Dead Engine

[Hawkeye]

Just called into the shop to ask about a service and tune-up. The mechanic said that he didn't need to look at the bike. He said that he has heard me go past a few times and the only thing he could do was put a bullet in it.

Basically, the top end is shot and is not worth doing anything with it.

Don't have the dosh to replace the bike as I'm trying to hold out until I get my full rather than getting another 250.

So my question is: given that the bike is a '87' Honda CBX250 , Are there any other engines that would fit the frame other than another CBX.
I just want to get over the next 6-8 months without having to replace the whole bike.

[Ixion]

What's he mean "top end is shot" and "not worth doing anything" ?

Dunno the CBX250, but Honda singles are usually fairly tough, and simple. Cam chain wear is a given on an OHC chain driven engine, but that's not too big a deal. Some Hondas did wear the cams and followers, don't know if the CBX250 was one.

Does the top end sound noisy? Rattles, clatter? Almost always top end problems will be noisy to the ear.

Has it gotten any worse? Top end doesn't USUALLY disintegrate fast, just slow wear (there are exceptions, and a broken cam chain is an obvious one - but a new cam chain is no big deal on a single). Even if it is the worse for wear , can you live with it until you are ready to move on ?

Are you comfortable wrenching ? Can you do it yourself.

Mechanic may just have been a doomsayer. Met that sort many a time, it's not the latest bazillion cylinder crotch rocket so its a waste of time.

Anyone familiar with Honda single bangers able to have a listen? Ms Celtic Sea Lily is down your way and hers is a similar model (I think) . Just to see if it sounds worse than normal.

I wouldn't panic too soon. I'm assuming you're just using it as a commuter/learner, and for such usage simple machines like the CBX250 will often defy the doomsayers for years and years.

Get a second opinion , I say.

[ZorsT]

I'll agree with Ixion.

Get a second opinion

[James Deuce]

CBX and CB250RS are different heads.

CBX go bang unfortunately, somewhat earlier than later. CB250RS will still be going when the next millenium AD rolls around.

I have 4 colleagues, all with CBX250s in their respective gargres, all wondering if I know anyone with a spare engine/head for a CBX.

I know where the mechanic is coming from, but I also think he is being a bit negative. Try another mechanic and get a quote for repairs.

[madboy]

So is it going or not at the moment? If it's going, and you only want it until you upgrade licenses, why worry about tune up and stuff? Just ride the bugger until it drops. Then upgrade to the "new" bike. Hopefully there's not too much of an overlap, if any, where the license does not equal the bike.

Jeez, the amount of cars I've wrung the nuts off, then flicked them expecting them to drop, and find out they're still going strong years later with no work done...

[Hawkeye]

What's he mean "top end is shot" and "not worth doing anything" ?

Does the top end sound noisy? Rattles, clatter? Almost always top end problems will be noisy to the ear.

Has it gotten any worse? Top end doesn't USUALLY disintegrate fast, just slow wear (there are exceptions, and a broken cam chain is an obvious one - but a new cam chain is no big deal on a single). Even if it is the worse for wear , can you live with it until you are ready to move on ?

Are you comfortable wrenching ? Can you do it yourself.

I wouldn't panic too soon. I'm assuming you're just using it as a commuter/learner, and for such usage simple machines like the CBX250 will often defy the doomsayers for years and years.

The bike is still useable. Starts first time and goes quite well for a single.
In the last few days it has decided to cut out whilst idling at lights etc. It will idle quite happily and then cut out for no reason. Bit of a bugger when your sitting at the front of a line of cages at the lights, or in slow moving traffic. It restarts no bother but I'm just a bit concerned that some nutter pulls away and rams into the back of me.
Thats why I thought I would get it looked at by a bike 'expert'.


Don't know much about bike engines. Rebuilt many a cage engine in the past.
So I'm quite comfortable with a wrench. If it was a cage I would immediately say it was head cams/ tappets buggered as that's exactly what it sounds like.
I would say that it is no worse than when I first got the bike but I don't know what a good cbx sounds like.
I'll probably pull the engine out at the weekend and take the top off and have a look. Do bike engines have rockers and tappets?
I need to get my hands on a manual.

[Ixion]

DOHC 4 valv ehead I think. So twin chain driven cams an bucket/shim followers. Just like an XK Jag (except 4 valves per cylinder) .So noise could be valve clearances, or worn chain, or could be camshaft wear.

Wouldn't think that would make it cut out when idling though , that sounds more like carb or plug. Both usually fairly sensitive on a single.

I'd shout it a new sparkplug, pull the cam covers if they're easy to get off (usually are) and look for any "oh shit" stuff. If it looks OK , see if the plug's fixed the idling problem, if not take off the carb and give it a good clean.

If all looks OK and it's just noisy, but not getting obviously worse, prolly see you through to your full. Just keep the revs down a bit away from the red line.

Ratty (Yamaha equivalent) was rattly for a year at least before I got round to replacing the cam chain- just got very slowly worse, I kept revs down to about 8000 normally, all good.

[nudemetalz]

Judging by the avatar, the CBX is the RFVC SOHC Model (CBX-250F).
The RFVC DOHC model was the CBX250RS non-faired model. From what I remember, they tended to hand-grenade a lot.

SWIFT ONE's model shares a lot with the XL/XR-250 of that year so I would think getting a complete engine or getting parts of an engine shouldn't be too hard or expensive.
Try Malcolm at Econohonda. He is just awesome and a fountain of knowledge.

Cheers.

[Hawkeye]

DOHC 4 valv ehead I think. So twin chain driven cams an bucket/shim followers. Just like an XK Jag (except 4 valves per cylinder) .So noise could be valve clearances, or worn chain, or could be camshaft wear.

Wouldn't think that would make it cut out when idling though , that sounds more like carb or plug. Both usually fairly sensitive on a single.

I'd shout it a new sparkplug, pull the cam covers if they're easy to get off (usually are) and look for any "oh shit" stuff. If it looks OK , see if the plug's fixed the idling problem, if not take off the carb and give it a good clean.

If all looks OK and it's just noisy, but not getting obviously worse, prolly see you through to your full. Just keep the revs down a bit away from the red line.

Ratty (Yamaha equivalent) was rattly for a year at least before I got round to replacing the cam chain- just got very slowly worse, I kept revs down to about 8000 normally, all good.

Thanks for the info Ixion. I will give it the once over at the weekend. Hopefully it will only be clearances. I stripped the engine off the frame when I first got the bike because the whole bike needed some TLC. Sanded and painted the frame and tank, glassed the fairings, cleaned and painted the engine but was too eager to get it back on the road again. I should have taken it apart whilst I had it out.
Gave it new oil but that's about it. So yes, it could probably do with a new plug and the carb stripped and cleaned.
I just thought that due to time constraints, I'd throw it in the shop otherwise it will probably be off the road for a couple of weeks if I do it myself.
I certainly did not expect his response!

[Hawkeye]

I took the bike to Boyles for a second opinion on Thursday.
He said that although it did sound noisy, until the head came off it, it would be hard to estimate the cause. At last a decent guy, not trying to rip me off.
Pulled the engine out today and took the top off. No sign of anything major.
Cam looks good and even the tappets are showing no signs of wear.
From my knowledge of cage engines, there seems to be quite a bit of travel on the tappets so I could be in luck and it's only the gaps.
I'm going to drop off the motor on Monday to get him to give it a quick once over. With the engine out, it shouldn't take him long so it keeps the price down. He even said that the rest of the bike was in good condition so it would still be worth spending $400 - $500 on the motor and still have a good bike.

First week-end in months where I haven't been able to get out and ride.