Scooterotica

you can use any piston...after all the boost port will be positioned to miss the ring pegs...
in one i use the ron moss ts1 piston,in the other i use the scooter restorations sr200 piston with windows milled in.
And jedan71,im only quoting what the mag concluded....with no other mods...just a reedblock, it was well down on power from the intitial stage4 set up

[quote="jedan71"]As a footnote. just the reedvalve alone without any piston windows reduced performance.

Camel, just jumping on the post due to your prev quote, does this mean all the after market like LTH, MB & ScootRs bolt on kits are useless unless you change the piston to be ported with a boost port barrel as well.

Would the retained crankcase pressure created by the one way valve effect of the reed valve not aid piston flow thus giving small benefits ands a fuel MPG increase and no spit back, but of course this be only optimised with a ported piston setup.


Sent from my G33M-S2 using Tapatalk[/quote
im a little confused with what your asking...
the facts were...just bolting a reed block onto a piston port set up gave no gain in fact reduced performance
the gain was achieved by cutting a window in the piston to give 360 degree inlet timing
the mag also stated further performance gains could be achieved by cutting a boost port into the barrel

Camel, meant no offense, just my own misunderstanding, would be good to learn more on the subject as I thought about using a bolt reed valve for my 175 alloy barrel.
Anyone got a electronic copy of that article? Getting hold of copies in NZ can be an effort..

YAMLAM wrote:Anybody used these ? http://beedspeed.com/lambretta-piston-2 ... -8833.html

Not a good reputation brand :

http://www.125ccsportsbikes.com/forums/ ... opic=61240

What about 225 bored indian cylinders, is there enough wall for proper boostports?

jedan71 wrote:Camel, meant no offense, just my own misunderstanding, would be good to learn more on the subject as I thought about using a bolt reed valve for my 175 alloy barrel.
Anyone got a electronic copy of that article? Getting hold of copies in NZ can be an effort..

PM sent

Ok I have taken the plunge and have started to work on my barrel, it has been rebored to accept a TS1 piston and a new 9.5:1 head from AF. I am looking at port timings in the region of 170-175 Ex, 125 Trans.

I am going to open the inlet port to resemble that of a TS1, now do I cut just a wide single boost port or two finger ports? Is there any gain to be had from 1 or 2 ports? These will end just below the level of the main transfers.

I have purchased a ScootRS reed block (small version) and the rest of the running gear is as follows - 28mm PHBH, Taffy copy exhaust, Gp 150 gearbox with 18x47 sprockets (giving 4.8 ratio, pulled well to Switzerland and back as a 200).

Any views on the boost ports greatly received, Andy

Andy W wrote:Ok I have taken the plunge and have started to work on my barrel, it has been rebored to accept a TS1 piston and a new 9.5:1 head from AF. I am looking at port timings in the region of 170-175 Ex, 125 Trans.

I am going to open the inlet port to resemble that of a TS1, now do I cut just a wide single boost port or two finger ports? Is there any gain to be had from 1 or 2 ports? These will end just below the level of the main transfers.

I have purchased a ScootRS reed block (small version) and the rest of the running gear is as follows - 28mm PHBH, Taffy copy exhaust, Gp 150 gearbox with 18x47 sprockets (giving 4.8 ratio, pulled well to Switzerland and back as a 200).

Any views on the boost ports greatly received, Andy

Have a read up on calculating the timed area of the exhaust and transfers as is. There'll be a guide on which ranges work best and this will guide you towards a transfer timed area (and hence duration and width) that is in sync with your exhaust.
The answer could be 1, 2 or 3 boost ports depending on the constraints of cylinder thickness, stud spacing, skirt layout, ring peg positions etc.

pasner wrote:......What about 225 bored indian cylinders, is there enough wall for proper boostports?

There isn't enough for same depth as a TS1, I managed to break through the wall and had a hole between the fins. Had to JB Weld a piece of ally over the hole It stayed in place for more than a season and was still in place when I retired it

YAMLAM wrote:Anybody used these ? http://beedspeed.com/lambretta-piston-2 ... -8833.html

Yes i have in two Ts's good piston i just changed the Rings to Riken ones run fine .

I wasn't up to adding a boost port on my Mugello 225. Running Atomic small reed and a Ron Moss TS1 piston with Mikuni TMX27 carb, Varitronic ignition, ADS3 exhaust and 4.7 gearing. Runs great and about 55mpg.