The issue with helicoiling spark plug holes is not usually failure of the insert itself, it's how you drill and tap the hole. If the hole and the freshly cut thread are not perfectly perpendicular to the seat, or the seat itself has been damaged (by previous repair efforts, possibly) it will be impossible to get a gas-tight seal. An engineering shop may be able to recut the seat, once the head is removed, which may be easier than building up a second-hand head, with all the valve lapping, new stem seals and re-shimming that would involve. I don't think a leak there would be causing the fast idle. Usually, that would cause a chuffing noise and uneven running, as one cylinder is down on power, but for an air leak to cause fast idle, it would have to be on the induction side, either downstream of the carbs or inside them. The lug on the Honda will need welding in some form, if it is going to have any strength. On screen it looks like you have 2 cracks, at about the 1 o'clock and 4 o'clock positions. The way I would tackle it would be to cut all the way through those cracks with a thin cutting blade on the grinder, and take out the piece. This should allow you to extract the rest of the bolt. The cut-off piece could then be cleaned up and the edges of the cut chamfered to allow good penetration of the weld in the joint. This is the point where you will need the services of a competent welder to reattach the piece (TIG would probably work best). After that, you could drill out the hole and either helicoil it or use a through-bolt and nut.
Thanks mate. The fuel on the xj exposed the problem I think rather than explained it. A new cylinder head is a fair amount of work but I think it is worthwhile doing.
If accessible i would chop the rear of that bolt flush with the frame (dremmel) drill through a very small hole, then widen it and put a thinner bolt all the way through. One with a nut on both sides possibly. Nylon nut and some lock tight. I was freezing yesterday, it is hard working on the bikes when its very cold. Cheers Nat
Thanks mate. I don't think that I can get to the back of the bolt to slice it off. I will come back to it. Just annoying me at the moment so I have hidden it!
I'd talk to a local machine shop about that bolt, it's a prime job for either chucking the lump on a milling machine and drilling it out properly, probably with left hand drills, or hitting it with an electroerosion rig (tap destroyer). If the crack is only on the lug, no problem with getting it welded up, re-drilled and tapped, good as new. As for the XJ, new head is the way to go for sure, but I'd be worried about why the carb was flooding that cylinder in the first place. Surely the float needle should have stopped it, even with the tank on prime?
Been there with a CBF500, the front engine mount bolt corroded to the extent that it cracked the engine casing mounting in two. I tried to salvage it, but in the end scrapped the whole bike minus a few salvageable bits, otherwise a good bike, tragic! An ex-Honda technician told me a long time ago to strip every bolt when you can, as soon as you can and Coppaslip it to the max, sound advice, it turned out! David
Keep chipping away at that bolt mate, it will drill out just take your time. Try and get a 5mm all the way through, take it steady with plenty of lube, then up to 8mm and finally the clearance size for the existing bolt. If you've managed to shear a bolt that diameter then it will not come out with an Eazysnap. One engine mount down is not the end of the world, plenty of chopped bikes running around with only half the engine mounts in place.
Just keep at it mate, Don't let it beat you. you dont need my opinion, so i will give encouragement. We all hit crap like this, you will work it out mate.
I think if the Honda was mine I'd have the engine out to give better access. If the engine mount isn't cracked right through you might get away with just drilling the bolt out. If it's cracked through it needs welding which may not mean a full engine strip but someone that knows there stuff to do it. Did seen a mobile welding guy on Internet. Think it was all metal welding services. Never used him but looks like he does that sort of stuff. Probably others about as well.
Shit mate you are having some serious bad luck! Aprilia, XJ and now the CBF. Hope it changes with the new project, Is that the one from Peterborough? Look forward to seeing it.
If I hid everything that I did wrong like he does, my channel would be empty! I think that we are almost opposite. The driver for him is very much the UA-cam content. I think that I am the other way around and UA-cam is just an offshoot of a hobby.
good plan to walk away, definitely - from your thumbnail I really thought you had trashed a bike big time! is the new bike ulez exempt maybe as it's a classic??
I'm into bikes and dogs the helicoil hasn't failed its the wrong kind of repair for the application, don't stop your dog from passing because it's inconvenient for you you wouldn't like it if you were pulled away from the toilet mid flow and you would cope less well
New cylinder head en route. Dog wise, I don't think that I would be happy being led on a lead either. Someone picking up my crap in a bag might be interesting though!
The issue with helicoiling spark plug holes is not usually failure of the insert itself, it's how you drill and tap the hole. If the hole and the freshly cut thread are not perfectly perpendicular to the seat, or the seat itself has been damaged (by previous repair efforts, possibly) it will be impossible to get a gas-tight seal. An engineering shop may be able to recut the seat, once the head is removed, which may be easier than building up a second-hand head, with all the valve lapping, new stem seals and re-shimming that would involve.
I don't think a leak there would be causing the fast idle. Usually, that would cause a chuffing noise and uneven running, as one cylinder is down on power, but for an air leak to cause fast idle, it would have to be on the induction side, either downstream of the carbs or inside them.
The lug on the Honda will need welding in some form, if it is going to have any strength. On screen it looks like you have 2 cracks, at about the 1 o'clock and 4 o'clock positions. The way I would tackle it would be to cut all the way through those cracks with a thin cutting blade on the grinder, and take out the piece. This should allow you to extract the rest of the bolt. The cut-off piece could then be cleaned up and the edges of the cut chamfered to allow good penetration of the weld in the joint. This is the point where you will need the services of a competent welder to reattach the piece (TIG would probably work best). After that, you could drill out the hole and either helicoil it or use a through-bolt and nut.
Thanks mate. The fuel on the xj exposed the problem I think rather than explained it. A new cylinder head is a fair amount of work but I think it is worthwhile doing.
Fuel flooding in to the cylinder is not due to a loose or leaking spark plug.
I agree but it did more than demonstrate the problem!
If accessible i would chop the rear of that bolt flush with the frame (dremmel) drill through a very small hole, then widen it and put a thinner bolt all the way through. One with a nut on both sides possibly. Nylon nut and some lock tight.
I was freezing yesterday, it is hard working on the bikes when its very cold.
Cheers Nat
Thanks mate. I don't think that I can get to the back of the bolt to slice it off. I will come back to it. Just annoying me at the moment so I have hidden it!
I'd talk to a local machine shop about that bolt, it's a prime job for either chucking the lump on a milling machine and drilling it out properly, probably with left hand drills, or hitting it with an electroerosion rig (tap destroyer). If the crack is only on the lug, no problem with getting it welded up, re-drilled and tapped, good as new.
As for the XJ, new head is the way to go for sure, but I'd be worried about why the carb was flooding that cylinder in the first place. Surely the float needle should have stopped it, even with the tank on prime?
Your right on both I think. Blue can wait. I am in no rush. The xj fuel is an issue (prob carb( but at least it letting go expose the larger problem.
How bloody frustrating!! You are now, surely, due some luck. Intrigued about the "new" bike, will be watching..... Cheers, Andy.
Fingers crossed!
Been there with a CBF500, the front engine mount bolt corroded to the extent that it cracked the engine casing mounting in two. I tried to salvage it, but in the end scrapped the whole bike minus a few salvageable bits, otherwise a good bike, tragic! An ex-Honda technician told me a long time ago to strip every bolt when you can, as soon as you can and Coppaslip it to the max, sound advice, it turned out! David
Retrospective advice unfortunately!
Keep chipping away at that bolt mate, it will drill out just take your time. Try and get a 5mm all the way through, take it steady with plenty of lube, then up to 8mm and finally the clearance size for the existing bolt.
If you've managed to shear a bolt that diameter then it will not come out with an Eazysnap.
One engine mount down is not the end of the world, plenty of chopped bikes running around with only half the engine mounts in place.
Cheers buddy. I will keep on keeping on
Hi
Helicoils are good for general thread repair but for gas seal a timesert or custom solid insert is best
That's what I used mate but it appears that I didn't make a very good job of it!
if petrol leaks out carbs its the float valve at fault
Probably but at least it exposed the issue
That XJ wants a match on it, some vehicles just dont seem to want to be saved.
It feels that way at times!
Just keep at it mate, Don't let it beat you. you dont need my opinion, so i will give encouragement. We all hit crap like this, you will work it out mate.
Thanks mate. Much appreciated!
I think if the Honda was mine I'd have the engine out to give better access. If the engine mount isn't cracked right through you might get away with just drilling the bolt out. If it's cracked through it needs welding which may not mean a full engine strip but someone that knows there stuff to do it. Did seen a mobile welding guy on Internet. Think it was all metal welding services. Never used him but looks like he does that sort of stuff. Probably others about as well.
You beat me to it, be surprised what a good professional welder can fix.
I may have to resort to that but stashed for now.
Chin up Nat ❤
Always
Oh dear! That is tough shit! I feel your pain.😢
Ffs Nat your not having much luck at the moment🙄👍
Things can ONLY get better!
Shit mate you are having some serious bad luck! Aprilia, XJ and now the CBF. Hope it changes with the new project, Is that the one from Peterborough? Look forward to seeing it.
That's the one mate. Thanks for the support. Things can only get better!
Are you del in disguise 🥸!!
If I hid everything that I did wrong like he does, my channel would be empty! I think that we are almost opposite. The driver for him is very much the UA-cam content. I think that I am the other way around and UA-cam is just an offshoot of a hobby.
🏍👍👍👍
💩🏍️👍
Gutted for you, but on a positive side, fixing these unplanned cock ups will make interesting content.
Tit in a shed!
good plan to walk away, definitely - from your thumbnail I really thought you had trashed a bike big time! is the new bike ulez exempt maybe as it's a classic??
I'm into bikes and dogs the helicoil hasn't failed its the wrong kind of repair for the application, don't stop your dog from passing because it's inconvenient for you you wouldn't like it if you were pulled away from the toilet mid flow and you would cope less well
New cylinder head en route. Dog wise, I don't think that I would be happy being led on a lead either. Someone picking up my crap in a bag might be interesting though!