Am I the Pontius Pilate of this CX500?

That's looking pretty impressive. CX is a good motor after waterpump seal and cam chain tensioner are done. It actually lasts much longer if you keep it around 6,000rpm or more, at low engine speeds it self destructs cam chain tensioners, sometimes taking out the case. The last models (+CX650+ had an automatic tensioner which lasts about 18,000 miles but a lot longer if you check at every service to make sure it's adjusting..
I guess you'll have a pair of plates made to convert rear wheel to spokes? (cut original 'spoke' bolts, bolt on plates, lace up)
Personally, in my experience, except for the original styling, the 'Plastic Maggot' isn't a bad bike, the motor is much easier to work on than any of the in-line fours and only takes about 20 mins to get 'on the bench' (after a bit of practice). Second year in Britain, the addition of fly-screen changed the look more than anyone thought possible. It even handled reasonably well (particularly for the time period)
 
irk miller said:
From here, it just looks like you need to adjust the bottom edge profile of the seat to match the frame. The frame has substantially more curve than the seat.

Thanks Mr Miller. Do you mean to follow the frame line as I've drawn down below?

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Yep. I'm reaching from a distance, but I assume since it's a fiberglass base, you can shave some off to match the frame better. Looks to me like the tail section may need it more than the front half, so it lowers the angle of the seat.
 
crazypj said:
That's looking pretty impressive. CX is a good motor after waterpump seal and cam chain tensioner are done. It actually lasts much longer if you keep it around 6,000rpm or more, at low engine speeds it self destructs cam chain tensioners, sometimes taking out the case. The last models (+CX650+ had an automatic tensioner which lasts about 18,000 miles but a lot longer if you check at every service to make sure it's adjusting..
I guess you'll have a pair of plates made to convert rear wheel to spokes? (cut original 'spoke' bolts, bolt on plates, lace up)
Personally, in my experience, except for the original styling, the 'Plastic Maggot' isn't a bad bike, the motor is much easier to work on than any of the in-line fours and only takes about 20 mins to get 'on the bench' (after a bit of practice). Second year in Britain, the addition of fly-screen changed the look more than anyone thought possible. It even handled reasonably well (particularly for the time period)

Thanks for the comment crazypj. This is a 1982 500 Shadow Australian model, and I don't know if had been upgraded along the way, but when I opened it it turned out to have an auto cam chain tensioner.

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I replaced the cam chain anyway since I didn't know what life it had, and since the back cover was off, I also changed the oil and mechanical seal on the water pump. I also replaced the gear change lever rod seal and the final drive seal.

I don't have a lot of experience working with engines but I found this engine relatively straight forward to work with, but without the manual I would have been lost, and I can't wait to test it out on the finished build. I only got to ride it around the block when I got it as the clutch was stuffed.
 
irk miller said:
Yep. I'm reaching from a distance, but I assume since it's a fiberglass base, you can shave some off to match the frame better. Looks to me like the tail section may need it more than the front half, so it lowers the angle of the seat.

You're spot on. Its a fibreglass base, and I agree that the tail looks to high. I don't have any shocks on and the bike is on its centre stand, which is pushing tail up a bit, but I do agree that I have to work on the seat base.
 
Personally I would cut some semi-circular clearance around top of shocks to allow rear of seat to sit substantially lower The angle at present is more reminiscent of German 'Streetfighters' from 90's. Bottom of tank 'slopes' down so you can't really follow it's line
 
no american 500s had the auto tensioner the 650s did

the austrailian shadow 500 of that year all had it as did europe and pacific rim
 
My understanding was that the original (manual tensioner) cam chain guide bolt would loosen, but that Honda did offer a recall and upgrade. Don't know much else with respect to the different regions or when they switched to the auto tensioner, which I also understand is trouble free.
 
I was working at Honda dealers when CX was launched, Honda ran one CX motor at 10,000 rpm for a week, (non stop on dyno) stripped it to measure wear, didn't find anything significant so thought bike was ready for general public. They expected people to 'mistreat' motor and use high rpm. Unfortunately, people teated it like a Harley and rode around in high gears at 'low' rpm. It was found the load reversals were causing cam chain flutter' which was breaking stuff (Harley had / has same problem with twin cam for same reasons) I did way too many CX's under guarantee / recall including crankcase changes when the mounting bosses broke off.
Officially, there were only 3 types of cam chain tensioner but I know in Britain we had at least 5 different types while factory was re-designing things.
The automatic is the best but an oil assist( if it had been available) would have been better. Luckily Honda still machined the inspection plug so it is possible to check tensioner operation
 
there never was a upgrade to the auto tensioner it cant be done simply

the crank support plate that holds the main bearing is different

the block is tapped for a different support and guide pin

the timing chain guides are different

the manual timing chain bolt has NEVER had a problem coming loose

the chain has way more adjustment (longer life) with the manual system

it is not to hard to convert them back to manual adjust i do this in high performance bikes and

racing 650 as the manual adjust system is stronger the auto tension system gets bet to death and fails

if it is left with a worn chain and gets beyond adjustment it will fail spectacularly
 
ps you cant see the indicator hole in the auto tensioner thru the timing port

even with a modern camera
 
No. I meant that Honda did an upgrade to the problematic early manual tensioner with a solution....not an auto tensioner.
So what was the problem with the early manual tensioner that has become part of CX folklore? Was thete a problem....was there a solution?
 
Personally I preferred the manual tensioner BUT, if you don't check every 1500~2000 miles it can get 'sticky.'
Check the operation of it by removing inspection cover, I used to 'rock' crank back and fore with lock bolt 'loose' to maker sure it was actually moving then turn to tightest position before re-locking. I seem to remember the manual instructions were not completely clear on adjustment or were confusing which is why so many got it wrong?
 
22thousand 1978 bikes ONLY

had a early chain guide plate that in one instance allowed the chain to snap locking the rear wheel and causing one death

it resulted in the 22k bike having a NTSB recall issued where the chain guides guide plate and upper re enforcing tab

were replaced

that was it

all the rest if mis information

to set the manual tensioner

put left piston to tdc firing

loosen the adjuster screw 1.5 turns

take a block of wood put it up against the side of the motor close to the adjuster screw

tap the wood block a few times

tighten the screw with a torque wrench

do this every i change and valve setting
 
Thanks for clearing that up cxman.

You are right...there is a plethora of misinformation and the tricky thing is deciding who and what to believe. ;)
 
22,000 total or in USA? Never mind, I looked it up, about 50,000 were made in 1978
In Britain it was an issue for more than a year. and recurred around 18~19,000 miles on any model driven 'gently'
The answer is to beat the hell out of it ;D
 
the real problem was a new chain stretches the most at the beginning of its life

most of the dealers were not doing the timing chain adjust till the 4500 mile service (if by then the customers brought them back)

so the chains got loose and slapped around and ate the crank support plate

or broke a guide

new chain needs an adjust at 250 500 1000 then 2000 then back to regular adjustments
 
So with an auto tensioner I don't have to worry about that but should replace chain at, say 50,000 km ?
 
it wont last anywhere near 50 k

maybe 30 but i would start listening after 23k you ca hear them when they start to bounce
 
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