Bonneville America Forums Forums Technical Forums Performance Mods TBS Needle advise...soon to install...

Just ordered some TBS needles for my Speedmaster. I've read all the posts on them, but does anyone have any late coming info on shimming them or not? What's the approximate idle screw adjustment anyone is using? Also, while I'm in there, is there really any benefit from drilling the slide out? I'm running 160/42s, a FREAK and long Sceptres.

As for drilling, I think that is just for throttle response, nothing to do with the actual mix...

I didn't shim the niddles... yet. I am still waiting on pipes, so once that is in I'll experiment more. I have my screws at 3.5 turns out to start, but haven't had a chance to do the one mile run and engine cut plug check. Hopefully this week.... Then I'll tweak the screws. maybe play with the shims a little.

Hi Robert,

You have the exact same setup as mine except for the pipes (mine are Epco). I installed the TBS needles last weekend and figured what the heck, the tops are off, might as well drill the vacuum holes in the slides.

As I had the tank off checking the valves, it was a very easy job and I would recommend that method. Much easier getting to the bolts on top.

I have no shims on there now and I only put about 40 miles on her so I am not ready to give my opinion yet but my first reaction is it felt a little sluggish! Darn, didn't expect that. One thing I did notice is nailing the throttle does seem a little crisper in the power band.

I am heading up to Bob's (Palm Beach Triumph) this weekend so I think I will pick up a few shims.

Even though the taper is better with the TBS needles, they are longer. A shim or two might help with my perceived sluggishness...

I think you are right Phil. The longer needles may need a shim or two. I have 4 shims, so I will be playing around with it.

I am tempted to shim mine as well. I'll be doing it this weekend and will report back. I mean, shimming is a 10-15 minute job including pulling the tank, so it's very easy to try.

What should I look for when buying a shim? Is it just a flat washer from the hardware store?

I got mine with a couple jets when I re-jetted a couple years ago, I think from bellacorse. In theory yeah they are just flat washers, but they are a specific thickness. Flat washers tend to vary a lot in thickness. I would lean towards finding some from a bike shop or even ordering them online from a dealer or something. That way you know you are getting the right diameters and thicknesses.

Please help me out with what TBS stands for...

"T"riumph "B"onneville "S"uper-doopers.....

ThunderBird Sport

http://www.motorcycle-usa.com/Article_Page.aspx?ArticleID=82

sounds like shimming is going to be a popular activity this weekend. Got mine on order from Brent, hope they get here in time. Mine has had just the slightest flat spot at lower speeds when I open the throttle (for instance when I am pulling away from a stop sign), but then when I open it up, starts pulling like a locomotive. Easy change, so why not try it, eh? And of course, another go at destroying my engine, oops, I mean shimming the valves....