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#115484 - 05/09/07 12:55 am Lost power 20 km from home - help needed, thx  
Joined: Feb 2006
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Matthew in TO Offline
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Matthew in TO  Offline
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Toronto, Ontario, Canada
Well, here I am riding along the Saint John River in New Brunswick, Canada, making my way home after a visit to Gagetown (see http://www.villageofgagetown.ca/ ) and a trip across the Jemseg cable ferry.

So, I'm riding at about 90 kph at a steady 5,000 - 6,000 rpm in top gear when all of a sudden I loose power. The motor's still running, but I'm getting very little or no response from the throttle. At first I thought I'd ran out of gas, but could still hear the exhaust, which was now making a very deep tuba-throaty noise, almost as if I had a hole in the side of my exhaust pipe. So, I coast to a stop, and with the clutch in, the motor dies entirely.

My next thought was that I had seized a piston, and perhaps the power loss was that only one piston was firing. So, I put her in neutral and got her started, which required constant full open throttle, otherwise the engine would die again in idle. I checked both exhaust pipes, and both were firing nicely, with no smoke. Next I checked the oil return, and it was functioning fine.

So, with no cell phone and myself stuck on a country road in the middle of nowhere, I fired up the motor again, kept her at full throttle and headed home, staying on the shoulder. As I changed up gears, the rpms never exceeded 4,000 rpm, even at full throttle (even in first gear), while the throaty-tuba like noise from the exhaust continued. The motor sounded like it was working extremely hard, while not exceeding 4,000 rpm and having trouble even in third gear of climbing the simpliest of hills. All the while, my top speed in this condition could not have exceed 50-60 kph, on roads signed for 90 kph or more. On some of the level roads in 4th gear and travelling at about 50 kph the motor would start to stall (likely due to the low rpms, even though I've got the throttle wide open) forcing me to drop down to third (without reducing the throttle) to get the speed back up before I went back to 4th.

Then after almost 45 minutes of this torture, I finally reach my homebase of Fredericton, which means traffic lights and stop signs. Problem is, as soon as I slow downto below about 20 kph, even will full clutch in and the motor rev'ing the engine dies, requiring me to dismount, shift into neutral, open the throttle fully and kickstart again, making a huge noise, but again, no smoke, and she starts perfectly every time, firing on both cylinders, but again with the tuba-hole-in-the-pipe exhaust tone. Good news is that I made it home, in time for an earful from the better half re. being over an hour late.

So, I'd welcome any advice (on the bike, not marital). My next thought was that my throttle cable has slipped, or that something is blocking the single carb, or perhaps the timing's off (due to my oil drip from the points cover perhaps). So, before I start pulling plugs, cables, fuel filters (I'd just filled up at a country fill station) and carbs, please help. Thanks. We've got to get this bike on the road in time for the CVMG Rally in Paris, Ontario, June 15-17.


1970 Triumph T100S (1969 T100S motor)
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#115485 - 05/09/07 1:10 am Re: Lost power 20 km from home - help needed, thx  
Joined: Apr 2006
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Colin_In_Ottawa Offline
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Ottawa Canada
Yesterday you retorqued the head and adjusted valves? Could the valves be too tight? Or did one adjuster on the exhaust side slack off so much that the valve is barely opening?
I would suspect something related to the day before.


*******************************
70 Bonnie
70 T100s Bobber
07 Bonnie
10 Tbird
#115486 - 05/09/07 1:12 am Re: Lost power 20 km from home - help needed, thx  
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T120C Offline
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Central Virginia
Matthew, my first two thoughts are that you gas line is clogged, maybe at the entrance to the carb, or if you have an inline filter... my second is maybe a jumped push rod... You did not say what kind of bike, but I had the jumped push rod on a tr6 once... same thing loss power, then after kicking it over about 100 times, I guess it jumped back and the bike would ride fine again, for about 10 miles then the same symptoms again... Compression test should help in diagnostics..., also cleaning the line is easy work and since you are experiencing the symptoms all the time, you will know when you stumble across something... Good luck, let us know what you find...

Jack


Jack
1967 MGB Roadster..
1959 Bonnie
#115487 - 05/09/07 1:32 am Re: Lost power 20 km from home - help needed, thx  
Joined: Feb 2006
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Matthew in TO Offline
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Matthew in TO  Offline
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Toronto, Ontario, Canada
I readjusted the valves today before the ride, since they were too loose from the first attempt (after my retorque), but did it correctly this time. The bike ran great for over three hours today at full revs before this.

The bike's motor is a 1969 T100S Tiger 490cc single carb in a 1970 frame. The motor was rebuilt in December. The rebuild included all new push rods, since I had one that was bent and spawling metal frag into the oil pump, causing wet sump. Pistons are new as well, as are connecting rod bushings. Main bearing were okay at the rebuild.


1970 Triumph T100S (1969 T100S motor)
#115488 - 05/09/07 1:38 am Re: Lost power 20 km from home - help needed, thx  
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triumphguy Offline
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Winchester Tn.
Check for bent push rod

#115489 - 05/09/07 1:39 am Re: Lost power 20 km from home - help needed, thx  
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Matthew in TO Offline
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Matthew in TO  Offline
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Toronto, Ontario, Canada
Quote:
Originally posted by Colin_In_Ottawa:
Yesterday you retorqued the head and adjusted valves? Could the valves be too tight? Or did one adjuster on the exhaust side slack off so much that the valve is barely opening?
I would suspect something related to the day before.
I'll have a look at valves and adjusters in the morning and report back.


1970 Triumph T100S (1969 T100S motor)
#115490 - 05/09/07 1:45 am Re: Lost power 20 km from home - help needed, thx  
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Matthew in TO Offline
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Matthew in TO  Offline
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Toronto, Ontario, Canada
Quote:
Originally posted by triumphguy:
Check for bent push rod
How? Do I have to pull the head? That's beyond my skill and tool kit.


1970 Triumph T100S (1969 T100S motor)
#115491 - 05/09/07 2:26 am Re: Lost power 20 km from home - help needed, thx  
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Mark Z Online content
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Mark Z  Online Content
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To check the pushrods, you don't have to remove the head, just the rocker boxes.

Also to check: 1. Stuck advance unit (if bike has original breaker point ignition). 2. Water or other contaminents in the float bowl. 3. Clogged pilot jet or air passage. (The idle circuit contributes to correct fuel metering even at low throttle openings.)

This may sound like a funny analogy, but one of my lawn tractors just did a similar thing, would only run at full throttle, with no load... turned out to be water and other crud in the float bowl (that tractor hadn't been run in two years). Cleaned it all up and now it runs fine.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
#115492 - 05/09/07 2:28 am Re: Lost power 20 km from home - help needed, thx  
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highway Offline
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hamilton on. can.
On a previous post you mentioned that the mechanic who rebuilt your engine had abandoned you.
After reading of the 45 minutes of torture you dealt to this sick bike, I can understand why. Best wishes for the bike, Rick.

#115493 - 05/09/07 2:54 am Re: Lost power 20 km from home - help needed, thx  
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trumpetloon Offline
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georgia
"I had just filled up"... check float bowls first... water does not burn very well! And ignore highway's response; even a new top end is cheaper than facing the wrath of "She Who Will Be Obeyed"!!!! wink


1974 TR5T
#115494 - 05/09/07 3:04 am Re: Lost power 20 km from home - help needed, thx  
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Matthew in TO Offline
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Matthew in TO  Offline
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Toronto, Ontario, Canada
Quote:
Originally posted by trumpetloon:
"I had just filled up"... check float bowls first... water does not burn very well! And ignore highway's response; even a new top end is cheaper than facing the wrath of "She Who Will Be Obeyed"!!!! wink
Thanks. I'll start checking tomorrow. No worries, there's one at every party.


1970 Triumph T100S (1969 T100S motor)
#115495 - 05/09/07 3:04 am Re: Lost power 20 km from home - help needed, thx  
Joined: Jan 2007
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AussieOn81Bonne Offline
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Hey there Matthew,

On a previous post you stated that you had idle problems (i think so anyway something along with tapping at revs after valve guide check??) i would think that this could be your problem as a blocked pilot jet can have this outcome. I too have had a similar thing happen and after a thorough carb clean all was well. If it were me i would ensure that i check the simplest explination first, then monkey around with rockerboxes and pushrods.

Parko


Once was blind but now can see
81 T140E
50's T'Bird
#115496 - 05/09/07 1:24 pm Re: Lost power 20 km from home - help needed, thx  
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Matthew in TO Offline
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Matthew in TO  Offline
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Toronto, Ontario, Canada
Thanks Parko. I'll check the carb, plus the valve clearances before I start taking apart the rocker boxes.

How do I clean the carb? My manual says use gasoline and a brush. I could use the gasoline outside in a basin, and an old toothbrush.

Quick question...is it possible for the throttle cable to slip or do they simply break?


1970 Triumph T100S (1969 T100S motor)
#115497 - 05/09/07 1:37 pm Re: Lost power 20 km from home - help needed, thx  
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BSACafe Offline
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Saint John, New Brunswick
Sorry if I missed this, but are you running points on EI? I'd suggest checking timing, coils, stong blue sparks, dirt in carb, broken or lose wires.


Jer

http://www.caferacer.ca

1968 BSA Lightning Cafe
1968 BSA Thunderbolt
1969 BSA Royal Star
1972 BSA Thunderbolt
#115498 - 05/09/07 2:13 pm Re: Lost power 20 km from home - help needed, thx  
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btour Online content
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Just noticed that you "just filled up" at a country station.

Before you go messing with the carbs, try dumping that gas, rinsing the tank, cleaning the fuel lines.

And I would be curious to know what fuel lines look like if first you, shutoff petcocks, drain float bowl, and let it stand till the inside of fuel lines dry.

What was the weather like? Temp. Humidity.

I think you might have just been unlucky, and got some real junk out of gas hose.

Sounds what happened to me after fill up at "country station". Just maybe some folks are getting rid of "old gas", or motor oil, or antifreeze, Or fuel oil by pouring it into the gas hose. Or maybe it is deliberate vandalism. A large country station would be the perfect place to do that.

(Just a big aside but I am wondering. A friend told him that a kid who worked at a station said there was a way for an employee to get free gas out without being caught. Would it be possible to pour something down the hose and make the meter of gas pumped run backwards. Like is it a simple paddle wheel type thing? Anyone know?)

The thing that changed last was, "you just filled up", as I read it. If that is right, dump the gas and drain the bowls, and clean tank and lines, and new filters.

Try the old gas in junk mower, if you want a confirmation.


Bob, Lifetime bike: '71 T120R, bought in '71 at Ken Heanes, England.
#115499 - 05/09/07 2:52 pm Re: Lost power 20 km from home - help needed, thx  
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2twins Offline
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Simple (but not complete) gas check: drain float bowl(s) into a cup or container, look for beading/seperation of water from gas.

From what you describe, perhaps you are only hitting on both cylinders after RPM's are up (more juice from alternator), and not well at that. Didn't you have an oil seal issue at the timing cover? Regardless, a simple inspection of points and point gap is worthwhile.


Woody 2Twins
#115500 - 05/09/07 3:26 pm Re: Lost power 20 km from home - help needed, thx  
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Matthew in TO Offline
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Matthew in TO  Offline
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Toronto, Ontario, Canada
Quote:
Originally posted by 2twins:
Simple (but not complete) gas check: drain float bowl(s) into a cup or container, look for beading/seperation of water from gas.

From what you describe, perhaps you are only hitting on both cylinders after RPM's are up (more juice from alternator), and not well at that. Didn't you have an oil seal issue at the timing cover? Regardless, a simple inspection of points and point gap is worthwhile.
Yes, I'm running the original points ignition. There is a small drip of oil getting past the seal, but it does not back up behind the points cover, and instead drips down to the motor and my foot.


1970 Triumph T100S (1969 T100S motor)
#115501 - 05/09/07 4:25 pm Re: Lost power 20 km from home - help needed, thx  
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andrewinpopayan Offline
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Halifax, Butt end of Europe
My bet is a burned or seized exhast valve, a compression test should show it. Are you sure you put gas into the tank and not diesel?

Time to buy some spanners and kit.


Gas pumps don't have paddles, they have a 4 cylinder dispacement meter, can be made accurate to within 0.2%.

There are plenty of ways to "racket" gas though, especially on older type pumps BUT what always catches the gas thieves is the "tote" meter that is mechanically connected to the displacement meter (looks like a mileometer).
I have caught a few dishonest employees at stations who thought they could get away with it. :rolleyes:


99% of carb problems are electrical.

1959 3TA

BMW R1150 Oilhead
#115502 - 05/09/07 4:45 pm Re: Lost power 20 km from home - help needed, thx  
Joined: Oct 2003
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RF Whatley Online content
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RF Whatley  Online Content
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North Georgia, USA
Matt -
IMHO taking things apart, especially the engine, at this point is a waste of good time and money. That is simply very BAD advice.

When your kids are sick, the FIRST thing you do is take their temperature to help you diagnose. On any engine... start with the 3 motor basics: fuel, fire and compression. One of those 3 is simply not behaving. Diagnose FIRST before you whip out the money gun. This is not the Wild West; we ask questions before shooting. Unless of course your bank account is feeling overly-full these days. :rolleyes: Make sense?

- If your plugs don't get moist on kick-over, then there may be water in the float bowl or your jet block may have fallen out. Water ALWAYS collects at the lowest point in the system, so all you need do is dump the contents of ONLY the float bowl onto a colored kitchen paper towel. The fuel will pass through and leave the droplets of water sitting on the paper. You can't miss them. If there is no water in the bowl, then there is NO water in the tank.

- With new plugs, test if there is fire at both plugs, then make sure your points haven't simply closed up. Points tend to close over time unless the ignition cam is greased. If closed, simply regap. When the engine is running, look for a bright blue spark which would indicate ignition capacitor issues.

- Borrow a compression tester. Kicking 6 or 7 times with the throttle wide open, your compression should be up around 130-140 PSI. Low compression is most commonly caused by tight valves. Set the valves to .004 and .006 like I first advised.

Using this system you'll find your culprit without guessing and spend a minimal amount of time and money to get an effective solution.

Hope this helps! bigt


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA

"Shop Boy" at Rodi British Bikes
#115503 - 05/10/07 12:13 am Re: Lost power 20 km from home - help needed, thx  
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Matthew in TO Offline
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Matthew in TO  Offline
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Toronto, Ontario, Canada
I've spent the day in the yard working on my 1970 T100S (1969 T100S motor). Here's what I've found thus far...

1) Carb/Fuel
As recommended, I took the carb float bowl plug out and drained the contents into a container (which I'd just washed and thoroughly and completely dried). Well, bugger me, what do I find but a clear separation of fuel and water in the container. So, I drain the entire tank and put the gas in my old beater car. Next I remove the in-line fuel filter and give it a blow, and out comes a whistle sound, followed by clear air, so something was in there. I can't open the filter up though. When I took off the tank I noticed that one of the front bolts had shaken loose and vanished, hope they still make those.

2) Plugs
I pulled both plugs. After kicking the motor over a few times the right plug was dry (even with the fuel lines now detached and carb drained), while the left plug was moist. Neither appeared to be in worse shape than the other, both were black, but not overly so.

3) Valve Clearances
I pulled the rocker box top and side caps and checked the clearances. On the right hand side, both inlet and exhaust were fine, with the right exhaust perhaps a little tight. The right exhaust clearance was fine now. I've now changed the clearance to 0.04" inlet and 0.06" exhaust was RF recommended.

Now, the left inlet seems to be where the problem is. The Valve adjuster is completely free, meaning I can move it up and down freely. I noticed this when I was manually turning the back wheel to look for valve movement for setting the clearances, and the left inlet adjuster would not move up or down under the mechanical power of the motor. When I went to touch the adjuster, I noticed it would move freely up and down in my hand. All the bits and pieces (bolt and allen key adjuster) are in place and appear in good shape.

The valve seems to be stuck in the open position, as the top of the valve stem is sticking up just slightly from the motor's head. Would this have caused the tuba-like racket? I haven't done anything about this yet, since I wanted your thoughts on probably cause and recommended next steps. I have two straight push rods handy, if this is the issue. I haven't found a compression gauge yet to borrow, so might just buy one.


1970 Triumph T100S (1969 T100S motor)
#115504 - 05/10/07 12:22 am Re: Lost power 20 km from home - help needed, thx  
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trumpetloon Offline
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georgia
Good on you for getting this far! As to the apparently stuck valve... some disassembly will be required. Possible causes are too myriad to explore at length but something either broke or got stuck to cause the valve to remain open. First, shine a strong light into the open spark plug hole and see if you can see the valve in the chamber. Also look at the top of the piston; we all hope it appears whole and not holed/beaten up.

Then report back and we'll give you further info... almost certainly the rockerbox will have to come off at least.


1974 TR5T
#115505 - 05/10/07 12:41 am Re: Lost power 20 km from home - help needed, thx  
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triumphguy Offline
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I say again -check for a bent push rod

#115506 - 05/10/07 1:07 am Re: Lost power 20 km from home - help needed, thx  
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triumphguy Offline
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Winchester Tn.
As Mark Z said "you would only have to remove the rocker box. " Maybe you can use a light and inspection mirror to look down the tube before you take anything off.

#115507 - 05/10/07 5:50 am Re: Lost power 20 km from home - help needed, thx  
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Matthew in TO Offline
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Matthew in TO  Offline
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Toronto, Ontario, Canada
Thx. BTW, my thumb-in-the-plug-hole compression test shows what appears to be equal pressure on both sides.


1970 Triumph T100S (1969 T100S motor)
#115508 - 05/10/07 5:52 am Re: Lost power 20 km from home - help needed, thx  
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Matthew in TO Offline
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Matthew in TO  Offline
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Toronto, Ontario, Canada
Quote:
Originally posted by triumphguy:
I say again -check for a bent push rod
Will do. Though this wouldn't affect the valve being stuck open would it, as I assume the spring or the valve itself must be stuck?


1970 Triumph T100S (1969 T100S motor)
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