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Project Zeal, Chain Smoker

I have been a tad lazy with the updates on this, but rest assured, progress is happening.

Slowly but surely, most days after work I have been plugging away at the Zeal.

Coming off the last post where I had started to reassemble the carbs, I got stuck in and cleaned the rest of the carbs, replaced the seals and reassembled them. I finally got my replacement brass screws, so took great care not to smash these ones to bits. Made in Japan, sent via USA to NZ.

I also received my cool little set of carb brushes from Aliexpress.

They were pretty good at cleaning out passages and jets. Most of them were clean, but I did manage to clear out a bit more baked on crud from the No1 main jet with them.

All the carbs mounted together

And with the choke rail mounted back on

The de-rusted idle adjuster looked much better

The only other thing left to do with the carbs was to bench sync them. Bench syncing the carbs is to make sure all the throttle plates open the same amount. The throttle cable acts directly on carb No3, with the other carbs all being triggered off that carb with a series of tabs and springs. There are adjustment screws on each carb linkage so that you can fine tune the interaction between the carbs.

There are many ways on the interwebs to bench sync a carb. I chose one of the easier ones, which is to use the idle screw to open the No3 carb slightly, and adjust the idle screw so there is a slight drag on whatever you use as a feeler gauge. In my case I used one of the carb cleaning wires.

Slightly open

And then use the same feeler gauge to slowly fine tune how far the throttle plate is open on the other carbs, working out from carb 3.

This should get the carbs all in the ballpark of being fairly similar.

Once I had finished that, I moved back onto the tank. Because the damn tank was now leaking, thanks to rust, I had to line it. I purchased a KBS tank repair kit off trademe. They seem to have good ratings and it was a good price.

I used the kit to degrease, and remove any rust the other rust remover missed. It seemed to do a good job. Then the tank sealer went in. I rolled the tank around a lot, to try to get a nice even coating. Unfortunately due to the design of the Zeal tank it was hard to drain the excess, so there is a little pooling and some runs in the tank, but it’s pretty well covered, which matters.

Once cured for a few days, I filled the tank with water and left it overnight to make sure it wasn’t leaking. Sure enough it was still dry on the outside the next morning, so the sealer has done its job. Yus.

In preparation for refitting the carbs to the bike, I wanted to attend to the nasty looking carb manifolds. They are a metal base with rubber top, and it was all cracking and flaking off. Not a good look.

I removed any flaking rubber, wire brushed the metal parts, and then used Sikaflex to seal them.

This is what I used. Sikaflex 227. It comes highly recommended for this job. Strong, fast curing, but stays flexible.

I smothered it all over, and filled the cracks

The old vacuum hoses were brittle and broke when removed, so I needed to make new ones.

And the refreshed manifolds were fitted to the engine

The carbs were great fun to refit… not. A lot of wiggling and jiggling got them in place, and then lots of fiddling got the damn throttle cables back into place.

Looks a little nicer than when I got the bike

I couldn’t help myself. I rigged up my trusty fuel tank syringe, used it to gravity feed the fuel bowls, poured some gas down the carbs, connected the battery and hit the starter. (yes, this video wasn’t the first first start, but it didn’t take much to fire up anyway)

It was a tad smokey, blowing plumes of smoke and even wisping smoke out when the engine was off. Filled my garage with smoke, even with both doors open.

It sounds great though, so much noise from the carbs. It wont idle without choke at the moment, and isn’t running prefect, but the carbs do need some tweaking and tuning, and maybe a tweak of the idle screw. My latest purchase arrived the other day which will help with this, a Carbtune Pro

The smoke was starting to clear up when I decided enough was enough, so that’s a good sign. The coolant was also warming up and circulating, and everything seemed to be going well… except one thing. The gearbox/clutch.

I’m suspecting this is an electrical issue, as there are a couple of them (like the engine run switch allowing the engine to start no matter which position it’s in, and not cutting the engine when set to STOP). When the engine is running in Neutral, it will idle and run happily, but the moment you put it into gear the engine will cut. I don’t think its related to the clutch, but feels like when it’s shifted from Neutral it cuts off.

With the clutch lever out, in gear, it won’t try to crank. With the clutch lever pulled in, the engine will crank over in gear but wont try to start (yet as soon as you shift to neutral it will start straight away). I’m guessing something weird going on with the neutral switch? Will need to investigate.

Now that I know the engine runs OK, hopefully I can sort the gearbox issue and make sure that works OK and then I will strip the bike down and deal with the frame. Fun Fun.


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