Oil leaking from exhaust flange

[bluesi808]

I have a polini sport 70 and a Leo zxr pipe and I noticed today I had oil leaking from the area where the exhaust flange of the zxr meets the bore. Is this normal? Also I saw that it wasnt butted up to the bore, i just installed the parts 700 miles ago. So I got out my tool kit and tightened it as much as I could. I'm wondering if it rattled loose and do other people have this prob too? The flange Is now about 2mm away from the bore I may b able tO tighten it a little bit more. But don't want to overtighten it. Is this okay? Thanks in advance

[skuttadawg]

I would get a new metal gasket and ARP studs or bolts . With exhaust leak your are lean and unable to perform as much on top end .

I am looking at Leo Vince sport and racing pipes instead of stock to be able to have higher rpms .

Can I ask your carb mm and both jet sizes as I am going to put on a 72BBK later . How many rpms can you top out at ? Whats your top speed and your weight ? I put on an unlimited CDI and it was the exact same grrrr. My dealer said maybe it needed lighter weights . Tried 4 gram was too light with 8,000 rpm limit and less on top end . After researching I was right its my pipes limit and according to the EPA tag it has a catalytic converter which limits flow .

I have a stock 49cc with 10.5 to 1 compression , mixed the stock 6 gram rollers with some of the 4s to equal 5 which works better , NGK iridium , a Japan ( unsure of brand as it does not have it stamped ) 19mm carb with 75 main jet and I can adjust the fuel/air screw since its not covered and idle can be adjusted with fingers since the screw is knurled . Plug chop its perfect jetting with airbox . I am 200 lbs and mostly hit 45 mph but can hit 50 at times and once it hit 55mph on level road . Downhill I can only go 55 mph then exhaust limitation prevents any faster speed , grrrrr .

I am wanting to hear what some have their scooter specs after mods to get an idea of what may work for me and less trial and errors . I am told a stock crank can hit 10,500 but not only in a burst and not a long duration that high . I found a forged racing crank that can go up to 18,000 rpms , yes18,000 which is Dremel tool speeds and beyond any road legal 2T , so no crank worries .

Are you air cooled or LC ?

[90GTVert]

It's normal for these small engines to vibrate all sorts of fasteners loose. The best simple setup I've found for avoiding exhaust issues is to use studs and two nuts on each stud. I don't have ARP or anything. My father works in a hardware store and I just had him order M6x1.0, 30 or 31mm length (I forget now) studs from Midwest Fasteners I believe it was. They don't stretch and bend and break like I've seen bolts do too many times.

Pick up a new gasket or two as well. That exhaust should use the ring style that compresses and sometimes you can use them over successfully, sometimes you can't.

[bluesi808]

I have a 17.5 dellorto not sure on jets as a shop called motosource tuned it. With just the springs and rollers the zxr comes with my keeway matrix would hit 60 mph but then i installed a stage 6 torque control clutch, toxik pulley, stage 6 drive face, koso torque slider, naruku clutch bell, motoforce rollers, daytona springs and torque spring.whe. I did that i had them tune it for acceleration. The top speed went down to. 53 mph at 8500rpm sometimes it hit 54 at 9300rpm, depends if there is a slight declne in the road. My weight is 180lbs but my matrix is pretty heavy. If i could start from scratch i would forget about 70 ccs and just go straight to the 90 ccs. The 70 ccs jut dont have the low end grunt im loooking for.