Triumph Rat Motorcycle Forums banner
1 - 11 of 11 Posts

·
Registered
Joined
·
80 Posts
Discussion Starter · #1 ·
what whould it sound like if, occationally (ie every few minutes, but not consistantly), a valve would stick? How would the engine react?
 

·
Registered
Joined
·
745 Posts
if it's an intake, the spark would ignite the mix and you have a backfire(forefire) thru the carb on the sticking side.

an exhaust would either be a miss from low compression, or the unburnt fuel would fire (backfire) in the exhaust.

as said above, do a compression check.

it doesn't have to be a "sticking valve"...it can be carbon wedged under a seat...that shows up as a valve gap increase.

if it's a burnt valve (eroded seat) it would be constant.

describe EXACTLY your symptoms...it can be an intermittent spark (leak) or even a fouled plug where the spark is following a carbon trail down the electrode instead of jumping the gap.

[ This message was edited by: modre on 2007-01-11 11:25 ]
 

·
Registered
Joined
·
80 Posts
Discussion Starter · #4 ·
when i'm sitting at idle, usually when the engine is on the cold side (or more probably more noticable when cold) there will occasionally be a click and the idle will stumble. if i don't have the idle adjusted at high enough rpms (or if the engine isn't warm enough and strongly idling), the engine will want to die when it stumbles, then it will pick back up to normal idle. there is no noticable loud backfire associated with the issue (which doesn't mean there isn't a misfire occuring). It doesn't occur consistantly, and it seems to lessen the warmer the engine is, but i have found that it doesn't totally go away.
 

·
Registered
Joined
·
745 Posts
sounds like a combination lean miss and advanced timing.

I like my idle at 500 rpm or less, but I suspect 6-700 is more in line with the timing at full retard.

I don't think you have any problem beyond a low idle and a starved engine trying to fit into EPA specs.

not sure what the timing curve is, but I suspect the range favors the performance at speed than idle.

which brings up the point of furthering my education:
does anyone know the timing specs?
I'm guessing at idle it's likely around 10-30 BTC?...when maybe 5 at full retard and 30 at full advance would favor the lower idle?

and is this different between the 360 and 270 engines?
 

·
Registered
Joined
·
566 Posts
500rpm! That's HD low.. I have mine at 1000rpm

At 500rpm it's 0deg, at 1000rpm 8deg and from 4500rpm (and full throttle) it's 32deg. All this with the TPS hooked up.
At part throttle you get a few deg more at anything but idle.

Unplug the TPS and you get 8deg at 500 and 13 at 1000, still 32deg from 4500rpm

plus minus 1deg
 

·
Registered
Joined
·
566 Posts
Your valves are fine, it's either an airleak or it's just lean, try one more turn out on the mixture screws
On 2007-01-11 10:01, Programr wrote:
what whould it sound like if, occationally (ie every few minutes, but not consistantly), a valve would stick? How would the engine react?
 

·
Registered
Joined
·
3,753 Posts
I get an occassional TICK for a few min's after a long hi speed run on the far left exhaust valve. Goes away & doesnt seem to affect the performance. Since it never presented a problem, I havent bothered w/ it. My buds America has 11000 mi & ticks on both the same valves. Still runs good, but needs adjusting for sure. I got 5k on the clock so not time for adjust yet? Bonne's are noisy! compared t Hondas etc.. Comes w/ the beast! When they need adjusting- its REAL noticable, & a pain in the a**- due to shims. All my old Jap bikes took an allen wrench or similar t oadjust. This reminds me of an XKE I hadsome years back. I am sure it will cost similar to adjust when necessary? O well still a cool bike!! :) :cool:
 

·
Premium Member
Joined
·
1,049 Posts
On 2007-01-11 18:05, CAPTDON wrote:
...When they need adjusting- its REAL noticable, & a pain in the a**- due to shims. All my old Jap bikes took an allen wrench or similar t oadjust. This reminds me of an XKE I hadsome years back. I am sure it will cost similar to adjust when necessary? O well still a cool bike!! :) :cool:
The valve adjustment really isn't that bad and you should only have to do it every 2 years/12000mi. The old allen wrench adjusters would quickly readjust themselves while the shims pretty much stay the same.

Triumph did a pretty good job on making the valve adjustment painless and the Haynes manual does an excellent job of explaining how to do it. For the price of a few shims (about $7.00 each at Bike Bandit) and maybe some seals and screws, you can easily DIY. The cams come right out without much problem and the cam cover has a rubber (hopefully reusable) seal. The only things to watch are to make sure you have something to lock the cam gears (see Haynes) and to be real careful when you break the Torx screws loose so you don't strip the Torx sockets. After you have done it once, it doesn't seem much harder than the old allen wrench stuff.
 

·
Registered
Joined
·
3,588 Posts
Good response raproe; however, I hope Daz doesn't read your sentence beginning with "The only things to watch are...." :-D

Larry
 

·
Premium Member
Joined
·
1,049 Posts
On 2007-01-12 19:43, RedBird wrote:
Good response raproe; however, I hope Daz doesn't read your sentence beginning with "The only things to watch are...." :-D

Larry
Actually, I learned about "the only things to watch are..." the hard way. If anyone is interested, I now have hands-on experience in how to remove a stripped Torx screw. That's why I wrote "After you have done it once..." The first time can be a learning experience.
 
1 - 11 of 11 Posts
Top