New Race tour piston gone for a burton

[clubbook]

Sorry drunkmunkey thought i'd posted carb settings. Not sure where they,ve gone!

Current settings with TS1 are
Needle - 5 EL68.3
Needle jet - not sure but one recommended by Chiselspeed for spec
Pilot 27.5
Main jet - now up to 350
Power jet - blanked off
Ram air filter

[clubbook]

Recently siezed my modified/tuned cast barrel with new MB race tour piston (ouch!) at about 45 to 50 mph, (this was after 300 or 400 miles) at reasonably high speed with no problems.

So........main jet cools efficienntly at wide open throttle, you have done 300-400 miles at high speed with no problems......but in the mid range 45-50mph (so 4000rpm-5000rpm??) it seizes.........as i say.......what are the rest of your carb settings?

Sorry drunkmunkey thought i'd posted carb settings. Not sure where they,ve gone!

Current settings with TS1 are
Needle - 5 EL68.3
Needle jet - not sure but one recommended by Chiselspeed for spec
Pilot 27.5
Main jet - now up to 350
Power jet - blanked off
Ram air filter

[soullad]

listen to yer Uncle Dan, jet for the whole of your throttle openings. And then check for air leaks?

[drunkmunkey6969]

what clip was needle on?

[clubbook]

Was middle now second from bottom

[drunkmunkey6969]

Was middle now second from bottom

And did that make it any boggier, or does it still pull OK?

[Dryballs]

Wow - those settings are richer than my TS1 with the same carb

I'd be looking for an air leak or ignition fault first of all.
Maybe take off your barrel and mag flange and just make sure everything looks OK. Maybe change your gearbox side oil seal while youre at it

Cheers,

db

[drunkmunkey6969]

Try a plug chop at WOT and same again at 1/2 throttle, i'd be interested to know if the new clip setting has cured your problem.

Also, you may have gone too heavy on the main jet whilst rying to compensate for a midrange lean spot, and if richening up the midrange has cured any lean spots, you may be able to come back down on the main. As DB says....your other settings sound very rich (both main and pilot).

If it is an air leak issue, oil seal leaks may show up as heavy white smoke from exhaust can, rough running and inability to tickover properly......place palm of your hand about 4 inches from end of can and rev scooter.....does it splatter oil all over your hand, is it bellowing smoke?

Oil seal failures/wear is quite common, when were they changed last?

Let us know how you get on.

[clubbook]

Was middle now second from bottom

And did that make it any boggier, or does it still pull OK?

Made it a little boggier

[clubbook]

Try a plug chop at WOT and same again at 1/2 throttle, i'd be interested to know if the new clip setting has cured your problem.

Also, you may have gone too heavy on the main jet whilst rying to compensate for a midrange lean spot, and if richening up the midrange has cured any lean spots, you may be able to come back down on the main. As DB says....your other settings sound very rich (both main and pilot).

If it is an air leak issue, oil seal leaks may show up as heavy white smoke from exhaust can, rough running and inability to tickover properly......place palm of your hand about 4 inches from end of can and rev scooter.....does it splatter oil all over your hand, is it bellowing smoke?

Oil seal failures/wear is quite common, when were they changed last?

Let us know how you get on.

No heavy smoking, runs really well and ticks over perfect!
Oils seals change last week, and 2 weeks before that following sieze of cast barrell. Using red double lipped Viton seals.

Have stripped engine today to find oil seals still in good condition, but gearbox oil in barrel. No cracks to casing or visible damage. But have found a discrepancy with thickness and depth of indian (SIL) gear side back plate which we think could be holding the oil seal at the wrong height. Changing this for MB one and see what happens!!

Cheers
Paul