Author Topic: 500-4 scrapheap challenge  (Read 2527 times)

Offline Nurse Julie

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Re: 500-4 scrapheap challenge
« Reply #15 on: March 30, 2018, 05:49:13 PM »
Just measured CB500, ruler in same place is 5 inches. Slightly difficult to measure as this bike has front mudguard on.
« Last Edit: March 30, 2018, 05:53:08 PM by Nurse Julie »
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline Colonial-Clive (yindi)

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Re: 500-4 scrapheap challenge
« Reply #16 on: March 30, 2018, 07:15:50 PM »
Hi, from front bolt to tyre is 6", from no 2&3 pipes 5" so you should have enough room, or you could rake the neck a tad..  ;)

Offline matthewmosse

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Re: 500-4 scrapheap challenge
« Reply #17 on: March 30, 2018, 08:44:54 PM »
I like what you are doing, I have a cb125 twin engine and Ns125r frame that are a similar idea, the frame had previous really dodgy welding on the monoshock mounting, given it was known to be tuned to accelerate like a banshee and do 110mph there was no way I wanted to put it back to standard format, so I got a replacement frame and v5c and intend the ns125r to become a ns125f, no big deal, cheap learner machine, might be fun. The old ns125r frame will be strengthened and twin shocked and get superdream wheels that failed to get sold at 99p on eBay. The rest of the running gear will be stuff that came in job lots or was given by various mates clearing garage space. Kids and getting laid off have slowed progress on bikes to a virtual halt as starting up in  self employment and the stresses on a marriage that career rollercoasters and kids bring do not leave a lot of shed time, but one day the project will come back to the front, like you, I find it good to head out to the shed and solve the problems involved in a 'custom' project to clear my head, though there are a few such projects in my shed, mini dumpers made from industrial grass cutters also fill that role and look to potentially earn a few pennies, plus damn handy things for my handy man jobs, save a lot of pushing wheelbarrows. 
Looks like you are hopefully about there on clearance. Weight wise my first 550 came in a job lot with several cb250s, I remember the engines were close or weight and width when I loaded them in the van. Might make a fun bike. If the clearance is too tight a tad more rake to the frame with careful welding, slab yokes to kick things foreward or leading link forks might make it both more interesting and involving and more unique. Equally a smaller diameter wheel and longer forks might increase clearance. ( trail bike forks?.)
Got a 500/4 with rust and a sidecar and loadsa bits. nice and original and been round the clock

Offline haynes66

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Re: 500-4 scrapheap challenge
« Reply #18 on: March 30, 2018, 10:15:12 PM »
thank you all for your input. i put another spare set of forks on which have no springs in, so the thing sits at full travel and it looks like it might be ok. i will be looking out for a 400n front end as the forks are a tad thicker and has twin discs but that is down the line a bit yet. new engine mountings are next on the agenda and i'm still unsure about downtubes.  i was thinking i would need to run tubes under the engine but having seen a few racing 400s, the frame seems to be stable enough to use the engine as a stressed member. i'll need some professional advice on that one, i think.
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Online Bryanj

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Re: 500-4 scrapheap challenge
« Reply #19 on: March 30, 2018, 10:26:18 PM »
lots of bikes used the engine as a stressed member and it was not unknown to build a "Trifield" a 500 triumph twin in an enfield 250 frame using dural plates
« Last Edit: March 31, 2018, 10:21:33 AM by Bryanj »

Offline SteveD CB500K0

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Re: 500-4 scrapheap challenge
« Reply #20 on: March 31, 2018, 07:20:53 AM »
I all the years I’ve been running this site, I believe that this is the first “transplant” that has been attempted!

Good luck and keep the posts coming

Steve



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1971 CB500K0

Offline matthewmosse

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Re: 500-4 scrapheap challenge
« Reply #21 on: March 31, 2018, 08:50:31 PM »
I think the cb250n used the engine as a stresed member didn't it? So my guess is it would handle the modest power increase as it's fairly smoothly delivered. That said bending up a set of removable cradle tubes might be worthwhile - I think the 650 used such a device, not sure if I'm right on that, bought a job lot of 650 stuff and one bit looks like it would have done that job.
Best fortnights work I had was work expirience placement  at metal malarkey engineering, one project we were doing was fitting a Cr500 motor tuned to over 90 bhp into a Cagiva mito 125 shoehorned in so as to look as close to standard as possible.
Got a 500/4 with rust and a sidecar and loadsa bits. nice and original and been round the clock

Offline haynes66

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Re: 500-4 scrapheap challenge
« Reply #22 on: April 23, 2018, 05:31:24 PM »
i've cut the frame about and cut some engine plates etc which is the easy bit but now the hard work begins. the cover on top of the engine was the first to be removed but two of the long bolts have snapped already so i think it's going to be a long slow slog at an attempted strip using heat, diesel and a little brute force. i'll post any updates as/if things progress.
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Offline matthewmosse

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Re: 500-4 scrapheap challenge
« Reply #23 on: April 23, 2018, 09:18:08 PM »
Paint it in old engine oil, being slightly acidic and very oily it really helps with freeing off old engines, especially mixed with a bit of carb cleaner and wd40. I used such a mix on a cb550  engine that was so corroded the clutch casing had dissolved, amazingly the top end was mint, especially things like camshaft and cam journals which whilst caked in oily mud cleaned up lovely.
Got a 500/4 with rust and a sidecar and loadsa bits. nice and original and been round the clock

Offline haynes66

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Re: 500-4 scrapheap challenge
« Reply #24 on: April 23, 2018, 09:46:08 PM »
thanks, i'll try that
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honda britain project
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Offline haynes66

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Re: 500-4 scrapheap challenge
« Reply #25 on: May 14, 2018, 10:56:55 PM »
i've been attempting to strip the motor but it's infuriatingly slow as nothing much is budging. the round cover has been removed but two screws have snapped. thankfully, most of the cam cover bolts and screws are loose but i will have to drill out a couple. to give myself a break, i've been cutting and filing engine plates which has been therapeutic. the first pic shows the piece removed from the frame.



i had some 5mm plate machine folded to give the frame some strength before tackling the engine plate



then i spent a while cutting and filing the engine plate itself. this is bolted on at this point to make sure of the sprocket location.  i slotted the bolt holes to get the engine height in the correct spot.



sat the frame on top to see where everything fits and it looks ok. the pod filter is an ebay cheapie to check for clearance. the next stage will be welding the rear plate in place and maybe think about downtubes although i dont want to spend any more money at this point in case the engine is scrap.






honda firestorm
silverwing 600 scooter
honda britain project
phil read rep project
YGS1 80cc yamaha
LE Velocette

 

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