1975 1500TC - Rich running

[bazyerma]

Hi

My 1500TC runs really well on the road but it seems very rich, is that as it should be or should adjust the mixture (Guess via the jet adjusting screw under the carbs)?

Regards

Barry

[GTS290N]

The above image is available on many sites, I personally think the lighter "good" colours are for moderns only, they run hotter and leaner.

This is a sticky on the main forum page:https://forum.triumphdolomite.co.uk/vie ... hp?t=33830

[cliftyhanger]

Have a read of this post
https://forum.triumphdolomite.co.uk/vie ... hp?t=33830

I expect it is mentioned, but worn spindles can cause rich running (as tuned at idle to compensate for wear, but too rich at higher rpm) and you have checked it has teh correct needles? No idea which carbs are fitted, but are the jets worn? (common with early fixed needles) and are the flaot levels are correct.
Balancing and setting the linkage can be issues too.

[marshman]

A 1975 1500 TC should be running HS4 carbs ( AUD665 F & R) and ABT needles unless it is a '76 model in which case it might have slightly later carbs, still HS4's but FZX 1258 F & R. still fitted with ABT needles. Later - 1977 on - had ADN needles which are similar profile but slightly leaner.

With modern fuel it is hard to judge mixture based on spark plug "colour". Normal way is just to set the mixture at idle using "piston lift" method or use a CO monitor on the exhaust.

My main concern would be running too lean at high load/revs when damage could be done to pistons.

[GlenM]

The 1500 TC had HS2 carbs, the HS4s were fitted to the 1500 Dolomites.

[marshman]

According to the SU data book it was HS2's up to 1973 then 1974 onwards it was HS4's

[GlenM]

According to the SU data book it was HS2's up to 1973 then 1974 onwards it was HS4's

Ah! Well, I didn't know that they changed them for the last couple of years of production. I've only ever seen them with HS2s.

[bazyerma]

Hi

Thanks all, the spindles dont seem to passing, spray some brake cleaner / gas around them an no change to the idle. Will change the plugs and adjust the jets a little and see if that helps without effecting the running.

Regards

Barry

[bazyerma]

Hi

Pulled the pulls and there are ok to perfect. Pretty sure the plugs have only done a hundred miles. I plan on doing alot more miles this summer so will check again in 200 odd miles.

Regards

Barry