Bonneville America Forums Forums Technical Forums General Tech Bad CDI

I had a previous post about stuttering a 1/4 throttle.
The problem seemed to go away after changing spark plugs.
Well it returned after a couple of hundred miles.
It now is stuttering again & shutting down.
It will just quit while cruising.
I will pull in the clutch & downshift & when I get down to around 10mph let the clutch out & it will fire back up.
It runs great on WOT.
From what I have read it sure sounds like a CDI.
Any comments would be appreciated.

One more question.
When I was running Thruxton needles when I would hit the rev limiter the bike would die.
I changed to TBS needles & the problem went away.
I know this probably sounds stupid,but could I have damaged the CDI?
Is the rev limiter & the CDI connected?

Ok, i just checked the fault finding guide in the haynes manual and i'll list anything pertinent that i don't recall you having checked.

POOR RUNNING AT LOW SPEED
1-low battery
2-plug cap or wires
3-bad coil
4-cdi...hopefully not !
5-pilot jet or air passage clogged
6-floats out of adjustment
7-leak in intake manifold
8-tank breather hose blocked or pinched....very common...did u check that?
9-valves out of adjustment
10-cyl head gasket

That should give you some ideas to look at. I didn't include things that were extremely unlikely or serious internal problems like piston rings and all that because obviously it's going to more than likely be something simple. And if it was something like that the only way you're gonna know is to have the dealer do a complete diagnostic. good luck.

Thanks Daz,
I checked most of those already.
The problem is that now the bike will shut down completely just cruising.
It will then restart after coasting a while.
I think that almost has to make it electrical.
Another thing I dont understand is when I had the tank off I did try to blow through the vent hose.
It seemed to be obstructed.
But I dont see how that could make the problem so intermitent

You need to determine if you are loosing spark when the bike dies. The spark comes from: The sensor in the electric side of the bike then goes to the harness (check all the connections and be sure they are greased) then it goes into the CDI box, out of the box into the two wires on each coil, then to the spark plug.
If it is no spark condition, I would first check all the wiring by starting at the sensor wires (check for pinched/shorts), then progress to the coils following the path above. Take every plug apart and apply dielectric grease to them. You can also put a very thin film ont eh CDI connection, but it usually is sealed better than all the rest of the connections.
You said the dealer will let you try another CDI box, but charging you $50 to do so, sounds like an easy quick test to see if this is the problem. You can swap the box out in about 5 minutes too. Pull seat, console, tank and there are two small 8mm bolts holding the box in place. Swap and replace tank and seat. You should know right away if this is the culprit from your description of the problem.
You could also get one of the spark testers talked about in previous discussions, sorry don't remember who mentioned them, but you can connect it and ride the bike and look at them to see if the spark goes away while riding. Cheaper than the $50 to the dealer.

I would still try the gas cap too before this though. Can you loosen the cap when it starts to die and will it fire up again?
When it dies, does it do it suddenly, or slowly cut out and die?
When it stutters, can you crack the throttle open and make ANY difference?

What work have you done recently to the bike?

Checked the plug wires for nice and snug at both ends? Wires seated good in the caps? (they are not the best quality wires) Maybe the dealer will let you try some new plug wires first?

Bring it to my house and I'll figure it out in less than an hour. Bring cold beer. (yea, I know, you're far far away)
Any other members near you?

The last couple of times it stuttered I cracked the throttle & the bike died.
When it dies it does it suddenly.
The last work I did was go from thruxton to TBS needles.
I even changed back to the Thruxtons.
Same problem.
Even went back to stock needles.
Same problem.
The TBS sure do make a dramtic difference over stock.
I put the TBS in again last night.
The Diaphrams are seated.
I have experience in knowing the symtons of them not being seated.
I will go out & see if I can fin the sensor.
My Triumph shop manual is hard for me to read.

The sensor is located inside the right side magneto cover. It is also full of oil so you can't just pull the cover off. It is a little square device that picks up the magnetic pulse as the magneto spins by it and sends this pulse to the CDI box. If you changed your sprocket or took the cover off before, you can easily pinch the little wires. It is just a small two wires and they come through the cover right near the little L shaped backet thing that holds the wires back directly on the two top screws of the sprocket cover. Check there for pinched wires and also check the little rubber grommet the wires feed out of the cover. I have only heard of one of them failing before, but unfortunately I have heard of many more CDI boxes failing.
Procomm is testing new CDI boxes for our motors and they have already made up ones for the 360º motors, brent sells them. Hopefully they will be available soon as theirs are only a couple hundred vs the $500 the dealers want for the original ones.
Good luck with it. Keep us posted.

edited cause I kant spel.

Symptomwise, it sounds like what mine was doing in NH. Have you tried to loosen the gas cap while it's sputtering? My bike would sputter a few times and if I'd crack the throttle wide open, it would usually die. But all I had to do was loosen the gas cap and she'd start breathing again.

my brother had the exact same problem on a Yamaha. Somehow, he got the idea to remove the fuel cap when it stalled,the problem was a blocked vent,easy fix, and probably a blessing, he bought the bike cheap because previous owner couldn't get the problem found and got aggravated!

Dinqua,
I did check the wires under the L bracket on the Sprocket cover.
They look ok.
the gromet looks ok.
Did notice that front sprocket seal is leaking again.
It is suppose to stop raining here sometime tomorrow.
I will see if I can try another CDI tomorrow.
Brent said that PROCOM box,s wont be out till the end of the yr.

Litzerski & Jefferson,
I did try unscrewing the gas cap when I was having problems.
It did not change anything.
I am also running a KURYORKIN<boy did I butcher that> Gas cap.
I am using that cap because it stopped the paint pealing problem I had in the Tank.

Dinqua,
I did check the wires under the L bracket on the Sprocket cover.
They look ok.
the gromet looks ok.
Did notice that front sprocket seal is leaking again.
It is suppose to stop raining here sometime tomorrow.
I will see if I can try another CDI tomorrow.
Brent said that PROCOM box,s wont be out till the end of the yr.

Litzerski & Jefferson,
I did try unscrewing the gas cap when I was having problems.
It did not change anything.
I am also running a KURYORKIN<boy did I butcher that> Gas cap.
I am using that cap because it stopped the paint pealing problem I had in the Tank.

Edited

Well, time to try the CDI from the dealer to see if this is it. Too bad they won't let you swap them yourself to try it out.
Maybe I can steal Matts when he passes out at the rally.

Sure sounds like symptoms of a CDI. Have you tried to hook up a spark plug tester and then ride? You can get them for cheap at an auto parts store, and I've seen them at a regular hardware store. They typically have an alligator clip and probe on them, with a light that flashses when you're getting good spark. Probably not bright enough during the day to safely see while riding, but at night it would be easy to tell.

When my CDI went bad, my local dealer wouldn't let me borrow one like yours will. Dwight ended up loaning me his, and that's when I found out for sure it was the CDI. I ordered a new one from Palm Beach Triumph, because I knew they'd get it quicker than most dealers out here, and since it was prime riding season I wanted one ASAP.

Seems to me these CDI boxes are failing far too often. Regular Bonnies have coil problems from what I've read on other boards. IMO Triumph cheaped out on these parts, and we're paying the price for it. These shouldn't be failing.

Derek,
I was going to try a spark plug tester.
But like you said they are hard to see while riding in the daylight.
The problem was getting worse so I was reluctant to try it at night unless I didnt have another alternative.
So I stopped by my Dealer & he made the offer.
So I will maybe go there tomorrow if it stops raining & get it.
It does seem very simple for me to install it.
Hopefully that will cure the problem.
I am not very happy about having to replace it.
The bike is only 2 months out of warranty with 8300 miles on it.
The front sprocket seal is also leaking again after it was replaced 3 months ago.
I still like my Triumph.
Have had 22 bikes in my 61yrs.
But the last two bikes I had before it were Harleys & I did not have any problems.
The Triumph is still a lot more fun to ride,when it runs.

The CDI is a very simple swap, just take off the gas tank and two mounting bolts later it's out. When mine went out, I was relieved to find the problem, but at the same time depressed when I knew what it would cost, $550. That's a lot of dinero for an igniter box. Sure wish Procom would get on with it and put one out there for our bikes. And that's the problem with our bikes compared to Harleys. Something breaks on ours and we're usually at the mercy of expensive OEM replacments. Own a Harley and you can find much cheaper replacements. Just check this ebay auction for a Harley Dyna CDI box that sold for $31 plus $10 shipping. The price we pay for having an exclusive bike.