Yamaha YSR "The Pole Smoker"

[Duke Blackwood]

Just went for its maiden voyage around the block and the rose tinted glasses have come off... holy shit. It will be an extraordinary achievement for man and machine if I can complete Te Urewera Undertaking on the ysr. It is comically unstable at all speeds. The brakes are surprisingly doughey for such a light bike. It swaps back and forth between unstoppable wheelie machine and bog monster. Unpredictably. And I found myself adopting the leg drag moto-x style even on the seal. And I saw a cop (haven’t installed my plate yet). 

 

Essentially, the absurdity has bolstered my confidence, and I can’t wait for this trip haha. I thought I was going to have quite a quick straight line bike compared to the scooters, but I’m beginning to think I may be the underdog, and the only way I’m gonna keep up is to ride the wheels off it. I will be a permanent roost. By the end of next weekend I’ll be a demon on this thing. 

 

But as a precaution, I’m gonna make some big ass crash bungs....

[datlow]

30 minutes ago, Duke Blackwood said:

big ass crash bungs....

https://www.thewarehouse.co.nz/p/milazo-training-wheels/R2109478.html

 

but seriously good stuff getting it all going

 

[johnnyfive]

I admire your courage. 

[Truenotch]

5 hours ago, Duke Blackwood said:

B7 Yuss! But damn, it could have been a YSR plate  . 

Sounds like a perilous machine. Can’t wait to see it in action. 

[Duke Blackwood]

More test riding tonight, once I got the fuel issue cleared up it ran far more consistently and I think it’s going to be wicked quick for what it is. It does have a problem though where after a spirited squirt when you clutch in the revs skyrocket and when the killswitch is hit to stop the overrevving it keeps on overrevving so I had to pick a high gear and dump the clutch with the brakes on to kill it. The theory is that it has the wrong plug and the one in it is waaaaay too hot. It’s gearing is currently really short, wheelie prone, but doing an indicated 70kmh at half throttle with a gear and a half to spare... on a gravel driveway in the dark. But I had a helmet on AND I have good life insurance.

[Lewis142]

Has anymore progress been made looks mint, I’m swapping a rxs100 engine into my ysr need to make some engine mounts up could you suggest how I’d do that? Guessing some flat bar steel would work?

[Duke Blackwood]

Hey Lewis, shit yeah heaps of progress, Ive just been really slack about updating my thread! The overreving thing was a combination of wiring and a split carb intake boot. Intake boot from the wreckers $15 and 15 minutes wiring for the old man and it was running OK. I was seriously running out of time for the big Urewera ride and as it transpired I loaded it onto the trailer and took a backup bike as the YSR had still never been ridden on the road. I installed. Larger rear sprocket (Which I had made myself on a waterjet) in the motel car park the morning of the ride and when we turned up @johnnyfive ‘S house I filed the teeth smooth in his driveway. The Urewera ride was my test ride. A 600km predominantly gravel test ride haha. Initially it was smokin and running quite rough, but as the pipe cleaned out it got faster and faster. It’s potential for tuning is still massive, its not half as grunty as it could be, but because its so light and small i still had it up to near 130kmh! I was passing cars on the open road haha. The gravel was a pretty tall order and in places I worked my way right to the back of the pack, not to mention developing a few cramps, but on the seal it was damn near untouchable and probably the 2nd fastest bike there (after @anglia4 s RG150). All the mods held up well and in particular the frame strengthening was really worthwhile. I had an issue on the first day where my float had jammed and the bike would only run at full throttle which was fucking sketchy on the gravel, lots of clutching, and the clutch was so heavy by the end of the day i was weaping in my helmet... and I spit my chain twice after gettting airborne fording streams... the second time bent my shifter shaft and caused a major gearbox oil leak, but we were so close to the end that I opted to ride on; and thus I completed the entire Urewera undertaking on the pole smoker.

It is the third greatest achievement of my life after my two kids.

This bike goes hard for what it is.

I have not even sat on it since hahaha.

[Duke Blackwood]

As for engine mounts; my TS185 engine is still in the ts185 front subframe, cut below the neck and bolted through to my down tube. The upper rear is made from angle iron and the lower rear is waterjet cut (which could easily be made with flat bar). I recommend welding a doubler plate on the main upper frame horizontals and putting a triangular gusset in the frame window under your thighs. My YSR had been running with that engine mounted (poorly) already when I bought it and the frame was one wheelie away from being two half frames...

The factory top triple clamp is only decorative too; it’s just there to mount the handle bars... I think it’s 1.6mm thick? So keep an eye on that... I’ve got CAD files for my triple clamps which you’re welcome to, but they’d be expensive to commission without some engineering contacts.

[Duke Blackwood]

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[Duke Blackwood]

[Duke Blackwood]

This is my most pressing repair, the shaft has been eaten by larger front sprockets in the past, probably why it bent so easily... lucky I’ve got spare engines a plenty.