Honda Twins banner
21 - 40 of 75 Posts

·
Registered
Joined
·
3,348 Posts
Discussion Starter · #21 ·
I measured the stock shocks against the CB700SC shocks I'm using, they're only one inch over (13" eye to eye) not two as previously stated.


Here's a look at the fit of the steering stem with my bearing cups added with the stock fuel tank in place.




Here's an overall view of where i'm at today.




And a shot of the frame slugs joining the cut rear frame to the front half, all bolted up. Chopping a frame with a light saber really does vaporize a lot of material...

 

·
Registered
Joined
·
3,348 Posts
Discussion Starter · #22 · (Edited)
Friday I got all of my fork parts cleaned up and ready to reassemble, they'd been apart and stored for several years and I'd never really cleaned them up. I used a big aluminum foil pan from a dollar-store and poured in half an inch of simple green then 2 more inches of tap water. I put in everything but the fork tubes and lowers and let them soak for 15 minutes before I started scrubbing them one at a time with green scotchbrite, rinsing with fresh tap water and towel drying each part. I really don't want anything to rust. Then I did the lowers, and then the fork tubes themselves. Its a bit difficult drying out the inside of the fork tubes, I stuffed a twisted rag in there but they still weren't as dry as I'd have hoped, so I sprayed them inside with wd-40 and left it at that. I'll let them air dry for a few days before getting back to them.
I picked up a set of cartridge emulators from an eBay seller, they're made by V-Twin Mfg and they're listed for Harleys with 41mm Showa forks. They measure 33mm in diameter, just a bit too small to fit correctly on these damper rods, so I'll be making up some adaptor rings to fit them properly. For about one third the price of Racetech emulators, i'll make them work.





 

·
Registered
Joined
·
3,348 Posts
Discussion Starter · #23 ·
These cartridge emulators fit my damper rods like this:



So I needed to make some adaptor rings to help them fit better:





Plenty of room for the springs to sit on top of the emulators too:



Racetech says to start the adjustment at 2 turns past where spring tension begins, I've asked a few friends and read a bit on the web and everyone says it's a little stiff for mixed street riding so I set them at 1.5 turns to start with.



The nylon lock of the check nut is fully seated on the adjustment screw, and the nut is tight against the valve body. It took several tries to get them the same, lots of room for error here.

Next up is to drill out the oil holes in the stock damper rods
 

·
Registered
Joined
·
3,348 Posts
Discussion Starter · #25 ·
Regrettably no they're not externally adjustable. I'd have to pull the fork caps, preload spacers and springs then reach in with a magnet on a stick to get them out of the fork tubes. Then i'll need to degrease them before finally readjusting them and reassembling for a test ride.

This is the first time I've messed with cartridge emulators, hopefully I'll like them.

There are lots of inexpensive sets on eBay in sizes compatible with most vintage bikes, they're listed for bikes like CRF50 etc. or just search your fork size.
 

·
Registered
Joined
·
3,348 Posts
Discussion Starter · #26 ·
I found some free time the other day and modified the fork damper rods per the Racetech directions by adding a third 5/16" hole.



Then I assembled the forks and filled with Dextron ATF, it's cheap and I had it handy.

The front wheel is from a 1987 CBR600F, 17" x 2.5", same axle, same caliper, same rotor...
The 750 forks are 1/2" longer than the 250's stockers.
Front tire is 110-80-17 (23.92" diameter) and rear is 130-70-17 (24.16" diameter)

 

·
Registered
Joined
·
3,348 Posts
Discussion Starter · #28 ·
Thanks! I'll probably have to admit you built yours first and credit you the idea behind it all... I had originally planned these parts for my CB750K3 but that project is on hold indefinitely pending fewer budgetary restrictions and better shop space. I've got a few other parts from that plan that I'll be using on this build, stay tuned.

I'm wondering about your left side exhaust that I read about here somewhere. Could that simply be the left exhaust from a 4-cylinder bike?
There seem to be very few options for these 250's and I'm reaching out into the unknown armed only with the dimensions of the exhaust gaskets. It seems they're common to XL500/600 and CB550F so there may be some room to modify a stock exhaust and have something new to show for it. I'd really like some stainless headpipes like these at CRK in the UK https://www.caferacerkits.co.uk/sho...pes-for-Honda-CB/p/71606394/category=21040231 buy they don't seem to fit these 250's just the 400's, and they're out of stock anyway.
Land vehicle Vehicle Motor vehicle Motorcycle Spoke



Craigslist if full of scams, but once in a while good machines come up cheap and sell quickly.
Like this: https://boston.craigslist.org/nos/tls/d/lathe/6389722314.html
$800 for a non-clunker South Bend 9A with a 40" bed and tooling, it won't be around long.
 

·
Premium Member
Joined
·
24,208 Posts
My exhaust is actually a 2-1 Hooker Header piece that was produced for a short time. This how the original unit looks on my CB400T1.
Land vehicle Vehicle Motor vehicle Motorcycle Mode of transport

This is the modified version on the road bike
Land vehicle Vehicle Auto part Motor vehicle Engine

These are the replica pipes I had made
Engine Auto part Vehicle Motor vehicle Fuel line
Auto part Engine Vehicle Automotive engine part Fuel line
 

·
Registered
Joined
·
3,348 Posts
Discussion Starter · #30 ·
Looks good!

--------------------------------------------


At this point in the build I'm starting to get curious about what the bike is beginning to weigh, I know it's far from complete but for curiosity's sake here it goes.

I did a little research and I know it's not a very accurate method, but for a rough idea at the weight I'll be using a bathroom scale under the front wheel, then under the rear wheel, and adding the two. I came up with 108lbs under the front and 127lbs under the rear wheel for a total of 235lbs.
Stock dry weight is 291lbs. Which leaves about 56lbs to go including exhaust,drive chain,handlebars,controls,front brake system,footpegs,shift and brake levers,rear brake stay rod and linkage,carb,airbox,electrics,lights and battery.

I don't have a stock set of wheels with tires mounted here to weigh against the alloys so that'll have to wait until I've gotten some out of storage. The freshly rebuilt and filled 41mm front forks with all four axle pinch bolts installed came in at 18lbs, the dirty old stockers wieghed in at 13lbs. I didn't compare the stock lower triple with the 41mm triple but i'm sure there's a pound or 2 difference.
 

·
Registered
Joined
·
3,348 Posts
Discussion Starter · #31 ·
Found a little time the other day to finish grinding the tabs from the frame tail and mount up an old CB750K rear fender. Tire Automotive tire Alloy wheel Vehicle Auto part
 

·
Registered
Joined
·
3,348 Posts
Discussion Starter · #33 ·
That's a good question, I took a look at a photo of a stock bike and I'm thinking the mufflers are only near the lower part of the shocks and it'll clear just fine, what do you think? How much room do you have between your shocks and mufflers?

 

·
Registered
Joined
·
13,085 Posts
Alan - good-looking work on this project, looking forward to seeing the finished product. I used the digital bathroom scale to weigh my 450, the method is supposed to be reasonably accurate if you put something under the wheel not being weighed that is the same height as the scale, to keep the bike level during the process. I used a block of wood virtually the exact same thickness as the scale.
 

·
Registered
Joined
·
3,348 Posts
Discussion Starter · #36 ·
I'll be keeping the stock seat, I've got some plans in the works but nothing to show for it at this point.
I'm hoping for some shop time soon.
 

·
Registered
Joined
·
3,348 Posts
Discussion Starter · #38 ·
I haven't been in the shop lately, but my plan is a rear rack/bodywork piece similar to the stock plastics but made of a single piece of .110" aluminum sheet. This rack will hold a small knock-off Pelican Case https://m.harborfreight.com/1800-weatherproof-protective-case-9-316-in-63518.html as a mini top box.
I researched how to go about bending aluminum sheet this thick, made a few test bends, and the best answer always came back as a bending brake, so I'm building one with some steel stock I have handy. Unfortunately I broke a drive gear on my Harbor Freight milling machine and had to order up a replacement that I've yet to install. I also had to order up some new tires for my old tabletop bandsaw, as the 30 year old rubber tires hadn't aged well and were causing issues.

Lately I've been collecting a few parts I know are needed, and a few parts I won't mention just yet, for another project on one of my partsbikes, think 250NH+comfortable seat+huge fuel tank+18r, 19f tires, bigger front brake+touring fairing....
 

·
Registered
Joined
·
3,348 Posts
Discussion Starter · #40 ·
I mocked this up the other day. ZG1000 Concours 7.5 gallon tank and Corbin seat from a GPZ900.
With some type of fairing this could be a fun and comfortable long distance bike. I conservatively estimate 500-750 miles with this setup between fillups.

I'm probably using these on another bike, but who knows.





 
21 - 40 of 75 Posts
Top