Author Topic: New resto - 79 RD400 Daytona Special  (Read 4478 times)

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Offline 5port

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Re: New resto - 79 RD400 Daytona Special
« Reply #30 on: January 04, 2023, 10:31:00 AM »
Yes, the VM30 needs the big rubbers.

5port

I did 28s on this one. I did a few TM30s on recent moto restos and got confused. :) I saw no reason to go bigger than stock as I am doing no porting or crank stuffing or anything really fancy.

OK, VM28's sound like plenty.  There are quite a few experienced RD racer/Tuners that think the 28 bored to 29mm is good for even a tuned RD. However, they will be modified to Primary type jetting and I would go that way with your bike. The OE Bleed type Needle jet is not very good with unrestricted intakes.  You will find leads on modifications for Primary jetting on Dale Alexanders and Dave Friests tuning write-ups.
 You do see VM 34's on some full RD race bikes and 34's might possibly suit them at the very top end.  However, remember that the piston port TZ350 was better suited to the big 34 and 38mm carbs but, the reed TZ700/750 stuck with 34mm.
All I can say is that my tuned Track RD350 runs great, straight off with Primary modified VM28's.

Cheers

5port     


5port

Offline Hammer 663s

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Re: New resto - 79 RD400 Daytona Special
« Reply #31 on: January 04, 2023, 05:15:13 PM »
Yes, the VM30 needs the big rubbers.

5port

I did 28s on this one. I did a few TM30s on recent moto restos and got confused. :) I saw no reason to go bigger than stock as I am doing no porting or crank stuffing or anything really fancy.

OK, VM28's sound like plenty.  There are quite a few experienced RD racer/Tuners that think the 28 bored to 29mm is good for even a tuned RD. However, they will be modified to Primary type jetting and I would go that way with your bike. The OE Bleed type Needle jet is not very good with unrestricted intakes.  You will find leads on modifications for Primary jetting on Dale Alexanders and Dave Friests tuning write-ups.
 You do see VM 34's on some full RD race bikes and 34's might possibly suit them at the very top end.  However, remember that the piston port TZ350 was better suited to the big 34 and 38mm carbs but, the reed TZ700/750 stuck with 34mm.
All I can say is that my tuned Track RD350 runs great, straight off with Primary modified VM28's.

Cheers

5port   

Thanks. I plan to bolt it all on as I have it, and then see how (if?) it runs. It hasn't been run in many years so I don't even know if it will. I expect a good bit of trial and error, and some parts (electrical) that might be bad.

I have a buddy with a Daytona with TMs that he can't get running correctly. Once I get mine figured out I will attempt to get his set up right. Reading many threads here leads me to believe that these are super sensitive pumps and intake/exhaust mods, not to mention porting/milling, can really change how they behave, and often for the worse. I sure do like me a stock bike that runs clean. ;)

Offline 5port

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Re: New resto - 79 RD400 Daytona Special
« Reply #32 on: January 05, 2023, 09:25:55 PM »

Thanks. I plan to bolt it all on as I have it, and then see how (if?) it runs. It hasn't been run in many years so I don't even know if it will. I expect a good bit of trial and error, and some parts (electrical) that might be bad.

I have a buddy with a Daytona with TMs that he can't get running correctly. Once I get mine figured out I will attempt to get his set up right. Reading many threads here leads me to believe that these are super sensitive pumps and intake/exhaust mods, not to mention porting/milling, can really change how they behave, and often for the worse. I sure do like me a stock bike that runs clean. ;)

Yes, good Flat Slide carbs could probably offer some advantages but, finding a good match and getting the jetting right through the range seems to be tricky.  For sure, the old VM carbs are well understood and if you run stock, no modifications are needed!
You might be able to jet your carbs without problems. However, with a non-standard, low-restriction inlet and different exhausts you might find it interesting, even though your porting is not wild.
If you decide to try the Primary jetting modifications have a read of the carb parts in my "RD350 TRACK BIKE" thread on these pages. 
Also, I would go without the X-over, they make it awkward in my experience.  I found they weaken the carb pressure signal and make low-mid range very difficult to get right.  But maybe that is just me?

5port     

5port

Offline Hammer 663s

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Re: New resto - 79 RD400 Daytona Special
« Reply #33 on: January 08, 2023, 01:19:32 AM »
A few shots from the last couple days. Motor is ready for the top end once I get the jugs painted. I will go to an electronic ignition so stopped here for now. Every seal in the motor is fresh, including motor mounts. I changed clutch fibers because the old ones smelled bad - burned - just due to age. Literally every other part is original.

I didn't take photos of the frame, but it's well along too with bars and forks mounted. I'll get some next week. Starting to get excited - this resto has gone very well and the bike is in great condition.

Offline 5port

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Re: New resto - 79 RD400 Daytona Special
« Reply #34 on: January 08, 2023, 11:26:31 AM »

Just in case you don't notice, the cylinder base gaskets are wrong way around.  ;)

5port
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Offline Hammer 663s

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Re: New resto - 79 RD400 Daytona Special
« Reply #35 on: January 12, 2023, 11:49:15 PM »
A few photos from the last couple week's efforts. I'll finish the brakes this weekend and then it's on to the minor painting needed to finish assembly. I think in another month or so I might be ready to try a first start. She hasn't run since 1994......

And yes, 5port, I flipped those gaskets. ;)


Offline Hammer 663s

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Re: New resto - 79 RD400 Daytona Special
« Reply #36 on: January 20, 2023, 11:05:14 PM »
More photos. Last night I tested the electrical to the extent I can w/o the motor in. After some repairs, all the lights, blinkers, and horn work except for those that pass signal through the generator and rely on the Neutral switch. Brakes are installed and stage 1 bled. In another few weeks I might be able to put the motor in the frame - I've still got to paint the jugs and assemble the top end. I've also selected and had mixed the gold I will paint the wheel spokes. As it sits it's very very original - only a few parts are not OEM.

Seat will get a layer of plastic then the seat cover.

https://youtu.be/mb1agretTzs
« Last Edit: January 23, 2023, 02:55:25 AM by Hammer 663s »

Offline Hammer 663s

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Re: New resto - 79 RD400 Daytona Special
« Reply #37 on: January 30, 2023, 06:38:22 PM »
Into some really tedious stuff now. Frame is about as far along as I can go until the motor goes in so I am prepping and masking for paint. I've got at least 20 hours into the wheels so far to get them to this stage, and another 10 to go with paint and reassembly. I've set up a paint area in the garage but it's just been too cold to try and paint in there, even with my heaters running. If I can get the jugs painted I have 6 hours of motor reassembly I can start on, and get it in the frame. I'm sure I'm well over 100 hours on this build so far, and approaching $10k invested.

Offline Hammer 663s

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Re: New resto - 79 RD400 Daytona Special
« Reply #38 on: March 05, 2023, 05:33:15 PM »
Weather has been absolute crap here - cold and wet - so I've made little progress on the paintworks I need to do to finish the motor. Little = none actually. But the tank is coming along well, and the seat recover should be done this week too. I could finish the damn thing in 2 weeks if I could paint - argh!!!!

A few photos of tank progress. It was dented up from garage moves over time so needed a good bit of TLC. I have a second tank I am repairing and will take to primer and sell at some point too.

Offline Motty

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Re: New resto - 79 RD400 Daytona Special
« Reply #39 on: March 13, 2023, 08:27:33 PM »
Thank you for taking the time to document your work with the rebuild, it's easy to forget how time consuming some of these things are
Richard

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Offline Hammer 663s

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Re: New resto - 79 RD400 Daytona Special
« Reply #40 on: March 29, 2023, 04:32:09 PM »
Been a while but still progressing. Tank is now repaired and painted - my guy hit the match almost perfectly. Tank is the only thing repainted - all else is original pearl white. The seat is also done. Fresh foam and plastic, and a new cover, installed by a shop that does auto restoration upholstery. I took a look at doing it myself but I'd have screwed it up. They matched the original technique with the cord secured by the original clips and it looks great. I've seen too many decent restos with amateur seat installs and it destroys the look. Weather here still sucks for painting so I've not finished the jugs so engine is not done. Plus race season is starting and that is chewing up weekends with my boy. He's getting good - got a sponsorship from a local shop this month!


Offline 5port

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Re: New resto - 79 RD400 Daytona Special
« Reply #41 on: March 29, 2023, 07:15:59 PM »
Looking good.  I think I spy a pair of BT45/46 tyres on the shelf, a v.good tyre for the road RD.
That workshop looks very smart!  I need it for my RD's and TZ!

5port
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Offline Hammer 663s

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Re: New resto - 79 RD400 Daytona Special
« Reply #42 on: May 25, 2023, 10:14:38 PM »
No update in a while. We are full-swing into motocross race season here, and that ties up a LOT of weekend time at the track, and weekday time in the shop. Now that my son is sponsored by a local shop, the commitments have increased a bit. But, it's all a lot of fun and he's riding well so we are all in!

Our weather has improved and I started painting. Most small items are now painted, and I need to clean them up and reassemble into working devices. I hope to have the bike fully assembled in the next 4 weeks and then use July for shake down and tuning rides.

Went with gold to match the factory gold lettering and stripes. I'm happy with how it came out so far. No, not OEM for the purists, but this is a slightly Mod build anyway due to missing parts.

Offline Hammer 663s

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Re: New resto - 79 RD400 Daytona Special
« Reply #43 on: May 30, 2023, 03:03:07 AM »
Almost done with the wheels. One hell of a lot of work but happy with how they came out. Top end goes on this week and then into the frame. Closer!!!!


Offline 5port

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Re: New resto - 79 RD400 Daytona Special
« Reply #44 on: May 30, 2023, 11:08:37 AM »
Yes, looks a very nice job.  Is that paint or powdercoat on the wheels?
I think it might go well with the pearlwhite and red gold highlights.

5port
5port