Another shot of the Enduronut prepped cylinder:

Ports reworked and polished, the head shaved and polished, piston slightly reworked for better performance, and gosh, wouldn't it be a shame to dump all that fresh new oily exhaust into a nasty old stock pipe? EN hooked me up with a fresh in the box, NOS Torque Engineering Chamber which will eventually find a home on the bike if it is not too loud.

This is what goes into a 125-175 conversion such as this:

Head, cylinder, piston, piston pin, circlips, rings, head and base gaskets, exhaust gasket, carb gasket, and piston pin bearing (it is different on the 175 than what is on the 125). I ended up not needing any of the round seals, but will replace them if need be later.

Now the teasers - The assembly has started. I am anticipating completion in about a week, depending on my free time. All the parts are here. I have left the oil and fuel tanks un-painted (i.e. left them stock), but anticipate that may happen later.

The motor went together nicely:

NOS clutch cable installed, fresh paint on the stator side covers (the other side was fine). I used Duplicolor Caliper Paint which ended up being almost a perfect match for the engine covers. Hopefully it will be more durable than most others. The little yellow hose behind the cylinder is a new crankcase vent hose.

To see just how dramatically the bike is changing, here is a before and after picture of the voltage regulator area.

Before:

After:

You can see the nice gold-toned plated NOS voltage regulator direct from Singapore!

Renthal (non-o-ring) gold chain and new factory sprockets were also added.

Below is a picture of the cylinder that Enduronut ported ....... as you can plainly see from the casting, this engine/cylinder is obviously a 125 ..... and not a 175!

That is Enduronuts hand, carefully replilcating the 123cc casting. by hand, on the base of the newly ported 175 cylinder . . .

The power of the Dark Side is great, and only true Enduroholics can be trusted to use it for good . . .

I got my carb back, after a full on dip in the cleaner, it is nice enough to eat out of. I changed out the main jet (Richer) for break in and installed it.

I also got the taillight rebuilt, new stainless socket heads for all mounting points and the new grey cable sheathing from Vintage Connections .

Other than blinkers, which I waited to install until after I got the bike all going (I didn't want to add any possible electrical issues until it was running right and all the stock stuff worked) the back of the bike was mostly done. I also needed to add the rear rack, but that would happen with the blinkers to minimize the possibility of scratching things.

I was working in some really close quarters on this thing and it had been pouring down rain for a few days, so the only picture of the whole bike I could get was two photo's stitched together. It makes the bike look somewhat out of proportion, but it will give you an idea of how things were coming along.


More soon!

_

OK - another day, another post.

The controls were next. Handlebars, levers, mirror mounts, grips, cables in place. I was able to get outside between showers and get a few pics showing the progress a bit better.



The lever ounts were stock and some modified mirror mounts were added, as I really hate the original style which tend not to stay put well. I also adapted some "dogleg" levers to work on the bike. The brake lever being a challenge, as the lever did not include a little nub to operate the early style brake switch which mounts under the lever.





I took a stock lever and laid it next to the dogleg to locate the spot, then drilled a small hole, and inserted a roll pin to operate the switch. Cheap and easy, and allows the later levers.








The rubber lever covers were located in a NOS bin of aftermarket stuff at a place called Bent Bike in Lynnwood, WA. Nice to keep the lever clean in really bad conditions. The bike is also using the repopped grips from the Motobiker store on Ebay . The ONLY grips to make the bikes like original.

I was next able to get it off the stand and test the shocks, both the front and the rear feel really nice.



I used 7.5 lbs oil in the fronts and the Showa shocks on the rear are set at their softest. I may need to increase both of those after riding it a bit. The steering is a lot smoother now, after cleaning and re greasing the steering head. This bike also has a factory steering damper designed for the DT series which is a direct bolt on! These really help on a bike which is mostly street ridden. Fits up under the steering head.

I was able to locate a couple of NOS factory paper air filters so the bike got a new breather!


I also spoke earlier of the NOS Torque Pipe that I got from forum member Enduronut. I was not ready to install it when I wrote this originally, but I had to get it out of it's hermetically sealed case and test fit it......

As you can see - it feels right at home!

The tires are Chen Shin. 4.00-18 on the rear and 3.50-18 on the front. They are copies of the old Dunlops and actually ride out pretty well. I will find a set of streetable knobbies in similar sizes for the bike, 'Cuz I really like the look of them. I have an extra set of wheels I could use for them too.

I will still be installing the stock pipe for break-in as we discussed. I just had to see what the chamber looked like on the bike! I really couldn't be happier with it! [:-!]

Since I planned on riding this bike on the street, I later did a short test on the comparative noise levels of the factory VS the Torque Engineering pipe. I live in a town where the police are not too strict on such things, but it is interesting. NOTE: The pipe in the test has an aftermarket spark arrestor which will be documented later in the thread.



More on the way!

I'm currently converting a AT2 125 to a 175 as well. Can't wait to a have an electric start 175. Would love to find an after market pipe for it too

Your project is looking awesome. I'm envious of that nice pipe. My CT1 pipe is getting the works as we speak.

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Sleeper!

The sleeper pipe on this bike would be the ultimate upgrade. The chamber is really overly wide, so it is a bit uncomfortable to ride with it - however, it Kics Butt with the better exhaust. If you build a true sleeper pipe then you will get the performance as well as the riding comfort, and of course, the correct "look".

If you are building that yourself, please start up a thread and document your work. Lots of folks will be interested!

Alas tis not my handy work. Handed it to Dave and Don at the Boron ride last weekend. Should be ready for the land speed attempts at El Mirage dry lake bed this weekend. I'm not competing. Just watching and putting around.
Your bike is looking real nice.

Give them a call and tell them to document the build and post it up :P

Seriously, I suspect there are a lot of other folks who would be interested!

What a great story! The similarities are too vaste here though Mako. :ohmy:
The first bike that I got my permit with in the same year, 1974, (the day I turned 15 1/2) was a yellow AT1 exactly like that, that I bought from an older neighbor. It was the first bike I snuck on the open highway, as well. That poor little thing made a zillion store runs.
I also later converted it to a 175 from a parts bike CT1 that I got for free. The downside was my electric start never worked and after a while, the battery would quit charging. Being young and broke, I converted it to the flywheel mag setup off the CT1 and never looked back.
The power difference between the 125 and 175 was obvious. My old Yamaha dealer back then told me that the 125 with the electric start and milder power characteristics was really made to be a "wife's bike". Not sure how true that was....
I finally stripped it with some mild porting and a Bassani pipe in 1976 for strictly "motocross" use when I got a Honda CB 350 for the street.
Great memories indeed! Thanks for sharing!

I'll Give it a shot.