Hornet 250 - Just not right

[Hmmmmark]

On the return leg of a round trip to Rotorua I found the bike to be considerably underpowered, since then a few niggles have presented themselves.

Before I take it into the shop or decide to buy any parts I'm hoping you might be able to help with my diagnosis

Symptoms are:
- Tapping at the head: 2.4ks ago I got the 24k service done at Cyclespot - they neglected to perform a valve clearance check as 'there was no noise' even though I had brought it in complaining of a tick when warm. Should've requested it done then, but it's still disappointing
- More Vibration than normal at 8k+ RPM
- Rough idle - sounds like it's missing at idle and also when not under load
- Occasional cough, splutter, die - has happened to me twice in the morning where it's refused to pick up RPM from idle and died.
- Underpowered - it's happy to putter around town but struggles to pull above 100
- Won't start without choke - even on a warm afternoon it struggles to turn over without choke

So I figure valve clearance needs to be done, but is there another persistent problem contributing as well? Ignition coils? Fueling?

Any help appreciated! Thanks

[tigertim20]

for the tapping Id look at the CCT to start with.

for the rest, Id check the plugs, look at the breather in the tank, and clean the carb for a start

[Hmmmmark]

for the tapping Id look at the CCT to start with.

for the rest, Id check the plugs, look at the breather in the tank, and clean the carb for a start

Gear driven cams so hopefully nothing's up with those.

Sorry should've mentioned plugs were changed at that service and carbs were cleaned/balanced in the months prior to purchase by a Holeshot mechanic by PO (though that may need to be taken with a grain of salt)

Will check the breather though, thanks!

[Hmmmmark]

Checked the breather hose - all good! No worries there.

However....


Crap..... Cracks on both sides of the airbox, right at the connection point to the carbs.

I always thought the intake noise was a bit loud, now I've discovered why. Also explains why it loves to start with the choke on.... I imagine this has been running the bike much too lean for a while now.

Any advice on where to pick up a new airbox from?

[nzspokes]

Sure thats a crack? Could be where the rubber boot joins the airbox.

If its just been serviced take it back and do some yelling.

[nzspokes]

Gear driven cams so hopefully nothing's up with those.

You sure about that? My 900 thats gear driven cams has a chain and a CCT to drive the gears from the cranks. As did my girls 600 Hornet.

[Hmmmmark]

Sure thats a crack? Could be where the rubber boot joins the airbox.

If its just been serviced take it back and do some yelling.

You sure about that? My 900 thats gear driven cams has a chain and a CCT to drive the gears from the cranks. As did my girls 600 Hornet.

These are the reasons why I defer to those more knowledgable than I.

Re: rubber boots at the airbox, the other side looks much worse - looks like plastic attacked with solvent. I just quickly went out and started it, couldn't feel any air movement around the, ahem, 'crack'. Will double check tomorrow.

So if the airbox checks out, anything else I would be wise to check out? Back to the plug leads or ignition coils?

[iranana]

These are the reasons why I defer to those more knowledgable than I.

Re: rubber boots at the airbox, the other side looks much worse - looks like plastic attacked with solvent. I just quickly went out and started it, couldn't feel any air movement around the, ahem, 'crack'. Will double check tomorrow.

So if the airbox checks out, anything else I would be wise to check out? Back to the plug leads or ignition coils?

I wouldn't dismiss that suspect rubber boot - looks like it could be a crack to me, and there's a good chance you won't actually feel any air movement around it even if it it is cracked. I once made the mistake of removing my carburettors for a cleaning without remembering to fully tighten all the pipe clamps when I put them back it. The bike ran like shit and it was impossible to get it running right until I realised the clamps were loose. It exhibited some of the symptoms you described here... seal the sucker up with something and see if it runs any better before poking around with anything else, just my 2c.

[nzspokes]

Start it and spray a mist of water at the crack. If the motor stumbles or changes note then its a problem.

[hayd3n]

man thats a dirty air box . when was the air filter last replaced??

also take the fuel tap out and clean the filter thats inside , mine was fooked on my 600

[Drew]

Checked the breather hose - all good! No worries there.

However....


Crap..... Cracks on both sides of the airbox, right at the connection point to the carbs.

I always thought the intake noise was a bit loud, now I've discovered why. Also explains why it loves to start with the choke on.... I imagine this has been running the bike much too lean for a while now.

Any advice on where to pick up a new airbox from?

That's the boots coming away from the box I reckon. They are a separate part so as to be flexible as opposed to the rigid air box material.

Air leaks on a CV carb are the first thing that sprung to mind when you described the symptoms.

Spray engine start at the area with the motor running, I am more than willing to bet it will rev a bit higher as it gets a mouth full of the stuff.

But the alignment is the true cause for the issue I imagine. The airbox seems to be at the wrong angle relative to the carb, so check it's mounted properly.

[Hmmmmark]

Thanks all for your input, I'm relying on the damn thing for my ride to work but it's not fun in this condition.

Good thing I have tomorrow off work to do some messing around with the bike.

Am keen to take the tank off and have a mess around with the box and the clamps, make sure it's all on nicely and give it a bit of a clean out while I'm there

man thats a dirty air box . when was the air filter last replaced??

also take the fuel tap out and clean the filter thats inside , mine was fooked on my 600

Air filter cleaned, but not replaced at said service. I've checked it out and it looks pretty good.

Now I might just be pointing out my own ignorance (as with the CCT), but the petcock is vacuum actuated - so no fuel tap, right? (there's no reserve either)

I'm keen to give it a clean out, but would appreciate a bit of guidance if you're willing. Any advice with:

1. to pull the tank off, how am I best to remove the vacuum line and the fuel line from the petcock?

2. If I want to clean the petcock, can I just put the tank upside down and remove it with fuel still inide the tank?

Thanks again for the help!

[FJRider]

Am keen to take the tank off and have a mess around with the box and the clamps, make sure it's all on nicely and give it a bit of a clean out while I'm there

Now I might just be pointing out my own ignorance (as with the CCT), but the petcock is vacuum actuated - so no fuel tap, right? (there's no reserve either)

I'm keen to give it a clean out, but would appreciate a bit of guidance if you're willing. Any advice with:

1. to pull the tank off, how am I best to remove the vacuum line and the fuel line from the petcock?

2. If I want to clean the petcock, can I just put the tank upside down and remove it with fuel still inide the tank?

Thanks again for the help!

There should be a spring clip on the fuel "tap" ... needle point pliers should do the job to remove it.

Unscrew the Petcock from the tank. The small filter is fitted to it's upper part ...

Rinse with fresh fuel and empty tank.

If tank inside is flaking ... put washed pea gravel into the tank and swirl around (dry) then flush again.

Shake tank ... if it rattles ... gravel is still in the tank.

Drain ALL fuel from the tank FIRST ...

If the tank inside is bad ... it may need lined ...

[Hmmmmark]

There should be a spring clip on the fuel "tap" ... needle point pliers should do the job to remove it.

Unscrew the Petcock from the tank. The small filter is fitted to it's upper part ...

Rinse with fresh fuel and empty tank.

If tank inside is flaking ... put washed pea gravel into the tank and swirl around (dry) then flush again.

Shake tank ... if it rattles ... gravel is still in the tank.

Drain ALL fuel from the tank FIRST ...

If the tank inside is bad ... it may need lined ...

So it turns out that my tank was only ever a pebble flick away from developing a hearty leak, right next to the petcock.

A portion of the tank has evidently held water for a while as after scrambling to contain all the fuel (thank god I prepared with a bucket 'just in case') I cleaned out the remainder which came with; rust, rusty goop, water, and fuel.

So it looks like a good fix, clean and lining is in order.

I'd love to get this fixed back up today - any advice on how to fix the rust hole?

Edit: I have electrical solder & soldering iron - could this do the trick?

Cheers!

[FJRider]

So it looks like a good fix, clean and lining is in order.

I'd love to get this fixed back up today - any advice on how to fix the rust hole?

Edit: I have electrical solder & soldering iron - could this do the trick?

Cheers!

There are threads here on relining tanks ... but it's not a 5 minute job. NO tank repairs are ...

Lining stops the continuing flaking issues ... but tank integrity is important first. Lining needs a solid base to attach to ... otherwise a small knock can have a major leak. (not ideal if you are a fair distance from home/civilization)

Rust holes need cut out first. Then (ideally) welded. Check the condition of the rest of the tank inside. Replacement may be the better option (E.mail a few wreckers)

Quick fixes seldom fix for good ... and can turn BAD really quickly.