the 3tj models 1rr and 2sp should have the same throttle housing and tube
not sure about the 6sp and 7sp, as these have flat slides but wouldn't surprise me if they had the same throttle system
you could check out the 600 3he or 4jh, probably the same or near enough, to do the job

as far as i know the standard is quick action
when adjusted properly mine has less than a 1/4 of a turn,
any quicker than that and it'd be an on / off switch

Don't the universal ones come with a few different ratios so you choose one to suit

well you learn something new every day chap now i forgot where i live

i found there's quite a few on the bay for silly money, but a google search will find you some peeps who make em for alot less
OR there's a few tutorials on how to bodge your own

venhill universal ones fit and the one i have lets you select 1/4 or 1/2 turn.

Taggy wrote:venhill universal ones fit and the one i have lets you select 1/4 or 1/2 turn.

Thread revival time, im in the process of fitting a Venhill universal QA but theres not enough space on the clipon unless starter/kill switch is removed. How did you go about fitting yours?

I fitted a mx bike universal starter/kill switch. It was a lot thinner than the one on the bars but I also had aftermarket bars. I'm not sure if they were slightly longer. But it might be worth a look? Ill see if I can get a pic of mine up later!

This could be why you see some race bikes without bar ends and the grip over sailing a little

Yes your right theres no way a venhill Q/A throttle will fit with the original bar end on and i dont want to run without it or start moving switches about as i still want the bike as original as possible, i have a pit bike Q/A throttle in the garage i'll try later and make some cables to fit otherwise is there any way of modding the stock throttle tube?

Mod the bar end.
If you buy Bike-it bar ends for a 600 or T'cat, they're aluminum so you can get them turned down to suit the throttle grip. If it's just a couple of mill then pack the bar end, I did this to fit a radial master using a nylon sump washer from a Ford, I had drill out the centre a little though