Triumphrat

turbohipster · 03-06-2010, 05:16 PM

Hi everyone. I bought a '98 Daytona 955i out of Craigslist a couple months ago. The owner posted it as a bike that needed only a new ecm to run properly. Supposedly he had paid for this diagnosis at a shop here in S.D. The bike would run and drive if push started, but would idle at 3,500 and no lower. It would not however start by pushing the starter button.
I have since found out it needs top end work as it has 90% leakdown. I found out he wasn't being truthful with me about getting the diagnosis. What's strange though is that when the power commander is hooked to the p.c. it reads 3475 rpm with the bike not running. I replaced the ecm with one from a running '97 and still no luck. It won't start with the starter. Is it wishful thinking that I could get the bike running with the poor compression diagnosis. Possibly a bad sensor, thus the high rpm reading when the bike is stopped? Or am I doomed? Should I try something else, or dive into a top end rebuild?
Any thoughts or advice would be greatly appreciated.
Thanks, Glenn

DEcosse · 03-06-2010, 05:57 PM

Welcome Glenn

Explain your non-starting condition a little better please:

Does the starter do nothing at all when you press the button?
Or do you hear starter spin, but it does not turn engine over?
Or does engine crank, just not start?
When you press starter button, do headlights go out? (normal)

The starter operation is completely independent of the ECM
Clutch switch is one interlock on the start function - lever needs to be pulled in;
Could be problem with the clutch switch - you can short the pins in the plug to see if that makes it work.

Is neutral light displayed on the instrument panel?

As for high rpm - does this happen with or without the PC connected?
Have you removed the PC to see if it makes a difference?
PC reading high rpm when not running is not correct - you may need to zero the TPS setting in the PC3 (follow the procedure in the PC3 manual)

High idle speed is normally associated with leaks in the idle control system - however you may also have throttle cable tight which is not causing the butterflies to close fully.
(this would also explain the high reading on the PC3)

bradtx · 03-06-2010, 06:20 PM

Glenn, No, you're not doomed, but this will have to get sorted out and it'll be worth it in the long run.

Some questions...Does the VIN on the ECU match the motorcycle's VIN? What happens when trying to use the starter? How many cylinders have low compression?

Brad

turbohipster · 03-06-2010, 07:19 PM

Let me try to answer everything and thanks for the help in advance!
The engine turns over fine, it almost seems there isnt any spark. The lights stay on but dim slightly. The clutch switch has actually "slid" out of the mount so as to let it crank without pulling in the clutch. When pc3 is hooked to laptop, tps reads zero and advances as you twist the throttle all the way through the range and to 100% and then back to 0 when released. All the while the rpm reads 3475-3480.
The ecm # matches the vin on the bike. When another ecm, from a running 97 t595 is switched out, nothing changes. pc3 is not currently installed. bike will crank and crank but not light off. Currently when switched ON the neutral, oil, and engine light all are lit. Oil light will switch off with extended cranking. Engine light always stays on. I thought swapping the ecm might correct this. Visual check shows complete closure of butterflies at 0 throttle, and they look to be synched. All 3 cylinders were exactly the same with 90% leakdown, but some might be expected as bike has 39k miles.
thanks again,
Glenn

bradtx · 03-06-2010, 09:05 PM

Glenn, Do you mean you have 90% of spec reading or a 90% loss? If 90% of spec reading I would check the valve clearances. If the clearances are too tight it can cause difficult cold starting. On the RHS rear of the engine is a large hose from the air box to the IAC manifold. Remove the hose from the bottom of the manifold with engine running and slowly cover up the inlet to the manifold. The engine should lose RPM and die before the inlet is compleately covered up. If not look for an air leak to the throttle bodies.

The engine lamp may stay lit until the engine starts. Do you hear the fuel pump prime when key is switched to run?

Brad

PS The headlights should turn off when the starter is thumbed, usually a faulty cutoff relay.

turbohipster · 03-06-2010, 09:43 PM

I believe it was 90% loss. The mech. acted as though it wasn't worth spending more money to diagnose the no start problem, i.e. pulling the valve cover to check clearances etc. I'm sure i'll need to rebuild the top end, I just felt it was strange that the pc3 was indicating a 3500 rpm engine speed when bike was off. As though a sensor was feeding the ecm a bad reading. I know they have a start up cycle so to speak mapped in, but thought possibly it wasn't being initiated because of a false rpm signal from a sensor.
The lights do stay on. probably the relay. Fuel pump primes for a secnd or two. then its crank crank crank as long as you want to.

bradtx · 03-06-2010, 10:50 PM

Glenn, Other than the idle issue, when it ran how'd it do? I can't see how it ran at all with such low compression! Still worth checking the valve clearances. Reason being that if the valves were never adjusted the valves can be slightly off their seat causing a low compression reading.

It's easy to do. Remove the sparkplugs and the cam cover. The cam lobes are egg shaped (I may be too simplistic). Buy a metric set of feeler gauges that read 0.50 mm and smaller, place in gear and rotate the rear wheel until the pointy end of the cam lobe is at 12 o'clock at each valve that is being checked. Measure the clearance between the bottom of the cam lobe and the valve. May not need to pull the head if there is no clearance, providing the valves haven't been cooked.

Brad

turbohipster · 03-07-2010, 12:43 AM

Thats what stumps me Brad. It ran awesome above 3500. Hauled Ayysh as they might say! I'll pop the cover and check it out tomorrow. Visually, when looking through the throttle bodies into the valves, as well as into the cylinder from the plug holes nothing looks cooked, scratched, burnt. nothing. Actually looks in good shape. I know it's impossible to tell by looking, guess I'm just hoping for the best. Thanks for the guidance. I'll continue the process of elimination.
Glenn

turbohipster · 03-07-2010, 05:23 PM

Quick update........ All intake valves are too tight. Unfortunately the clearances are adjustable with shims only available at a dealer. Special tool also required to depress the followers, so you can change the shims without removing the cams. In reading Haynes, apparently '02? on cams MUST be removed to adjust valves. Would rather not if possible.
Definitely not giving up now!
Glenn

PhxMan · 03-08-2010, 12:29 AM

The Triumph tool makes things easy but not required !! Small screwdriver works with a bend in it, just depress the bucket and pop old shim out, new shim in. If my memory is not failing me, some Yamaha shims will work too. 1st Gen 955 used shims over bucket, 2nd Gen has buckets over shims, and does require cam removal. With 60k plus on my Sprint the exhaust valves have never required any adjustment !!