Daytona troubles

"bob and john" (bobandjohn)
07/29/2020 at 09:56 • Filed to: None

Intresting situation. Bike having troubles. No CEL.
Symptoms. When the bike gets hot, i can feel a slight vibration in the motor. Its 100% engine, not wheels. But only when hot.

Also, i loose a small amount of power. Not a lot, but noticeable.

Also didnt want to start at first. Spun the crank once and died.

Again, this is all when hot. When cold, its fine.

Electrical? Stator? Fuel related? Im going to check the battery/charging system in the AM, but im at a loss here...

EDIT: bike has a full akra, a tune for it, no EXUP, no cat, no O2. Yoyodyne slipper clutch and some visual mods.

Its has about 17k km on it, and I think its due for a valve service.

I’m posting this hereso that we all learn from this. I’m genuinely curious as too what it could be, I’m going to pull the stator cover and take a look. maybe its worked its way loose? would explain a lot actually.....

DISCUSSION (17)

Highlander-Datsuns are Forever > bob and john
07/29/2020 at 10:15

I am going out on a limb and saying it needs a valve adjustment. That would explain the rough running and small amount of power loss without a CEL for misfire.

Grindintosecond > bob and john
07/29/2020 at 10:36

maybe when hot a valve is starting to stick a bit and get slow on the return? just throwing it out there. Injected right? Whens the last time injectors were cleaned out? Is that a thing anymore?

bob and john > Highlander-Datsuns are Forever
07/29/2020 at 10:38

yea, but the powerloss isnt all the time. its like a switch tbh....

but I DO need to get the valves done....maybe a *cough* harder / more revv ing then anticipated life would be the cause....

bob and john > Grindintosecond
07/29/2020 at 10:39

never cleaned, but i DO have an ultra sonic cleaner at home. Not the worst idea.

This is what we'll show whenever you publish anything on Kinja: > bob and john
07/29/2020 at 11:02

- Air/Fuel ratio too lean (By far the most likely cause)
- Engine idle level set too low (You will not be allowed to adjust it on all models - especially not on newer motorcycles)
- Clogged charcoal cannister in the fuel tank ventilation line
- Faulty Lambda Sensor (Does not always flash a warning in the dashboard)
- Fuel pressure too low
- Leaking intake rubber hoses between throttle valve housing and cylinder head
- Throttle valves not correctly synced
- Throttle position sensor (TPS) not correctly adjusted
- Valve clearances are too tight
- Low compression.

Or so says the internet.

Future next gen S2000 owner > bob and john
07/29/2020 at 11:16

Valve would make sense as others have pointed out. They expand when hot. So any seating issue could be exasperated.

I’m not sold though. Valves tend to tighten up, well relative to the cam. When I checked my valves they were all in spec but trended towards min clearance rather than excess clearance. I think the seats get hammered into submission and the spring holds the valve up, reducing the clearance. Plus, I’m not convinced valves would cause the vibration.

I want to say I had an issue with starting hot on mine a few years back. It was the stator and these bike’s are known to eat stators, at least my generation was. Check that first before you dig into the motor.

Regulator/Rectifiers are known to go as well but those tended to be on the early bikes. They had it worked out for the most part by 2010. A stator or R/R would leave you dead in the water battery wise wether hot or cold.

How old is the tune? How many miles on it? I would go back to the factory tune and see what happens. If the new tune is lean or creates excess heat, it might start to pull timing to prevent detonation. That would give you less power and only be noticeable when the bike is hot.

I don’t know how old the mods are but I think the O2 sensor delete and the aftermarket tune are working against you. Check the easy stuff first. Getting into the head to check the valves is a pain.

Biggus Dickus (RevsBro) > bob and john
07/29/2020 at 11:25

Valve lash will shrink when hot which could cause a valve to s tay slightly open. Though as valves wear they tend to get looser instead of tighter.

Victorinoo > bob and john
07/29/2020 at 11:35

What year is the bike? I know that modern bikes have gone the OBDII route (like new bmws). That would make diagnostics easier.

When are you experiencing issues? Under load or at idle?

bob and john > Victorinoo
07/29/2020 at 11:48

2012. It does have OBD2.

when hot really. but it comes on like a switch. It doesnt build as the heat does.

bob and john > This is what we'll show whenever you publish anything on Kinja:
07/29/2020 at 11:49

the AFR is set in the tune and the O2 was removed so it just runs that. Valve clearances makes the most sense to me if i am honest.

bob and john > Future next gen S2000 owner
07/29/2020 at 11:53

not an aftermarket tune. triumph OEM racing tune.

Future next gen S2000 owner > bob and john
07/29/2020 at 11:55

Well....there goes my theory.

bob and john > Future next gen S2000 owner
07/29/2020 at 11:57

yea.

i will be checking the charging system tonight as, well, its fucking british. I have the track bike next to it so i can just grab the part from ther e if it needs to be replaced.

OhCrikeyTheRozzers > bob and john
07/29/2020 at 12:54

Just chiming in to say that even manufacturer tunes can do weird things. Bought my Tiger 800 XC used with a LeoVince slip on and Triumph Arrow tune. Previous owner thought it was perfect but I found it caused poor fuel mileage, stumbling at low revs in first, and a few other issues if I recall. Triumph dealer ended up going back to factory and it solved things immediately. Not sure if that’s helpful but just something to consider.

bob and john > OhCrikeyTheRozzers
07/29/2020 at 13:10

well, yea, because that was the wrong tune for that pipe...

I’ve not had ANY issues. Runs stronger and smoother then my 11 did with a stock tune and arrow slip on.

oh well. Step 1 will be check the stator and do valves

Victorinoo > bob and john
07/30/2020 at 08:54

Hmmm the fact that it comes on so hard makes me doubt that it’s a valve adjustment issue because that should Always be there. I would plug in a generic obd scanner and look for anything odd. Look at coolant temp sensor, misfire counter per cylinder, etc and see if anything points you in the right direction.

bob and john > Victorinoo
07/30/2020 at 09:25

yea, thats what I’m thinking.

Someone mentioned it might be the stator which worked its way loose which would actually kinda explain a lot.

I’ll tug the engine cover off this weekend and take a look at it