Author Topic: Stranger than usual noises from engine (Read 9179 times)

young gun · **on:** January 16, 2014, 03:47:31 pm

Hi guys,

I don't know if some one can help identify this sound that is coming from my engine, it's been getting progressively louder over the last few weeks. The bike is driving fine with no unusual things happening.

Here's a video:

http://youtu.be/YBkHxsjNNC4

azcatfan · **Reply #1 on:** January 16, 2014, 04:01:53 pm

Yikes! Sounds like something is loose in the chamber! Maybe pull the decomp to see if it's intact.

High On Octane · **Reply #2 on:** January 16, 2014, 04:10:37 pm

I'm not sure what that is. Almost sounds like a broken valve spring. I'd it coming from the front/top of the motor or from the transmission/kick starter area?

Scottie

young gun · **Reply #3 on:** January 16, 2014, 04:11:12 pm

Decomp?

High On Octane · **Reply #4 on:** January 16, 2014, 04:12:09 pm

Decompression valve.

young gun · **Reply #5 on:** January 16, 2014, 04:16:16 pm

Jees I'm having no luck with this bike lately

Scottie it sounds like it's coming from the engine head though it's very hard to pinpoint. This sound started maybe 2 months ago and it's just got progressively louder but it's only there when the engine is hot, i.e in the afternoon after it's been in the sun, in the morning it doesn't make this noise at all which is why I wasn't concerned. These bikes make a lot of clatter so it's pretty difficult to decide whether it's a good or bad clatter

It's going to have to go to my mechanic then. I live in a complex so I'm only allowed to do minor repairs to the bike. Taking it apart is not an option for me unfortunately.

DonK · **Reply #6 on:** January 16, 2014, 04:20:32 pm

Could be anything.
I had a loud noise start and got louder over time, found out it was piston slap.
Guess you can't really know until you open her up.

young gun · **Reply #7 on:** January 16, 2014, 04:21:12 pm

Oh and another thing. My starter motor stop working ages ago, as in it would work but not engage, then it just stopped completely. When I press the starter button nothing happens. So I kick start the bike, which it usually starts 1st time. To be honest, I've no complaints with how it's running right now other than the gearbox missing a gear every now and then.

young gun · **Reply #8 on:** January 16, 2014, 04:22:23 pm

So you rate it needs to go in to the mechanic? It's last service was 1500kms ago, it still had another 1500kms to go.

Blltrdr · **Reply #9 on:** January 16, 2014, 04:38:32 pm

Hard to pinpoint from video. I would get a stethoscope with a probe from Harbor Freight http://www.harborfreight.com/mechanics-stethoscope-41966.html and check for the location that way.

cyrusb · **Reply #10 on:** January 16, 2014, 04:39:18 pm

The noise appears to be vacuum actuated? Only happens when the throttle is closed and the engine is decelerating? Am I getting that right? Maybe it is the decomp..

young gun · **Reply #11 on:** January 16, 2014, 04:46:16 pm

Yup only when I let go of the throttle. I use my decomp daily, I've found no issues with it but it's a good place to start. I thought it may be from where the exhaust pipe joining the cylinder head as that's the kinda locale where the noise is coming from and like you said, it only happens when I release the throttle. Just odd but it's a pretty scary sound, something sounds like it's loose in there.

cyrusb · **Reply #12 on:** January 16, 2014, 04:58:26 pm

You may be right with the pipe, too. Touch these things with a stick, you may be able to stop-feel the vibrations.

ace.cafe · **Reply #13 on:** January 16, 2014, 06:08:05 pm

Sounds sort of like an exhaust leak to me.

young gun · **Reply #14 on:** January 16, 2014, 06:32:31 pm

Ace, Is there anyway to seal the exhaust properly?

ace.cafe · **Reply #15 on:** January 16, 2014, 07:09:42 pm

Yes.
First, take the whole exhaust system off completely.
Then fit the header pipe into the engine, and bend the brackets however is needed to get it to hold naturally and fairly in place when the brackets are on the bolts.
Then, if there is a loose fit of the header into the exhaust port hole, you can cut a beer can into about one - inch wide strip of aluminum, and wrap it around the end of the header, like tape, and then push it into the exhaust port hole again to see how it fits. The idea is to fill the gap with the aluminum strip, so it makes a tight fit and fills the gap. Normally, one full wrap of the aluminum strip is enough in most cases. If you can do it with one wrap withe the ends butted perfectly together, then it will seal the best.
This fixes it in a way that has no goop or putty to burn off or crack off, and can be removed and replaced as many times as you want, like a permanent packing.

Then, put the rest of the exhaust system back on.

young gun · **Reply #16 on:** January 16, 2014, 07:31:52 pm

Thanks Ace, I'll give that a shot on the weekend.

neil · **Reply #17 on:** January 16, 2014, 08:11:16 pm

Hi Y. G. If your starter motor stopped working ages ago, bet the sprag system broke and now some gear is spinning and when you let off on the throttle a piece of the gear is rattling around enough to cause that sound. The starter motor is right up front and what ever is causing the sound may appear to be up near the top of the engine. If you haven't removed the offending sprag gears, my bet is on that system as the cause of the noise. Congrats on using the kick start to fire off your bullet. Not very difficult if you do it the right way.
Not very difficult to remove the sprag gears either.

Neil and Buzzy the Bullet.

ace.cafe · **Reply #18 on:** January 16, 2014, 08:17:35 pm

Quote from: neil on January 16, 2014, 08:11:16 pm

Hi Y. G. If your starter motor stopped working ages ago, bet the sprag system broke and now some gear is spinning and when you let off on the throttle a piece of the gear is rattling around enough to cause that sound. The starter motor is right up front and what ever is causing the sound may appear to be up near the top of the engine. If you haven't removed the offending sprag gears, my bet is on that system as the cause of the noise. Congrats on using the kick start to fire off your bullet. Not very difficult if you do it the right way.
Not very difficult to remove the sprag gears either.

Neil and Buzzy the Bullet.

This is a good point.

young gun · **Reply #19 on:** January 16, 2014, 08:50:48 pm

Yeah it's why I mentioned the starter motor working because it was also a suspicion. A friend of mine has removed his starter motor and sprag clutch so it may be worth chatting to him about the procedure. I'll try checking the exhaust 1st as this is a pretty easy fix if that's the problem, if not I'll need to investigate deeper.

The sprag clutch is definitely an issue on this bike, it has been since I bought it. I would rather be rid of it tbh and considering how easy this bike is to kick start I don't even know why they bothered?

High On Octane · **Reply #20 on:** January 17, 2014, 02:23:50 am

Quote from: neil on January 16, 2014, 08:11:16 pm

Hi Y. G. If your starter motor stopped working ages ago, bet the sprag system broke and now some gear is spinning and when you let off on the throttle a piece of the gear is rattling around enough to cause that sound. The starter motor is right up front and what ever is causing the sound may appear to be up near the top of the engine. If you haven't removed the offending sprag gears, my bet is on that system as the cause of the noise. Congrats on using the kick start to fire off your bullet. Not very difficult if you do it the right way.
Not very difficult to remove the sprag gears either.

Neil and Buzzy the Bullet.

That is why I asked which end the noise was coming from. I was thinking the spread as well.

Scottie

cyrusb · **Reply #21 on:** January 17, 2014, 03:34:07 pm

Could be the sprag, but that squeeky sound sure sounds like it is produced by a high pressure exhaust leak.

azcatfan · **Reply #22 on:** January 17, 2014, 03:55:07 pm

Quote from: cyrusb on January 17, 2014, 03:34:07 pm

Could be the sprag, but that squeeky sound sure sounds like it is produced by a high pressure exhaust leak.

Exhaust leak, or, I didn't mention it because it seems too easy, but maybe a nut has backed off of something and the washer is vibrating around? Check all the nuts and bolts as always.

cyrusb · **Reply #23 on:** January 17, 2014, 04:16:02 pm

Ace had it earlier. Sounds just like the waste gate of a turbo system. And it happens at the right time, deceleration. Your not turbocharged are you?

young gun · **Reply #24 on:** January 18, 2014, 06:17:43 am

Well that should be an easy fix, I'll look at that this afternoon and back to you but the sprag clutch needs to go anyways.

My exhaust bracket broke about 2 - 3 months ago, but that was on the rear of the bike. It was replaced long ago but maybe the exhaust shifted a bit. I'll try the tin can idea Ace suggested. Must be honest, it does my head in that there is no proper gasket that can be fitted but that's just the way it is I guess

And no, no turbocharger

young gun · **Reply #25 on:** January 18, 2014, 05:16:13 pm

Ok I took the pipe off and yup, definitely leaking, you can see where the gasses are escaping. I tried your trick Ace but the gap was too small so I just put a washer under the main support bracket in hopes that it may change things. I'll ride it again on Monday and see where it leaves me.

I was chatting with my mechanic and he suggested black silicon that galvanizes with heat. If the problem persists I may go that route. Is there any risk to the motor if I just leave it as is?

baird4444 · **Reply #26 on:** January 18, 2014, 05:25:37 pm

High temp RTV sealant has been used by many. The key
to this is to let it cure for 24 hours before startup.
- Mike

ace.cafe · **Reply #27 on:** January 18, 2014, 05:48:55 pm

Silicone sealer works. It needs to be re-done each time you remove the exhaust system, though.

If you leave an exhaust leak unrepaired, eventually you will burn an exhaust valve, or possibly also seize a piston. It will also make tuning the engine very unpredictable and irritating, because you won't be able to get it to idle smoothly, and it might stall out a lot.

young gun · **Reply #28 on:** January 19, 2014, 08:05:44 pm

Okie dokie well I'll look at sorting that out during the week then. I'll take the bike for a ride tomorrow and see if I'm still having the same problem after refitting the exhaust. I expect it to be so but who knows

Thanks for all the comments guys, I'll post up where I go to from here

young gun · **Reply #29 on:** January 21, 2014, 06:29:10 am

Hey guys,

Ok so its definately the exhaust. Took the bike for a ride this morning and it was fine. I accidently stalled the bike while parking, kicked it again and brushed the exhaust with my foot on the down stroke and the noise is back. On closer inspection, I could feel where the exhaust gases are escaping and its the same place where there was a discoloration on the pipe when I took it off.

My question now is, will this stuff work?

http://www.henkel.com/fullproductlist-electronics.htm?redDotUID=0000000HXQ

I have to buy in South Africa and this is a product I can get locally. And the fact that it is grey makes me happy as well

Oh and just as a side note. When removing the pipe on Saturday, I removed the silencer 1st and started the bike just to see how loud it was. All I can say is I have no idea how some of you guys get away with that!

jees I would be pulled over straight away if my bike was that loud!

ace.cafe · **Reply #30 on:** January 21, 2014, 12:22:37 pm

Yes, that stuff will do fine.
Let it cure for the full 24 hours before starting up the bike, or it might blow out. It typically will last about a year, if you don't have to take off your exhaust for any other reason.

young gun · **Reply #31 on:** January 21, 2014, 01:33:10 pm

Thanks Ace,

I'll do it all on Saturday

Arizoni · **Reply #32 on:** January 21, 2014, 10:19:21 pm

This has a slightly higher temperature range
http://www.all-spec.com/products/81160.html?gclid=CNSUtf-jkLwCFYhbfgodN1UA4A

Permatex Ultra Copper Silicone Gasket Sealer says it has an even higher temp capability.
http://www.motorcycle-superstore.com/22864/i/permatex-ultra-copper-silicone-gasket-sealant

These might not be available in South Africa but on the other hand, they might.

young gun · **Reply #33 on:** January 22, 2014, 06:52:22 am

Hey Arizoni,

I can get from Permatex:

http://www.autozone.com/autozone/accessories/Permatex-Ultra-Grey-rigid-high-torque-RTV-silicone-gasket-maker/_/N-25a0?itemIdentifier=306563_0_0_

High On Octane · **Reply #34 on:** January 22, 2014, 11:48:05 am

Permatex Ultra Black is the way to go. I keep that stuff stocked in my garage at all times.

Scottie

ERC · **Reply #35 on:** January 22, 2014, 02:32:53 pm

I've found the ultra copper to last the longest. Redcat and I put it on his Bullet about 14000 mi. ago and it's still holding. ERC

ace.cafe · **Reply #36 on:** January 22, 2014, 03:07:30 pm

If you guys keep this up, you are going to ruin the Bullet's reputation for being unreliable!

young gun · **Reply #37 on:** January 23, 2014, 06:53:50 am

Well I went with the grey, I applied it last night and i'll take the bike for a ride tomorrow. Lets hope it sorts out the issue

young gun · **Reply #38 on:** January 24, 2014, 01:12:21 pm

The good news is there was an exhaust leak and patching it up has definately seen an increase in performance. Or maybe it's just me. The bad news is the noise is still there and it seems to be radiating for the cylinder head.

So it'll need to go to my mechanic to check out. He said he would sort out the sprag clutch (remove it) for $30 so I may just get that sorted out at the same time though I don't think that's the issue.

ace.cafe · **Reply #39 on:** January 24, 2014, 01:28:34 pm

If it actually is coming from the cylinder head, there are several possibilities which would need to be investigated.
It could be something as easy as some worn out rockers.
Or you could have dropped a valve seat, which is a bit more costly. Dropped valve seats often occur if the engine has been overheated, and an exhaust leak can be a cause of overheating. This is not uncommon on Bullets.
You just need to look into it. It can be fixed, no matter what it is, so it's not the end of the world.

young gun · **Reply #40 on:** January 24, 2014, 02:57:39 pm

No I know that. These bikes haven't been around for 75 years unless they could be and tbh, it's why they were so attractive to me

Problem is, the new house with a garage is only scheduled in a few months time so alas I can't look into it. It will have to go to the mechanic

Thanks for everybodies help! I'll keep the thread updated

72westie · **Reply #41 on:** January 24, 2014, 03:35:48 pm

Have you checked your valve clearances recently? I had a customer's bike drop a exhaust seat, the pushrod had a little less then 1/4" of clearance.

Pop off your tappet cover and set the piston at TDC and check the pushrods for up and down play.

young gun · **Reply #42 on:** January 28, 2014, 05:04:26 pm

It goes in on Thursday so I find out then

young gun · **Reply #43 on:** February 08, 2014, 09:24:30 am

And the verdict? The 1st suggestion in this post, the decomp cable needed replacing

so got that replaced and I has the sprag gear removed.

You guys know your stuff!

High On Octane · **Reply #44 on:** February 08, 2014, 01:30:49 pm

So did the shop get it fixed or are they still wrenching on it? Glad it was something simple.

young gun · **Reply #45 on:** February 09, 2014, 06:37:31 pm

Coincidently I have a Royal Enfield mechanic that lives 3kms from my house

which is crazy since I think he is the only royal Enfield mechanic in my county

Anyways the short answer, yes. He replaced the cable, did something to the clutch so now it seems like my bike doesn't slip out of gear and best of all! No sprag clutch

I still need to get a stopper for where the starter motor is but I'll get that next time I buy from hitchcocks

ace.cafe · **Reply #46 on:** February 09, 2014, 09:20:55 pm

Good news.
Thanks for reporting.

young gun · **Reply #47 on:** February 19, 2014, 06:33:45 am

and since he had to remove the primary case, he checked out the clutch. I don't know what he did but before the bike was constantly missing a gear or slipping out of gear (normally 2nd to 3rd or 4th to 3rd). Seems like its been sorted out now! Yay! this is great news, the bike was becoming a real drag to ride because of that. I'm now loving every second of it again

Now just to sort out the front brake wobble.