[gavinfdavies]

Oh dear oh dear. Let's hope the warranty covers this. Damned if I'm accepting 'parts only' bullshit.

[Otto_Ing]

Same thing happend recently on an another RE forum. It really would be great to find out what caused this. I would like to replace the thing beforehand.

Good Luck with the warranty claim, it should be pretty obvious imo.

[gavinfdavies]

Same thing happend recently on an another RE forum. It really would be great to find out what caused this. I would like to replace the thing beforehand.

Good Luck with the warranty claim, it should be pretty obvious imo.

You'd hope you wouldn't you? I have a horrible suspicion that the UK warranty is 12 months parts & labour, then 12 month parts-only.

All the bits are still inside, so should be able to see what's-what later. For reference, the bike had done about 9000 miles, and had covered about 3,000 since the last service.

[gashousegorilla]

Oh dear oh dear. Let's hope the warranty covers this. Damned if I'm accepting 'parts only' bullshit.

  Yeeeeeshh !!!    Gavin, peer into that hole and see if the bolt that holds the sprag gear on the end of the shaft is in place.

  I'm thinking if it is not ?   It spun out like we have seen before, and maybe got caught between the gear and the chain... snapping it.

[GSS]

OMG

That is just horrendous.....they should cover this.

[Kevin Mahoney]

Thankfully you weren't hurt. Could have been a chain tensioner that overtightened the chain (happens), a piece of hardware that let loose or a bad chain.

Not sure that I understand the UK warranty. The US is and always has been 2 years - 24 months. Part of the difference is due to the fact that RE did not pay for labor or even parts in many countries. We always insisted that in the US it be done that way and we were unusual among distributors. Because we traditionally sold more bikes that the other countries we had a bit of a bigger lever. They really did not like me talking about it to the other distributors. Fortunately most state laws in the US also back that theory up.

We (CMW) always backed up the product regardless of whether RE covered us or not.  In fairness to RE they rarely denied legitimate claims. They would not have questioned this failure at all and I doubt they will now.  My guess is that you will get it covered in full and if not I would not accept no for an answer.

[gizzo]

Wow that really sucks, Gavin. Good luck with the repairs.
Kevin, could you possibly expand on the chain overtightening thing? I had the primary cover off  a while back to sort an oil leak and noticed the tensioner is a lot like an oversized camchain tensioner: it tightens up but won't allow any slack at all. In a camchain's case it seems to cause premature wear on the  chain. TIA.

[gavinfdavies]

Wow that really sucks, Gavin. Good luck with the repairs.
Kevin, could you possibly expand on the chain overtightening thing? I had the primary cover off  a while back to sort an oil leak and noticed the tensioner is a lot like an oversized camchain tensioner: it tightens up but won't allow any slack at all. In a camchain's case it seems to cause premature wear on the  chain. TIA.

This might help a bit, plus it shows others what's we're talking about

[Kevin Mahoney]

The graphic shows exactly how the tensioner works. Also note that RE says that it requires no service there or in the primary which eliminates the "owner abuse" or lack of service excuse.
There have been cases of the tensioner overtightening. Not a lot in the US and to my knowledge not in recent models. The tensioner is a one way ratchet, but can be released if you go inside of the case.

The real question I guess is what actually caused the primary explosion, the tensioner may have nothing to do with it. Thankfully the engine didn't lock up.

[cafeman]

Chain is off the engine sprocket so I would guess the cause is  with the clutch assembly and or a broken chain that balled up

[Otto_Ing]

Gavin, could you have a look from beneath if the tensioner is assembled correct way round. It is supposed to be eccentric and can be assembled wrong way round, which could push the chain sideways maybe?

[phoenixt]

Gavin, could you have a look from beneath if the tensioner is assembled correct way round. It is supposed to be eccentric and can be assembled wrong way round, which could push the chain sideways maybe?

They should have had the shaft and hole through the case shaped to prevent that.

Steve

[VanHalenMan]

This might help a bit, plus it shows others what's we're talking about

Where can I guy like me find this PDF guide thing you all seem to have! Share the wealth!

[Jellyroll]

Jeez. My gut sayeth the damage done with so few miles deserves a new engine and some serious ass kissing from RE(with tongue). Holy crap, guys, this is some really scary detonation, considering most of us if not all ride this jewel 'In A Spirited Manner, From Time To Time'. I can see going out to riding over ones' head, but the chance of losing ones' life to a problem that never should have occurred. This needs to be addressed and rectified by RE immediately. Why not a recall?

[L4V]

Where can I guy like me find this PDF guide thing you all seem to have! Share the wealth!

I just looked in the funky "manual" that we bought from CMW and it's not in there.

[gavinfdavies]

Just an update on this old topic - one of many I'd forgotten that I'd started!

The bike was fixed and ready to go around the end of September 2016, just as I was moving house. The only thing I had to pay for was the engine oil, since RE don't pay for that. Given that the bike & engine were hardly stock I didn't mind, since I know that independent mechanic made sure RE UK asked no awkward questions. However, my see-through push-rod window got sent back on the old engine!

Since then I've done a total of 90 miles on it. I'm now in the process of getting a load of mods completed so that it's how I want it.

[Jako]

Did you or RE  positively  identify the cause ?

[gavinfdavies]

No the root cause, no. I just got shot of the bike. It went bang on Sunday, was collected on Monday. And I rode home on a new bike (Hyosung GD250R) on Thursday. Retrieved bike 2 months later with intent to do up and sell, but haven't got round to it yet.

[adamzworld]

Hi Gavin, I appreciate that this happened a few years back, but I've had exactly the same thing happen to my bike. Can I ask when they replaced the engine under warranty, did they say anything about the air filter mod you've done to your bike? I've done something similar and removed the air box replacing it with a cone filter so I just wondered whether they mentioned it at all? Also did you have to take the bike to an approved RE service centre or could you choose where you had the work done?

Thanks in advance for your help.

[gavinfdavies]

Hi Gavin, I appreciate that this happened a few years back, but I've had exactly the same thing happen to my bike. Can I ask when they replaced the engine under warranty, did they say anything about the air filter mod you've done to your bike? I've done something similar and removed the air box replacing it with a cone filter so I just wondered whether they mentioned it at all? Also did you have to take the bike to an approved RE service centre or could you choose where you had the work done?

Thanks in advance for your help.

Sorry for the VERY late reply. Don't come on here often. Haven't touched the bike in a year or two. I took mine to an independent but approved RE dealer in Taunton. Most RE dealers are owned by the importer, and hence have a vested interest in not paying out. My independent RE dealer (key point being that he's approved) didn't mind the mods, as it wasn't his money! :-) Hope it all got sorted. They should fix it anyway, as there is no way an airbox mod would make a primary chain snap!

[kelsoo]

I recently started getting a horrid clattering when starting both on the button and kick. I thought the perhaps it was the sprag clutch  as it was quiet when running. Anyway I popped the case off today and the bolt and washer for the primary sprocket fell out in to the oil pan.

Check that bolt folks.
Not sure of the torque settings but its getting locktight before it goes back in.

[gizzo]

Wow. Good thing you caught it before it got catastrophic.

[Taurim]

Torque is 48 Nm but there is an important point. On a new bolt there is some red stuff in the thread which is probably meant to provide some sort of lock but not as strong as Loctite red or blue.

This kind of thing : https://threebond-europe.com/technical/seminars-adhesives/pre-coated-bolts/

I replace this bolt for a new one any time I remove it (which is quite often recently  )

Same thing for any nyloc nut inside the engine (clutch, magneto rotor...)

[kelsoo]

Well I to a close look at the bolt and couldn't see any signs of thread lock of any colour. 
I put locktight on it and reassembled and blow me if it's still clattering so I suspect the sprag clutch is away.
No doubt it would contribute to the bolt coming loose
Very disappointing on a less than 4000 mile bike.

Some good news though I fitted a 650 interceptor tank (Ravishing Red) a bit of a fiddle parts wise but I love the traditional look with flat bars flat seat and leather panniers. I'll post the mods in a new thread when I've got it up n running.

[JerryGT]

I am firmly convinced that the cause of this fatal engine damages lies in a chain tensioner that is far too tight, in connection with an inferior and weak primary chain.
In addition, the chain tensioner is often installed the wrong way and presses the tensioning plate crookedly onto the chain. The embossed lettering must point towards the center of the engine.

Wrong:
https://www.royal-enfield-forum.de/extimages/up.picr.de/35845519sq.jpg

Right:
https://www.royal-enfield-forum.de/extimages/up.picr.de/35846224nm.jpg


In this example, the deviation is not very large, there are some cases where the spanner is about to slip off any moment.


Also, I bet at least every second GT drives around with a loose primary sprocket bolt and/or clutch basket nut.

[gizzo]

I am firmly convinced that the cause of this fatal engine damages lies in a chain tensioner that is far too tight, in connection with an inferior and weak primary chain.

I think you're right, and it's why I removed the spring from the tensioner in my engine. It doesn't seem to have changed tension since I did it a few years ago. Idk how many kms, but its some.

The tensioner orientation, my bike I can only get it in one way because the lower frame tube is in the way but other people have different experience.

But on the bright side, looks like mine's the right way around.