The RD400 drag bike

[MK_WF]

Concerning the ignition, I'm not sure if the Vape is the best choice for a drag bike.
Performance wise it's absolutely ok, but you could save some weight & cost by getting rid of the complete rotor/stator asy and just fit a small trigger wheel & pick up plus a decent DC CDI (Ignitech, Zeeltronic, HPI) that's being fed from a small 14.4V LiFePo.

On my race bike I run that setup and it works just fine.
Ask Dave Whattam about his opinion - he's also doing plenty of Ignitech applications for RD's.

[AMCQ46]

Martin, that was also the direction I was imagining, to just have a pickup on the crankshaft.

If you could post up some images of the pickup, that will get me thinking.

Also what carbs are you using there? They look designed to be used at a steep intake angle (with the float bowl and slide still horizontal and vertical), where as mine have the float bowls at such an angle that I am not sure they should work. Last owner said he adjusted the float height to compensated, but it doesn't look right in my logic.

Thanks for the tip of Dave Whattam

[MK_WF]

My setup wouldn't help you as I went for the dark side (aka cheap and dirty).
I removed the magnets from the rotor, so the inertia was reduced significantly but let me keep everything else in place (mounting plate & pickup). Just the stator had to go, too, and voila - minus 1.6kg accomplished.
The Ignitech offers a wasted spark elimination, so I can run two independent HT coils.
Also have the shift light and shift sensor option active (which enables upshift without clutch).
The ignition & power valve maps are 3D (advance/position vs rpm vs TPS).

Other weight savings were done by an R6 front end (which shaved off 6kg from the usually used RGV250 lump) and DIY aluminum tank/rear subframe.
Designed & welded the pipes on my own, too.

The carbs are RGV250 VJ21A (the early models) which have 32mm.
The later VJ22B and Aprilia RS250 had 34 mm but a lot of unnecessary stuff like solenoid air valves. They're much harder to set up.

Here's a small video that I just dug out today on another occasion

[AMCQ46]

Clutch all back in then spotted that whoever painted the clutch side engine cover didn’t bother to mask the gasket face !!

So 2hrs of scraping needed to get back to the metal





I used some gasket compound on that side to compensate for any imperfection and put a light coat of grease on the engine side so hopefully the gasket will pull off next time I have to take the cover off.

Oh and it now selects the gears


Sent from my iPhone using Tapatalk

[Duffy1964]

Great job Al, getting there bit by bit.


Sent from my iPhone using Tapatalk

[sirch345]

Good to hear "it now selects the gears", well done Al

Chris.

[MK_WF]

On the 350 YPVS models I've seen plenty of clutch covers that had paint on the sealing surface.
And a couple of them were bone stock, so I assume Yamaha didn't care, too.

As I always use additional thin layer of Dirko silicone sealing, I never had issues leaving the paint on.

[AMCQ46]

After all the time off for weddings, New Zealand Holidays and Christmas, I am back onto it with the RD400.

After trying for ages to work out if the FEMSA ignition was wired correctly or working in anyway, i gave up and bought a new ELEXTREXWORLD ignition system designed for race TZ Yamahas (no battery’s) but also fits and works for tuned air cooled RDs.

So now I have sparks , just have to sort out some kind of fuel tap solution for the PW50 tank.

[lloydie]

One step closer

[tony.mon]

See if you can get it running in time for the Brand's Hatch trackday I booked for April.
You'd still beat me to the first corner, but I might stand a chance to get you back at Druids ...

[sirch345]

2B14D541-F53F-4816-A5FF-C0E692DAB25D.jpeg

After all the time off for weddings, New Zealand Holidays and Christmas, I am back onto it with the RD400.

After trying for ages to work out if the FEMSA ignition was wired correctly or working in anyway, i gave up and bought a new ELEXTREXWORLD ignition system designed for race TZ Yamahas (no battery’s) but also fits and works for tuned air cooled RDs.

So now I have sparks , just have to sort out some kind of fuel tap solution for the PW50 tank.

That's looking more like it Al

Chris.

[neil]

If it gives you a bit more incentive dates are up for top speed days at Elvington and Melbourne on Straightliners website. Open day weekend is 25/26 February and first top speed day is Monday is 27th March. Guy Martin often has a go on his Hayabusa, Henry Cole says he's going to have a go this year as well. Good luck with it.

[AMCQ46]

Thanks Neil, that gives me some real deadlines
So the good news is it starts and runs ….. I can safely say I will piss off my neighbours when I try and test ride it up the lane , it CRACKLES, rips and snarls like a demented beast!

I cant be arsed trying to put a video on here, but I can WhatsApp it to anyone who is interested

But then the throttle cable broke inside the twistgrip

So spent the afternoon making a new cable end with solder.
I drilled a 6mm hole in a piece of wood, cut a slot for the cable go in so its cleaned and frayed end is In the middle of the hole, put a 6mm drill tail back in the wood from below to set the required width of the cable end and then filled it with solder….. worked a treat

[Duffy1964]

Great news it’s alive Al send me the video please


Sent from my iPhone using Tapatalk

[lloydie]

It’s alive , well done