performance question

[ozbonnie]

Today I was riding with another Bonnie.
Very similar setup 865 06 T100 and my 07 865 Bonnie black.

The T100 has a stock airbox and madaz pipes, I have an airbox open on both sides with a unifilter and madaz pipes.

Off the line I pulled away strongly but from 70 mph (115 kmh) I was hauled in and left behind.

Those that understand performance could you tell me why this may be?

 

[Nick Morey]

It might be a carb jetting thing... I rejetted first for D&D pipes and again for K&N pods according to store's recommendations. Noticed more juice both times and I remember particularly my bike felt stronger at top end with second rejetting for pods.

 

[BlueJ]

+1 on the jetting. Another possibility is maybe they had a 19T front sprocket?

 

[ozbonnie]

No sprocket difference. The right side opening on the airbox is very new but I had rejetted for the more open pipes already.

The fact that I was faster to 60 + mph and then fell away is the concern

 

[BlueJ]

I can guess what your torque curve looks like: Mine. You're jetted fine right up until WOT and then it falls apart. Without knowing your A/F ratio it's hard to say, but it's possible you're too lean up there, now that you opened the airbox.

 

[Nick Morey]

You probably need a bigger main jet. I got a bigger one with pod filter change. Not sure, but I believe pilot jet was same size as one for D&D pipe changeover.

 

[dschief]

If you have not increased your mains since opening the airbox, you are too lean! More inlet air makes a heck of a lot bigger difference in the air-fuel ratio than any pipe ever will.

 

[ozbonnie]

Thanks all, new jets will be ordered in the morning.

 

[Nick Morey]

Thanks all, new jets will be ordered in the morning.

If you don't have a pilot adjustment screw tool you will want to get one...

 

[Nick Morey]

Here's a cool graph...

Good stuff here:

http://www.gadgetjq.com/keihin_carb.htm

http://www.dinqua.com/Triumph/carbs0.html

 

[dschief]

Nick, that's a really good graph! You always hear what carb circuit does what at which throttle position, but I've never seen it mapped out like that. Kudos to whoever made it!

 

[BlueJ]

That graph is from the much-vaunted (and very useful) Jenks Tuning Guide.

 

[coopv2]

Thanks all, new jets will be ordered in the morning.

Hi mate, I recently picked up a modded air box from West Aust, along with an assortment of bits, it came with dual opening, restrictor plate delete, and uni-filter, and 127 mains.
I removed one of the stupid velocity stacks from the left side, and opened the stock hole out to the filter, fitted 42 pilots and 138 mains, and was not impressed, next dat I went to Powerhouse Dyno tunning to see my buddy Steve, We run the bike up and the fuel was way too rich so I dropped the pilots down to 40 and left the needles with 1 shim, and tried out the 127 mains the air box came with and it was perfect, actually a little rich in the mid range, but thats ok, so I did not remove the shim. Pulls hard, makin just under 65hp and 55tq at the back end.

 

[ozbonnie]

Thanks for that info Coopv2,

I had sent an email to madaz asking what they normally ship their pipes with in terms of jets.

Haven't heard back yet but you have given me the info I needed.

As I am in WA I would assume the jetting would be the same for me.

 

[coopv2]

Thanks for that info Coopv2,

I had sent an email to madaz asking what they normally ship their pipes with in terms of jets.

Haven't heard back yet but you have given me the info I needed.

As I am in WA I would assume the jetting would be the same for me.

no worries, I am running a open 2 into 1 as well, drilled the vacuum hole on the slide out to 3mm.

 

[sportyone]

Thanks for that info Coopv2,

I had sent an email to madaz asking what they normally ship their pipes with in terms of jets.

Haven't heard back yet but you have given me the info I needed.

As I am in WA I would assume the jetting would be the same for me.

I have Madaz pipes too, great pipes, great sound, but I was told that they are no longer making them or are not around anymore ?
so don't hang about for a return email mate ! :shh:

 

[ozbonnie]

I have Madaz pipes too, great pipes, great sound, but I was told that they are no longer making them or are not around anymore ?
so don't hang about for a return email mate ! :shh:

It would appear you are correct. Their website doesn't mention pipes at all. Seems they are now just a racing outfit. Or they have gone completely and a new group has taken over the name.