Bonneville America Forums Forums Technical Forums Performance Mods Anyone with a Dynojet kit installed

I have a 790 speedmaster with dynojet needles and springs with 130 mains and 42s, with short TORs and drilled air box now. I have dual K&Ns on order and I am going to build my own freak kit. Yes I know about the jetting calc but it does not address the dynojet needles and springs. Anyone have first hand experience? I am thinking 145 and possibly changing to bigger idle jets as I am out 4 turns on the mixture adjustment now before the K&Ns and still a bit lean. Pulls hard all the way but steady 4000rpm is very rough

Don't have experience with the dynojet needles, just put in the TBS needles in my bike (see CT Tech Day results post) and its running well, but I am now wondering if the Short TOR's don't quite flow as well as some of the other pipes out there and thus limit the main jet size?? Others seem to run 130 mains with Uni / drilled airbox (my current setup), but I still may be a little rich on top. thinking of trying 128's. With separate filters and TOR's hard to say. One thing, I've read though is that if you are more than 3.5 turns on the mixture screw, its better to go up on the pilot jets and turn the screws back in. Also, mine is a 2007 865 and that may affect things too. Not sure if the 790 bikes had a more aggressive cam, which may be another reason, I seem a little rich on top.

You can "assume" that the DJ needles, with clips in the center, are about the same as TBS needles.
Also, those TOR's don't breathe as well as most open pipes, still pretty restricted.
If you have a problem with a certain THROTTLE POSITION you can easily correct it if you know where the problem area is. Use the Mikuni Tuning Manual and follow their method of using tape and marks to find the problem throttle position. Once you know what throttle position you need to correct, you can change mains/needles/clip posiotion or whatever and dial it in really nice that way.

Thanks Pat for confirming what I've hear about the TOR's. Also thanks for your web site, its really helped me to get to where I am today, which is still a major improvement over the stock tune. Bike runs a lot stronger and now I'm down to the finer points. Nice that there is so much support from the Triumph community. Since, I don't want to replace the TOR's I may try the 128 mains after I get back from vacation and see how they work. Take care.

I just got a similar kit installed. My dealer uses a UK Sport kit with custom adjustable needles. See my post "2-year service and more" on this heading. I immediately noticed a quicker response in the early part of the throttle curve. I used to have a very slight hesitation on quick starts - gone now.

I also got a HP increase with the changes - see dyno runs on post.

Thanks for the input

Switched the idle jets to 145s for now and the flat spot is gone pulls even all the way to 100mph. Now just have to wait for the K&Ns to show up before I attach the mains. Have a carb screw kit coming too. I doubt there are cheaper softer screws available than the ones on those carbs.




Pet peaves the design engineers must have got a new box of tools when they came up with the Speedmaster and desided they had to use every tool in the box by the end of the day. Really front rubber clamps blade, back ones allen, one torx, one Phillips two sizes of allen and one hex head to get the battery box loose. Gets a bit ridiculas .....while I remember got to switch the balancing phillips screw for an allen screw next time would be much easier to balance with an allen wrench which would allow finer adjustments and stay put when you bump the throttle between adjustments.

Dealer prices ....Brents price jets $6 for two dealer price $12.95 each To quote dealer when I showed them the Brent page print out with pricing "Oh those are probably not the good jets!" Had to bend over and take it on the pilots but ordered the mains from Brent.