Any knowledge of Honda CB 250 G5

[Fazed]

Tyre compounds and brake pad materials have come on a lot since 1976 so I wouldn't be too worried about that. As has been said, tinware might be a problem, but you're on a welding forum... .
The lack of oil to the cam/head blighted many a Honda, an external oil feed conversion is available (popular on XL engines) and camchain tensioners were made of cheese.
Having said that, if it's still running after 34 years, it can't be all bad

 

[tigler]

The brake pad thing is very true. I had always thought the front disc on my 1975 Ducati 750 Sport was cr4p , but I changed the pads to AP and there was a transformation in braking of a religious order !! Before that I was going to convert it to twin disc but I'm totally happy with it now !!
One of the issues with these early Hondas was the procedure to clean the centrifugal oil filters , it was such a hassle that it was typically ignored , until the engine went bang or wore out prematurely.

 

[Fazed]

Yep, decent pads and braided hose can transform many bikes. Why the Jap 4 don't fit braided hose as standard is beyond me, it must add pence to the list price of a new bike. IIRC only Triumph fit them as standard.
The lack of oil thing I think (apart from the daft idea of cams running directly on the head) had something to do with bad casting flash in the oil galleries. This happened on a lot of Honda models in the 70s/80s. The flash was starving the oil flow to the head and bottom ends rarely suffered. This happened to a mates CBX1000 years ago. The top end lunched itself within a few thousand miles (new bike too, at the time.) The motor was rebuilt by the dealer, few thousand miles later... guess what happens!

 

[SirDick Diodenob esquire]

Yes wet weather braking was bad , it was even worse on the Honda than on the Norton and that had drum brakes on the front . There is a hinge pin about 10 to 12mm diameter on the front brake and this seized in the alloy main brake bracket making the brakes work even less efficiently , was a ****** to remove but had to be done , all for a part costing 50pence . Mine was metalic light blue , have some old photos somewhere , the previous owner fitted a perspex american cop style windscreen covered in been there stickers plus two extra large round spot lights plus air horns and crash guards and back box with enormous extra brake light , it looked ridiculous as I rode along with my L plates on and full Belstaff suit , my learning curve was quick and I ditched the accessories .

 

[Robotstar5]

Nobody mention a CX500.........

I've had 2 CX500 (one from new) probably one of the most comfortable bikes I've ridden, economical & reliable.

 

[tigler]

Yep, decent pads and braided hose can transform many bikes. Why the Jap 4 don't fit braided hose as standard is beyond me, it must add pence to the list price of a new bike. IIRC only Triumph fit them as standard.

The issue is public liability. Manufacturers are very cautious of the safety of things like braking systems. The main industry standard for road vehicle brake hoses is an American standard , SAE 1402 from memory , and this has served well for decades with almost no failures. The hoses perform well when new but begin to lose their ability to resist expansion and elongation after a few years , even so , they will go on for years to provide safe service.
Because of this manufacturers are extremely reluctant to use any other type of brake hose , they simply don't want the liability of any fatalities or injuries caused by a product that doesn't conform to an industry standard component.
You surprise me when I read that Triumph use Stainless braided brake hoses.
From an aftermarket perspective , stainless braided are the way forward though , it was one of the products that our family business used to supply.

 

[Robotstar5]

There is a hinge pin about 10 to 12mm diameter on the front brake and this seized in the alloy main brake bracket making the brakes work even less efficiently

Got home on my CB500T one night to find the front disc glowing dull red hinge had seized holding fixed pad against disc, kept the hinge pin greased after that.

 

[MrFluffy]

I had two of them in the past. Along with the much nicer to ride but not much faster cb360g5 variant. I had a k4 from the same period too at one point.
Pro's er, they handle better than the later wet dream, the engine is nicer without all that extra balance shaft mularky that the dream had from memory.
Cons they do suffer camshaft bearing problems and the cam runs direct in the head without bearings, so finding a good head would be difficult. I bushed the head on mine and made up some phosphor bronze bushes and assembled it, line bored them in situ job done.
The front brake is awful, I remember the disc is chrome plated so it just stopped working in the wet. We were going to skim the plating off in a lathe at one point but I sold the lot off to somebody who wanted to restore them. And the pivot tends to seize so you only use one side of the disc, its a terrible design for winter use. But, your going to smarten it up and potter round a bit, for that its probably enough.

In all much of a muchness, better than a dream or superdream, more of a actual bike, but back in the days of points and condensors, and mechanical regulators with points in them etc. You could probably graft on a later solid state unit hidden away and get some electrical reliability. The 360 motor is much nicer for bimbling about as its loads more torque and less frantic. Maybe you could stick the 360 cylinders on the 250 bottom end. A lot of the stuff of the period was like that (xs etc)...
Personally Id pick something else to restore, most of the cost will be in the parts rather than the purchase price, and at the end of the day the g5 was a bit of a plain jane 250 learner bike. Unless you have some specific emotional attachment to one of course.

750 sport tigler, noice... my brother had a 750gt that had been caferacerized with rearsets and clipons etc, it had the twin brembo's up front with cast iron discs etc. He ended up taking one disc off as he said it was overbraked after he binned it under braking! I have twin cast iron full floating brembo's on my 90's bimota, and THAT really is amazing, even compared to the 6 pot monsters of today...

 

[Bigjoe]

Well an update chaps,
Went over to see it this morning.....in a barn which was in the middle of very big field...well it was in a dry barn but the original engien was missing and the forks were pitted so i left it where it was ,it was cheap but i dont have a lot of money to throw at it (plenty of time)...so if anyone knows a possible project then let me know.

Joe

 

[tigler]

The front brake is awful, I remember the disc is chrome plated so it just stopped working in the wet. .

Thought those '70's Jap discs were stainless ??


"so if anyone knows a possible project then let me know."

My suggestion would be an MZ TS250 Supa 5. Cheap , cheap parts , thoughtfully engineered and can be tinkered with endlessly to improve and make even more useable. Lots of nice features , like a rubber mounted engine , totally enclosed drive chain , everything can be serviced and repaired , etc , etc.

 

[pedrobedro]

I've had 2 CX500 (one from new) probably one of the most comfortable bikes I've ridden, economical & reliable.

I had the follow on from it, NTV600 for 19 years and it was a lovely bike with minimal maintenance due to the shaft drive and single sided swing arm made life easy for wheel removal. An Irish chap bought it and rode it 270 miles to Stranraer to catch the ferry then back to Belfast. Confident or what ? The only thing I did beside clean it was service and fit battery.

 

[Bigjoe]

I had considered an MZ or similar,there's something i like about that style/type of bike.

I shall keep my eyes peeled!