another jetting/exhaust thread

[Buford_VMI86]

I'm going to take delivery of an '07 T-100 in the next week or so. I want to also get the Triumph accessory mufflers (p/n A9608023). Their service guru says that they have had good results by not rejetting with these mufflers. Is there anyone in this forum who has bolted these mufflers on, and not rejetted the carbs? I'd like to know what results people have had in that situation.

Before everyone starts harping on the timeworn laws of stage one upgrades, I do know the basics. I have worked as a professional motorcycle mechanic. I'm just interested to hear what anyone has experienced with these specific slip-ons on a non-jetted Bonnie. Thanks!

By the way, I did a search and tried to find the answer to this question. I know the forum probably doesn't need another jetting thread.

[Geoff]

they do run ok, but the lean situation is even leaner. stock jets are 110, the triumph performance mufflers will run even better on 112 or 115 jets. the d-screws should be tweaked from stock, to about 2.5 turns out
G

[Buford_VMI86]

Thanks for the reply. I just wanted to make sure doing this wouldn't result in some dramatic problem, like a hole in a piston. I figured it was unlikely, but it's more comforting to hear it from other folks.

Is there anything unusual about changing out the jets? I don't remember ever messing with a heated carb before.

I'm almost wondering if changing the mufflers is even worth it to me.

[Stealth]

I have a question for you? The stock TOR"S come with 115 jets. why not put them in? I had TOR'S I put the 115 in ran good went up to 125 jets was perfect sound performance etc.

[badrufus]

I would advise rejetting to 115s with the TORS. As Geoff said, they come lean from the factory in order to pass environmental regs, so while you might be able to get away with not rejetting, I wouldn't want my bike running that lean. Rejetting on the bike is relatively easy--the only frustrating part is getting the Phillips-head screws off so that you can remove the float bowl and gain access to the bottom of the carb. Most of us have used this as an opportunity to remove the Phillips-heads and replace them with nice stainless steel allen heads, available from newbonneville.com at moderate price. Subsequent work goes much more quickly. It is not necessary to remove the carbs to work on them, but you'll probably want to put together some small tools such as mini-rachets with different bits, including a 3mm allen head bit to remove the new allen head screws later on. A "D" tool is required for adjusting the idle mix screws. Early Bonnies had the idle mix screw covered with a plug to discourage adjustment, but since, I believe, 2005, the screws are not plugged, but have a special "D" shape to them. The tool also is available from newbonneville.com. There is nothing special about the carbs being heated--you will just want to disconnect two electrical connections at the bottom of each carb and remember to reconnect them when you are done. I would highly recommend looking at Peter Jenks Tuning Guide in order to get oriented. Many have started from Jenks' recommendations and adjusted as needed, but it provides some good info on these specific carbs, and well as a very helpful photo of the underside of the carb with the float bowl removed. If you go to the bottom of the Jenks page and click on link, you can get a pdf and print out the whole tuning guide.
http://http://www.triumph-bonneville...products_id=96

[Buford_VMI86]

Originally Posted by Stealth

I have a question for you? The stock TOR"S come with 115 jets. why not put them in?

Beats me. Like I said in the original post, the service tech at the dealer said they had good results by not installing them. I'm not defending any position here, I just wanted to know what people had experienced by not rejetting for these mufflers (i.e. I'm trying to find out how much BS he was feeding me... galoshes level or hip-waders level).

I understand the school of thought that the engineers who designed the accessory kit probably know more about the mechanical ramifications than the local technician. But, it's also hard to argue with actual results.

In all honesty, I am fairly lazy, and if I can get away with not doing something... sign me up. I've worked on enough motorcycles to last a lifetime. My Snap-On stuff has got a real nice layer of dust on it.

[PAAS]

The reason the TORs come with 115s is because that is what Triumph recommend you fit when these silencers are used on a 790cc Bonneville. The 790 has/had different needles in the carbs leading to a different main jet requirement to the 865cc Bonnie (your bike) when free(er) flowing silencers are fitted. Triumph state that TORs can be fitted to the 865cc Bonnie without changing the main jets so your dealer is not giving you BS as far as Triumph are concerned. However, the comments made by others that the bikes come lean from the factory are also correct, so I would also recommend fitting the 115s.

I bought my 865cc T100 second-hand with just over 500 miles on the clock and it came to me with the standard silencers. I recently fitted some aftermarket silencers to it and when I opened up the carbs to put bigger mains in I found it already had 115s in it. I suspect the original owner had TORs fitted by the dealer from new but sold it without them fitted. Unbeknown to me I've done the last 9000 miles with standard pipes and 115s instead of 110s - I didn't notice the bike running rich at the top end of the rev-range! Probably because it wasn't.

[Buford_VMI86]

I appreciate the input... and trust me... I understand about bikes being lean when new... and getting even leaner with pipes.

But, my goal with this thread was to see if anyone had tried these mufflers without rejetting.

I guess what I'm finding (so far) is that everyone goes ahead and does the jets. That's all well and good; it's just not the question I asked. Thanks anyway.

[lucky23]

paul, what are the symptoms to look for if it IS running rich/lean on the top rev range?

[Buford_VMI86]

Originally Posted by lucky23

paul, what are the symptoms to look for if it IS running rich/lean on the top rev range?

I'm not Paul, but I stayed at a Holiday Inn Express last night. A lean bike (which is what they were talking about) runs hot. Your plugs will read white. Low CO and high (or low) HC readings on the EGA machine. Also using an EGA machine, you can run the engine up to midrange RPM. If the HC rise before the CO, it's lean (they should rise together). Pipes turn blue (although, with a single wall pipe like on the Bonnie, even a well tuned engine can blue them). Misfires. On the far end of the spectrum, you could melt stuff in the combustion chamber.