Author Topic: Icy Bikes - '76 CB400f resto - getting ready to change out the transmission (Read 13332 times)

zachz · « **on:** April 13, 2011, 12:16:37 PM »

Picked this up a few weeks ago for $450 and will be diving into it soon - will be my first SOHC4, and am looking forward to getting her going. Was, of course, running when parked about a year and a half ago. Has ~23k on the clock. Missing the LH side cover, chain cover, tools, and sundry other bits and bolts. Has some ace bars that did a bit of a number on the tank, but the tank is solid otherwise. Have a new-to-me wiring harness waiting to clean up some of the electrical nightmare. The exhaust manifold is solid, but a bit beat up. Aftermarket exhaust being held on with a bungee cord. Have headlight, seat and a few other pieces missing from these pics.

DSC00085 by z5

DSC00087 by z5

Wish me luck!
Z

DarcyCB400F · « **Reply #1 on:** April 13, 2011, 03:38:30 PM »

Good Luck Zach!
Keep us posted! Lots of great advice here on the forum. Pictures are a must!

kap384@telus.net · « **Reply #2 on:** April 14, 2011, 11:10:01 AM »

Like the sound of another resto. Will be following!

zachz · « **Reply #3 on:** April 14, 2011, 09:53:49 PM »

A few details I left out -

Engine is free and turns over.
RH controls were pretty much shot.
Plugs look like they were running rich, but no obvious problems otherwise.
Small hole in alternator cover, roughly the size of a nickel (visible in first picture above)
Small holes drilled in lower corners of rear fenders... probably for turn signals at some previous point.
Kick-start arm was misadjusted when I purchase the bike - was contacting rear engine cover.
Some gasket weepage at head gaskets.

I'm anxious to try to get it started up, but want to go through the proper steps to save myself trouble down the road - so will clean out the carbs, change the oil, freshen up the gas (e.g. dump and refill), replace the whole harness, get the brakes properly bleeded, etc... sigh.

Just sold my other bikes to make room for this one - a good '77 CJ360t runner plus its '76 parts bike twin. The brothers I sold them to have the intention of brining back the parts bike, which I was very happy to hear - it was a bit more than I was going to get back together and going, but I did give it some though, and started into the engine top end. No choices now but to get the 400f on the road!

-CB-Jamie- · « **Reply #4 on:** April 15, 2011, 08:48:14 AM »

Good luck with it,
These 400f's are lovely little bikes, good to see another one in poor condition being looked after and hopefully getting a new lease on life.
Jamie

zachz · « **Reply #5 on:** April 15, 2011, 02:52:57 PM »

I'm hoping to get it to be a reliable runner for this season, maybe get the tank and side panels stripped and redone, and then do a full strip-down this winter to get to do things right.

MoMo · « **Reply #6 on:** April 15, 2011, 05:07:35 PM »

Welcome and good luck with the project. You mentioned bleeding the brakes-on a bike sitting that long you will need to disassemble both the master cylinder and caliper and clean out all the crud. You may need an mc rebuild kit and possibly a new piston(if it is pitted) and seal for the caliper. Kevin, a member here, sells a phenolic piston if yours is badly pitted. There is a ton of info here...Larry

zachz · « **Reply #7 on:** April 15, 2011, 06:22:25 PM »

Good call on the brake system. Hoses, seals and the like will be on order. Sitting still and rolling it around my garage, it is functional, though I do get a bit of a squeak from the disc... Will need a new reservoir cap seal as well.

zachz · « **Reply #8 on:** April 17, 2011, 09:17:25 AM »

Removed the old wiring harness and got the essential parts of the new one in place last night.

Touched the starter leads together and was happy to hear the start spring to life.

Wasn't getting a spark, and after a few minutes of investigation, I realized that I hadn't connected the points leads to the new harness. That said, it was 12:30am, I blew the 15a fuse when one of the leads hit the handlebar and didn't have a spare, and decided that was a good point to call it a night.

The previous harness:

Old harness by z5, on Flickr
Work in progress with new harness being installed:

In progress by z5, on Flickr

zachz · « **Reply #9 on:** April 20, 2011, 08:44:51 AM »

Brief update -
Checked the compression with a cheap, push-in tester last evening. Showing at least 106 psi on all cylinders. I know that I didn't have a great seal with the gauge. Compression appears to be good.

After reviewing the wiring diagrams and double-checking connections, and having a shot RH control, at least as far as wiring goes, I shorted the kill switch wire in the harness (black to black/white) and touched the starter leads together. Got more than just the spinning starter this time - a bit of a burble from the bike, but not constant ignition. Good, now have fuel, air and compression - just need to get the details sorted out. The carb for cylinder #1 is leaking from the float bowl, or somewhere in that vicinity, something fierce, so it's time to get some seals and get them cleaned up.

zachz · « **Reply #10 on:** April 22, 2011, 01:03:50 PM »

She runs.
http://www.flickr.com/photos/zachz/5643810571/#secretbfdae0d773

zachz · « **Reply #11 on:** April 12, 2012, 10:52:31 AM »

After a long delay in posting, a quick update:

Got her running, timed and tuned up last spring. Had issues with the coils - was initially only running on two cylinders, so I replaced the coils with a different set. Would still occasionally only run on two cylinders for the first few minutes in the morning, then would suddenly start going on all four, requiring a quick dial back on the idle adjuster. Replaced the tires to try to get rid of a low-speed shake/shimmy, which is improved but still present a bit (I wonder if the frame is slightly tweaked, or if the rear wheel is simply slightly out of adjustment. I do need to go through and even up the spokes). Ran well for most of the summer.

Started to swap out the plugs for a fresh set when I apparently either overtightened or else exacerbated a previous over-tightening on the #1 cylinder plug. Riding down the street on my 400 with my wife on her '65 S65, the threads in #1 plug hole gave out. Finished our short trip and made it home, but the birth of our daughter, and the general early onset of winter in Alaska pretty much ended the riding season there. Picked up a helicoil kit to fix the threads and am finally digging into the project.

When I pulled the head off the other night, I found this inside two of head bolt cylinders (which I'm assuming are oil galleries, however they must be clogged down lower as the stuff that fell out did not appear to be terribly oily, though it had been sitting for x months) - I didn't realize that pine needles could be used for lubrication purposes.

A few pics:

Anyway, hopefully things will helicoil without drama and reassembly with new gaskets (and perhaps some fresh paint) will reduce the oil weepage.

zachz · « **Reply #12 on:** April 13, 2012, 10:03:13 AM »

Pulled the cylinder block off off last night. Only did one stupid thing with a block of wood while removing it. The gunk in the non-oil gallery stud holes managed to hang up the block while lifting it up. Cylinder sleeves and the pistons themselves look to be in great shape with no scoring or excessive wear.

Ready to drill out the plug hole this weekend and get the helicoil installed. What does the brain trust here recommend - paint the head, block and cam cover while off the bike or to simply thoroughly clean, reassemble, mask off and paint in-situ?

kslrr · « **Reply #13 on:** April 13, 2012, 11:55:36 AM »

If you must paint it (depends on how good it looks after a good cleaing), it would easier to do pre-assembly but then you got to be extra carefull not to ding it up during assembly.

zachz · « **Reply #14 on:** April 16, 2012, 12:37:06 PM »

Looks like the helicoil was a success. Now I need to get the cylinder block gasket off and start reassembly.

Picked up an extra, used tank with cap and petcock off of the auction site - cost was similar to just painting. Fingers crossed that its condition is similar to what was pictured.

zachz · « **Reply #15 on:** May 02, 2012, 11:01:45 AM »

Quick update - head is at the machine shop and ready for pickup. The 'new' tank arrived yesterday and is looking good, though full of varnish and crud. Will hit it with simple green later this week.

CB400f by z5, on Flickr

I have to wonder if someone fit a different seat to the bike - seems somewhat large, the more I look at it. Either way needs a new cover.

LesterPiglet · « **Reply #16 on:** May 02, 2012, 11:08:08 AM »

Yeah, that wrinkle looks odd. Nice bike.

Mugen_Stumpo · « **Reply #17 on:** May 02, 2012, 11:53:14 AM »

the seat is not a 400 seat... looks like it could belong to a 500

zachz · « **Reply #18 on:** May 04, 2012, 04:05:51 PM »

The simple green is soaking in the tank. I sprayed a bit of Brakleen inside and the varnish that disappeared revealed what looks to be a gorgeous tank surface underneath. Hopefully the remainder of the tank interior is as nice.

Got the head back. Looks good and am finally ready to reassemble, after a slow, cylinder block gasket-scraping exercise. Pictures to follow.

What is the best way to prep the plastic side covers for paint? I've been using #0 steel wool, which is working well but taking a while. Better suggestions?

Anyone have an extra CB400f seat and want to trade for a maybe 500f seat?

zachz · « **Reply #19 on:** May 14, 2012, 10:55:03 AM »

Got the engine reassembled on Sunday. Got the cylinder block back on, looked at my set of gaskets and o-rings, and realized I'd left the small rings that go around the base of the piston rings off. Pulled the block back off, figured out that you need to fit them evenly in quadrants rather than start in one point and squish them around (to keep from having a small bubble of extra o-ring with nowhere to put it), slid the pistons back in and got to reassembling the remainder of the engine.

Reassembly under way

As this was my first reassembly, I took my time, making sure that the parts were fitted properly. After getting all of the pieces back together, I checked the valve clearances clearances, reinstalled the carbs, fit the foot controls, set up the new push/pull throttle cables, fit the battery, and spun the starter with the coils disconnected to prime oil throughout the system. After all that, I hooked up the coils, added some fresh gas and crossed my fingers. I must've set the timing or valve spacing incorrectly as it didn't fire and sounded as though the valves were breathing at the wrong time. Two steps forward, one step back.

Have a couple(!?) of seats on the way to me in the mail... slow but steady.

zachz · « **Reply #20 on:** May 18, 2012, 01:01:57 PM »

Fired her back up last night.

Was briefly scared a few days before that I'd messed up the helicoil job as I was seeing a bit of pressure seep out #1 cylinder plug. Upon closer inspection, and a quick search through the forum here, I realized that the plug washer was fully crushed and no longer offering a seal. With a new plug in there, no pressure seepage.

Found that I had knocked one of the points pivot arms out of alignment when turning the engine over for setting the valve clearances. After a quick removal and disassembly, I straightened it out and re-established good contact. With proper point spacing, it fired up and ran poorly. After adjusting the timing plate with it running, got it going reliably on all four cylinders. Still need to get things dialed in, as there is a marked difference between the 1&4 cylinders and the 2&3 cylinders, in terms of exhaust pipe temperature.

zachz · « **Reply #21 on:** May 30, 2012, 10:26:37 AM »

Further quick update -

After additional testing and reviewing of various threads here - thanks TT - found the points and at least one of the condensers was bad. Right or wrong, decided to go with a Dyna S. Arrived on Saturday and got it flanged up in about 30 minutes. Most certainly running on all four now, and it feels good driving around.

The yellow tank in my avatar picture, however, continues to be a work in progress. I let the Simple Green sit in the tank for about a week, and on dumping it out, it was quite nasty looking. Investigating inside the tank shows it may have been Kreemed in the past? Can't tell, but there is a bit of white-ish sludge in there. Will try to get a picture. Have the POR-15 tank kit, but am hesitant to use until I get the majority of the crud out of there. Slow but steady. At least the cruddy black tank is in good, if ugly, shape.

zachz · « **Reply #22 on:** May 30, 2012, 11:48:46 AM »

Oh, and on comparison with a 350F seat pan, the seat on the bike was a (marginally) recovered 350F seat. Have a 400F seat now and need to get the proper mount bracket, as the one on the 350F seat doesn't quite flange up properly.

zachz · « **Reply #23 on:** July 13, 2012, 11:08:35 AM »

Trying to find the correct screw size for the wire that goes to the oil pressure switch. I'd found it after a long time searching the archives here but can't seem to turn it up again. Does anyone know the size of screw I need off the top of their head?

zachz · « **Reply #24 on:** February 13, 2013, 01:07:48 PM »

Quick update after a long lull in posting - bike is in hibernation for the winter.

To dos:
I've got a new set of clutch plates to swap in before spring to solve my 5th gear slip problem.

Also have a new set of bearings for the steering stem to install.

Need to pick up a Carbtune and really get the carbs dialed in. Fuel economy was much too low last year (~25 mpg).

Need to grab appropriate bolts to mount up the new to me chain guard.

Still never had anyone answer the question on the proper screw size for the oil pressure switch - so if anyone knows.

A few pictures from last season:

Untitled by z5, on Flickr

CB400f by z5, on Flickr

Test fit II by z5, on Flickr

Progress? by z5, on Flickr

News:

Author Topic: Icy Bikes - '76 CB400f resto - getting ready to change out the transmission (Read 13332 times)