DT175A racer.

[Nathan S]

And for Mainline:


I have little doubt that Scott will be annoyed at me when he sees this... 

[vandy010]

it just so happens, i have an MX175a/b head sitting in my shed that i probably won't ever use.
hmmm, i wonder.........

[Nathan S]

Fired it up today.

Had some issues with the ignition - the stator was kaput, and then I fitted a wrong flywheel (which made it run backwards...). Took a little while to sort out, but no real drama.
On the bright side, I've now tested my small pile of CDI boxes....

Plus there's a crack in the exhaust, and the carby leaks a bit of fuel. And the jetting is a long way out (too lean off the bottom, too something up high).

BUT, it still goes great - much better than I expected. Much better than I was willing to explore in a wet suburban backyard... Hopefully I'll get a chance to take it for a blat at a mate's farm to sort it out before the next HEAVEN round.

And fudge me, its noisy! Even noisier than the YZ125A (which runs the same pipe), but maybe it won't seem so bad at a race track?!
Fitting a silencer is going to be tricky, as any extended stinger will get in the way of the DT seat latch.

[mainline]

I don't think he'd mind too much, you've done a nice job of fitting it, it looks like it belongs there.

[JC]

Nathan,

I love ya attitude too - making something worthwhile cheaply out of a DT175 is no mean feat!

Well done.

I've been toying w the idea of something similar based around a 185 Suz.

Is yr YZ 175 a real YZ175 or YZ125 w DT top end?

[Wombat]

Guts effort there Nathan! I've ony just opened this thread and read it from your first post.
Great description too - the whole thing came together beautifully and looks good, well done!

[Nathan S]

Mini-update:
Was way too lean on the main jet. Given that it was a150, this isn't really a suprise.
Did some research and found that the factory YZ175C mainjet was a 380.
Fitted  370, and it was way too rich.

Went through my collection of jets and carbies, and discovered that I had nothing between 170 and 370 (!?).
So I bought a 220, 270 and a 320.
The 220 was a huge improvement, but I fitted the 270 to see what happened, and it was even better.
Fine-tuning will be on Saturday.