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Discussion Starter · #1 · (Edited)
Hello all. Brand new to the forum.

I'd like some advice on the aftermarket silencers for my T-100.

Some history first. I changed my stock silencers to the Triumph off-road ones because I did not care for the wimpy sound of the stock silencers.

This was done at the dealer where I bought my bike and they changed the main jets in the carbs (as I was told was necessary).

My issue is this; now occasionally, (sometimes more frequent than others), there is a pop issued from the exhaust, that for lack of a better term, bugs the crap out of me.:(

When I asked the dealer if this was normal, they said yes, these type of pipes will pop.:confused:

I have tried changing from the recommended 89 min. octane gas to 91 and back and it does not seem to change.

What causes this occasional pop in the exhaust if anyone knows?

I don't like it so much, that I am thinking of spending a grand for Staintune silencers and putting back the stock jets in the carbs.

The jets would go back to the stock ones as Staintune silencers do not require larger jets or any other modification.

I wish I knew about them before I bought the Triumph off-road ones.

Any thoughts, advice would be greatly appreciated.

TIA,

Mike
 

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Did you remove the air induction system? If not, it's more than likely the source of the exhaust popping you're experiencing... regardless of what pipe you're running.
 

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I had popping on deceleration when I put on TOR's too, and I turned out the a/f mixture screws a bit and it stopped. Can't recall if I still had the AI in though, but I think not.
 

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A lot of people tune to create pop and crack, to match the bikes of the 60s. My bonnie had mototwin t120 silencers and they cracked and popped like a symphony orchestra on full song - it was perfect. I miss it.
The efi Thrux has Norman Hyde pipes that slotted straight on and the pop is reduced by about 80% much to my annoyance.
It is a matter of taste - it can be reduced or eliminated - but you need someone with a dyno that really knows what they are doing.
 

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Discussion Starter · #5 ·
Did you remove the air induction system? If not, it's more than likely the source of the exhaust popping you're experiencing... regardless of what pipe you're running.
road dog, no I have not removed the AI system. I just trusted the dealer mechanic to do or advise me on whatever was necessary.

I live in Cal. and it is actually not legal for a dealer to install pipes which are strictly for off road/track use on a street bike.
 

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I have Staintunes (and no AI) and they pop a little bit on deceleration. I adjusted the idle mixture screws to minimize but not eliminate it.

I'll be downsizing my jets from 120 to 115 when the riding season starts, but I doubt that I'll go back to the stock 110. Your dealer probably installed 115, which should be fine.
 

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Discussion Starter · #7 · (Edited)
I had popping on deceleration when I put on TOR's too, and I turned out the a/f mixture screws a bit and it stopped. Can't recall if I still had the AI in though, but I think not.
davidc, I am not knowledgeable enough to go messing with the A/F mixture. I'm afraid that I would just end up screwing things up.

At this point, I guess I'm trying to find a cure for the popping or, change to a pipe with the tonal quality I like without the popping. Which would be the Staintune. The former would be alot cheaper.

It seems to me though, that this SHOULD be something that could be resolved with just some fine tuning.

I mean, what causes the pop anyway? Seems logical that it has something to do with the modified pipes/jet combo and A/F mixture.

It never did it with the stock pipes. I just wanted a better sound. The stock pipes are a bit wimpy sounding.

Thanks to all for the quick and insightful responses. I have learned alot already from you and now am seriously rethinking spending a grand for silencers which may not remove the issue I have.
 

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Yes, '08, a bit of tune will fix what ails you. TOR's sound great, as many will agree. No need to drop a grand to fix it, although I have heard great things about Staintunes. I wish I would find a pair just layin' on the side of the road. I'd scavenge 'em, LOL.
Instructions abound on this site how to do things like that, so if you have a buddy with basic mechanical skills, he can help. The air/fuel is simply turning a screw [made easier with a D tool].
 

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Yep, the idle mixture adjust is exactly what you're looking for. It's simple, made slightly more complicated by the need for a special tool, but that tool is relatively cheap.

Look at the picture on page 9 of the Jenks manual to locate the idle mixture screw. You'll need a "D-tool", obtainable from NewBonneville.com or other aftermarket vendors.

http://www.triumph-bonneville.com/images/Carb Jetting Info 2007.pdf

http://www.newbonneville.com/html/d_tool.html

Turn the screw out (counter-clockwise) a 1/4 turn at a time from its current setting, on each side. Your popping should go down.
 

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Popping can also be caused by leaking joints between the silencers and headers. I had this. Have a feel around the joint while the bike is running (don't touch the pipe!) and see if there is any exhaust gas leaking out. In which case the silencers need to be reinstalled and some high temperature sealant added.

In all likelihood though - the AI system is probably a big part of it.
 

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Popping can also be caused by leaking joints between the silencers and headers. I had this. Have a feel around the joint while the bike is running (don't touch the pipe!) and see if there is any exhaust gas leaking out. In which case the silencers need to be reinstalled and some high temperature sealant added.

In all likelihood though - the AI system is probably a big part of it.
I've heard where someone who smokes may use the smoke from the ciggarett to see if there are any air leaks around the joints. If you don't smoke but have a hippie near by, you may be able to bum one of their incense sticks off of them to use. :D

As for the A/F mixture. Very easy. Get your hands on a "D" tool, turn the A/F mixture clockwise until it gently seats. I took a sharpie pen and marked the tool as well as the carbs as a refference point. Started with 2 turns out. Took a test ride and started adjusting by 1/4 turns until I had it dialed in with test rides after each ajustment. I wound up with a total of 3 turns out and believe the popping may have stopped. However I'm running British Customs Predators with AI removed, stock airbox with snorkel removed and jetted to 135mains / 42pilot's. I'm just waiting for it to stop raining/snowing here in the Seattle area. Then I'll be able to take a little bit more of test ride.
 
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