Yamaha RD400F refresh

[SoCal250]

After tearing into the front brake system on my Daytona (posted here), I started working on painting brake parts and a new set of engine covers.


The brake parts were cleaned up with parts cleaner then run through a few cycles in the ultrasonic before final cleaning and wipe down.
The case covers were media blasted and then prepped for paint with acetone and masking. Unfortunately painting took several days due many varied issues: wind outside, moving inside the garage and then not having good visibility, and a horrible Thursday where gardeners on both sides decided to fire up their blowers for extended periods of time causing dust impurities in the paint finish.
In the end, it was primer followed by about 3 coats of VHT black satin caliper paint, with some light 400-grit sanding and an overnight rest between coats.
That was followed by about 20-30 minutes in the sun to start curing the paint.


and then 1 hour in the BBQ at 240F



They look pretty good.
Next up is draining trans & oil tank on the bike and removing all the case covers and the oil pump. And then install of the newly painted bits.

[Simmons1]

[SoCal250]

Covers are ready for install


Front brake components are finished too. Caliper and master are painted and rebuilt. Master also got new SS hardware on the cap and a NOS lever.

[Kawtriplefreak]

Beautiful work   

[RDryan]

Wow that is first class, good job. I have a GSXR1000 that got into an accident a long time ago and I used that same paint to refinish the stator cover after sanding out the road rash. However I never took the cover off the bike and obviously didn't have the same curing/dry effect as your finish. So well done I say!

If one doesn't have a BBQ grill can they put parts into an electric kitchen oven and do the same?

[SoCal250]

If one doesn't have a BBQ grill can they put parts into an electric kitchen oven and do the same?

You could but I wouldn't recommend it. The paint off-gasses quite a bit and your house will stink and so will the oven afterwards. I would assume the fumes can't be good for you.   

[SoCal250]

Progressing slowly...

Left cover installed.  
I never really liked the polished covers that a previous owner did before I purchased the bike almost 20 years ago. So I gathered some used pieces and refinished them in order to do the swap. I didn't want to undo all the polish work that someone spent a lot of time doing.
BEFORE:


AFTER:


Tomorrow it's on to the right cover, along with new FZR1000 clutch frictions and rebuilding the oil pump.

[SoCal250]

Front brake components are finished too. Caliper and master are painted and rebuilt. Master also got new SS hardware on the cap and a NOS lever.

Unfortunately, the caliper has to come apart again (3rd time). The piston is sticking (stuck solid) in the bore. Not sure why, but the seal is binding. The bore, seal groove, and piston are completely clean with no corrosion, and the piston slides in and out smoothly without the seal. Install the new seal and once the piston is pushed in it's a no go.    Two steps forward, one step back.

[RDryan]

Looks a lot better with the painted cover. Curious to know why the brake piston is sticking, I'll have to stay in tune. Sounds like a fitment tolerance issue between the seal,piston and caliper? Of course me being me I just got one of those cheap Chinese reproduction calipers for the 250/350's also not sure if they're available for the 400's.

[SoCal250]

Looks a lot better with the painted cover. Curious to know why the brake piston is sticking, I'll have to stay in tune. Sounds like a fitment tolerance issue between the seal,piston and caliper? Of course me being me I just got one of those cheap Chinese reproduction calipers for the 250/350's also not sure if they're available for the 400's.

There are repro calipers available for the '76-78 RD400, but I'm working on a Daytona Special which uses unique one-year-only single piston calipers. Repops are not available.
Pretty sure my issue is seal related since there is good clearance without the seal between the piston and bore. Tempted to try the old seal but it's at least 20 yrs old and has a few blemishes in the rubber when viewed with a magnifying glass. Currently, with the new seal the interference is enough that 70-75psi compressed air will not budge it

[SoCal250]

Right engine cover is off and oil pump is removed. Clutch pack pulled and partially reassembled. Aiming to get the clutch finished up tomorrow, and then tackle the pump rebuild and few other things.
Also need to remeasure the clutch springs because the numbers i wrote down don't jive with the spec in the Yamaha manual or my tech notes.

[RDryan]

Looks a lot better with the painted cover. Curious to know why the brake piston is sticking, I'll have to stay in tune. Sounds like a fitment tolerance issue between the seal,piston and caliper? Of course me being me I just got one of those cheap Chinese reproduction calipers for the 250/350's also not sure if they're available for the 400's.

There are repro calipers available for the '76-78 RD400, but I'm working on a Daytona Special which uses unique one-year-only single piston calipers. Repops are not available.
Pretty sure my issue is seal related since there is good clearance without the seal between the piston and bore. Tempted to try the old seal but it's at least 20 yrs old and has a few blemishes in the rubber when viewed with a magnifying glass. Currently, with the new seal the interference is enough that 70-75psi compressed air will not budge it

It's interesting as I assume you would use a OEM replacement seal but know from experience that even a slight difference in size really can make a difference.

[SoCal250]

Aiming to get the clutch finished up tomorrow, and then tackle the pump rebuild and few other things.
Also need to remeasure the clutch springs because the numbers i wrote down don't jive with the spec in the Yamaha manual or my tech notes.

Got the clutch pack reassembled yesterday, so that's now done. Also went through and remeasured the springs to confirm the lengths I wrote down the other day, and they matched. Not sure what I have in there, but they're indeed longer than stock by about 2mm and darker color than OE. All measured between 38.12 and 38.60mm (OE spec is 35.4~36.4mm).


And I got a little surprise when I removed the oil pump drive from the old clutch cover so I could swap it over.  Fortunately I have a replacement pin on hand.


I believe my engine was done by Gary at Spec2 around 2004-2005, just before I purchased it. Not sure who is responsible for the drill bit fabrication, but I would assume Gary did the springs when the engine work was done.

[Kawtriplefreak]

Nice!

[SoCal250]

Finally! A day with some progress and positive outcomes. 

I pulled apart the clutch pack again and checked everything. Nothing looked out of place. This time I reassembled without the rubber cushions. And Eureka! Problem solved! I now have a firm clutch lever and just need to make some fine adjustment at the linkage set screw in the left cover. This is how I was expecting it to be after swapping plates.

For my second project I pulled apart the front brake caliper again. I measured and compared the old seal with a the new seal and another new OE seal fresh out of the package. All were almost exactly the same. Then I checked my piston for out-of-round and it was OK.
Next I polished the seal groove in the caliper with red scotchbrite, then did a little red scotchbrite inside the bore, followed by 1000 sandpaper and finally 1500. The piston just got a little 1500 treatment. After cleaning, I thought about reassembling with the old seal just to test things out, but after looking at it closely I didn't want a future leak. So I put the new seal in and did my usual assembly process. And everything is good now! Tested with 20psi air and the piston moves as expected. Another issue resolved,