Mugello 225 Port Timings

[Tom Russell]

Hi all,

Helping a mate to try improve a Mugello 225 engine, though I'm a bit out of touch with things, so need some help from you guys!

I think the 225 barrel and head are one of the early versions, with 4 small dowels used to locate the head, and with the spark plug precariously close to the frame!

Anyway, I've done a few searches on here and other forums, and it appears these kits didn't/don't perform too well out of the box, and this ties in with when I recently rode it, with it feeling quite flat (for want of a better description).

Even though we've stripped the motor, and all appears ok, I haven't got the engine on the bench as yet, to measure the current port timings etc. (if I can remember how to do it?? ), but assume they are standard and that no one has as yet got their dremel on the barrel (though I did notice that the base of the cylinder has the number 570 etched into it - is this just a production number?!).

He is currently using a ScootRS/PM copy pipe and a 35mm TMX Mikuni, and there isn't really the funds to change/improve on these at the moment. Though if there was, I'd probably be trying to persuade him to go for a JL4 race pipe, which I seem to remember worked really well on piston port motors (though is there anything else out there now which is generally recognised as a better power pipe?).

So, initially, we are are just looking at the most cost effective way of improving the engine/kit - mainly to be used for blasting around town and fast dual carriageway riding (not really looking for a touring/rally set up), and therefore looking for some help from our resident experts on here to try and achieve this?!

Fitment of 60 stroke crank would seem to improve the port timings, but then that might be a bit expensive (what's the best budget 60mm crank for this type of motor and cost??).

So, what do you all reckon, get the barrel ported?? And if so, I'd be very interested to know what the desired port timings would be to work best with the ScootRS/PM copy pipe (or the JL4 race, if I can persuade him to stretch to this), because as mentioned previously I really can't remember (from my previous racing days etc.) what numbers we should be looking at??

Finally, as I know he's going to ask me, what sort of bhp/torque output are we likely to achieve from this - hopefully improved - set up??

Thanks in advance,

Tom

[coaster]

Others will have better advice on port timmings but there would be no point in splashing out on a JL4 unless the timings are addressed. The ScootRs pipe is quite revy so is not suited to the Mugello's very conservative port timings, a JL3 or even a clubman would probably improve matters.

[Tom Russell]

Others will have better advice on port timmings but there would be no point in splashing out on a JL4 unless the timings are addressed. The ScootRs pipe is quite revy so is not suited to the Mugello's very conservative port timings, a JL3 or even a clubman would probably improve matters.

Yep, totally agree with you - though maybe I didn't make it very clear - but we most definitely want to sort the port timings to make the kit work better with the current ScootRs pipe (or maybe JL4)

[Darrell Taylor]

the early kits had a piston ring peg location that causes a problem even on std cylinders so draw the peg location on the crown and check it doesnt run on the edge of the transfer port,if it does then swapping for the later piston will sort it as the pegs have been moved round more to the rear these also have the hole for the boost port so if u wish u can add a boost port too

if your looking for bang for buck tuning then the crank id forget as will be labour intensive and add little to power output
cylinder tuning and a modified head will add good power but only if it has a good pipe to work with it so id look at the money you can obtain from selling the scoot rs pipe and deduct that from the price you can buy a jl4 be it new or 2nd hand then the 3 to 4 bhp gain youll see will represent very good value for money and then power can be released from the tuning work
22 to 28 bhp should be achieveable depending on the power delivery desired

[Terrible Taff]

Hi all,

Helping a mate to try improve a Mugello 225 engine, though I'm a bit out of touch with things, so need some help from you guys!

I think the 225 barrel and head are one of the early versions, with 4 small dowels used to locate the head, and with the spark plug precariously close to the frame!

Anyway, I've done a few searches on here and other forums, and it appears these kits didn't/don't perform too well out of the box, and this ties in with when I recently rode it, with it feeling quite flat (for want of a better description).

Even though we've stripped the motor, and all appears ok, I haven't got the engine on the bench as yet, to measure the current port timings etc. (if I can remember how to do it?? ), but assume they are standard and that no one has as yet got their dremel on the barrel (though I did notice that the base of the cylinder has the number 570 etched into it - is this just a production number?!).

He is currently using a ScootRS/PM copy pipe and a 35mm TMX Mikuni, and there isn't really the funds to change/improve on these at the moment. Though if there was, I'd probably be trying to persuade him to go for a JL4 race pipe, which I seem to remember worked really well on piston port motors (though is there anything else out there now which is generally recognised as a better power pipe?).

So, initially, we are are just looking at the most cost effective way of improving the engine/kit - mainly to be used for blasting around town and fast dual carriageway riding (not really looking for a touring/rally set up), and therefore looking for some help from our resident experts on here to try and achieve this?!

Fitment of 60 stroke crank would seem to improve the port timings, but then that might be a bit expensive (what's the best budget 60mm crank for this type of motor and cost??).

So, what do you all reckon, get the barrel ported?? And if so, I'd be very interested to know what the desired port timings would be to work best with the ScootRS/PM copy pipe (or the JL4 race, if I can persuade him to stretch to this), because as mentioned previously I really can't remember (from my previous racing days etc.) what numbers we should be looking at??

Finally, as I know he's going to ask me, what sort of bhp/torque output are we likely to achieve from this - hopefully improved - set up??

Thanks in advance,

Tom

Hi Tom

Just prepped a 225 for a customer. At first the port trimmings were very odd! (No base gasket)
176' Exhaust
116' Transfers
160' Inlet

Piston came to top of the cylinder just short of 0.2mm, decided to use 1.5mm pack plate under the cylinder to reduce the inlet period & advance the exhaust & transfers.

180' exhaust
126' transfer
154' inlet

Now the set up of the scooter was a 25mm Dellorto through a modified air box & a Gori exhaust.
Power output 15.6bhp @ rear wheel with a good wide spread of power from 5000 to 8000rpm!
Well impressed due to the air box being used & an easy 75-80mph potential.

The spark plug position being close to the frame tube was the only issue but got around the standard NGK cap not fitting by using a rubber NGK cap. Not what you expect from a kit costing a lot of money!

Depends how much power you want, this is a good touring setup with no fuel spillage over the paintwork & looking very close to standard at first glance!
This gives a 60% improvement over the standard SX200.

Ian Frankland
Taffspeed
07794 003276

[Tom Russell]

the early kits had a piston ring peg location that causes a problem even on std cylinders so draw the peg location on the crown and check it doesnt run on the edge of the transfer port,if it does then swapping for the later piston will sort it as the pegs have been moved round more to the rear these also have the hole for the boost port so if u wish u can add a boost port too

if your looking for bang for buck tuning then the crank id forget as will be labour intensive and add little to power output
cylinder tuning and a modified head will add good power but only if it has a good pipe to work with it so id look at the money you can obtain from selling the scoot rs pipe and deduct that from the price you can buy a jl4 be it new or 2nd hand then the 3 to 4 bhp gain youll see will represent very good value for money and then power can be released from the tuning work
22 to 28 bhp should be achieveable depending on the power delivery desired

That's brilliant, thanks Darrell, exactly the sort of feedback I was looking for!

[Tom Russell]

Hi all,

Helping a mate to try improve a Mugello 225 engine, though I'm a bit out of touch with things, so need some help from you guys!

I think the 225 barrel and head are one of the early versions, with 4 small dowels used to locate the head, and with the spark plug precariously close to the frame!

Anyway, I've done a few searches on here and other forums, and it appears these kits didn't/don't perform too well out of the box, and this ties in with when I recently rode it, with it feeling quite flat (for want of a better description).

Even though we've stripped the motor, and all appears ok, I haven't got the engine on the bench as yet, to measure the current port timings etc. (if I can remember how to do it?? ), but assume they are standard and that no one has as yet got their dremel on the barrel (though I did notice that the base of the cylinder has the number 570 etched into it - is this just a production number?!).

He is currently using a ScootRS/PM copy pipe and a 35mm TMX Mikuni, and there isn't really the funds to change/improve on these at the moment. Though if there was, I'd probably be trying to persuade him to go for a JL4 race pipe, which I seem to remember worked really well on piston port motors (though is there anything else out there now which is generally recognised as a better power pipe?).

So, initially, we are are just looking at the most cost effective way of improving the engine/kit - mainly to be used for blasting around town and fast dual carriageway riding (not really looking for a touring/rally set up), and therefore looking for some help from our resident experts on here to try and achieve this?!

Fitment of 60 stroke crank would seem to improve the port timings, but then that might be a bit expensive (what's the best budget 60mm crank for this type of motor and cost??).

So, what do you all reckon, get the barrel ported?? And if so, I'd be very interested to know what the desired port timings would be to work best with the ScootRS/PM copy pipe (or the JL4 race, if I can persuade him to stretch to this), because as mentioned previously I really can't remember (from my previous racing days etc.) what numbers we should be looking at??

Finally, as I know he's going to ask me, what sort of bhp/torque output are we likely to achieve from this - hopefully improved - set up??

Thanks in advance,

Tom

Hi Tom

Just prepped a 225 for a customer. At first the port trimmings were very odd! (No base gasket)
176' Exhaust
116' Transfers
160' Inlet

Piston came to top of the cylinder just short of 0.2mm, decided to use 1.5mm pack plate under the cylinder to reduce the inlet period & advance the exhaust & transfers.

180' exhaust
126' transfer
154' inlet

Now the set up of the scooter was a 25mm Dellorto through a modified air box & a Gori exhaust.
Power output 15.6bhp @ rear wheel with a good wide spread of power from 5000 to 8000rpm!
Well impressed due to the air box being used & an easy 75-80mph potential.

The spark plug position being close to the frame tube was the only issue but got around the standard NGK cap not fitting by using a rubber NGK cap. Not what you expect from a kit costing a lot of money!

Depends how much power you want, this is a good touring setup with no fuel spillage over the paintwork & looking very close to standard at first glance!
This gives a 60% improvement over the standard SX200.

Ian Frankland
Taffspeed
07794 003276

Hi Ian,

Thanks for your reply!

The engine is for Denbigh, who says "hello"!

I think we are going to go down the JL4 route, so any idea what sort of port timings would work best with this pipe. We are NOT looking to go full race spec, just a set up that compliments and works well with the pipe on the road.

Cheers,

Tom

[camel]

i think the head could be swapped too...ive the same kit which im goin to put on a bike,like terry sais the barell needs jacking up,but the combustion bowl on my head is massive so going to change mine when i build it

[Tom Russell]

Hi all,

Just thought i'd post an update on the Mugello engine that we've put together for my mate Denbigh.

Jerome at Readspeed worked his magic on the barrel - mainly to address the port timing issues - which now uses a thin packer on the base (probably about 1-1.5mm thick) and he's also done some work on the original head.

So, along with the original Mikuni TMX 35mm carb, and a JL4 exhaust, we now have 25bhp (and 18lbs torque) on the Readspeed dyno, and according to Denbigh it's lovely to ride.

He's now considering a reedvale - especially after reading the article in latest Scootering - mainly to save on fuel costs, but for now, as you can imagine, he is well happy and going to enjoy

Cheers,

Tom

[Darrell Taylor]

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