Honda Twins banner

1 - 20 of 78 Posts

·
Premium Member
Joined
·
1,615 Posts
Discussion Starter #1
Just as a foreword, this is going to be a very intermittently updated project thread, as I am primarily focused (money and time
) on my 1983 BMW R100RT.

After a year or two of tinkering and adding the random odd and end from all the wonderful knowledge on this forum and of course 66Sprint, I had a pretty good runner:



Fast forward a couple years and a few other bikes later, I was going on a ride the first non-snowy day of Spring 2017, and all of a sudden the engine started to stumble, and had a sudden loss of power. I pull over and realize that my bike is on fire! Based on the performance of the bike at time of failure and the location of the fire, the engine seems to have backfired through the carburetor and lit my UNI foam air filters on fire. I called 911 and a police officer in the area responded to my call and doused the bike with his fire extinguisher. The damage was done: My frame was singed, part of the wiring harness melted, the alternator wire and connection to the wiring harness has melted, melted components gooped all over the frame, and carburetors were coated in fire extinguisher powder. I got the bike towed back to my house and it spent the riding season tucked in the back of the garage under a tarp.



Not sure why, I decided to take another look at the bike this past weekend. I decided that if I am going to turn this old bike around, I better do it right this time and do a full rebuild from the bare frame up including a partial engine rebuild (at least the top end to address an oil leakage). I started with disassembly of the easy stuff, and will start to take detailed photos/videos of the nastier stuff.

I started disassembly and took photos and videos of the process and started cataloging all my removed parts in labeled ziplock bags. Throughout this process, I was making a mental note of what could be salvaged, and what should be replaced or upgraded with a modern equivalent. I think I am going to go the resto-mod route, as a 100% restoration is going to be completely out of budget!



Here are some things that I found during the disassembly:
1. A portion of the wiring harness and the alternator wiring TO the wiring harness is completely scorched, so much so that the connection point between the two melted to a clump of burnt plastic! My alternator was good when I last checked it out two years ago. I will see if I want to just replace the alternator with a used one/modern upgrade or come up with some DIY wiring connection.



2. I was running a "Hondaman Ignition" system that used the points as a trigger for the unit. The unit appears to be burned, and it may be the reason why I was not getting spark when I did a post-incident diagnosis.

3. My refillable battery has lost its vent hose and has been leaking battery acid, and has acid-burned parts of the frame, exhaust and swingarm. In the future, I will pony up for a maintenance free one.

Next up will be removal of the front end and engine removal. I will have to start shopping around for a frame powdercoater in my area.

By the way, I came across the Common Motor Collective when looking for replacement parts. I wish this company was around back in my initial project stage!
 

·
Premium Member
Joined
·
1,615 Posts
Discussion Starter #2
I have started buying some bits and pieces for tinkering around this winter. I am excited! New starter solenoid, carburetor rebuild kits, gaskets and seals, new grips, and throttle cables. I am just glad Honda parts are a fraction of the cost of BMW!

I am fielding some quotes for media blasting and powdercoating the frame and swingarm. If I recall correctly, there are some spots on the frame that should NOT be painted/coated to ensure that electrical components are grounded. Any pointers on where I need to indicate this to the powdercoaters? I will cross post this to the CB360 Frame subforum.
 

·
Premium Member
Joined
·
1,615 Posts
Discussion Starter #3
Got through the process of removing the front end (forks, triples, and wheel) and the center and rear stands. Almost too easy...

Popped off the top and bottom steering bearings. They were FILTHY! Luckily I have a set of tapered bearings that I picked up around 5 years ago and never installed! Getting those races out was definitely a challenge. Required the use of a long punch and a hammer to drive out!

Engine was drained of oil and will be coming out in the next few days.

I think I found a good powdercoater about an hour away who does little projects like this on the side for not a lot of dough and will be dropping off parts by end of the month once I get every soft part out and at least run some degreaser through the oily parts.
 

·
Premium Member
Joined
·
1,615 Posts
Discussion Starter #5
Hmmm....
NOS Wiring Harness for $240.....or a "clean" used one off eBay for $60...
NOS Alternator for $250-$500, or a decent looking one off eBay for $50...

eBay it is!

Ordered approximately $600 worth of upgrades and replacement parts of Common Motor. Heck I even saw parts that I never knew were missing/needed replacement! My "shopping" list grows...
I have decided that I am going back to regular points ignition and swapping my modified CB450 carburetors back to the CB360 set I picked up off an old parts bike in 2009.
Engine removal this weekend and I will run the parts I want powdercoated through some degreaser before I schedule a drop off with the powdercoater.
 

·
Registered
Joined
·
2,509 Posts
Total bummer about the fire! Hope you enjoy the process of this build.
Did you ever get an answer able bare metal areas?
Not sure about the 360, but for the 350, all I can think of is 2 places the ground bolts to(battery and a separate green wire on the left of the lower backbone) and where the points/condenser mount so the condenser can ground to the frame.
 

·
Premium Member
Joined
·
1,615 Posts
Discussion Starter #7
Total bummer about the fire! Hope you enjoy the process of this build.
Did you ever get an answer able bare metal areas?
Not sure about the 360, but for the 350, all I can think of is 2 places the ground bolts to(battery and a separate green wire on the left of the lower backbone) and where the points/condenser mount so the condenser can ground to the frame.
Thanks! Yeah I am really excited about the upcoming work. It will be a nice project to keep me busy over winter.

Back in 2008/2009 was when I really started learning about tinkering around with this bike, and I had the most rudimentary of tools at my disposal. There was not that much information about working on these bikes readily available and the shop manuals required a bit of "interpretation". I was scared of stripping my bike down for a thorough restoration. Now I have amassed a pretty good set of mechanics tools, and I have some work on other bikes under my belt, I am more confident this time around! Having the right tool for the job makes life 10x better. Plus CMC has amazingly good quality rebuild videos on youtube to baby me through some tougher bits. In stripping the CB360 down I am amazed at how simple it really is! (Watch me eat those words in a few weeks/months!).

I am almost 100% sure that the spots you mentioned are the only ones that need to keep a bit of bare metal showing. I am going to mark up the frame with painters tape notes to the powdercoater at these spots to ensure that he keeps at least a small ring of bare metal showing. Otherwise I can always chip away at it if need be.
 

·
Premium Member
Joined
·
2,931 Posts
Question - where did you buy the seat and did you find it comfortable.

I've been kicking around that style seat for a Café Project that's been sitting on my bench for the past 2 years.
I moved and packed up everything and have recently been getting my shop areas back to useable shape.

Anyway I like the idea of the café style seat without serious modifications.

Just wanted the opinion from someone who has ridden on one.
 

·
Premium Member
Joined
·
1,615 Posts
Discussion Starter #9
Question - where did you buy the seat and did you find it comfortable.

I've been kicking around that style seat for a Café Project that's been sitting on my bench for the past 2 years.
I moved and packed up everything and have recently been getting my shop areas back to useable shape.

Anyway I like the idea of the café style seat without serious modifications.

Just wanted the opinion from someone who has ridden on one.
The seat was from an eBay vendor in Vietnam called hondaclassic31 (I don't think they are around anymore). I was a bit hesitant to buy from overseas, but I was pleasantly surprised (although shipping took approximately a month and change). IIRC, it was around $150 with shipping and included it's own seat pan, rubber bumpers, etc. The quality of construction is top notch!

That said, the "cafe racer" style riding position is not very comfortable. In my early 20's, I didn't complain and could easily ride from Chicago to Milwaukee without any issued. However, now in my 30's I can't ride in that position for long and have been using the bike as a local put-putter. Rear-set pegs MIGHT improve the comfort level to change riding position to something less cramped, but I don't want to go through the expense and redesign process of the shift/brake linkages.
 

·
Premium Member
Joined
·
1,615 Posts
Discussion Starter #10
Good progress today! I took a 1/2 day off because there was no projects going at work, so I unbolted the engine from the frame and used a 1:4 mixture of simple green to clean of years of road gunk and chain lube from the frame.



Wife was kind enough to let me take the engine into the workroom for disassembly and tune-up.



I popped the side covers off knowing that I wanted to give them a nice clean and I was going to replace the rotor and clean out the oil filter.



Much to my dismay, the Hondabond that was used in a previous top end rebuild about 6 years ago or so seems to have "melted" and dripped and hardened all over the cylinder head. It will be a matter of delicately picking and peeling that old gunk off. I think on this job I will use the product recommended by CMC.

Another item that concerned me was the fact that in removing the cylinder head cover bolts, one of them turned loosely as if the threads in the head cover were stripped, unlike the others that were torqued down. I will investigate that further and take photos at a later time.
 

·
Registered
Joined
·
284 Posts
On powder coating, tape (thick duct tape) or plug all threaded areas BEFORE sandblasting! Sandblasted threads have an etched surface that will rust quickly and seize fasteners later (even if you oil 'em up). Once sand blasted it's impossible to get a mill finish back on threads. I always clean threads well and mask and instruct the sandblaster not to blast threads. For female threads I put old bolts (or new cheap bolts) in the holes so the blaster can't miss. Male studs, I wrap them well with duct tape. Buy a set of metric taps and dies.

Oh, and ditto smooth machined surfaces like the upper shock mount studs.
 

·
Premium Member
Joined
·
1,615 Posts
Discussion Starter #12
On powder coating, tape (thick duct tape) or plug all threaded areas BEFORE sandblasting! Sandblasted threads have an etched surface that will rust quickly and seize fasteners later (even if you oil 'em up). Once sand blasted it's impossible to get a mill finish back on threads. I always clean threads well and mask and instruct the sandblaster not to blast threads. For female threads I put old bolts (or new cheap bolts) in the holes so the blaster can't miss. Male studs, I wrap them well with duct tape. Buy a set of metric taps and dies.

Oh, and ditto smooth machined surfaces like the upper shock mount studs.
I dropped the frame, swingarm, triple tree, battery box, and a bunch of small brackets and parts with the powdercoater. I am VERY impressed with their shop. They usually do large commercial work as their bread and butter but do car rims and bike parts on the side. They have a huge facility and pointed out the trays of sacrificial plugs and bolts to protect machined surfaces, collars, and threaded connections from the sandblasting and powder coating process. They also convinced me to go with a semi-gloss finish, which I was totally OK with.

In regards to the spinning valve cover bolt, I think I will just replace it with a longer one. It should do the trick.

Here are some photos/videos of my close up inspection of the engine components. Do you guys think I am OK with reusing what I have, or am I need of replacements/resurfacing:

Valve rocker arms:





Pistons:





Valves:







Camshaft lobes:


Cam Chain Tensioner:


Cam Chain Guide:


Side question:
As I was manhandling the engine, the cylinders were nudged off the seating surface and released some oil around the mating surface with the rest of the engine. Do I need to remove the cylinders and replace that bottom gasket, or is that OK to be left as-is (compression readings were good before teardown).

 

·
Premium Member
Joined
·
1,615 Posts
Discussion Starter #13
Cross-posted the questions above to the CB350/CB360 Engine discussion.

Not really too much progress on the bike since my last post, as I was working on a spline lube job on my BMW R100RT which was a story in itself. I had $500 worth of goodies come in from CMC:
- CB360 air filters
- Modern Rectifier/Regulator
- Modern Starter Solenoid
- Engine Overhaul Gasket Set
- CB360 carb boots
- Ignition Points Allen Screw Replacement Kit
- CB360 Engine O-Ring Replacement Set
- CB360 Throttle Cables
- Replacement Grips
- Condenser
- Vacuum Port Nozzles
- CB360 carb-synch tool/screwdriver

Sadly I will have to do another large order for other components as I progress further.

The replacement alternator came in (bonus: free neutral switch!). It looked to be in pretty good physical shape. I purchased some electrical contacts cleaner and dielectric grease, so I will clean it up and do the same to the connections in the used wiring harness once it arrives.

Additionally, I camped out in the nuts and bolts aisle of Ace Hardware to replace all my (stripped) engine cover screws with Allen head screws. To my disappointment, for the length of the screw required, my only option was to go for the black (oxidized?) Allen head screws, as the maximum length of the stainless steel equivalent stopped way too short to reach the threads. I found myself in the same situation in Home Depot, Menards, and Lowe's. Oh well...I'd rather go for function over form, and this isn't a 100% restoration project anyway. I will be adding some anti-seize to each of these screws to facilitate future work on the engine.
 

·
Super Moderator
Joined
·
5,549 Posts
Common motor sells stainless bolt kits for the engine as do other online suppliers.

The black ones will rust eventually and look like crap.

Sent from my SAMSUNG-SM-G891A using Tapatalk
 

·
Premium Member
Joined
·
1,615 Posts
Discussion Starter #15
Last night, I pulled off the cylinders, labeled and visually inspected the pistons and rings. Base gasket has seen better days.

1. Once the piston clips were removed, the piston wrist pins were pretty stubborn to remove! I had to tap them out with a soft punch and a hammer!

2. Both pistons had this wear mark on the surface on each face (as shown in photo below and 180 degrees on the other end). Is this normal?

 

·
Premium Member
Joined
·
1,615 Posts
Discussion Starter #16
Called up some machine shops / engine rebuild shops for estimates for measuring my cylinders and honing them. Turns out very few of them are open on weekends! Once I can snag a Saturday appointment, I will drop off the cylinders and the spec sheets. Fingers crossed I don't have to bore out to a larger size!

I did an acetone test of the valves and I had no leaks from any of the intake or exhaust valves. I shot a PM to TOOLS1 about potentially cleaning up and inspecting the valve train.

I cleaned up the engine side cases with hot water and Simple Green and peeled off any old gasket. I opened up the oil filter for cleaning...ugh I should have done this more often! There was a lot of crud in there that had to be scraped out with a metal pick. Once I get the right side case rubbed down with some scotch brite and very fine steel wool, I will replace the kickstart gasket and get it mounted back on the engine.
 

·
Premium Member
Joined
·
1,615 Posts
Discussion Starter #17
UGH! I need your help guys! As I was rotating the engine around the workbench, I found the following washer lying nearby. I slapped myself since I am meticulous about labeling and packaging everything. I looked through the parts diagrams in the CB360 Manual, and did not see this size washer in any of the diagrams. Can anyone ID this?!?! I am going insane trying to figure out where it goes. The only home for it that seemed to work is the oil pump idle gear shaft, but that already had its proper washer installed.



 

·
Registered
Joined
·
2,509 Posts
Quite porky, isn't it?
Does it go behind the clutch basket?
Too fat to go on the kick shaft?
Those are the only 2 places I can think of
 

·
Premium Member
Joined
·
1,615 Posts
Discussion Starter #19 (Edited)
Quite porky, isn't it?
Does it go behind the clutch basket?
Too fat to go on the kick shaft?
Those are the only 2 places I can think of
Note: ID is 10mm. Clutch basket was not removed so that is out, and the kick shaft is way too thick for it.

I am wondering if it might be part of my BMW, as I took the transmission out to do a spline lube...
EDIT: Nope, all BMW washers accounted for.
 

·
Super Moderator
Joined
·
5,549 Posts
One of the spacers for the actual engine being mounted into the frame? If I remember correctly there is one on one of the bottom bolts.

Sent from my SAMSUNG-SM-G891A using Tapatalk
 
1 - 20 of 78 Posts
Top