS...
This post is really to show anyone interested enough what the options are when it comes time to decide how best to orientate the 3.25:1 gearbox to my DECOLINER's mini-moto engine. Who knows, it may be of some help to anyone considering this motor/gearbox set-up for a project they have in mind.
Pics show the options. Time for me to decide which motorized chain-line I'm going to go with. Problem is, whilst aesthetically I prefer the look of the gearbox installed horizontally, I also prefer the look of the lower down chain-line when the 'box is installed vertically.
I'll also have to think carefully about installing a really effective chain tensioner given that I'm using an almost double length chain compared to a regular mini-moto's set-up.
I like the down position. It ties in with the side plates and the lower chain line looks better also.
Just my opinion.
I like it lower as well. Both for esthetics and safety.
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After mulling things over these last 24 hours, I agree Jim. Couldn't live with that awkward-looking higher chain line.
But with the gearbox installed vertically I do need to fit suitably short pedal cranks to avoid them fouling the 'box. So I've fitted a 'Truvativ' US-to-Euro bottom bracket conversion and ordered-up a 32T chainwheel with 130mm long taper-fit crank arms and a suitable crank axle.
Seem like short crank arms? With a pull-start motor fitted to the Decoliner I'm not planning on doing much pedaling other than to activate the rear coaster brake.
Another option for the crank arms is to use a wider set. There are three piece sets made specifically for this issue compatible with American BB that will fit your frame.
Here's an eBay link. You might find them in the UK also.
The 130mm (actually stamped 127mm) crank arms and rubber pedals I ordered from eBay showed up in today's mail. These short crank arms combined with a 3R crank axle to provide sufficient offset give just the correct amount of clearance to prevent the pedals fouling the lower edge of the gearbox casing (see pics). There's about 4mm of clearance - not a lot I admit but as they say, a miss is as good as a mile.
Yeah, maybe I could have went instead with the wide crank set Jim at TRM suggested - but these are most definitely not available here in the UK. What's more, the Californian seller Jim provided a link to says in his listing 'DOES NOT SHIP TO THE UK'. Even if he did, I can guarantee the shipping cost, plus 12% import duty and 20% VAT would have at least doubled the cost and therefore soured the deal. Total? approx. £80! I'd expect them to be hallmarked for that! (lol) For sure my 130mm long crank arms and 3R crank axle sourced from a UK eBay seller costing a mere £17 seem a no brainer solution in comparison.
Believe me, I tried without success to buy a set of those US-adveritsed wide cranks for use on my previous build, the Indian board tracker tribute, but back then neither of the two US sellers advertising them had them in stock. So I went instead with a home-brewed solution and welded another crank boss onto the left side crank arm which provided the clearance my left side pedal needed to clear the Indian's pull start casing. (see last pic).
It goes without saying, I'm always grateful for all the helpful suggestions and encouragement received throughout this build from forum members. Keep 'em coming.
I like the shorter crank arms, looks great!
WORKIN' ON DECOLINER's EXHAUST...
These latest pics show progress on the Decoliner's exhaust. I've temporarily posed the exhaust on the bike to show how things are shaping up. Just not sure yet how long the tail pipe will finally be - so it may be cut down in the near future. I'm pleased how the flexible Polylock section of the system allows me to curve it to match the underside of the TRM tank's profile.
Exhaust work involved cutting the flange off the manifold, removing an inch from the manifold's length, then re-attaching the flange. There wasn't much access room so I silver soldered the flange back on rather than risk making a bad weld bead that wouldn't allow the fixing bolts to snug down correctly - which was exactly how the Chinese welds were on the factory pipe!
Next I removed a small amount of material from the tail-end of the expansion chamber so one collar of the 400mm long x 32mm dia. flexible stainless Polylock pipe was a snug fit inside it. I ordered the Polylock flex from a custom exhaust shop on eBay here in the UK. Made to measure and delivered in 48 hours. Cost? £14 inc. shipping. That's what I call great service and a terrific deal.
The 35mm stainless tail pipe was an off-cut I had lying around from when I built my replica Morgan 3-Wheeler a couple of years back. Turned out the fish-tail tip - which is nothing more than one of three alternative nozzles which came with my hot air gun - was a perfect interference-fit inside the tail pipe.
Baffles...? We don' need no stinkin' baffles...
Now I just need to re-paint the expansion chamber section of the exhaust, then as soon as a couple of exhaust brackets I've ordered arrive, I can fit it permanently.
Wow...serious piece of artwork!
Love that exhaust!
The ducktail fenders I ordered from Classic Cycles in Germany over the weekend showed up today - so I wasted no time fitting them to DECOLINER. Ducktail fenders were unobtainable in the UK and purchasing them from the US would have been just too expensive what with import duty and taxes. They were pricey enough from Germany, but for me, ducktails were an absolute must-have for the deco look I was after - so I bit the bullet and had Classic Cycles ship me a set. Now they're installed I reckon they were worth every penny. I feel my DECOLINER is beginning to take shape the way I envisaged.
Today I also marked and drilled the exhaust's fishtail to make it a little more 'period' looking. Just a minor detail - but it all adds to the finished picture.
The expansion chamber is now re-sprayed in silver hi-temp paint, so I'm itching for the brackets to get here and get the exhaust bolted up.
Bit of a minor set-back today. I'd ordered a plastic mini-moto gas tank from an eBay seller who's listing described the tank capacity as '1.5 Litres'. Soon as it showed up today I could see it was way too small. I filled it with water and decanted the contents into a measuring jug. Sure enough, way short of being as described - a mere 0.7 Litre. Back to the drawing board.... I may just make my own gas tank from aluminium.
Such a nice clean build going own here!
TANK LIGHTS INSTALLED...
Not been able to do much on DECOLINER these last few days. This weekend I found it hard to tear myself away from watching TV coverage of the Elite Women & Men's road race in Bergen, Norway.
However, I did manage one small job, installing the 12v marker lights into the tank. The nickel-plated bezels really set these off nicely. Is it just me who's reminded of ET when I look at these pics...?!
CHAIN GUARDS / FENDER BUMPER FABRICATED...
With both of DECOLINER's chains fitted, I turned my attention to designing/making the left/right chain guards. In keeping with the bike's deco theme, I wanted to create the impression of 'speed whiskers' flowing from the polished alloy motor mount all the way back to the tip of the rear fender, so I fabricated the guards using aluminium rod which will eventually be mirror polished to match the motor mount. Pic shows the guards loosely in place.
LEFT/RIGHT CHAIN GUARDS INSTALLED...
Now the alloy chain guard parts have been polished, here's a sequence of pics showing the components and their installation. Can't yet fasten the rearmost end of the bumper guard to the fender till after the tail-light I've ordered shows up.
Sharp-eyed folks may have spotted that I've drilled pedal crank arms.
FUEL TANK ... PARTS READY TO ASSEMBLE
DECOLINER's alloy fuel tank parts are now ready to be welded...
Haven't yet decided if the tank will be on display or hidden inside a leather bag suspended behind the Brooks saddle.
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