Scooterotica

Hi to all.

I just got a Taffspeed MK 4 Goldline for my PX and after seeking information about it I have not found anything but generic information like in Scooter Center, SIP ...

My engine is a 221 Malossi, RD reeds and Keihin 35 AS and I wonder if you could tell me the degrees of intake and exhaust most recommended for the Taffy and your impressions and tips about it.

Thanks

Any ideas about the timing?

Can anyone give me information about the function of the pitot tube that comes with the exhaust?

Up

santacama wrote:Hi to all.

I just got a Taffspeed MK 4 Goldline for my PX and after seeking information about it I have not found anything but generic information like in Scooter Center, SIP ...

My engine is a 221 Malossi, RD reeds and Keihin 35 AS and I wonder if you could tell me the degrees of intake and exhaust most recommended for the Taffy and your impressions and tips about it.

Thanks

Hi there,

I have not sold any of my TAFFSPEED Mk4 Vespa exhausts since February 2010 when I when into hospital for an operation.

If you have purchased an exhaust system after that date it is a copy from Veitnam!

That aside;
You say that you have a reed valve unit fitted? Has the crankcase been opened out to remove the sealing pad area in the case?
If this has been done then you have the potential of 360 degrees of inlet period.

Use the cylinder as manufactured, with the standard stroke crankshaft 57mm not a 60mm as you are doing - it alters the transfer & exhaust timings too much!
Fit a PX125-T5 4th gear to drop the gearing so peak power output in 4th drops from 80mph to 70mph!
If not then it is very hard to pull maximum rpm in 4th.
The cylinder head needs to be reprofiled with 18cc in the combustion chamber when the piston is dropped into the head. The squish needs to be set at 1.2-1.5mm this extra volume gives you 22.5-23.5cc when fitted. (10.3>9.9 to 1 geometric compresion)

The internal tailpipe is there to reduce noise & keep the back pressure in the exhaust system.

I hope this has been of help,

Ian Frankland
Taffspeed
Tel: 07794 003276
Email: sales@taffspeed.co.uk

Terrible Taff wrote:

santacama wrote:Hi to all.

I just got a Taffspeed MK 4 Goldline for my PX and after seeking information about it I have not found anything but generic information like in Scooter Center, SIP ...

My engine is a 221 Malossi, RD reeds and Keihin 35 AS and I wonder if you could tell me the degrees of intake and exhaust most recommended for the Taffy and your impressions and tips about it.

Thanks

Hi there,

I have not sold any of my TAFFSPEED Mk4 Vespa exhausts since February 2010 when I when into hospital for an operation.

If you have purchased an exhaust system after that date it is a copy from Veitnam!

That aside;
You say that you have a reed valve unit fitted? Has the crankcase been opened out to remove the sealing pad area in the case?
If this has been done then you have the potential of 360 degrees of inlet period.

Use the cylinder as manufactured, with the standard stroke crankshaft 57mm not a 60mm as you are doing - it alters the transfer & exhaust timings too much!
Fit a PX125-T5 4th gear to drop the gearing so peak power output in 4th drops from 80mph to 70mph!
If not then it is very hard to pull maximum rpm in 4th.
The cylinder head needs to be reprofiled with 18cc in the combustion chamber when the piston is dropped into the head. The squish needs to be set at 1.2-1.5mm this extra volume gives you 22.5-23.5cc when fitted. (10.3>9.9 to 1 geometric compresion)

The internal tailpipe is there to reduce noise & keep the back pressure in the exhaust system.

I hope this has been of help,

Ian Frankland
Taffspeed
Tel: 07794 003276
Email: sales@taffspeed.co.uk

l got my exhaust from a friend that got it from Scooter Center, is a good one, not a copy ....:]
Inlet is 360, squish 1,3, compression 10,5:1, short 4 gear, ...... but stroke is 60 and timig 126/186. Do you see any problem?

From what you say the port timingd are there should be now issues with it all working.

Ian Frankland
Taffspeed
07794 003276

Terrible Taff wrote:From what you say the port timingd are there should be now issues with it all working.

Ian Frankland
Taffspeed
07794 003276

Sorry Ian but I do not understand what you mean. If timings are to high I can lower the barrel 1 mm

Hi Santacama

If the port timings you have given of 126 trasfer & 186 exhaust are correct all should work well.

However from what I calculated I beleive that with the piston coming to the top of the cylinder you should have;

126 main transfers 47.0mm from gasket face to top of port
123 secondary transfers 47.5mm from gasket face to top of port
115 boost transfers 49.0mm from gasket face to top of port

186 exhaust 32.5mm from gasket face to top of port

The cylinder head installed volume set @ 23.0cc for a corrected comp ratio of 6.3 to 1
This requires the cylinder head to have a recess of 1.5mm for the squish clearance.

Set the ignition timing @ 18 degrees = 1.86mm btdc

Check my calculations with a degree disc on your engine case as not all crankcases are the same.

Remember to use a PX125-T5 36t 4th gear so that the engine will pull 4th much better.

Best regards

Ian Frankland
Taffspeed
07794 003276

Thanks.

My timings are correct -+1 degree y use a disc.

I will tell you how it goes.