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Interesting stuff ! Something else for me to experiment with.

Early Canadian Models, specifically the 79 did not have the clean air system The caps on the Valve cover where there but the ports in the cover were blocked with a plate and there was no plumbing. Not sure about later Canadian models.

My Vulcan 1500 has the same passive air induction system. Like everybody else, I initially blocked the hoses off with a couple of marbles and I purchased the block off plates intending to remove the entire system but I found the bike seemed to run smoother with the system operational (admittedly that could all be in my head) so eventually put it back to original (i.e. removed the marbles).

"I found the bike seemed to run smoother with the system operational (admittedly that could all be in my head) so eventually put it back to original (i.e. removed the marbles). "

That's a candid and honest comment ! It all comes down to what works for the individual person and particular bike.

Agree with Scotch here as mileage on the motor simply must come into it.

One other thing we all have to take into account here is the quality of petrol we use in our 40 year old bikes.
This differs massively in quality from country to country and brand to brand.

If I set my carbs and ignition here in the UK with regular 95 RON petrol, it runs "ok" but it runs so, so much better on the 99 RON from Shell " Ferrari Juice !"

Scotch has put a lot of thought and time into making his 1300 run as well as possible for a 40 year old bike in modern day times and keeps mentioning we cannot forget the age of the motor, carbs and ignition system we are all working with and the mileages we have covered, which is so accurate and correct and has to be taken into account when setting things up here in 2020 !

I am sure if we took the time to look at many other 40 year old vehicle Clubs and Forums we would see very similar mods and alterations taking place to keep their vehicles up to date too...................we are not alone !!

All very interesting stuff this, from people who have the time, ability and knowlege to test and try things, often with very worthwhile and satisfying results.

Pete F
UK

Pete, if using Shell Optimax 99 octane fuel, I wonder if you could safely advance your ignition timing, and in doing so gain power? I used to have an old Ford XR3i , and as an experiment I started using 99 octane, and advanced the timing a small amount. The engine perked up significantly, with no adverse effects whilst I owned it. Obviously, in these old engines without knock sensors, care has to be taken not to set too much advance.

Jim,

You are spot on with your assumption, and I have set up 1300's I have owned in the past with 99 Octane and they did run sweeter and start better.................but due to the lack of Shell Petrol Stations and Stations that sell 99 Octane up here in Northumberland and Scottish Borders where I most of my miles, I inevitably had to fill up with the regular "pond water" 95 Octane................and it ran like a bag of $hite !!

Definitely going to play around with the ignition timing over the winter when the bikes off the road and in the garage.

All the ZRX1200's I have had I have fitted with a 4 degree ignition advancer plate which makes a lot of difference generally as they dont have adjustable ignition timing.
This is a well recognised mod for ZRX1200 Owners, which is manily due to the poor quality of fuel over here in the trash can of europe.

Pete F
UK