Tales from the Emporium

[NordieBoy]

That's a cool shot Fran! Have you submitted it for the calendar?

Not yet, I'm only allowed to submit 2 more so I'm saving up

It's amazing how much weight gets packed into stock exhausts, I shaved off over 2kg going to an SXC can on the 640.

That's the main reason I like the SuperTrapp 2.5kg over the stocker 5.5kg.
The bonus of the supertrapp is that it dosn't get as hot and is smaller diameter and further away from the side panel/saddlebags -

I'm not interested in the extra power/torque

.
Downside is the noise level.



mx_rob on TT is trying an FCR-MX 39mm carb on his DR now and thinks it should get better power, better torque and better mileage.
It fits onto the carb boot and just needs a manifold adapter made...

[clint640]

The 640 uses the same BST40 carb as the DR, the FCR41 comes std on the 625SXC & is a common conversion for the 640. I've ridden an SXC & you definitely get more instant power with the pumper but outright power & torque aren't much different (it was totally stock though). It wasn't enough difference for me to want to spend the $$$$ on the FCR anyway.

I've heard one or two say the FCR is more efficient but most reckon they use more gas. It probably depends on tuning & riding style quite a bit.

Cheers
Clint

[NordieBoy]

The FCR-MX has a bearinged slide and accelerator pump.
Rob has been told he should use the 41mm but he's going for the 39mm to keep the gas flow speed up and he's mainly interested in torque and mileage not overall HP.

[NordieBoy]

Sounding good...

It runs! I started out with all the 450 Yamaha jets... my poor engine! We were leeeeean. It still lofted the front wheel way easier than with the BST. Back to the garage and off came the carb. Every jet that came in the OEM 450 Yamaha carb is useless except the slow air and main air jets. I upped the pilot 1 step to 48 and installed an EMM needle with a 168 main. Holy snikies this thing is a buldozer. I'm so friggin pleased with this thing already and I haven't even begun to test all the jetting. The FCR seriously enhances the strength of the power band on this bike just like I was expecting. Roll-on from a dead stop will lift the front wheel right off the ground. No way would the BST allow the engine to torque down that low and pull so hard. I think the bike is pissed at me though because it seems to have ajusted it's own rev limiter down lower. Seriously though, this thing hits the limiter so fast that is seem like a two stroke with a way too big main jet. And when you shift it it just yanks you so you know you wasted acceleration in over reving the engine. The torque and roll-on are just amazing though.

So right now my initial metering point on the needle at first crack of the throttle whet from 2.75mm to 2.71mm. I'm sure I'll need to select a different needle, a little bit leaner, but my goal is to have it right in the middle or one clip lower at sea level so the boys in the clouds will have some place to go and so that it will have plenty of adjustment for those that want to run or go back to a stock muffler. I'll be selecting my final pilot to run at 2 to 2-1/2 turns out for the same reason. It will also leave plenty of play room for the guys seeking maximum fuel mileage. The main will obviously have to be changed for the stock muffler and for the guys at big elevations.

Thing (1) I don't like: The throttle return spring. Wow this thing is light! Just the weight of my hand can have the thing accelerating away. Some guys might like it but I find it a bit too easy to twist. I will check into a stiffer spring... and since I bought this carb used the PO might have installed the light spring I've seen advertised for them. I guess I'll just talk to Sudco... maybe they'll know right off what I need. Anyway, it's dinner time... jetting continues tomorrow after work!

[NordieBoy]

Came home in the pouring rain today via the Sherry River Road part of the Dusty.
I can see where it'd be annoying if they closed the gate at the other end...
What's with having the middle couple of Km's of a road closed to public use anyway?

It is a nice bit of road though.

Came past all the rally cars parked up at the old Tapawera Forestry Camp service area doing the final round of the NZ Rally Series.
Blew away an RX7, RX3 and Escort
They were keeping well below 100 and I was keeping just below 110.

[NordieBoy]

FCR39-MX update from rob_mx on TT.
Sweet...
Not affected by wind/airbox pressurisation etc and runs really well at very low revs.
The BST has problems at really low revs as the slide is held up by vacuum and that only happens on an intake pulse. As the pulses are quite far apart the slide drops significantly between pulses - snatching and not smooth.

[NordieBoy]

Went over the Takaka Hill yesterday to Motupipi and the first day of Top of the South MX Champs.
Got a few photos and also some footage of The Hill (to be youtubed) so people can see the whole hill from the Takaka side coming back to Motueka.

[NordieBoy]

Deleted the movie...

[NordieBoy]

New version...
Takaka Hill ride - The Musical!

[Mole_C]

Any reason you drilled the holes in those places instead of just at the top, bottom and sides Nordie? Would more smaller holes be better or worse?

[tri boy]

Two things I learn't from the vid Fran.

1 Sth island has reaalllllly long earth tremors, (8-9mins)

2 You have too much blue sky. I'm coming down to take it back to fog town.

Nice work.

[windboy]

Nice day, nice road.... Tricky passing that last one before the summit nordie, was it a ford cosworth?

[NordieBoy]

Any reason you drilled the holes in those places instead of just at the top, bottom and sides Nordie? Would more smaller holes be better or worse?

No reason.
4x9mm holes would probably be the sweet spot.
At 7.5mm I noticed an improvement and at 11mm I think it's just louder and closer to the edge of the metal.

[NordieBoy]

Two things I learn't from the vid Fran.

1 Sth island has reaalllllly long earth tremors, (8-9mins)

2 You have too much blue sky. I'm coming down to take it back to fog town.

Nice work.

1. Thumpers vibes combined with 15 fps. Next time I'll try 30fps 320x240 but that's only 1h 45m on a 2gb card instead of over 3hrs.

2. Not much blue sky here now. You been already?

[NordieBoy]

Nice day, nice road.... Tricky passing that last one before the summit nordie, was it a ford cosworth?

Nah, a little Laser or something.
The camera is mounted on the left handlebar. Up at head level I can see over most things.


Must.....get.....camera.....helmet.....mounted.... .
(Before Carl does something nasty to me)