Daytona

[motodreams]

So, my first question is regarding the intake manifolds. These are hard and cracked, not cracked through yet but won't be long. I see they are available repop but only find two choices for the oem carbs. One set has no stuffers and no vac ports. The other style has the stuffers but large ports/barbs for a crossover hose. Does anyone make a manifold for the Daytona type that has the small ports/barbs for the exhaust valve /check valve tubing?

Welcome. Nice looking bike!

Here's a method for returning rubber to pliable and soft again. This of course is for parts that aren't cracked. Before hunting around for parts and spending money on repop rubber bits I would first attempt to retore the original pieces. 

I don't believe there are repro 2V0 manifolds available. Only the regular 1A1 RD400 type and the RZ/Banshee type.

Has anyone had success with this previously?  I had hard manifolds on my RD200 and it did not do a thing to soften them.  It was extremely hard to hunt down wintergreen oil and it was a total failure...

[Organicjedi]

I believe he is referring to the 2V0 manifolds that are unique to the Daytona. They have metal inserts for connecting a rubber hose instead of the larger ports that are found on the RZ/Banshee manifolds.

It amazes me how much R&D Yamaha put into the Daytona only for it to be a one year model. But I digress...

[~JM~]

Used black RTV massaged into the exterior of a CR250 intake manifold once. They were hard to replace at the time.

[Clem]

The key withthe Daytona is patience. I just finished restoring mine, took 3 years. I found a set of NOS intakes like you are looking for by searching ebay for 2VO vs 2V0.Get creative, XS400 of the same year shares some parts with the Daytona.

[cygnus]

I'm a patient guy, when it's my project  In this case I need to move it along but using the best practice I can with what's available in the time I have keeping his goal in mind.

Thanks for posting those used manifolds, one is cracked but the other may not be so I will ask him. I got these and the carbs off tonite and while both are stiff only one is cracked. I also dont like how the seal rings look but a skim of hylomar should seal. I would really like new ones but will have to make do. I to have done the rtv rub but won't since its not my bike. The hose barbs are threaded and just screwed into the manifold, but the repops dont have the flat surface to seal them into or I would just drill a set.

[cygnus]

x

[cygnus]

On the good news front these items look good.

[Clem]

That is a clean pump! No mice there, Lol

[m in sc]

if you have the means, get banshee ones and lathe down an adapter to fit in there threaded to 1/8" npt for the ports, or whatever the stock thread is on those.

if you look here.. while these are urethane styles, you get the idea. i had a plug in there to do some tuning. thats the way i would go, just using black oem banshee ones. (for a customers bike)

[cygnus]

Excellent idea. I see this set at Economy which is more inline with his budget. I'm sure the quality isn't near what the Banshee set is but leaps and bounds better than old used I would imagine. The way these are made I could cut down the large brass barb near flush and fab a sleeve with a "crown" so they almost looked like the originals......may not even have to tell him hahaha.

https://www.economycycle.com/shop/yamaha-rd250350400r5ds6ds7-parts/fuel-and-airintake/manifolds-yamaha-rd250350400r5ds6ds7-parts/manifold-kit-with-cross-over/

[cygnus]

Other than stuck slides the carbs came apart well. Looks like he had drained them. I'll have to take the Farmall linkage apart as its stiff as a board.

[cygnus]

I owe some updates. I have been nibbling away at it, but, I work in the ag industry and the current grand solar minimum and associated interesting weather has made spring tillage/planting an exercise in craziness resulting in tons of overtime and odd hours. For the moment I will just show what i decided on the intake manifolds . I know it seems like a lot of time/trouble but he really wants to keep it functionally/aesthetically original as possible so that's what I'm trying to do for him.

I wasn't happy with any of the intakes commonly available for a variety of reasons. So I did some research into what the other countries models used that didnt have the exhaust valve. Basically the 400 E/F elsewhere seemed to share the manifold setup of the RD250/Rd350 LC models. Their manifolds looked to have the reed stuffers and a much smaller than the Banshee style crossover tube resulting in a much shorter/smaller boss on the manifold. I wanted to keep the height of the boss such the oem holder for the check valve would fit in the cylinder fins exactly where it is supposed to.

https://parts.fo/yamaha/motorcycle/1981-rd250lc_4l1_999-748dd11ca7-intake#

I had a german friend with a 250LC measure manifolds from his spares and they were a spot on match to the Daytona manifolds. The part number for the manifolds is    2R9-13565-01-00, the wire clamps for the crossover are 90467-15012-00. So from the Eu I ordered a set of made in Japan Tourmax (good quality parts) CHY-47 reproductions made for the 4L1 models specifically.

[cygnus]

I dont have access to a lathe at the moment so I contacted Jeff Derstine (JRD on the triples forums who provides some fine services/parts) and submitted some bad drawings for adapters to use the oem hose barbs and he turned these out for me. I then hand radiused them to match the inside of the manifold bore. So, not oem but they wont look too out of place and if an NOS set of manifolds pops up all will be same/same and they can be easily swapped in.

[cygnus]

The pair of manifolds shipped from the EU was $80 so the same price as one oem which are still available. Its a viable option for anyone restoring one of these who wants to keep the exhaust valve for purposes of originality. You could also get the smaller crossover tube that matches these, 2R9-14465-00-00, if one wanted to experiment with tuning a standard 400.

[cygnus]

 I'll add my dimensions for the sleeves in case anyone wants to follow this path in the future. They fit perfect, you will just have to radius the inner extension to match the manifold bore.