DR Jetting Specs

[TT]

Maybe a question for oldfart, but I want to run a DR400 carby on an SP370 engine.
Any ideas what changes I should make to the jetting, if any?
btw running stock DR filter and airbox and exhaust system.

[Curly3]

Sorry to but in Tony but while we're talking about jetting, I've got a DR500 that I want to put on methanol and was wondering if there is a standard % of increase in jet size, as a starting point.
Oldfart?

[oldfart]

Slide,   Graeme is the one to talkto about Methanol as he runs a yammy tt 250 on .

Tony,  run with STD jet sizes  starting point    ...... pilot srew 2 turns out
                                                                      pre set screw @ front underside around 1/2 to 3/4 turns out
                                                                      pilot # 15
                                                                      main 132 .5
                                                                      float level     22.5 mm
                                                                      neddle centre position
 The 370 I bought off you some time back is still going strong with the above settings.

[TT]

Thanks oldfart. I knew you'd have the answers.
Much appreciated. 

[cloggy]

 I couldn't get my 400 to run right on the standard carb. If you have problems here's my experience.
DR400 carb fine with free flowing exhaust and air snorkel removed.
 Once I'd opened up the intake trumpet it all went to hell in a handcart
I discovered that the 370 carb worked much better with more power. The problem was the 400 single taper needle. The 370 has a double taper that is a 370 specific part. I have several carbs of each and one day I must get round to seeing if they swap. Apart from the 1 mm bore size there's quite few other differences between the carb bodies.
I just couldn't get the part throttle mix right but I do have an aftermarket cam and the inlet lip ground off. Also I never tried it with the airbox completely removed.  The airbox on the 370 is more restrictive than the 400.
The sum total of my mods is an engine that has noticably more torque low down and mid range , but is probably not a lot different maxed out