Scooterotica

J1MS wrote: Hello mate, nice to hear its running...

Runs real well, except for the blowback. If it was mine, i'd prolly not worry to much and just turn fuel off before ignition, which I do anyway, but this has to go to someone and to tell a customer that they have to turn fuel off is not good. I tell customersto do the fuel/igniton thing when I sign off on any scoot/motor, but that is just advise, not something that has to be done, if you get my drift.
Don't really want to downjet the idle circuit as I feel when coming back to idle after a good thrashing, she might lean out.
What to do, what to do

wasn`t this thread was it.http://scooterotica.org/tempforum/viewt ... f=7&t=5952" onclick="window.open(this.href);return false;

I've run a few weisco190's and it works well with tv175 crank and a 2mm packer plate. gives good torque with the right porting and carb. with a sx crank it requires milling top and bottom of barrel.

Wouldn't it be simpler to pop a racetour piston in it for excellent reliability at that state of tune? I'm pretty sure they'll have the correct size and crown height.

Special X wrote:Wouldn't it be simpler to pop a racetour piston in it for excellent reliability at that state of tune? I'm pretty sure they'll have the correct size and crown height.

Not really, Wiseco's are cheap over here . If I would have bought a packer instead of making one(and failing miserable on the first one made), it would have been no different than just a standard overbore.

Back to ma' blowback. Could this be being caused by how much the piston skirt clears the inlet at TDC, about 6mm? I bought the idle down to 47 and it's still doing it on two different carbs. No way I am dropping the idle to 45. BTW, timing is at 21, strobed at about 3-4k rpm.

I always set my electronic ignition to 19 degrees. but depends on compression.

the fuel standoff could be cured by a weaker slide, unless the inlet timing is a tad too much i wouldnt worry

if you dont want to go up to 64mm you could use a suzuki ep 175 piston.
same dimentions as er/ts 185 just smaller ie they start at 62 mm and go up to 64 mmthen after that just move on to the ts 185 piston.if used on your tv crank you should be able to use some quite conservative port timings.pretty much standerd.

grimspeed wrote:if you dont want to go up to 64mm you could use a suzuki ep 175 piston.
same dimentions as er/ts 185 just smaller ie they start at 62 mm and go up to 64 mmthen after that just move on to the ts 185 piston.if used on your tv crank you should be able to use some quite conservative port timings.pretty much standerd.

Thanks for that info. It does seem a shame to have to go to 64mm, leaving all that valuable Innocenti steel in a pile of dust on the boring bar

Just buy an alloy one and have it cleaned up / ported. You'll be glad someday that you did.