XS650SH 1981 Special Jetting and Mikes XS exhausts

[Chris 650]

Hi Guys

Hoping someone can help with thoughts on the following Q?

For my Special, Haynes manual Specs the standard jets on my bike as follows:
Main 132.5
Pilot 42.5

I am looking at buying Mikes commando Exhaust system PN #07-0747however in the instructions Mikes is suggesting re jetting to work with this system is.
main #142.5 to 147.5
pilot #45
air Jet #127.5

The main Jet Seems to be very high.
I have read others who have reed comments suggesting it is almost bolt on and go with no re jetting......

Can i get / advcie / help on this?
I am in Australia so want to try to get this correct first up.

Attached is the system i am looking at

Appreciate any help guys

Cheers Chris

 

[650Skull]

Hi and welcome,

If your bike is an Aussie original then it would have had/has points with BS34 carbs. The Aussie BS34's have a 336-YO Needle jet coupled with a 5lX11 Jet needle, these are now commonly known as a Canadian BS34 set up but was used outside the US in Europe, Oceania and Canada, and maybe other places as well.
After checking the jets in your carbs for confirmation on what you have, and depending on what you have, buy some extra jets , maybe one lower and 2 higher, again depends on your jetting now.

Buy original Mikuni Jets. jets R us or do a google search in Aus, Prices will scare you for here

You need to know what jetting your running now. You never know, someone else may have re-jet them sometime.

The US had heavy EPA restrictions that was mandated for their carb set up, that is part of the reason Mikes recommends the jetting change................ We did not have the same restrictions.

Uni filters or pods, (pods not recommended), or original filters. The type of filtration can have an affect on jetting as well.

Put the exhaust system on before doing any changes to any jetting. Work from a base and do one thing at a time and record the results.

A lot of electrical differences between the US and Australian XS650 Specials 80 and later, remember this when asking questions on here relating to electrical and ignition systems

 

[pete xs]

Hi Chris
The one I would use is the 142.5 mail and the 45 pilot
What inlet filters are you using
The standard air boxes
Or pods

 

[5twins]

Yes, the jetting recommendations from Mike's do seem a bit optimistic. We installed the Commando system on my buddy's '80 Special. We went one up on the pilots (#45) and two up on the mains (#137.5). We didn't change the air jet. He has UNI pods as well but two up on the mains seems to work well. I think the #45 pilots will be right for you but for mains, I would get 137.5 and 140. Try both to see what is best. If you do have the adjustable "Canadian" needle, that may need to be leaned as you increase the mains.

 

[jaybird51]

Chris, have an 81 with the same setup as you. Pipes ,pods, etc. I have mine at 45 pilot, 140 on the mains with canadian needles in the middle slot. The plugs are a nice light brown and the bike runs nice and strong. Good place to start. Jetting is always different on every bike and depends on where you live. Have fun "down under"

 

[Chris 650]

Thanks guys this is really helpful and appreciated

On the airfilters i am just using the old standard filters box system. i dont want to change to much from standard and put further Q? marks on the jetting.

I take it also the exhaust from Mikes is a good system as well?

Cheers

 

[5twins]

Yes, the Commando exhaust is very nice. I think it's one of the nicest available for this bike. That is of course, until someone starts making true universal Conti replicas, lol. I'm really surprised the Chinese haven't started doing this yet.

 

[MacMcMacmac]

I picked up a set of Commando pipes last summer for $30 in the local classified. They look and sound sweet. They do seem to be a cut above in quality as well.

 

[650Skull]

Thanks guys this is really helpful and appreciated

On the airfilters i am just using the old standard filters box system. i dont want to change to much from standard and put further Q? marks on the jetting.

I take it also the exhaust from Mikes is a good system as well?

Cheers

Doesn't make any sense to go up 4 on the mains and 1 on the pilot when you still using the Air boxes and filters. These motors have a rep for washing the bores when over jetted

Start from the original settings and work up from there.

And please report back on what you have finished up with, may help others

 

[Chris 650]

Thanks everyone for the help

just one more Q? and think I know the answer but just wanted to tap the knowledge bank to make sure.

I referred to getting Mikes commando Exhaust system PN #07-0747 which is the straight system. Thinking more on this think I might get the up swept pipes Part #07-0764 see attached.

On Mikes XS site this system doesn't have any instruction etc or year of special that it fits. I take it this system would still work & fit ok and the information you guys have already posted still applies?

Notice couple you guys are in Au, for your interest I am in Melbourne, north east Greensborough if any one was close by.

thanks again cheers chris