Mugello 225 Port Timings

[Tom Russell]

thats great news tom and glad it worked out sounds a good job Jerome has done
id consider a 30mm carb and breathesweet as a good move ,you should see similar power with much improved fuel consumption with improved response and as a 30mm carb is cheaper than a 35 mikuni then you should be able to sell the mikuni for similar money to the new dellorto
the reed route is costly for little gain when compared to a well set up piston port and with breathesweet will run clean under the panel
what mugello was it 4 or 5 port and is there a dyno graph ?
i have a dyno graph for a mugello i did this week to post up too

Hi Darrell,

Thanks for your comments and suggestions

A 30mm carb is exactly what Jerome also suggested, so I think that is also next on the shopping list

I'll suggest the breathe sweet filter option to him as well, as Jerome also thought the reedvalve wasn't really worth looking at.

It was a 4 port Mugello (i believe an early one) and I'll get the dyno graph up ASAP!

Cheers for now,

Tom

[Darrell Taylor]

heres 1 i did this week 225 mugello 4 port, customers scoot wouldnt pull 4th approx 4.6 gearing so was considering a gearbox/gearing change, i said for similar money id tune it to pull the box
despite peoples concerns i thought the port durations were quite good but the port areas were mismatched and improvements could be made here and there to port angles ,the top end was fitted with a cheap piston which had thick cast rings so limited port width to 65% bore ,i reset the top end with different gaskets to obtain improved compression and squish clearance.i mainly ported the exhaust port only to suit mildly revised transfer and inlet durations ,this runs a jl3 exhaust and 30mm carb

standard gasket areas remain on inlet/exhaust and base gasket as no power gain to be found there

the 3 graphs are the std built motor from camlam in red 15.55 hp 12.7 torque(nice build just jetted safe)
the same motor after setting up on the dyno in blue 18.60 hp 14.04 torque
the same motor after stripping porting rebuilding 23.21 hp 18.87 torque

[WINTERMODEL150]

heres 1 i did this week 225 mugello 4 port, customers scoot wouldnt pull 4th approx 4.6 gearing so was considering a gearbox/gearing change, i said for similar money id tune it to pull the box
despite peoples concerns i thought the port durations were quite good but the port areas were mismatched and improvements could be made here and there to port angles ,the top end was fitted with a cheap piston which had thick cast rings so limited port width to 65% bore ,i reset the top end with different gaskets to obtain improved compression and squish clearance.i mainly ported the exhaust port only to suit mildly revised transfer and inlet durations ,this runs a jl3 exhaust and 30mm carb

standard gasket areas remain on inlet/exhaust and base gasket as no power gain to be found there

the 3 graphs are the std built motor from camlam in red 15.55 hp 12.7 torque(nice build just jetted safe)
the same motor after setting up on the dyno in blue 18.60 hp 14.04 torque
the same motor after stripping porting rebuilding 23.21 hp 18.87 torque

very impressive results again Darrell

[Special X]

154 inlet, 124 transfer, 174 exhaust, lowered compression reprofiled head (By MB) along with 30mm PHBH, and ScootRS exhaust worked very well indeed on my 186 Mugello. The 225 Mugello suffers from low transfer timing, along with (usually but not in the scenarios quoted above) very short inlet timing. A little bit like a std lambretta barrel thats had a bit filed off the top of the exhaust port which is why it gives std lambretta performance as is.

[Tom Russell]

Yep, as has been said previously, very impressive results Darrell!

I should imagine your waiting list for tuning is getting longer, and longer!!!

Keep up the good work, and thanks for all the info and feedback on this site, which is a wealth of information!

[Darrell Taylor]

Yep, as has been said previously, very impressive results Darrell!

I should imagine your waiting list for tuning is getting longer, and longer!!!

Keep up the good work, and thanks for all the info and feedback on this site, which is a wealth of information!

Thanks Tom
yes got lots to do plus my regular racing work,must say im enjoying the variation of work and the many cylinder configurations available on the lambretta,s is keeping my interest up,im finding out more and more and you never stop learning on a 2 stroke ,got to find time to build my own now which will be my first attempt at a race engine so can push the boundarys some,all the parts are there just no time spare as yet
the info and feedback im glad you,ve found of use

[Darrell Taylor]

154 inlet, 124 transfer, 174 exhaust, lowered compression reprofiled head (By MB) along with 30mm PHBH, and ScootRS exhaust worked very well indeed on my 186 Mugello. The 225 Mugello suffers from low transfer timing, along with (usually but not in the scenarios quoted above) very short inlet timing. A little bit like a std lambretta barrel thats had a bit filed off the top of the exhaust port which is why it gives std lambretta performance as is.

the few 225 ive worked on had almost same durations as Ian had shown 176 116 160
so the transfer and inlet timing werent short for the ex duration in use and target operating rpm
the compression was too low already so i raised it ,if yours went better with a lower comp head then it probably had too much advance or was set too lean

[Tom Russell]

This Readspeed tuned 25bhp Mugello 225 kit is now up on Ebay item 230918753269 if anyone is interested, please get in touch ASAP.

Cheers