Honda CB250N - It was going too well. then I found this? Project Bike - Part 60

All I needed to do was understand an oil leak, but then I realised the scale of my problem.

[@jamesallen4050]

Repair it Ryan! Don't spend your money on parts, just a good local welder/mechanical engineer. I bet you could whip that engine out in an hour, get it welded properly, and back in again in just a few days for relatively not much money. It's one of your last hurdles with this bike. You're doing great. 👍🏽

[@RyansGarageUK]

Cheers James, i can certainly remote it very quickly, i dont immediately know anyone to fix it properly. But i am speaking with a skilled engineer tomorrow on another matter.

[@glynnwilliams3192]

Totally agree with James . Fixing a crack on a cast aluminium casing isn't as hard as it used to be . Just have to get someone who knows what they are doing .

[@NatsNackersYard]

Absolutely gutted for you mate. Absolute bummer

[@RyansGarageUK]

Cheers Nat, if it wasn't challenging everyone would be doing it. 😀

[@Free_Ranger_CT110]

With the engine being a stressed member of the frame on the super dream, riding the bike is probably opening up the crack. As others have already commented, a weld job or for a permanent repair two replacement cases. Good luck.

[@RyansGarageUK]

I hadnt thought of the stressed element, that makes sense. Cheers.

[@derekdingwall]

What a pain Ryan ,I agree with another follower about the JB weld until you get yourself sorted out with another case,I'm pretty sure the casing could be welded also but probably from both sides🤔👍

[@RyansGarageUK]

Cheers Derek, I'll certainly consider all my options.

[@KuroSanArts]

Well on a plus side, you're going to be an expert in this model bike after you're done!

[@RyansGarageUK]

Well I'd say more experienced, but still far from an expert. 😀

[@mikefennelly3310]

Thanks for the horn position answer 😊👍, l had a cracked engine casing years ago and got some low temperature aloy welding sticks off ebay they worked for me , there some vids on KZbin using them 😀

[@RyansGarageUK]

Thanks Mike, hadnt considered it may ne possible for a home weld repair. Cheers.

[@mikefennelly3310]

@Ryan's Garage UK as l remember I cut a v shape into the crack and then filled it with the aloy weld stick it held as long asl had the bike anyway , but I'm sure more clear on a KZbin video 😊👍

[@tuoppi42]

Good opportunity to check the engine completely when you disassemble it for welding. You can help the welder and probably save on expenses by cleaning the parts of oil. Avoid using brake cleaner or give it good time to evaporate, that stuff produces toxic fumes under UV light. Taking both case halves including the bolts and torque values in case they want to weld it under tension might be a good idea.

[@RyansGarageUK]

Thanks Tuomas, they're all good points.

[@Paul.Gascoyneuk]

That is a downer I remember early on you pointing out the crack on the top casing , maybe look into having it welded and take it from there and I agree a kickstart on the scrambler adds character to the scrambler project , I’m certain you’ll source a decent casing if you go down that route , anyhow keep up the good work your inspiring and teaching as you go 👍👍

[@RyansGarageUK]

Thank you, it will certainly keep me busy one way or another.

[@jimbo9310]

Hi Ryan if you are going to strip it anyway try getting it repaired first . I remember you mentioning the crack in the casing. Keep up the good work Ryan and I feel your pain . On the plus side we get extra videos thanks 😊👍

[@RyansGarageUK]

Thanks Jim, 🙂

[@jd6549]

Ryan I agree, get the case welded. I once swapped a Honda engine cases as they were new and very cheap, but as mentioned below you have to get the shells to match. A good aluminium welder should sort that crack out easily. You may not even have to strip the engine. Seek some advice from a local alloy welder, they are usually very good as it is quite difficult to do properly. Good luck John🇬🇧👍

[@RyansGarageUK]

Thanks John. Good Advice. 👍

[@RustyWrecks]

if you buy a top case the crank bearings will need to be changed for a different size as the top crank bearings fit in the top case and your crank bearings wont fit, so I would strip the engine down and get it welded, either way you would have to strip the engine and getting it welded will be cheaper than new big end shells and a case. if I can help in any way give me a shout, great video.

[@RyansGarageUK]

Thank you Pete, very helpful as alwaays.

[@alfiedodah9799]

I was wondering what happened about the crack.....the best solution is to have it welded. A replacement upper crankcase will not be an option because it will need to have the same crankcase code as yours Crankcase carriers are machine matched to the upper crankcase and are not interchangeable. A replacement upper crankcase that does not have the same code as yours will give you main bearing failure. A replacement upper crankcase with it's matching carrier but NOT with the same crankcase code as yours will also give main bearing failure as your bearing shells are colour coded for the correct clearances with both your crank and crankcase codes Changing the upper crankcase and replacing bearing shells with those to give the correct clearances is not an option as new bearing shells are unobtainable..... In summary 1.Get the crack welded 2.replace the upper crankcase with one that has the exact code as yours 3.get a replacement bottom end

[@RyansGarageUK]

Thanks Alfie for a comprehensive summary of my options. Appreciate it very much.

[@nailseaphil3989]

my money would be on having it welded. there's not much that cant be welded these days. you never know you may just have to take the engine out of the frame but not strip anything. obviously a lot depends on the crack which I don't think we've seen yet. good luck either way.

[@RyansGarageUK]

Thank you. I may need that luck.

[@timparker9235]

I had completely forgotten about the crack - I remember you showing that very early on in the build. can't add any more to the comments below on a solution other than I would photograph it and take it to a local welding shop asking their advice - fingers crossed for you Ryan. about the refusal to rev past 8000 rpm - will it get to 10,000 when warm without load? if it does then that might suggest to me it's not a fuel problem - also dont forget that the rings haven't seated in yet so you are probably down on power at the moment. I could be wrong but just throwing ideas at you - good luck

[@RyansGarageUK]

Thank you Tim, im giving thought to all my options, and ill test revving out of gear and see what it does.

[@lewiscoleman8116]

You can do a temp patch with jb weld, you can get the case tig welded by most ali welding specialist fabricator. If you change the case you will need both as they are machined together as a matched pair

[@RyansGarageUK]

Thanks Lewis, i hadnt considered they need to be kept as a pair, and that certainly add complexity to my options. Maybe i start with jb weld and see how that ends up.

[@RyansGarageUK]

Thanks for confirming that Lewis is offering sound advice. 👍

[@colinculverwell325]

@@RyansGarageUK if you go with the jb weld make sure the repair area is throughly cleaned.

[@InTheShedUK]

That's such bad luck. Looks like its either a matched pair of casings or a good local welder to repair the damage.

[@RyansGarageUK]

Thank you. I agree both are options,

[@martinowl]

It can be welded. Many years ago I had the sump of a cb400/4 repaired by welding after overtightening the sump plug causing the alloy to crack! What a numpty!

[@RyansGarageUK]

Cheers Martin, im going to try to find someone to discuss this with.

[@robertadams4415]

Good luck mate

[@RyansGarageUK]

Thanks Robert.

[@robertwinsper7409]

Your breather pipe should be connected to a nipple on the airbox, upper RH side if memory serves me correctly. The breather inlet hole is below the air filter so you effectively have an air leak between the filter and the carbs, that will be making your mixture a bit lean and you are letting dirty air in. As for the crack find someone who can weld it up for you. You might not even have to strip it down much.

[@RyansGarageUK]

Hi Robert, as I undestand it the breather hose only connected to the Airbox on the 400cc. At least I can't see anywhere on my airbox to connect it to. I have been speaking to experienced local guys about the crack and I'll explain what they said this week.

[@robertwinsper7409]

@@RyansGarageUK It was always connected on my 78 250N. A bit of emissions control, the idea being it would eat its own oily fumes. Is the nipple present but capped off? I saw a few 250Ts and very early CX 500s with caps on the breather ports on the airboxes.

[@matthewharmer1656]

A simple welding job,crack on!!!

[@RyansGarageUK]

Hi Matthew, whilst I don't disagree in principal, I've never welded in my life, so for me it's not simple. I'm speaking to a few guys that are well experienced in this and you'll hear the result of that soon.

[@slammermx]

OMG I owned that bike when I was in College, I ran it till it died.

[@RyansGarageUK]

Hi Robert, you owned this bike!! Thats good to know. When i bought it i was told it had been donated to a college, maybe that was you? Its keeping me busy but should be back on the road without an oil leak by next weekend.

[@jediknight2350]

you could just use low melting point aluminium solder only need a blow torch and it be stronger than new

[@RyansGarageUK]

Hi, I have recently considered that, but when I spoke to a few people It seemed to me I would have to strip the whole engine to a case, which I did want to do at that time. May consider this in the future.

[@tommoso55]

Get it welded Ryan

[@RyansGarageUK]

Id like to if i can, but maybe going for short term fix first.

[@MrSportster12]

If you don't mind a bit of a bodge for now J.B.Weld could be your friend.

[@RyansGarageUK]

Hi Stu, that has crossed my mind, although i only have access to the outside without a full stripdown, and not sure if that would seal it or not?

[@MrSportster12]

You haven't got much to lose and it could see you through the summer and do a proper repair over Winter. Also it may be possible when it's apart to alloy weld for a permanent fix?

[@Ramonthebiker]

I had a case welded when I had a problem once and it was fine - good as new. As regards the revving, I can’t recall from your earlier vids but did you put the carb jets up a size? Ethanol fuel runs leaner so better jetting improves power

[@RyansGarageUK]

Thats good to know a weld should be successful. I hadnt changed the jetting, at least not intentionally.

[@andyshondaxlsrestorations4733]

J.B weld👍

[@RyansGarageUK]

Thanks Andy, i may well end uo resorting to that.

[@andyshondaxlsrestorations4733]

@@RyansGarageUK it's certainly worth a go it could be a £10 fix👍

[@malcolmgibbs-e5c]

im guttered for you

[@RyansGarageUK]

Thanks Malcolm, sure ill sort it somehow.

[@ravemachinekaraoke12]

Well theres a block here in manchester, missing head your well come.

[@RyansGarageUK]

Thats a kind offer, thank you. Im considering my options but may be interested. 👍👍

[@ravemachinekaraoke12]

@@RyansGarageUK It's free if that helps.

[@RyansGarageUK]

Thank you, that's fantastic, and it's offers like this that make the time and effort of uploading my challenge worth while. I think I'm going to initially keep my existing engine if possible. But that may not be successful. We will find out together.

[@stephenwalsh8184]

🏍👍

[@RyansGarageUK]

Thanks Stephen.

[@CaptJerry]

A bit of a 'thrown' in the air one, is that a Motad 2 into 1 exhaust? Maybe needs tuning to that pipe, as it was a 2 into 2 from standard!

[@RyansGarageUK]

Hi, thanks for the suggestion, you are correct the exhaust is nonstandard, although others suggested to me it shouldn't make much difference. I have since improved its running in later uploads.

[@tomlibero3780]

Allen Millyard only!

[@RyansGarageUK]

I wonder if he happens to be visiting my area carrying a tig welder with a little spare time ???

[@andrewtodd5016]

Got a case or a full engine if you want one

[@RyansGarageUK]

Thank you Andrew, i may be very interested. Im just considering my options before i make a decision. 👍

[@RyansGarageUK]

Hi Andrew, I'm going to try to retain my original engine if possible, but I don't yet know if that will be successful or not. I truly appreciate your offer, and it's a huge reason why taking the time and effort to upload my efforts is worthwhile.

[@geoffmccord4880]

Get it tig welded its in a spot that cant be seen

[@RyansGarageUK]

Hi Geoff, you're correct it's hardly visible, and have been speaking to experienced welders and I'll share what they say next week.

[@geoffmccord4880]

@@RyansGarageUK Great definitely a cheaper option

[@susanbeech7613]

Oh bum x

[@RyansGarageUK]

Yep, i agree. Bum indeed

[@stevezephyr]

Have the case welded, @JamesAllen is spot on, don't waste your cash.

[@RyansGarageUK]

Thanks Steve, i've been talking to local welders, and I'm not keen to waste my cash either.

[@stevezephyr]

@@RyansGarageUK great stuff, I've a friend that runs his own engineering business, he's done some amazing engine casing repairs including some that seem impossible. He's based in Atherton, Lancashire if that's any he3.