Scooterotica

Been having a bit of trouble jetting my TS1 - even with a rich needle (55) can't get mid range to richen up. Anyhow, phoned Andy Francis to order a richer needle and, fair play, instead of just selling me a new needle he took the time to ask a few questions and came to the conclusion that something is a miss and he suggested a leak down test. Done the test and there is evidence of leaks on two out of the four cylinder stud nuts.

What's the remedy for this? Any suggestions much appreciated

tighten them up ...... sorry. if the head is not leaking does this mean the problem is at the bottom and travelling up the barrel stud holes? i.e cracks in the casing threads or gasket.

Whenever I've had this its down to the base gasket disintegrating when the top end is torqued down especially with the thin blue AF gaskets. For this reason I tend to use the thin alloy gaskets or none at all sealed with Threebond.

If the gasket has a tear from the inner face to the stud hole gas can escape or be drawn in that way.

wack 63 wrote:Whenever I've had this its down to the base gasket disintegrating when the top end is torqued down especially with the thin blue AF gaskets. For this reason I tend to use the thin alloy gaskets or none at all sealed with Threebond.

So the best thing would be to strip top end and replace both gaskets?

Sealing the base is the only way to stop the leak, you should be ok with the head gasket but use a sealant on it.

I had the same problem recently. It was caused by a porous weld where my casings were modified to big block.

It was very obvious to the naked eye so it was easily fixed by a bit of dremmelling then filling in with jb weld.

Obviously it's only relevant if you've had welding done, but worth mentioning.

wack 63 wrote:Sealing the base is the only way to stop the leak, you should be ok with the head gasket but use a sealant on it.

When I put the engine together I wasn't happy with the squish clearance, too big, but as it was together I left it. Now I have an opportunity to remedy it. Would I be ok to use threebond only on the base and a thin alloy gasket with threebond on the head? I have noticed though that there isn't much meat around the stud holes at the base, would sealant only suffice?

you can use sealant only, yambond is very good, rayspeed do some thin alloy base gaskets in lots of thicknesses so you can set the squish just right, when i tuned my ts1 i had the barrel shortened by .5mm to lower the port timings,i only used the thinest alloy base gasket they had, then tried various head gaskets until i got the 1.5mm squish ,realy improved the driveability and power,i also added a reed packer and mb inlet manifold, was probably as quick as my rb250 when done.

I wouldn't use Threebond on the head but saying that I watched the Casa Team use it at Cadwell. I prefer Wellseal but various Loctite products can be used.