GoldStar Silencer

[naveenroy]

Ok, perfect time to ask my question here. I guess what you call "popping" is the misfire/backfire that happens on Goldie silencers. So loud that most of the times, other commuters on the road turn back to look. Please correct if wrong.

I have a Goldie (don't know who was the creator or the father, don't have a name to go with it like Shakeel, Pune etc) which is completely without any packing. I can actually see through it from end to end - it is shaped like a Goldie thats it. But I like the sound, so no worries. But I get this "popping" sound too. Gordon said that this can be rectified by a larger jet - how can I get this done? Any mech I can approach?
Another question - since I have such a Goldie with no packing at all, if I ride my bike for long distances without changing the carb settings, can this adversely affect the engine?

Last question to JayPrashanth - where and how can I get a Shakeel Goldie? Guys in RTMC have loads of jokes about how long it takes to get a Muneer Goldie, so if the Shakeel Goldie is better, how can I get one?

[JayPrashanth]

Originally Posted by naveenroy

Ok, perfect time to ask my question here. I guess what you call "popping" is the misfire/backfire that happens on Goldie silencers. So loud that most of the times, other commuters on the road turn back to look. Please correct if wrong.

I have a Goldie (don't know who was the creator or the father, don't have a name to go with it like Shakeel, Pune etc) which is completely without any packing. I can actually see through it from end to end - it is shaped like a Goldie thats it. But I like the sound, so no worries. But I get this "popping" sound too. Gordon said that this can be rectified by a larger jet - how can I get this done? Any mech I can approach?
Another question - since I have such a Goldie with no packing at all, if I ride my bike for long distances without changing the carb settings, can this adversely affect the engine?

Last question to JayPrashanth - where and how can I get a Shakeel Goldie? Guys in RTMC have loads of jokes about how long it takes to get a Muneer Goldie, so if the Shakeel Goldie is better, how can I get one?

I've PM'ed you Shakeel's number. Sustained high speed riding with a goldie on could burn your exhaust valve if don't upjet. If you ride a Enfield with a VM carb, you can find plenty of jets on JC Road. Having said that, there are plenty of wrong sized jets floating around in JC road. Best option is to purchase a few drill bits and drill out the JC road jets according to your specs.

Cheers,

Jay

[jingaboysr]

Naveenroy, I think what you have is the free flow goldie which you get from Sandhya motors, Bangalore.

And Yes @Jay, I too have this question.. long rides and goldie, can that cause any problems to the exhaust valve?

Regarding this popping, is that the thug thug sound that comes when you ride in high rev and then sudddenly let go of the throttle? If it is, then I had this issue with my short bottle silencer in my erstwhile AVL mac 350. And my mech rectified it by adjusting the carb tuning...

[jingaboysr]

Originally Posted by JayPrashanth

I've PM'ed you Shakeel's number. Sustained high speed riding with a goldie on could burn your exhaust valve if don't upjet. If you ride a Enfield with a VM carb, you can find plenty of jets on JC Road. Having said that, there are plenty of wrong sized jets floating around in JC road. Best option is to purchase a few drill bits and drill out the JC road jets according to your specs.

Cheers,

Jay

Jay could you also PM me shakeel's number.. Thanks.

Also on a similar note.. I know that upjetting the carb is a long process, trial and error by checking with combinations of main jets, pilot jets and several plug chop tests.. I am really interested do do this, but due to time constraints I would like to get this done by a professional mec.
As you guys are from bangalore, I want to ask you, is there anyone in bangalore who does this pretty well? Like someone specialised in this?

[naveenroy]

Originally Posted by jingaboysr

I am really interested do do this, but due to time constraints I would like to get this done by a professional mec. As you guys are from bangalore, I want to ask you, is there anyone in bangalore who does this pretty well? Like someone specialised in this?

Hehe, you took the words out of my mouth, help please.

[Gordon]

I have the Pune Goldstar on my bike and running stock jets, without a single misfire. Its just tuned to the right mixture setting.

[Darth Sid]

Why does that popping sound occur, though? A lean mixture causes it but how does it affect the exhaust valve?

[raghu4222]

Hi Guys,

I have a Machismo 350 '06 and have fitted a goldie out here @ bangalore. I do feel a drop at the higher gears, but the initial is good for me. And the sound it gives is jus awesome!!!

Raghu

[JayPrashanth]

Originally Posted by raghu4222

Hi Guys,

I have a Machismo 350 '06 and have fitted a goldie out here @ bangalore. I do feel a drop at the higher gears, but the initial is good for me. And the sound it gives is jus awesome!!!

Raghu

Raghu,

Imho, you are feeling a drop in the top end due to the smaller rear tyre and not the goldie. Could also be that this feeling is being alleviated due to the lack of upjetting too.

Cheers,

Jay

[Rennjit]

Originally Posted by JayPrashanth

..Best option is to purchase a few drill bits and drill out the JC road jets according to your specs..

Could you pls say how you guys check orifice size of a drilled jet or rather how you make sure that what you got is exact size wrf specified no:

[JayPrashanth]

Originally Posted by Rennjit

Could you pls say how you guys check orifice size of a drilled jet or rather how you make sure that what you got is exact size wrf specified no:

To measure exactly, my friend has a pin gauge set which are nothing but numbered wires. This can measure the jet orifice. Basically it is a trial and error process. Once the orifice number is noted and corresponded it to the jet size, jets are drilled out. The disadvantage with this method is that we need a orifice-jet number chart from the manufacturer or a set of original jets to match with. This, because orifice numbers vary from the numbering on the jets.

Cheers,

Jay

[sudharma]

Originally Posted by Darth Sid

Why does that popping sound occur, though? A lean mixture causes it but how does it affect the exhaust valve?

Lean mixture creates very high temperature hot gases. This will eventually burn out your exhaust valves in high speed sustained run. The rich incoming fuel mixture helps cylinder head cooling to some extent.

[Darth Sid]

Originally Posted by sudharma

Lean mixture creates very high temperature hot gases. This will eventually burn out your exhaust valves in high speed sustained run. The rich incoming fuel mixture helps cylinder head cooling to some extent.

Thanks for the response, Sudharma. Ok, that's the exhaust valve. Why the occasional loud popping sound on killing the throttle at high RPM, when the mixture is lean?

[Beast_of_Burden]

Originally Posted by Darth Sid

Why the occasional loud popping sound on killing the throttle at high RPM, when the mixture is lean?

I had the same popping issue on my LB500, it was cured by adjusting the idle F/A mixture screw. Here is something I found on the Mikuni site.

Mikuni American Corporation

Why This (normally) Happens:

1) When the throttle valve is in the idle position, fuel does not flow out of the main system (needle, needle jet, main jet). Fuel is only delivered to the engine by the pilot (idle) system.
2) The combined effect of the closed throttle and elevated engine rpm is to create a fairly strong vacuum in the intake manifold. This vacuum, in turn, causes a high air flow rate through the small gap formed by the throttle valve and carburetor throat.
3) Under these conditions the pilot (idle) system cannot deliver enough fuel to create a normal, combustible air/fuel ratio. The mixture becomes too lean to burn reliably in the combustion chamber. It gets sent into the exhaust system unburned and collects there.
4) When the odd firing of the lean mixture does occur, it is sent, still burning, into the exhaust system where it sometimes ignites the raw mixture that has collected ---- the exhaust then pops or backfires.
5) Completely stock Harleys do not do this until open-end mufflers, such as the popular Screamin' Eagle slip-ons, are installed. The exhaust must be both free-flowing and have an open exit for the popping to occur.

[Darth Sid]

Beast of Burden,

Thanks for your input. It was very helpful. That answered my question. I guess in a Bullet the popping would be really bad for the exhaust valve because of the exiting burning mixture as well as the hot lean-burnt exhaust as explained by sudharma.

It even validated my brother's explanation of the extra loud popping sound due to a leak where the muffler meets the header pipe. He gave me that reason for the sound when my bike used to do that when I was ten years old. I still remember the soot under the bend pipe...

By the way, I richened the air fuel mixture a little. Now, the popping has almost gone and the machine has a solid punch - well, as solid as a normal 350 can be. Heh heh!