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Dead RD400 resurrection

Started by JBeasty, April 04, 2022, 03:55:41 PM

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JBeasty

OK, so after a few weeks of vacillating, I've come to the conclusion that I should probably have my crank looked at by a professional. The one local guy I was able to talk to that didn't cut me off as soon as I said 1977 RD400...  said I should go on-line and find a reputable mechanic/machinist who has experience with RDs. Duh, so here I am. Is there anyone on the west coast (If not the SF/Bay area) that you guy's can recommend?  :help:
1977 RD400

Aloha808

I just got my rebuilt crank back today.    John Ritter did the work. 

I am not sure how busy he is.  He is a member here.  Check out the "General Services for Hire" section of the forum home page.

It was easy conversing with John about the process.   

JBeasty

Yes, I saw that - Thanks. I may end up checking him out if I can't find someone a little closer to me. Looks like he's in Tennessee?
1977 RD400

lawnboy

Garret at GRA2STROKES is up in Wash. He's on here as well. Also in the services for hire section

JBeasty

1977 RD400

JBeasty

FYI, GRA2STROKES is no longer providing any services - he emailed me back this am.
John Ritter got back to me, said he can do my crank and asked me to call him. I left a message for him.
He said he can do my barrels, but "...cylinder boring jobs are only done if I am porting the cylinders usually." So that's what I'll do. I know (I think) that porting improves flow, does it effect low end performance negatively? Or is that more of a timing thing?
He's not set up to do Daytona heads, unless I agree to cut them in half. So I'll be looking for someone to "do the squish" on my head.
What I'm hoping to achieve is good overall performance while not hurting reliability.
1977 RD400

m in sc

id cut the head. pretty common on race bikes in particular, and makes servicing a bit easier. .02


2steve

Porting can be done in a way that preserves the lower end of the power band. Chuck Quenzler called it "update porting." I used to have to coax power wheelies especially when heat soaked, but no longer.

Lower end of powerband initial kick is still there. Still on stock bore too, but he honed and provided modded ProX pistons. Felt compelled to be able to bolt on the stock pipes and still have it run great.

JBeasty

#83
Just got off the phone with John Ritter. What a nice guy! He suspects my crank may have been rebuilt at some point. Had me check my rods, and said they are Daytona Rods based on the 2T2 stamped on the side. He also gave me some pointers on measuring my crank, before I just send it off to be rebuilt if it doesn't necessarily need it.

M in SC, I may just do that. He said he hates to chop the heads up because they're so rare. Is there any benefit to using the Daytona head vs stock?

2Steve, good to know. We started to talk about different porting options, but we got side tracked.
1977 RD400

m in sc

no real benefit aside from looks. John is a hell of a nice guy. 

JBeasty

Got my bottom case cleaned up, already getting dirty again - I keep finding gasket goop EVERYWHERE  :bang:
There is a wear spot on the inner right rear (from 1st gear rubbing?)
Also, the hole on the right side that supports the gearchange lever/shaft is galled up from me pulling it through. Not sure if there's anything I can do about that other than honing it out a bit? 
1977 RD400

JBeasty

So I cleaned up my crankshaft and took some of measurements again. I was only able to take runout measurements on the ends of the shaft with the bearings in place. I used a v-block supporting the inner bearings. Left side is 0.003, Right is 0.0025. Don't know what is considered way out of alignment, but this seems pretty close to spec to me?
Small end axial play: L is 38.5, R is 39.0 - Not sure how much force I should use when moving the rods left to right, so I just went light - enough to make contact with each side. I can make the numbers go up a thousandth or so if I force it more.
I checked the con rod side clearance with a feeler gauge: L is 0.012, R is 0.009.
The outer bearings roll good, no rough spots. The inner bearings also roll good, but there's a slight resistance - from the middle seal?
Given that if I ever get this thing running, and I'll just use it to ride around for fun - are these numbers OK? . I'm no speed demon, I'm retired.
Also, not sure if it matters, but with Daytona rods AND head, does this then correct the squish? Or are the RD400 rods all the same length?
Thanks for any and all input, JB
1977 RD400

SoCal250

Quote from: JBeasty on June 02, 2022, 02:08:10 AM
So I cleaned up my crankshaft and took some of measurements again. I was only able to take runout measurements on the ends of the shaft with the bearings in place. I used a v-block supporting the inner bearings. Left side is 0.003, Right is 0.0025. Don't know what is considered way out of alignment, but this seems pretty close to spec to me?
Small end axial play: L is 38.5, R is 39.0 - Not sure how much force I should use when moving the rods left to right, so I just went light - enough to make contact with each side. I can make the numbers go up a thousandth or so if I force it more.
I checked the con rod side clearance with a feeler gauge: L is 0.012, R is 0.009.
The outer bearings roll good, no rough spots. The inner bearings also roll good, but there's a slight resistance - from the middle seal?
Given that if I ever get this thing running, and I'll just use it to ride around for fun - are these numbers OK? . I'm no speed demon, I'm retired.
Also, not sure if it matters, but with Daytona rods AND head, does this then correct the squish? Or are the RD400 rods all the same length?
Thanks for any and all input, JB

JB,
Do you have a factory shop manual? It has the specs for the crank tolerances.
You can also find some crankshaft info in the Tech Library under the Yamaha section (Yamaha Tech Bulletins).

RD400 rods are the same length, 1976 through 1979. Squish and chamber vol are corrected by machining the head, (and matching with the piston and head gasket used). By the way, the OEM head gasket for the RD400C-E is 0.020" thick and a separate gasket for each side, while the RD400F is 0.055" and 1-piece. If the Daytona head is cut in half and machined for the thinner standard RD400 gaskets, it allows for working on one cylinder at a time instead of having to replace the gasket on both cylinders. :twocents:
75 Yamaha RD125B   75 Yamaha RD125B (project)
75 Yamaha RD250B   75 Yamaha RD200B (project)
73 Yamaha RD350     77 Yamaha RD400D   79 Yamaha RD400F  
91 Yamaha TZR250R  89 Yamaha FZR400   05 Yamaha FZ6   
05 Yamaha XT225TC  82 Honda MB5  02 Aprilia RS250 Cup (sold)

JBeasty

Quote from: SoCal250 on June 08, 2022, 08:27:20 PM
Quote from: JBeasty on June 02, 2022, 02:08:10 AM
So I cleaned up my crankshaft and took some of measurements again. I was only able to take runout measurements on the ends of the shaft with the bearings in place. I used a v-block supporting the inner bearings. Left side is 0.003, Right is 0.0025. Don't know what is considered way out of alignment, but this seems pretty close to spec to me?
Small end axial play: L is 38.5, R is 39.0 - Not sure how much force I should use when moving the rods left to right, so I just went light - enough to make contact with each side. I can make the numbers go up a thousandth or so if I force it more.
I checked the con rod side clearance with a feeler gauge: L is 0.012, R is 0.009.
The outer bearings roll good, no rough spots. The inner bearings also roll good, but there's a slight resistance - from the middle seal?
Given that if I ever get this thing running, and I'll just use it to ride around for fun - are these numbers OK? . I'm no speed demon, I'm retired.
Also, not sure if it matters, but with Daytona rods AND head, does this then correct the squish? Or are the RD400 rods all the same length?
Thanks for any and all input, JB

JB,
Do you have a factory shop manual? It has the specs for the crank tolerances.
You can also find some crankshaft info in the Tech Library under the Yamaha section (Yamaha Tech Bulletins).

RD400 rods are the same length, 1976 through 1979. Squish and chamber vol are corrected by machining the head, (and matching with the piston and head gasket used). By the way, the OEM head gasket for the RD400C-E is 0.020" thick and a separate gasket for each side, while the RD400F is 0.055" and 1-piece. If the Daytona head is cut in half and machined for the thinner standard RD400 gaskets, it allows for working on one cylinder at a time instead of having to replace the gasket on both cylinders. :twocents:

Woah - I see I made a major typo with the Small end axial play numbers I posted. It should read:
Left side= 0.0385in, Right side= 0.039in
I'm using a reproduction service manual. Thanks for pointing me to the Tech Library - I found info for RD 350, but not the 400. Similar specs though. I don't have a lathe or any way to support the crank from the ends, so I'm supporting it in the middle with a v-block - hence I can't measure runout in the middle.  I guess it's obvious I'm trying to get by without doing the crank. My numbers seem (to me) so close to spec. This bike is so beat to $#!t, I'm afraid of throwing too much money at it.
1977 RD400

pidjones

"Love 'em all.... Let GOD sort 'em out!"