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RD400 Upgrade, Courtesy of Supertune

Started by 2steve, June 15, 2019, 10:21:21 AM

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Completed the job except for break in and carb re-tune.  The blue cloud upon 1st start up was the best.
Runs great, except intentionally rich right now.  Never snapped, crackled and popped at idle, but sure does now  :)
Front wheel lofts in 1st gear without effort. Will have to re-jet and see where it is after some break in.  Chuck did a careful and good looking update porting/compression-pee-hole-plug job so I could run it with good success on the stock pipes, which are still in very good shape.
Using FPP's right now.  Front wheel RD350 with drilled rotor, 'cuz lighter weight on the front is a good thing.


Made a couple mistakes:  Left crank seal in backwards, (copied the previous job and didn't read the obvious "outside" wording on the seal), cracked the case while the goo was still fresh, pried it out and put it back in with some Ultra Black RTV to fill in the pry marks on the OD of the seal.  That stuff is the best! 
Blew the main fuse from having a positive wire in the incorrect spot near the points.  Always take photos so you can more easily catch that stuff:


Unconventional rotor marking and timing job featuring tape, Harbor Freight digital caliper, scribe tool and ohmmeter:

m in sc


Really thankful that you fixed me up with those special fasteners  :patriot: :thumbs:


Way to go Heave, may your life be filled with 2nd gear wheelies and no seizures. The caliper and tape thing was a little sketchy though, did you learn that at Auto Society?


That's full on Auto Society technique right there.  Not willing to round up a real tool.  Got to read real digital numbers instead of having to comprehend little lines on a dial  :haw:


That's a bit sketchy but as long as you take your time, it should be OK.  That's nice work on those transfers, particularly the auxiliary which is small and a PIA to get right.


Yeah, it took a long, long time. I was not feeling well and the wife was having to stay with her mom, to take care of her. Just sat down on a stool next to the table and worked for a few hours - no interruptions.

Checked it all over and over again until I was more than confident :busey:

It's a whole new world.  Can't wait to bring the pilot and main down one step when it seems safe.


Still haven't "broken in" per Chuck's instructions but making short runs about once a week.

Now happy to report that 2nd gear front wheel lift can be accomplished with a quick wide open throttle at around 6k. That's running rich and heat soaked  :thumbs:

40 more miles or so and plan to bring the pilot down to normal first, then the main later.  If it wheelies in 2nd with basically stock port timing, the main can't be too far off on the rich side.


Keep it sunny side up Heave. Party on Wayne.


Bringing this thread back to life! Great build man. Where did you get those FPP chambers? Are they still available to buy these days? I'm nearing the end of my RD350 build and I'm not happy with my DG chambers.

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College friend always had them on his Daytona Special for 30-some years. He found some raw unfinished millenniums and gave me those. "Keep it in the family" he said.
They were for DS7/RD250 but work very well.
You'd have to keep your eye peeled on eBay or similar.
Hope your build finishes well!