Engine check post BoB

[Skunk]

Finally got round to stripping down the TF125 to check out the damage from the 'nip-up'. At first I was surprised at what I found.

I've had a think about things and now it's your turn. Remember that this is a factory standard engine - the mismatched chamber and matching the transfers to the cases is the only attempt at performance enhancements.

See what you think...

And one pic of the ZXRD400 project as it is today.216778

[gatch]

Water in the cylinder ?

[Skunk]

Water in the cylinder ?
Nope. Even the inside of the header is rust brown...

[Kickaha]

See what you think...

Mechanical incompetence, fuck you're hard on gear:shifty:

[Skunk]

Mechanical incompetence, fuck you're hard on gear:shifty:Nothing wrong with it. It's ready to run.

[Ocean1]

Dude!! There's some fookin' big holes in the side of your cylinder!!

[pete376403]

Running lean? Is the motor running oil injection or pre-mix? If pre-mix, have you jetted to compensate for the fact that a portion of the fuel going through the jets is now oil, therefore the mixture is leaner than before? (assuming that the motor was originally oil injection)

[TZ350]

As a matter of interest, what oil are you running?........different oils, different shades/color on the piston crown........any burnt oil/carbon on the underside of the piston crown

[Skunk]

As a matter of interest, what oil are you running?........different oils, different shades/color on the piston crown........any burnt oil/carbon on the underside of the piston crownMotul 800 premix

[Skunk]

Running lean? Is the motor running oil injection or pre-mix? If pre-mix, have you jetted to compensate for the fact that a portion of the fuel going through the jets is now oil, therefore the mixture is leaner than before? (assuming that the motor was originally oil injection)Jetting is fine, the bike has done about 50 hours prior to this 'nip-up'.

[pete376403]

Was the weather anything out of the ordinary when the engine seized - hotter, cooler, etc. Was the tuning close enough to the ragged edge that this would have made a difference?

[Buckets4Me]

some sidecar guy's been pissing in the fuel tank again :p

[Skunk]

Was the weather anything out of the ordinary when the engine seized - hotter, cooler, etc. Was the tuning close enough to the ragged edge that this would have made a difference?Tuning is good for any conditions; 40° and dry to 8° and wet have been repeatedly tested, though the BoB is 55 mins and the engine 'played up' at 45 mins...

I'll tell you all the cause by Monday night so there is an end in sight.

Buckets4Me - you have no idea how close to the right track you are.

[TZ350]

Was the carb sucking water thrown up by the back tyre?.......

[F5 Dave]

So I can't see any damage. So no nip up? Check the carb, any blockages of pilot jet etc?


[edit] from reading above, so did you find water or gunge in the fuel?

[Skunk]

Was the carb sucking water thrown up by the back tyre?.......

Nope. Open carb but it's protected from that sort of thing.

[Skunk]

So I can't see any damage. So no nip up? Check the carb, any blockages of pilot jet etc?

[edit] from reading above, so did you find water or gunge in the fuel?

No nip up. Carb is fine apart from the cause... No jet blockages.

[Skunk]

You pretty much got it Dave.
The bike has a fuel filter. A very fine mesh one.
A 'new' old fuel tank has been fitted. The filter is letting very fine iron 'powder' into the fuel system and burning it. You can see the build up around the plug.
The 'nip-up' was the spark plug failing to fire properly due to short circuiting. My guess is that as the BoB was a longer race than the bike has done before the iron had time to build up without cooling down and breaking away.
Time to seal the tank I think.

[F5 Dave]

Suzuki tank. They always do it. Best to seal in warm weather or a hot water cupboard, but it would smell it out. An old vacuum cleaner on blow helps airflow.

[Yow Ling]

Well thats kinda interesting, the plugs in my lc get like that after a couple of years, so now i know whats going on Thanks