Truenotch

Truenotch's Tiny Tracker - Yamaha MX100

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There's a fair few thing to sort out (as you'd expect), but the first thing I wanted to know was how it would look without all the superfluous 1980's bits. I stripped it back and was pleasantly surprised by its bones: 

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Popped the head off to have a look at the cylinder: 

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Yip, the bore is quite rusty. After a quick measure it's still at the factory size (52mm) and there are piston options for up to 3mm overbore in .25mm increments. First big job on the to-do: rebore. 

Then I got it naked: 

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I decided it might look better with the bars from the FS1, so I bolted them on and pushed it outside for a few pics: 

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Oh yeah, did I mention it's small? Here's its stature compared to the FS1. The seat height is quite low with the '80s bolster seat removed. 

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It also has a decent dent in the tank that'll need dealing to at some stage... and I'm definitely leaning towards paying someone to do it. 

 

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Then I decided to delve a bit deeper. These are CDI, which I'm stoked about as the points are the biggest letdown on the FS1. 

I was pleasantly surprised to find that the magneto cover screws came out without needing an impact driver. The cover took a couple of taps to come off, and then this gushed forth: 

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I need to get my flywheel puller back from @flyingbrick to assess the situation properly, but that bad boy was full of rusty water! I'd say the cover area was at least half full by the look of the flywheel. 

I'm quite confused about how it got in there... My current theory is either that water has slowly seeped in during it's time stored outside or the thing was driven through a lake before it was parked up and maybe took a mouthful of water into the engine, which has eventually come out through the crank seals? Who knows! 

 

More investigation required. 

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That's funny, I have a yamaha mx1000. A glorious 250...... 

 

 

 

 

 

 

 

 

 

 

 

 

Watts per channel.. 

 

 

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10 minutes ago, yetchh said:

That's funny, I have a yamaha mx1000. A glorious 250...... 

 

Watts per channel.. 

Hah! Steve and @mark105 had a similar experience with Steve’s DX100. Apparently his bike is a keyboard.

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Pulled the flywheel off: that’s one crusty stator plate! 

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Any bright ideas on the beat way to clean the coils?

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PCB cleaner. They have a shellac type varnish on the old ones and any alcohol will dissolve it

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Jesus.. what a mess.

What about a soak in vinegar? Should (im no chemist, only guessing) disolve all the rust and leave the varnish and copper alone?

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Gave the magneto and cdi pickup a good clean and threw it back on. Checked for spark and it was strong. Win!

Today I collected a POS RX125 parts bike that had a DT100 engine. I took the gamble that the engine would be the same as it had a fresh oversized piston and machined barrel. 

Turns out there’s quite a few subtle differences, but it’s mostly the same. The barrel has the same casting numbers and looks identical. 

Got it home and started ripping bits off it. 

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fitted the barrel to the MX100 

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Chucked on the FS1 tank as it still has some premix from the East Cape mission. It looks quite good with this tank! 

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Got it together enough for a test run.

 

Success! It runs. That’s one win for the weekend :) . 

 

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35 minutes ago, TimShadboltfan27 said:

Let me know if you wanna flog any rx125 bits off I could be keen...

Flick me a PM with your shopping list. At this stage I’m only using the engine, rear wheel, swing arm and some electrics.

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