T5 tuning

Have a T5 project. Go for Malossi172 and Cosa clutch. Dont want to do any changes on motorcasing. Exhaust and carb? Shall use it for touring, - no racing, only cruising 80-110kph, but can be all day touring. Need high torque and power in mid range and a longlivity engine. Thought about going for LeoVince and Si24. Any good reason to go for SIP Performance (high torque) and bigger carb? Any other good advise?


the 24/24 it is good if you want to keep it as close as original as possible.
Bigger carbs for this kit are better still.
Mikuni 27 it is very good but as a big body you need some work to get it in place. If you want an easier installation get a dell’orto 28 you wiull loose in comparison with Mikuni just the smoothness but you won’t loose power or just a little.


When not doing any changing on the casing, will I still get some extra (and useful) power out of expantion-pipe (as PM Evo), instead of using fex sito plus?
Going for Si24/24E carb (what I have), - or buy a PHBH28 (without reed). With fex PM Evo would it be very much better (and „safer“) to go for PHBH28 ?


the 20 teeth is slight too short. You should go anyway for the 21 cosa. It is just slightly longer.
In your situation and for your use what I will do is:

I would keep the 24/24 and go for a simonini if a sito plus grounding is a real problem.

You know it is a question of compromise, maybe you won’t have the same power but will be better to drive.
If you don’t like this set up for torque or low end power don’t spend any more money for more expensive exhaust or carb. You will have more power where you don’t need and even less power where you need.

Thank you Curare!
What about carb? Have a Si24,- is that OK? Anybody having experience with Mikuni TMX27 (that should also give more power in lower rpm, - and is it suitable on a original motor-casing)…?

…just red the very first question were you are saying you will be using your scooter mostly for touring and everyday use.
The problem is that for this kind of use you don’t really need to tune it! It is that we want always a little more…
If your taste are reasonable just go for SITO plus and stay with your carb.
But I can feel from the other question that you are not really sure that you could manage to stay with this thinking you could have put bigger carb and so on…
In this case, since the possibility of wanting more is present from the beginning it is wiser to plan something more and wait, if not you will be changing and changing. If you do the meccanic by yourself it is ok, but if you give it to somebody, at the end it will cost you more and you will have the feeling your scooter it is never ready since it is always missing either a racing cranck or a bigger carb or…


yes, I understand. For the question of reed you got it right: it is absolutely useless if you don’t do the right milling to the the cranckcase, it would work but not as it should…
…the T5 engine as always had problem of low end power and torque and even in the malossi kit you will get the power preatty high in rev. This means that up hill you have to change gear often and let the engine stay in the highish rpm. And this caracteristic would not be solved with the use of a bigger carb. You will get even better high rev power but not better low if not a little worse.
Yes sito plus as a little problem with ground clearence, if you need ground clearence then the right hand exhausts are better in this respect. Simonini it is the best affordable exhaust.
But…if you can get a p200 engine this will be perfect for your need. Put a Malossi kit with a 28-30 (petrol pump could be necessary but not expensive and easy to install) a Simonini or if you can afford it RZ right hand, a short 4th, and globally you will be more satisfied for your need. But it is more money since you already have the T5 engine. You know money it is often an issue so it is difficult to say. Objectively a say what would be better for your need not for your wallet!
In case you stay with the t5 the Polini kit will give you less power but a little more torque and maybe globally better for your need.
Of course this is my opinion…

Out of what you say Curare, it’s maybe OK to use original clutch, and not change to Cosa FLII 21 cogs, - when going for bolt on Malossi172 with a moderate exhaust and si24/24E or PHBH28 carb? Maybe it will be a bit hard to ride i 4th with the 21 cog-clutch?

…as usual I have to write again to complete the answer because a red your question again…
yes Mikuni will give you better response and slow mid power. If you are after the last drop get it one but I can’t see how you could be unhappy with a dell’orto 28. Mikuni or Keihin are for the ones who did everything else on their engine or for the one that like esoteric…[H]

…it will be enough[H]


T5 engine kit are made to rev high, as the basic T5 engine as well,
If you don’t do extra tuning and are just after a bolt on cylinder exchange be carefull for the exhaust you will be using. If with no extra tuning job you get an expansion as PM, SIP etc, your low will suffer and your high won’t be as good to justify the low rpm power loss. More so you will have hard time to hit the target high rpm power to use well your four gears. In a bolt on job I will sure will be globally more satisfied with the using of a SITO plus or less radical expansion as Simonini. If you want more then you need to make your engine rev higher. That means the use of bigger carb, the use of a more radical expansion as PM , SIP or TAffspeed. At that point of course I will use a keihin style carb and consider reed as well.


malossi best kit performance and reliability for t5.
For your use don’t use Leo Vinci.
If you want mid-power range get a PM exhaust but expensive.
If you can’t afford get a Sito plus. Of course less power but very good mid low power.


Thanks again!
Found Koso on SIP homepage. Looks good. But still maybe a complete PHB28-kit should be good enough?

Thank for good answer Curare. I’ve a -71 GTR with 2-ports engine. Have got a OK T5 engine without cylinder. The plan is to just bolt on a Malossi 172. But as said, for me it’s mostly touring. But we have lots of hills here, -and nice to have some extra power. Speedlimit is mostly 80 and 90 kph, and traffic will then in practice be 95-105 kph, - and its nice to follow the traffic, and not have everybody passing. Thats the problem with the old, original 2-ports 125ccm. Sito Plus is OK, but the problem is that it easly hits the ground in the roundabouts/curves. Maybe Simmonini could be a OK alternative, and maybe together with a PHBH28.
I suppose it’s impossible (or useless) to use a reedvalve without milling/changing in casing? Could go for P2-engine, but find the T5-engine attractive, with Malossi172.