Scooterotica

What determines the difference between a race pipe and a tour pipe ??.....I ask this question because I have been looking at the Franspeed tour pipe and cant see any difference from the race pipe in the photos. Is it just the end can or is the main body a different circumference ? Are the main bodies hollow or do they have chambers in ?......Im thinking of changing my race pipe for a tourer so thought I would ask.....
Cheers
Bizz

Others will give a better answer but my understanding is that end cans are the same (apart from fittings) for both types of pipe. The difference is in the 'tuned length' of the expantion chamber which is hollow (no seperate chambers) and is designed to reflect a pulse back to the cylinder at a particular point in the reve range. Torquey touring pipes tend to be short and fat and race pipes longer and thinner. That's my understanding but happy as ever to be corrected

The exhaust mostly determines the running characteristics of a 2 stroke engine, followed by the porting of the cylinder, intake, etc...... different tuned lengths, different cone angles, different length of stingers etc all play a part in setting the engine's performance, i.e. at what revs does the power come on, how much power, how much torque, at what revs does it stop making power, does it allow the engine to over rev beyond the optimum power curve, etc.

A touring exhaust would give power over the entire rev range but peak power at maybe 6,000 to 7,000 rpm with maybe a maximum rev capability of 8,000 or so, for reliability and drive-ability. A race exhaust would make peak power at maximum revs allowing fast top speeds and with a broad enough power and torque curve to provide drive out of the turns on a race course, with a maximum rev of say, 9,000 to 11,000 rpm for Lambretta engines. Definitely not the RPMs you'd want to "cruise" at.

Thanks for that GP Kevo I have a Franspeed Race on at the mo, but I'm not keen of the "always seems like I'm thrashing it" sound. I dont use it for thrashing around (except around Cadwell :bigsm: ) and I always seem to cruise everywhere, so thought I might give the Franspeed touring pipe a go
Bizz

bizzly wrote:.....I ask this question because I have been looking at the Franspeed tour pipe and cant see any difference from the race pipe in the photos......

If you are looking at Andy Francis website, last time I checked (a month or two back) he had the same pic on for both the JL3 and the Franspeed Race. I did tell him....

coaster wrote:Others will give a better answer but my understanding is that end cans are the same (apart from fittings) for both types of pipe. The difference is in the 'tuned length' of the expantion chamber which is hollow (no seperate chambers) and is designed to reflect a pulse back to the cylinder at a particular point in the reve range. Torquey touring pipes tend to be short and fat and race pipes longer and thinner. That's my understanding but happy as ever to be corrected

its the other way around really,torquey low revving pipes are of a longer tuned length ,racey pipes for higher revs are shorter tuned length.

Don't dismiss the 'race' ones though. The 'race' JL4 on my 185 peaked at 7200. Not exactly 'race' revs.

bizzly wrote:Thanks for that GP Kevo I have a Franspeed Race on at the mo, but I'm not keen of the "always seems like I'm thrashing it" sound. I dont use it for thrashing around (except around Cadwell :bigsm: ) and I always seem to cruise everywhere, so thought I might give the Franspeed touring pipe a go
Bizz

Bizzly, have a read through my 'Exhausts...again' thread (on the previous page). There's some info / advice regarding this subject, as I have exactly the same 'problem' with my NK rally pipe.
One suggestion was to 'up' my front sprocket by 1 tooth (at present on my ts1225 I have an SX200 box, 15x46 sprockets), which would take the final ratio from 4.8 to 4.7 (i think!? ).

The JL4, being a copy of the Taffspeed Race Group 4 exhaust, probably works better with race ported 200's and up. It works well with TS1's, especially ported ones and definitely pulls high RPM's then. I find with my TS1 Annihilator I mostly "cruise" on the jet needle. If I ride WOT then the revs continually increase as does the speed.

sean brady scooters wrote:its the other way around really,torquey low revving pipes are of a longer tuned length ,racey pipes for higher revs are shorter tuned length.

Thanks Sean, as a matter of interest, what part does the diameter of the expansion chamber play?