Speed 400 - 100mph.

Would a complete new exhaust system help, deleting the cat and a straight through pipe?

Delkevic have several systems for not a lot of money which would save several kilos and might give you an extra horse or two.

You could also try going down one or two teeth on the rear sprocket but that might be a bit too much, the only way to find out would be to try it

 

You are doing well, my Speed 400 never got near that, even indicated on the standard speedo!

I guess weight would be the first thing (exhaust and cat, but that could affect the ECU and maybe the MOT in the future), then the only thing is more BHP!!

 

Looking at pics (I don't have mine anymore) it's quite an upright riding position - what about some straight bars to tilt you forward/lower, and maybe a flyscreen like this to clean up the air around the headlight/instruments/handlebars...

 

Are you on the 400 Forum? You could have a search there -
Triumph 400 Forum

I found this after a quick look around, although he has obviously spent £££.

"First mod was a Hitchcox slip on. Not cheap ,but quality has to be paid for. Improved mid range and gave a beautiful exhaust note. Not happy with jerky throttle I got down to business. Fuelx lite. DNA performance air filter Removed feed to filter. Removed the cat and fitted a TEC header pipe. Tried my Hitchcox slip on but to no avail. It sounded like a pissed off T.Rex. Disappointed I bought a TEC slip on with a quiet baffle. Last but not least I fitted a 16T engine sprocket. Well well. It sounded ok ,but did it go? You betcha. I allowed the fuelx lite a few miles to settle down and gave it the beans. To say it surprised me is an understatement. Ive since covered 400 miles and it appears to get better every ride. Accelerating has improved enormously and top end goes off the clock. the extra tooth pays dividends but to get the best the g.box must be used. Of course ive,got no warranty now but the rev limiter ensures no harm to the engine."

 

Are you on the 400 Forum? You could have a search there -
Triumph 400 Forum

I found this after a quick look around, although he has obviously spent £££.

"First mod was a Hitchcox slip on. Not cheap ,but quality has to be paid for. Improved mid range and gave a beautiful exhaust note. Not happy with jerky throttle I got down to business. Fuelx lite. DNA performance air filter Removed feed to filter. Removed the cat and fitted a TEC header pipe. Tried my Hitchcox slip on but to no avail. It sounded like a pissed off T.Rex. Disappointed I bought a TEC slip on with a quiet baffle. Last but not least I fitted a 16T engine sprocket. Well well. It sounded ok ,but did it go? You betcha. I allowed the fuelx lite a few miles to settle down and gave it the beans. To say it surprised me is an understatement. Ive since covered 400 miles and it appears to get better every ride. Accelerating has improved enormously and top end goes off the clock. the extra tooth pays dividends but to get the best the g.box must be used. Of course ive,got no warranty now but the rev limiter ensures no harm to the engine."