GoldStar Silencer

[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, can you PM me shakeel's number?

[sandeep1025]

Originally Posted by Chetanya Sharma

Hi guys,
Firstly about the Pune-made goldstar by shaqueel is the best sounding and is a of very good quality. There are two types of goldstars: One is for the bullets which were manufactured before 2001/2002, they had a smaller (and had a smaller diameter) bendpipe compared to that of the new ones, both cost the same. Rs1500/- w/o chrome plating and courier. His number is +91 9822994432, Aashu Fabritech Pvt Ltd, Wanowarie, Pune. I got mine for Rs1700/- w/o chrome plating and he had sent it through the Pune-Bombay Taxi Service. I had to collect it from Dadar Taxi stand, which was a pain! But I got it the very next day of ordering it.

The Delhi made goldstar comes for Rs 1300/- with chrome plating and is not inclusive of courier charges, it is made by Sans Inc, the guy's name is Saurab Katar, his number is +91 9999251103. Although I am not sure of the quality, but it seems his work is decent enough and I will be checking it out next week in Delhi.

The number +91 9822994432, Aashu Fabritech Pvt Ltd, Wanowarie, Pune. is wrong , had called this number on sunday afternoon , the guy on tyhe other end was very pissed off coz he got calls from various other guys as well , but i was able to explain him how i got this number(did not mention the T-BHP site though).
Will visit Shakeel personally this week sometime ,will also post his number once i have it.

Bye TC

[JayPrashanth]

Shakeel: 09822004432

Cheers,

Jay

[sandeep1025]

@Jay , Thanks a Lot ,
But i didn't call him , just walked in his Workshop , didn't meet him , but bought a Goldstar for my Bike(Luckily they had one already manufactured) , fixed it there itself, man , the sound was Loud and Awesome , everyone wanted to have a look at my bull,
Attached is the Visiting Card of Aashu Fabritech :

Cheers

[sandeep1025]

@mods : The card is attached with Clear intention of helping with information to fellow BHPians and not for advertising ,

[sans]

Finally,How much did u pay ?

[sandeep1025]

Rs.1500 w/o Chrome Plating

[blackfire_9]

Originally Posted by 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!

To get a fairly good estimate about the fuel air mixture, you can also look at the bend pipe of your bike, just around the place it leaves the head (exhaust). Under ideal conditions it should have a very light yellowish/goldenish hue to it, whereas a blue/purple is something that shows a very lean mixture.

Running lean is not just a threat to the exhaust valves but to the entire engine. The exhaust valve is one the things which would go bad first but in totality a lean mixture destructs an engine. A rich mixture is also bad, but it is a lot more forgiving than a lean mix.

Happy thumping,
Prakhar

[Beast_of_Burden]

Originally Posted by sandeep1025

@Jay , Thanks a Lot ,
fixed it there itself, man , the sound was Loud and Awesome , everyone wanted to have a look at my bull

@Sandeep - I am curious of the goldstar myself, now that you have had it on for a few days appreciate it if you can post a more detailed impression. Which part of the freq spectrum is it loud, does it kill most(preferably all) of the higher frequencies and just let the bass through? Can you feel the power pulses distinctly? Just a thought, if it is attracting that much attention, is it unreasonably loud?

Originally Posted by Darth Sid

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!

Let me also mention a couple of other causes of the popping especially the new bikes with PAV and airbox/filter combinations.

1. There is a rubber tube that connects PAV to the intake flange. If it is disconnected, this amounts to a leak in the intake flange and air being introduced directly between carb and cylinder leading to a lean mix and hence popping.

2. Any leaks in the rubber manifolds connecting filter to airbox or airbox to carb or the intake flange could also cause leaning out of the mix.

Check the above first before twiddling with the F/A mix screw. However I dont quite understand fully why a slightly leaking exhaust would cause this, is it because it is effectively a freer flowing exhaust and contributes to the circumstances required for the popping to occur?

[Darth Sid]

Originally Posted by Beast_of_Burden

Let me also mention a couple of other causes of the popping especially the new bikes with PAV and airbox/filter combinations.

1. There is a rubber tube that connects PAV to the intake flange. If it is disconnected, this amounts to a leak in the intake flange and air being introduced directly between carb and cylinder leading to a lean mix and hence popping.

2. Any leaks in the rubber manifolds connecting filter to airbox or airbox to carb or the intake flange could also cause leaning out of the mix.

Check the above first before twiddling with the F/A mix screw. However I dont quite understand fully why a slightly leaking exhaust would cause this, is it because it is effectively a freer flowing exhaust and contributes to the circumstances required for the popping to occur?

First, the answer to the bold part is in your post below. You were answering my query about the cause of popping sound from the exhaust. On the page whose link you provided, which also contains the text in your post, is this - "[FONT=Arial]Any source of fresh air into the exhaust system can create or worsen the conditions that bring about exhaust backfiring. The most common entry point is the junction of the header pipes and mufflers. Even a small air leak can dramatically increase the intensity or likelihood of exhaust system backfiring."[/FONT]
With reference to the bold part in the post below, when air is sucked into the muffler through a leak where it meets the bend pipe, the 'pop' gets augmented because of the increased oxygen in the muffler where the mixture is burning. The accumulated F/A mixture in the exhaust has more oxygen supporting the combustion or popping. (My bike used to do that when I was ten - a loud pop like a gunshot and a foot-long flame!) I suppose it's a bit like a gas stove burner or bunsen burner. At the neck of the burner is an air hole which, when closed, gives a yellow flame but when open gives a blue flame which is hotter.
I wonder if someone can confirm or contradict this.
At the time I richened the F/A mixture, I was using a HP free-flow conical filter - the stainless steel one that is so free flowing, it allows dust through as well. I rode the bike without richening the mixture significantly for a while. It seemed alright and gave me the same performance as with the stock air filter. I figured that was good enough. If it's giving me the same performance, that means the fuel-air ratio is the same as before. However, there was no popping sound with the stock filter. When you pointed out that the F/A mixture may be too lean, I richened it further. The result was greatly reduced popping and increased acceleration. I was racing with Pulsars and winning!! Maybe those guys didn't know how to push their bikes hard because Pulsars are quick and Bullets are not. Anyway, performance was great. So, leakage was not an issue since the only rubber part in the air channel was the filter's flange. With such a free flow filter, leakage was not a concern.
Now I'm back to the stock filter/airbox and the engine no longer revs instantly as it used to. I wonder, is it the stock old model airbox that's so restrictive or the felt/cloth type filter element?

I've heard the exhaust note of a TBird with Goldstar-type muffler and I don't think you'll like the sound. I mean if you've heard it, you'll know that it will take you even further away from the CI engine's exhaust note. The sound has little bass and is very sharp. But, I've heard the sound of only two AVL/LB engines with that exhaust. My two cents. Actual owners will give you better feedback.

Originally Posted by Beast_of_Burden

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]

Originally Posted by blackfire_9

To get a fairly good estimate about the fuel air mixture, you can also look at the bend pipe of your bike, just around the place it leaves the head (exhaust). Under ideal conditions it should have a very light yellowish/goldenish hue to it, whereas a blue/purple is something that shows a very lean mixture.

Running lean is not just a threat to the exhaust valves but to the entire engine. The exhaust valve is one the things which would go bad first but in totality a lean mixture destructs an engine. A rich mixture is also bad, but it is a lot more forgiving than a lean mix.

Happy thumping,
Prakhar

For the past many years (at least 27 out of 30) of my bike's running, the tappets had been kept loose 'fauji style'. When the bike would approach, you'd hear the tappets before the exhaust note! That helped prevented browning of the bend pipe. The first bend pipe did turn brown, though, over the years. Got it changed 6 years ago and then 1 year ago. The current one doesn't seem to have changed colour, though.
Are you sure the bend pipe should be yellowish with optimum fuel/air ratio? I know for sure that a blue bend pipe is really bad sign. I was aware that a lean mixture overheats any engine but didn't realise that the exhaust valve is the first part to go.
I recently saw a CI500 modded dirt bike style. It had a K&N filter and Goldie exhaust. The bend pipe was blue way down to the point where it is attached to the base of the down tube. I wanted to ask the owner if he had rejetted the carb because it didn't seem like he had. Didn't get the chance to ask, though. What do you think?

[JayPrashanth]

Originally Posted by Darth Sid

For the past many years (at least 27 out of 30) of my bike's running, the tappets had been kept loose 'fauji style'. When the bike would approach, you'd hear the tappets before the exhaust note! That helped prevented browning of the bend pipe. The first bend pipe did turn brown, though, over the years. Got it changed 6 years ago and then 1 year ago. The current one doesn't seem to have changed colour, though.
Are you sure the bend pipe should be yellowish with optimum fuel/air ratio? I know for sure that a blue bend pipe is really bad sign. I was aware that a lean mixture overheats any engine but didn't realise that the exhaust valve is the first part to go.
I recently saw a CI500 modded dirt bike style. It had a K&N filter and Goldie exhaust. The bend pipe was blue way down to the point where it is attached to the base of the down tube. I wanted to ask the owner if he had rejetted the carb because it didn't seem like he had. Didn't get the chance to ask, though. What do you think?

Excessively retarded timing or an extremely lean mixture causes blueing. The brown/golden exhaust is the result of rich running. Loose tappets don't have to do anything with blueing as such.

Cheers,

Jay

[Darth Sid]

Originally Posted by JayPrashanth

Excessively retarded timing or an extremely lean mixture causes blueing. The brown/golden exhaust is the result of rich running. Loose tappets don't have to do anything with blueing as such.

Cheers,

Jay

The brown/golden exhaust is result of slightly rich running or excessively rich running? How so? I understand the effects of a lean mixture/excessively retarded timing.

Loose tappets, in my experience, makes the engine more tolerant to sustained hard riding. If I loosen the tappets enough to have perceptible play and loud clatter, the engine heats up as much after 30 minutes @ 60-80 km/h as with the recommended setting after 15 minutes @ 50-60 km/h. The engine runs really cool and the exhaust beat becomes solid but throttle response and general acceleration get reduced significantly (possibly due to reduced valve lift; not sure.) Great for puttering around but not for, say, racing. I'd like your comments on this.

Sid.

[JayPrashanth]

Originally Posted by Darth Sid

The brown/golden exhaust is result of slightly rich running or excessively rich running? How so? I understand the effects of a lean mixture/excessively retarded timing.

Loose tappets, in my experience, makes the engine more tolerant to sustained hard riding. If I loosen the tappets enough to have perceptible play and loud clatter, the engine heats up as much after 30 minutes @ 60-80 km/h as with the recommended setting after 15 minutes @ 50-60 km/h. The engine runs really cool and the exhaust beat becomes solid but throttle response and general acceleration get reduced significantly (possibly due to reduced valve lift; not sure.) Great for puttering around but not for, say, racing. I'd like your comments on this.

Sid.

Sid,

The yellowing of the exhaust just near the exhaust is due to extreme rich or extremely lean mixtures. In case of extreme rich mixtures, the unburnt fuel ignites in the bend pipe instead of the combustion chamber resulting in rapid increase of temperatures in the portion of the bend pipe where it is connected to exhaust manifold. In case of extreme lean mixtures, the head sturggles to dissipate head quickly enough, resulting in the part of the bend pipe being used for heat dissipation which causes it to be heated to higher temperatures that causes yellowing. A slightly rich misture or a slightly lean mixture will not cause yellowing or blueing.

You're right about the drop in performance. With loose tappets, you're effectively reducing the engine's performance and power output, which usually shows up as lesser heat generated. There is a downside to this too. Loose tappets over a long time would cause wearing down of the valve train. This, because the valve train components will get hammered into each other because of the increased tolerances.

This, while being harmful to the valve train, is better than being stranded with a burnt valve due to a very tight push rod(tappet) set up. Over the past year, I've met plenty of mechanics and time and again, they deliberately adjust the valves with the clearances on the looser side. There are two reasons for this. The first being the fact that mechanics always want to err on the safer side. This, because no two Royal Enfields are the same and most mechanics don't use feeler gauges to adjust the push rods accurately, instead they rely on their thumb pressures. Experienced mechanics pull this off successfully while inexperienced ones muck things up.

I mentioned this fact about no two Royal Enfields because of the varied clearances that each Royal Enfield comes with, especially those with the pre-unit construction engines. So, the mechanics can't really effectively determine how the push rods(especially on AVL engines) will expand as the engine heats up. Hence, they prefer erring on the safer/looser side. My theory on this matter is that, plenty of bullet owners go on long rides/tours and don't mind minor drops in performance(and resultant long term valve train damage) as long as they get a cooler running engine that will get them to their destinations without any mechanical issue. On the other hand, bulleteers wanting to win traffic light GPs usually want the valves to be set up with just the right clearances as they don't like performance drops. This, imho, is the right approach as they are running the ideal set of valve clearances.

If you are going to ride hard with loose push rods, brace yourself for valve train damage sooner than usual. Therefore, a correctly set up valve clearance is your best bet. Why run with loose push rods when you can manage to run with just the right settings?


Cheers,

Jay

[jingaboysr]

On a similar note..

I did a long ride with my CI 500 last week, >1000kms in 3 days. The roads were awesome and I was cruising in 80-90s continuously for 1-2hours without breaks... The funny thing I observed is that though I started my ride with an optimum setting for the tappets, by the time I finished my ride, the tappets got REAL tight, it was very difficult to start my bike once it cooled down. I also noticed that the compression was also very very bad towards the end of the trip to an extend that there was no need to use the decomp at all....

I've seen and heard tappets getting loosened themselves on long rides, but them tightening themselves.. seems a mystery for me. My mech told me it can happen rarely. Has anyone seen /heard abt this?