Basic tuning

Hi,
I’m riding a 1967 Sprint with a standard PX150 engine and exhaust. Starting to think about some mild tuning for quicker acceleration. Not that bothered about top end.

What’s the best way to do this if I want to do it stage by stage? Should it be carb first, then exhaust, or the other way round? Should I simply stick a kit on the engine? I believe a DR 177 can just be bolted on.

Will I see any difference if I just replace the 20/20 carb with a 24/24 from a PX200?

Thanks in advance for your input.

Cheers,

KK

hello,

I don’t think is a good idea changing first the carb with 24/24.
this is what i think the most satisfactory step by step tuning.

DR 177 or PINASCO kit
these kits will improve your engine in any range.
DR needs more attention and tends to size. Be gentle the first 1000km. And rich carburation. CHeck the ignition time. DR 18, PINASCO 20

A bigger carb and air filter will be the second step. If you put it after the first 1000km is good so you don’t have to resist to open the trottle.

Then you can change the exhaust. SITO PLUS is a good economic all rounder. More power RZ right, but much more expensive.
Remember after changing the exhaust you need to change carb main jet with a bigger jet or your mix will be too lean.

                                 [:drink:]

as cur says,for reliability pinassco every time mate we had this a few pages ago, i tried both a 24g and 24 e carb and could not get it set up at all, foned every tuner on tips and they said i was waisting my time as they are a bastard to set up,in the end i went back to standard carb a messed with jetting along with a simo pipe , use the coldest plug you can get your hands on, b8,b9 watch for pinking, cur i no pinasco is round about 20 but i had mine at 18 and it still was pinking kits a pain in the ass until set up properly, for the money u will spend what, £100 on kit ,£70 for exhaust for a few more quid u could get a 200 or if your lucky a t5 motor, worth thinkin about[:look:]

Thanks all for your advice, sorry curare, didn’t mean offence with my sito plus remark - i said at the beginning i’m not that interested in top end, more low down torque and mid range. the other thing i’ve heard about sito plus is that the ground clearance is a problem, especially when cornering 2-up or going over speed bumps (loads in london). do you think this is true?

KK

hello,

I forgot to reply to your question about speed bumps and cornering 2.

I touched the ground with everything.
Sometimes cornering, sometimes sidewalk, bumps. It depends what exhaust you buy it will have the tendency to touch the ground in a style or in another.
except if you change tires size… it improve ground clearence, grip and you will up gear at the same time!!
You see there is almost everytime something to do and money to spend!
[:roll:]

Thanks for your advice, although i’ve heard that Sito Plus’s are a bit of a waste of time.

hello,

the tire can be wider than standard and bigger in diametre, there are many option on the market, just have a look at SIP chassis section tyre you will understand what I mean.
The bigger the diametre the longer the gearing will be.
Choose the same size front and back and same type, if not handling will change. If you want to change handling… then it is matter what you would like to change directionality stability…

[:roll:]

hello,

offending?
Don’t even think about it.
We share our experiences. That’s all.
And is always fun. Expecially when we have different point of view !!!

                      [:)]

hello,

I forgot to reply to your question about speed bumps and cornering 2.

I touched the ground with everything.
Sometimes cornering, sometimes sidewalk, bumps. It depends what exhaust you buy it will have the tendency to touch the ground in a style or in another.
except if you change tires size… it improve ground clearence, grip and you will up gear at the same time!!
You see there is almost everytime something to do and money to spend!
[:roll:]

hello,

just to make it clear, as it seams we had also a little discussion with others about exhausts few days ago.

I tested many exhausts and you have to consider what you want from it!
Maximum power even though not much torque, more torque, more medium range power, more high rpm power…
The DR kit is a nice kit has good torque but it doesn’t like to rev high.
So why loosing what he does well trying to improve what he can’t
do?
For example if you don’t want to spend too much the best power you get with Simonini but this Power will come at high rpm. Low it is not that strong. Is a little like the Polini even though better. And like the Polini is loud as hell.
Sito Plus is like a standard exhausts but better. If you will cut it to see inside as I did you will see that there is somework inside.
You won’t get the power of the Simonini, but you will have better low rpm power and torque and better spread. It drives better.
And is much quieter.
Just to let you know, when I had a DR 177 with 24/24 I preffered the standard exhaust to the Polini or Simonini, not for the power but for the way the power was spread.
With Sito Plus you have around (on my engine bank test) with a DR kit and 24/24 about 2more hp a little more torque and almost the same curve as a standard one.
But of course if for you the best is only on the basis of max HP go Simonini.

                                    [:roll:]

What do you mean by upgrade tyre size? I’m using 3.5 x 10 at the moment, the standard size. do you mean getting wider tyres, which means wider rims?

KK

hello again,

please go and have a look to my last answer to gp200, it was for you.

…you might have more ground clearence but too long gearing won’t make you that happy… better be carefull everynow and then.

[:sleep:]