1983 Triumph T140W 750 TSS; 8 valves & electric start!

[otherwise]

Damm, this means my identity has been reviled and you now know what i do for a living... I'm one of the good guys honestly

Sounds like you do that very thankless job, people love to put s**t on you but always call you when they're in trouble. If so good on you, ya have my respect. "one of the good guys" you say, don't put the job down, 99.9% good guys.

 

[Sea Dog]

Damm, this means my identity has been reviled and you now know what i do for a living... I'm one of the good guys honestly

Yes, Phil is top bloke, a rarity in my work unfortunately.

just to clarify, lowest notch is the top one? leaning out the fuel?

Phil guarded your identity being the gentleman he is. Of course you are one of the good guys....you frequent TT, own a few Trumpies AND own a TSS. Top bloke in my opinion .

Oooops. I meant top notch to lower the needle to lean out the mixture. I'll stick to my day job.

SD

 

[mikechev]

[/QUOTE]Oooops. I meant top notch to lower the needle to lean out the mixture. I'll stick to my day job.

SD

I thought you increased the fuel when you opened up the engines breathing?

Anyway, took her out for a quick blast today to try out the new mufflers, your right SD they transform the bike, revs more freely, faster pick up and sounds great. Did you try them on the road with the glass packing in? they do sound good but are tad loud (ish).

Oh! and the carb springs make the throttle a lot lighter, not as light as a modern bike but as you have the other mod done with the new springs your might be.


Going to a swap meet this weekend (weather permitting) still searching for a good RH side panel.

Mike

 

[Sea Dog]

Just couldn't get the Bings tuned right. Even though I got the mixture spot on for the mid range (Lots of stopping and removing plugs for a read, moving needles and adjusting float levels), things were just not right between the 3500 to 4000 rpm range. Only noticed when pulling moderate to hard in 5th gear, a surging sensation was experienced. Once over 4000, back to business.

Add to this, on one of my test runs she dropped onto one cylinder...intermittent at first then completely. Dam ! Stop, get off bike, have a think. All this test riding and I had run out of fuel ! :y148: Turn on the reserve and back home to fill up.

So off to Google and see what I can find.....(not petrol stations). First hit and I had struck gold ! The problem, slightly loose screws on the choke housing. The fix, remove choke housing, apply a thin smear of grease to both sides of the gasket, refit housing and locktite screws.

What a difference ! Not only is the surging fixed, but I have better power from 2000 rpm. Great result....and I thought it was those new better breathing Dunstall mufflers. Now I know how a dog feels after chasing its tail for two days.........great when you catch it !

 

[otherwise]

Happy dog, good on ya.

 

[mikechev]

Just couldn't get the Bings tuned right. Even though I got the mixture spot on for the mid range (Lots of stopping and removing plugs for a read, moving needles and adjusting float levels), things were just not right between the 3500 to 4000 rpm range. Only noticed when pulling moderate to hard in 5th gear, a surging sensation was experienced. Once over 4000, back to business.

Add to this, on one of my test runs she dropped onto one cylinder...intermittent at first then completely. Dam ! Stop, get off bike, have a think. All this test riding and I had run out of fuel ! :y148: Turn on the reserve and back home to fill up.

So off to Google and see what I can find.....(not petrol stations). First hit and I had struck gold ! The problem, slightly loose screws on the choke housing. The fix, remove choke housing, apply a thin smear of grease to both sides of the gasket, refit housing and locktite screws.

What a difference ! Not only is the surging fixed, but I have better power from 2000 rpm. Great result....and I thought it was those new better breathing Dunstall mufflers. Now I know how a dog feels after chasing its tail for two days.........great when you catch it !

Just got back from a long ride and had the same problems (apart from the running out of fuel) now i know what it is! Top Tip of the day SD.

Off to the shed.. on second thoughts better let the bike cool down a bit

Cheers

Mike

 

[CarlS]

Very good, SD; I am glad you found the problem. Thanks for posting the solution.

 

[DaveM]

Good on you finding that one and I can see how it can cause a lot of head scratching

 

[grandpaul]

Sounds similar to the Mk II carbs; when the enricher pluger's rubber tips get hard and cracked, they leak fuel when the "choke" is off! Easy fix, but many an hour wasted troubleshooting unless you know what to look for.

 

[Sea Dog]

Arrrh. Right hand spark plug thread stripped in the head. It had been feeling a little doughy when setting up the tuning and finally called it quits. Left hand one went about 6 months ago and had no problems fitting a heli coil in situ. This time I will remove the head as I need to replace the push rod tube O rings as they are starting to weep. All part of the fun owning a classic.

 

[DaveM]

This is a stickler as if you do the wrong thing that plug will over heat and burn the piston, don't ask how I know this

 

[Sea Dog]

This is a stickler as if you do the wrong thing that plug will over heat and burn the piston, don't ask how I know this

That sounds interesting Dave. Could you please explain this. Last thing I need is a hole in the piston.

SD

 

[DaveM]

Well from what happens to me I put inserts in to compensate for the threads being stripped. The compound of the insert was different to what the head was so the plug overheated and melted a nice whole in the piston. Now as you know this causes other issues as you now have all that molten metal going down into the motor and that then needs to be sorted out. This was many years back so the actually details I cannot now recall but I thought it may be worth a mention

 

[Sea Dog]

Dave,

You have solved a mystery for me. When I was seriously into tuning the surging out of the TSS, the left hand plug (one with the steel heli coil ) was reading slightly hotter on the insulator than the right hand plug (screwed directly into the original aluminium thread)

When I get it running again with the new heli coil I will carefully read the plugs and see if they are both the same and expect them to be a little hot.

Thanks Dave, a nice pearl of wisdom. I'll let you know how it goes.

SD

 

[DaveM]

Yes please do as I say it was a long time back but I sure remember it

 

[devo]

hmmm...
so its obviously down to the heat conductivity of the steel coil over the origonal ali thread.
I also wonder if threadlocking compounds would have an effect.

 

[otherwise]

I'm a little surprised that heat conduction as described could cause that holed piston. I'd be thinking not sealed properly causing excessive leanness but these old girls are funny things and can stop for reasons still unexplained.

 

[grandpaul]

I'm also skeptical about heat conductivity from a thread insert holing a piston...

 

[DaveM]

Well it happened and I went through about 3 sets before we found out why it was doing this and this is why I remember it Removed the inserts had the plugs welded closed and then redone and it was sorted. Each time this did happen I was on a long run of some sorts so the prolonged ride seemed to do it. Also remember I was living in an area that would have average temps of around 35 degree Celsius = 95 degree Fahrenheit during the summer periods

 

[grandpaul]

And you are certain it was not ill-fitting inserts allowing flow between the base metal (incorrectly re-threaded) and thread insert, to affect the mixture, leaning it out?