Mikes xs650 breather valve.

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Depends on how much oil you get out the breather before fitting the valve, if its wet sumped a small hole is not going to help anyway.
 
marinatlas said:
Hi is that so necessary to drill the small hole inside to let oil by pass ?
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I think that's an old swooshdave idea. My opinion is that if your blowing that much oil through your breather, it can't be breathing all that well and you have other (lets say 1972 type) issues. Raise it up is what I say. So many try to split hairs. For goodness sake, we're just trying to relieve a little pressure to stop leaks, not create a perpetual motion motor.

If you really want a performance boost, try a low carb diet. I dropped 45 pound off my bike that way.
 
I tried low Carb but got more power with twin Carb.
Low Carb with single Carb just made me cranky and slow :mrgreen:

Glen
 
Hi kommando, thanks , that's just because most of the "Mikes" I had fitted on my bikes were without holes, the Comstock one on my Seeley do not have any, but the last one I had picked up at Holland Norton Work for a friend had one drilled , as per Mikes advise on his site ...!

https://www.mikesxs.net/pdf/manuals/15-0677.pdf
 
I just checked out Mike's installation instructions.
I always thought PVC was a type of plastic (polyvinyl chloride) :evil:
 
worntorn said:
I tried low Carb but got more power with twin Carb.
Low Carb with single Carb just made me cranky and slow :mrgreen:

Glen
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Hi ya Glen,
I can't argue with what you say and common sense should surely dictate any conclusion.
However, I will reiterate. I have ran twin 30mm amals, 32mm amals' 32 JS flatside Keihins and brand new 32mm Premiers all with a full array of jettings and settings and none can compare to the single 40mm Mikuni tm.
I wish you and others could ride my bike to redline or a nice cruise at 90mph, you just might sing a different tune if your pride will let you.

There is no real argument here for this may be unique to my cam/head configuration (JS1, slightly modified RH1) which is really nothing extra ordinary. The fact that no one else has tried this but me, others are left to assume that I am full of shit. I am sorry, sorry that no one else has the fortitude or balls to give it a shot. I do know user BAZ is running the 36mm of this type with the same success.

I realize that I should probably be PMing you this response but it is the useful end of this thread so what the heck.
You opened the door,
Cheers, Peter
 
One of these days I will give it a try. Bought an 850 project today, it might be a good one to fit a large single Carb to.
Actually, I don't doubt that the large single Carb works well.

It's just that you mentioned something about low Carbs and I could't resist....

Glen
 
pete.v said:
worntorn said:
I tried low Carb but got more power with twin Carb.
Low Carb with single Carb just made me cranky and slow :mrgreen:

Glen
Click to expand...
Hi ya Glen,
I can't argue with what you say and common sense should surely dictate any conclusion.
However, I will reiterate. I have ran twin 30mm amals, 32mm amals' 32 JS flatside Keihins and brand new 32mm Premiers all with a full array of jettings and settings and none can compare to the single 40mm Mikuni tm.
I wish you and others could ride my bike to redline or a nice cruise at 90mph, you just might sing a different tune if your pride will let you.

There is no real argument here for this may be unique to my cam/head configuration (JS1, slightly modified RH1) which is really nothing extra ordinary. The fact that no one else has tried this but me, others are left to assume that I am full of shit. I am sorry, sorry that no one else has the fortitude or balls to give it a shot. I do know user BAZ is running the 36mm of this type with the same success.

I realize that I should probably be PMing you this response but it is the useful end of this thread so what the heck.
You opened the door,
Cheers, Peter
Click to expand...

But how good would it be with TWO 40mm TM pumpers ?

Yeah baby ...!!!
 
My old SU conversion used a 1.75" carb and whilst it's not a performance mod, that's 44mm ish
 
pete.v said:
worntorn said:
I tried low Carb but got more power with twin Carb.
Low Carb with single Carb just made me cranky and slow :mrgreen:

Glen
Click to expand...
Hi ya Glen,
I can't argue with what you say and common sense should surely dictate any conclusion.
However, I will reiterate. I have ran twin 30mm amals, 32mm amals' 32 JS flatside Keihins and brand new 32mm Premiers all with a full array of jettings and settings and none can compare to the single 40mm Mikuni tm.
I wish you and others could ride my bike to redline or a nice cruise at 90mph, you just might sing a different tune if your pride will let you.

There is no real argument here for this may be unique to my cam/head configuration (JS1, slightly modified RH1) which is really nothing extra ordinary. The fact that no one else has tried this but me, others are left to assume that I am full of shit. I am sorry, sorry that no one else has the fortitude or balls to give it a shot. I do know user BAZ is running the 36mm of this type with the same success.

I realize that I should probably be PMing you this response but it is the useful end of this thread so what the heck.
You opened the door,
Cheers, Peter
Click to expand...
Actually it's a tm40 I had on my commando it's not fitted at the moment as I resorted back to twin amals because I have a knee and foot problem and starting the bike is much easier with the amals , maybe 1 or 2 kicks but with the TM it can be between 2 or 3 to maybe 7 or 8 kicks,as soon as I can I will re fit the TM ,it definitely gives my bike more power between 0 and around 110 mph on my commando which is a stock 750 motor it will pull into the red easily if I want it to,I have had lots of different carbs on this bike including a single 32 CV a 34 VM then a 36 VM etc but they don't come close to the 40mm flatslide mikuni pumper for power I just wish it started better!!!!
 
Getting back to Mikes breather valve, reading thru old threads here it seems that as with carbs, there are two camps. There are those that say the breather eliminated oil leaks and those that say it made no improvement.
I guess if the oil leak is severe it needs to be fixed, a breather valve alone can't do it.

Glen
 
baz said:
Actually it's a tm40 I had on my commando it's not fitted at the moment as I resorted back to twin amals because I have a knee and foot problem and starting the bike is much easier with the amals , maybe 1 or 2 kicks but with the TM it can be between 2 or 3 to maybe 7 or 8 kicks,as soon as I can I will re fit the TM ,it definitely gives my bike more power between 0 and around 110 mph on my commando which is a stock 750 motor it will pull into the red easily if I want it to,I have had lots of different carbs on this bike including a single 32 CV a 34 VM then a 36 VM etc but they don't come close to the 40mm flatslide mikuni pumper for power I just wish it started better!!!!
Click to expand...

I cannot recall the last time it took more than 1 kick to start. I twist the throttle twice, push it through once key off and away I go. When starting hot I just kick it and go. I will say this, it sure starts better with the Smartfire over the Maggy.

It was 60 degrees in Michigan Saturday. It hadn't started since the warm up we had in December. "1 kick only, Ryan" An awesome 50 mile jaunt in a Michigan January? Killer.
 
worntorn said:
Getting back to Mikes breather valve, reading thru old threads here it seems that as with carbs, there are two camps. There are those that say the breather eliminated oil leaks and those that say it made no improvement.
I guess if the oil leak is severe it needs to be fixed, a breather valve alone can't do it.

Glen
Click to expand...
I sure agree with that. Due diligence needs to be taken on all assemblies.
 
worntorn said:
Getting back to Mikes breather valve, reading thru old threads here it seems that as with carbs, there are two camps. There are those that say the breather eliminated oil leaks and those that say it made no improvement.
I guess if the oil leak is severe it needs to be fixed, a breather valve alone can't do it.

Glen
Click to expand...
since i built my 750 from parts i have always had a reed valve from an acetylene torch fitted to the timing cover thats tee'd to the timed camshaft breather pipe then back to the oil tank, had this setup for over 20 years never really had an oil leak even with a very worn out bore,unlike my previous 850 commando, but good engine breathers can only help matters they will never replace careful engine assembly
 
pete.v said:
baz said:
Actually it's a tm40 I had on my commando it's not fitted at the moment as I resorted back to twin amals because I have a knee and foot problem and starting the bike is much easier with the amals , maybe 1 or 2 kicks but with the TM it can be between 2 or 3 to maybe 7 or 8 kicks,as soon as I can I will re fit the TM ,it definitely gives my bike more power between 0 and around 110 mph on my commando which is a stock 750 motor it will pull into the red easily if I want it to,I have had lots of different carbs on this bike including a single 32 CV a 34 VM then a 36 VM etc but they don't come close to the 40mm flatslide mikuni pumper for power I just wish it started better!!!!
Click to expand...

I cannot recall the last time it took more than 1 kick to start. I twist the throttle twice, push it through once key off and away I go. When starting hot I just kick it and go. I will say this, it sure starts better with the Smartfire over the Maggy.

It was 60 degrees in Michigan Saturday. It hadn't started since the warm up we had in December. "1 kick only, Ryan" An awesome 50 mile jaunt in a Michigan January? Killer.
Click to expand...
so do you use the choke ? do you open the throttle as you kick it over? the only way mine will start is ignition off full choke on kick through twice then ignition on kick again with no throttle and sometimes it will start,if i pump the throttle twice it will wet the plugs ,also when its warm its difficult to start, these problems disappeared when i re fitted the twin amals
 
I used a Motormite 80190 check valve for years. $2.50 from my local auto parts store. Cheaper and easier to mount than the Mikes XS unit. Worked great but a friend gave me a Mikes valve for Christmas a couple of years back so that's what I have used for the last 20,000 miles. They both work equally well.
 
baz said:
so do you use the choke ? do you open the throttle as you kick it over? the only way mine will start is ignition off full choke on kick through twice then ignition on kick again with no throttle and sometimes it will start,if i pump the throttle twice it will wet the plugs ,also when its warm its difficult to start, these problems disappeared when i re fitted the twin amals
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Choke only when really cold. I have back off the accelerator pump linkage by about 2/3rds, a lot. Just don't need it all that much that it offers, a little is enough.
I swear, starting is never an issue, cold hot or otherwise. I will take a video and post it to you soon, when its much colder for effect.
 
Torontonian said:
Both valves are great. The Motomite costs less than a bar beer.
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Marked difference between the two. One's a placebo, the other actually reduces crankcase pressure.
 
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