Let go at 14k RPM (maybe higher) probably when it went over a bump and the engine rev'd its nuts off without a limiter...

Just check your fekin expansion tank please!

A blown head gasket isn’t the end of the world (as long as it doesn’t keep happening ) The smoke is probably scorched coolant steam. Check your plug for ‘sopping wet crud’. Check your radiator level again, it’s bound to of dropped...

Blown up is when the piston detonates and scores the crank and casings to fuck...

I have had engines where the connecting rod has let go and gone straight into the gearbox, that my friend is ka put!

Come to me when your engine has done that to you.

Occasionally it’ll catch a spark but that’s followed by loads of smoke, same as while kicking it really

For now das ist kaput!

Popped out for the local meet, bike had been swell besides the previously mentioned issues then one minute, nothing.

I got the bike started a couple times but noticed huge amounts of smoke pouring out behind me as the bike limped and struggled up the road

I got off and smell was nauseas and toxic smelling as anything

And now I am stuck on the corner of a road for two days running

You'll know it when you see it!

Whatever you do, DO NOT and I mean DO NOT buy those shitty fucking Chinese "Racing Coils". Go Genuine or Go Home!

Oh fuck no! 🤮

Racing CDI’s used to be all the rage when I was tuning my lexmoto a few years back that was until everyone cottoned on the fact it turns a bike with a perfectly good hardline ignition and then removes the limiter all together so the bike could Rev so high the valves flutter.
Needless to say a lot people threw valves and blew their engines up.

Moral of the story, the Chinese don’t care about the product they produce just as long as you buy it.
Like c’mon, we’re talking about people that sell switch blades and ZK’s on wish here hahaha

But yeah, furthermore having seen how many things like spark plugs or even V force’s have counterfeit reproductions I always take the time to background check the seller so I ain’t being mugged off.

New racey red NGK HT lead will be getting ordered Friday.
I’ve always wanted one but didn’t actually think they made a difference other then cool points

This brings me to the next thing, my bike actually sometimes to run alright suddenly?

Every now and again she’s hesitant to pull through or you’ll be WOT in band and then it’ll cut out then come back on again

I’m also finding you have to roll on the throttle with the Rev’s and that it seems to like going through higher gears more but other then that alright?

The cutting out at high revs does sound like it could be your HT lead starting to deteriorate, when that happened to me it manifested itself as a high-rpm (9k +) misfire. Not much fun when overtaking etc.

Made a huge difference when I soldered a new one to the coil output, the job took about an hour so the bike was no longer at operating temperature when I tested it but the front wheel came up as I pulled out of the driveway! 1992 but I'll never forget how it transformed the bike.

If I can dig out a loose coil and some lead I'll do a forum post with pictures

Did you check the coolant expansion tank? That coolant has to have gone somewhere!
Keep an eye on the temp gauge and radiator level, please bud...

Good news the cooling issue was nothing more then being short of coolant. What I thought wasn’t a lot ended up being roughly half to three quarters a bottle of putoline coolant that got swallowed up before hitting the full limit in the rad.

Coolant issue now fixed!

I’ve not had a drop of fuel come out the overflow either, woo!

The addition of a reliable working petcock is a bonus too.

I’ve readjusted the PV so it’s no longer perfectly flush with the exhaust port but align with the hole in the pulley.

This has proven to work a lot better in combination with the OEM pipe I’m running. Torque for days.
The shut off point powerband/power wise is 10.5k with no overrev,
the exhaust port not opening further I’m pretty sure would prevent this anyway however if say for example you where running a ported setup or something like a dep pipe known for its over-rev capabilities then you’d definitely want your exhaust perfectly flush.

I enjoy my ride a lot. I actually couldn’t got off the bike and struggled to turn around to go home. So much so I ended up running out of petrol and having to walk 3 miles to the petrol station with a dead phone.

This brings me to the next thing, my bike actually sometimes to run alright suddenly?

Every now and again she’s hesitant to pull through or you’ll be WOT in band and then it’ll cut out then come back on again

I’m also finding you have to roll on the throttle with the Rev’s and that it seems to like going through higher gears more but other then that alright?

I think your head gasket may be blown. If you can’t find a leak in the radiator or hoses. Check the level of fluid in the expansion tank. If it’s full to the brim it’s a red flag for the head gasket...

Keep an eye on the temp gauge when riding and check the radiator level after...
Good luck bud!...

Beforehand though you might want to take a look at the R/H powervalve cover behind the expansion chamber as these have a habit of breaking around the retaining bolt and rattling due to exhaust pressure and the broken bit stopping it falling out completely.

It happened to me once on an RD500LC (it uses the same part x 4) and it made that exact noise. Everyone I was riding with ripped the p!$s out of me because we all thought it had blown up but I rode it 50 miles to get home and just replaced it. Hope that's all it is!

I’d left to tick over for 10 minutes and didn’t have any anomaly with temp. Gonna take her for a test ride soon. I am hopeful that’s solved it though.

I have noticed a noise that sounds a lot like a bearing of some sort gone in the top end. At first I thought it was just because I had the powervalve cover open that there was more of a raw noise but when you listen I definitely doesn’t sound right

link text

Failing that if a bearings gone that’ll explain a lot!

And the radiator is full too? If it is then it’s definitely worth trying another thermostat. I don’t even know how many I’ve got in my collection anymore! I brought an old style glass thermometer to check opening temps accurately (only a few £), also to tell me what position on the temp gauge was what, instead of lucky dip!

@Stevie-Wonder

Have you not checked the radiator level yet? I would check that first job. Second would be swapping out the thermostat. Running lean made my bike run ‘hotter’ but not that hot!
Also check for overflowed coolant at the expansion tank filler. Sticky crap below it on the chain guard and swing arm...

No overflowed coolant. I do have a spare thermostat off a 4FU head I could try too.

@Calum dont remind me 10 hour shifts grafting in 30 degree heat does a number on you though

@Stevie-Wonder
Did you check the radiator coolant level?...

Nah after I took it for a ride I just put it back and haven’t touched it since.

Been saying to myself I’d do a little bit here and there after work but this heat has been killing me off and leaving me so fucked where the only thing left to do is have a beer and chill out.

However today I’m going to go through that checklist today and try do as much as I can.

Also the jetting in the carb is the exact same as it’s always been since I’ve had it so jetting shouldn’t be an issue, the only thing that could’ve changed slightly is the air screw.

I’ll keep an ear out for detonation as that’ll give an indicator to wether it’s the engine running lean being the problem or it just being a cooling problem.