1997 Hornet CB250

[mnishi]

Hello, new to this so need some help here please.

I have got a 1997 Honda Hornet CB250 which doesn't start at present. It has been sitting for over a year. When I try starting the bike, it doesn't start? and I noticed that the coolant overflow was bubbling so thought I'd check the coolant.

I drained the coolant, and it was brown. So assuming that there is a block somewhere/screwed engine? Assuming the head gasket or something may need replacing too. I have read in a few places to perform a coolant flush (50/50 mixture of vinegar and water) but because the bike doesn't start, how would this work?

In terms of the bike itself starting, I have thought to change the spark plugs, (complete the coolant flush, somehow), change oil and oil filter, put a new battery in and then see how it goes from there.

So basically wanting some help as to what I can do to diagnose this and get the engine at least running?

If you need more details, please let me know.

Any help is much appreciated.

Thanks!

[Delerium]

Hello, new to this so need some help here please.

I have got a 1997 Honda Hornet CB250 which doesn't start at present. It has been sitting for over a year. When I try starting the bike, it doesn't start? and I noticed that the coolant overflow was bubbling so thought I'd check the coolant.

I drained the coolant, and it was brown. So assuming that there is a block somewhere/screwed engine? Assuming the head gasket or something may need replacing too. I have read in a few places to perform a coolant flush (50/50 mixture of vinegar and water) but because the bike doesn't start, how would this work?

In terms of the bike itself starting, I have thought to change the spark plugs, (complete the coolant flush, somehow), change oil and oil filter, put a new battery in and then see how it goes from there.

So basically wanting some help as to what I can do to diagnose this and get the engine at least running?

If you need more details, please let me know.

Any help is much appreciated.

Thanks!

I'd change the fuel and oil as well. Unsure on that particular bike. But on mine I can drain all coolant (it's at the lowest point of the system).

Refill with distilled water for flush. Changing fuel might be enough to get it going. Brown coolant may just be start of corrosion.

[mnishi]

Thanks man! Appreciate it.

I did change the fuel but doesn't seem to want to crank over.

I did use vinegar and water solution and just poured through the radiator cap, and it did come out clean. But of course, not running the engine means its not actually flushing the entire cooling system. Any suggestions to mitigate this?

Thank you for your help.

[F5 Dave]

Get the thing running and worry about the coolant if you want to run it for more than a min. At which point it would be good to take the thermostat out and run a hose in both directions till it runs close to clean then refill with coolant. Not totally uncommon.

Ok so what do you mean by won't crank over? Try jumper leads and a squirt of engine start if that doesn't help.

[actungbaby]

Just suggestion from my own mistakes. Hold off jumping in spending on oil battery.spark plugs. Anything really. Drain oil check for metal water in the oil.
You know. If you need head gasket. Price up your parts. Head gasket base gasket. Been told best change that with head gasket.but thats your call.work out when u can afford what u need. Leave taking apart so u remember order of things.u might well get head looked at at engine engineer. Can have valve seats cleaned up. Its up to you but costs u more in long run. Esp buy battery and left un charged. Wish u the best sure be cool bike.
Cbr 250,s are like mini gp bike from 60,s rev to crazy revs

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[actungbaby]

Oh get piece flat carboard push head bolts through so you know where each went.i also take photos with my phone. Where cables go. Engine layout etc.
Dont be afraid ask questions.

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[AllanB]

So it turns over on the electric starter but does not fire up?

Ignore the coolant until it gets running. Just put water in it until you have it running. No point wasting money on coolant if she won;t go.

Have you got spark?

Good fuel?

You need both to go bang.

Oh - check the air cleaner - who knows maybe there is a family of mice nesting in the air box stopping any air getting into the carbs. Shit happens.

[mnishi]

Thanks guys! Very helpful stuff. I did drain the oil, and found no metal. Just dark brown oil really. Also drained the coolant. I changed the spark plugs and tested them for spark and they all seem to have spark. I also drained the old fuel and put some new fuel in, still, nothing.

I suspected that there was an oil leak and a fairly certain there is. So currently taking the engine out so I can replace a the gasket.

Oh, also need to note that I took out the carbs so they too will be cleaned soon!

The air filter seems new, in real tidy condition.

Aside from this, any other suggestions?

[mnishi]

Oh get piece flat carboard push head bolts through so you know where each went.i also take photos with my phone. Where cables go. Engine layout etc.
Dont be afraid ask questions.

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That’s some great tips. Loving the idea of a cardboard!!!

[actungbaby]

Wasint my idea i noticed local engine reconditioning place does it too. Must seen on you tube video. I look at those too search cbr 250 head gasket somone will have something on there.

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[WALRUS]

These run the same engine as an MC19, don't they?

I know the 19's and 22's have mostly had pretty hard lives, having most of them being spent with teenagers atop them, thrashing them hither and dither.

When I was last rebuilding the engines for my MC19 track bikes, I found that Webike and Wemoto were valuable resources for finding parts, gasket kits, etc etc. If that's the way things end up going, I suggest checking them out.

[mnishi]

These run the same engine as an MC19, don't they?

I know the 19's and 22's have mostly had pretty hard lives, having most of them being spent with teenagers atop them, thrashing them hither and dither.

When I was last rebuilding the engines for my MC19 track bikes, I found that Webike and Wemoto were valuable resources for finding parts, gasket kits, etc etc. If that's the way things end up going, I suggest checking them out.

That's great. Thanks a lot for that. Since I have decided to take off the engine, I will do a complete re-build.

Although not a mechanic myself, will be following some youtube tutorials and the owners manual for some tips.

Aside from this, is there anything I should be aware of? Of course not just as simple as taking a few bolts off, and taking the old seal on and chucking a new one one - any other recommendations?

And yes, MC19 all the day. Lovely high revving motors

[AllanB]

Have you checked fuel is actually getting into the carbs? It may be a simple blocked line, fuel filter or similar.

[mnishi]

Have you checked fuel is actually getting into the carbs? It may be a simple blocked line, fuel filter or similar.

Yes, the fuel is flowing.

[OddDuck]

That's great. Thanks a lot for that. Since I have decided to take off the engine, I will do a complete re-build.

Although not a mechanic myself, will be following some youtube tutorials and the owners manual for some tips.

Aside from this, is there anything I should be aware of? Of course not just as simple as taking a few bolts off, and taking the old seal on and chucking a new one one - any other recommendations?

And yes, MC19 all the day. Lovely high revving motors

Engine rebuild - OK, here's a few quick ideas, no particular order:

Cash is easy to run out of when doing this work, strongly suggest buying tools as the need arises, not trying to guess what you'll need in advance. There'll be a lot of trips back and forth but if cash runs out then the job stops.

6 point sockets are best unless you're dealing with a 12-point fastener. If a 1/2 inch format socket is a bit too big in a cramped area you'll need to run a few 3/8ths sockets and accessories. If the socket won't fit square then stop the job and go shopping, no matter how annoying it is. A ripped up bolt will hold you for a whole afternoon.

CRC / WD40 / PB Blaster - this stuff works but has to soak in and that takes time. Spray the jammed fastener and then give it an hour at least (three is better) before trying to undo anything.

Ziplock bags (Lots of, range of sizes, Stationary Warehouse) for fastener groups and parts. Cardboard works very well for bolt arrangements as discussed earlier. Oiled parts like camshafts need to be in sealed bags or else the oil will evaporate off (if it's apart for months) and then they'll rust.

Labels. Label everything!!

Photos. As above. I've found I get the best results from avoiding flash, that means long exposures and therefore a tripod, see how you go of course.

Storage boxes. Storage space i.e. under the house... the bike's volume is going to expand dramatically as it comes to bits, get things off it and straight into storage, don't litter the work area and make yourself an obstacle course.

Lighting. Make sure you've got good lighting. I painted my garage walls white and put in 6 overhead lights; it's made an incredible difference to what was a cave.

Torque wrench, get one if you haven't already. Some of the cheaper brands (Bahco, Toledo) are actually OK but I'd avoid Kinchrome, if unsure ask around or here.

Fasteners to be torqued: they should spin together to closing by finger and thumb. If they don't then you aren't going to get accurate torques. You may need taps to clean up female threads, male threads can generally be cleaned up with a brass wire brush.

If the manual says to use Loctite, well, that's there for good reason...

Degreaser is good. I've had a good run with the 30 Seconds Automotive stuff (white jerrycan, red fluid, mix with water and give it a few minutes before using). Everyone's got their own preferences.

Impact driver: you will almost certainly need one of these, and a bench with a vise with soft grip jaws, to get the carburettors apart. The screw heads on these are made of very soft steel and have to be treated with great care, a normal screwdriver is quite likely to tear these up.

You can purchase sockets and extension bars, drivers etc individually as you need them, that saves a lot of coin. M10 offer that option these days, it's also possible to do this at places like Repco, Twigg's, Trade Tools, etc etc.

Measuring gear - I've found a good set of feeler gauges, a manual set of vernier calipers, and a 0 to 25mm micrometer invaluable when doing engine work. If you're checking gudgeon pins, pistons and bores you may need transfer gauges and 25 -50, 50 - 75 micrometers etc. Good brands: Mitutoyo, Insize. Stanley is OK only (they do feeler gauges at least) and actively avoid Kinchrome, particularly the digital vernier calipers. They look the business and they're easy to buy but they're awful. Web orders through Trade Tools have worked for me, see how you go.

I imagine that's way more than enough for now... the main bit of advice I'd offer is take it step by step, take your time, never hurry or take on too much at once and you'll get there.