Bike seems weak.

[corksil]

Maybe I mentally readjusted to the power of a bigger bike after riding one for a while. On the other hand my bike feels weak.

Coming up on 30k miles of hard abuse.

Best way to check engine health would be a compression test? What sort of numbers should I see? Time to order a compression tester that will work on the 250r. Any suggestions?

Maybe it's time for an overhaul and ninja 315cc frankenbike with 300 crank, conrods, 2mm overbore.

[subxero]

compression is just one aspect of engine health. Any compression tester with the correct plug hole adapter should work fine, but it is nice to have something to compare values with to see how accurate the gauge is. There are different ways to make a system to do such.

If the test comes back low, then you at least know you need top end work, piston, rings. If it doesn't come back too low then you still have all the valves and other things to consider being a reason for "low power" $50 worth of dyno time could save you $$$ on unneeded engine repair/work and tell you if it is actually low on power.

on a side note, this thread should probably be in new gen tech area

[Ghostt]

Have you done the valves? Checked the ignition system? Spark plugs? Fuel system? Etc.....

["A"]

Check the usual suspects, start with the easy ones, air/fuel filter, spark plugs, fuel tank rust, valve clearances and timing chain.

[corksil]

Yeah I've done all the usual crap.

Compression test and a leakdown test?

[corksil]

Would a compression and leakdown test be an adequate marker of engine health?

[MrAtom]

don't you have any specs of your bike? 0-60 times recorded or anything like that? if you do, i'd record some more compare 'em.

[corksil]

I don't try to benchmark my performance machines. I use them frequently enough that I have a feel for exactly what they can do.

Riding this bike every day for years... It's getting weaker.

Being a competent mechanic isn't about turning wrenches all day.. it's about the intuition to know how the machine works and when it's not working to it's maximum potential -- and the intuition to know what may be causing the inefficiency.

It was getting a little hard to start up cold. Doing the valves brought back a little low end power and helped it fire up more quickly. The race cams took a bit of a hit to midrange and low end power. A bigger main jet realized significant top end gains. Intuition told me I need a bigger pilot jet to help with an off-idle stumble during acceleration but laziness had me turn up the idle and deal with it without going into the carbs again.

Now it's a little weak starting up, and needs more choke for longer until I can turn off the choke without it faltering while cold.

Intuition tells me I still need a larger pilot jet, and that varnish is building up around the valves causing them to not seat properly when 'closed' -- that explains the low end faltering further.

I don't want to tear this bitch apart again and lap the valves until I ultimately must.

Would be nice if I could do a leakdown test or something of that nature to confirm my suspicion.

Leak down test on a motorcycle... is this a common practice? Never heard of it being done before..

[crazymadbastard]

Leakdown test would tell you what is leaking. Air out the carbs or exhaust-valves,air out the pvc system- piston and rings. Air out the side -hole in the engine.

[corksil]

That's what I figured.

Now I've gotta find a motorcycle leakdown tester. Gonna be tricky with those tiny spark plug holes.