Giving up a bit of blast for the sake of longevity

[Doggitter]

I've wondered about somewhat rebuilding one of the hot 4stroke mx motors specifically for adding longer life and reliability. What have you guys heard as to things people have done to do this? Valves, piston, increased oil capacity, etc?????

[William1]

Maintenance.

 

Anything else, you are better off selling the race bike and acquiring something more suited to your needs. A trophy wife is always going to be a trophy wife. Even her 'worn out jeans' are terribly expensive.

[coktm]

Replace the Ti valves with stainless, stick with a lower compression piston, if you have a carb jet it a little fat to make it run cooler, high flow water pump impeller (probably no real help), and external oil cooler are the first things I would do to increase reliability. As said before, solid maintenance, not hitting the rev limiter all the time, and keeping you engine from overheating probably will do more for reliability than building a "mild" engine.

CoKTM

[DR.billZ]

Keep it stock...

[Doggitter]

Well I do have my reasons for looking into this, and picking a different bike isn't one of the solutions.

 

coktm, have these methods been done and proven to make a huge difference, or is it just the common sense list you're going by? Is there something else that needs to be done that hasn't been tackled due to cost or complexity?

The oil capacity is indeed one thing I would want improved, the oil cooler could be a route to fix that, along with the bigger side case I've seen for a ktm.

[legend2]

Aside from maintaining it. Don't fix it unless it's broke. Modern 4t will surprise you on how long it will last even a abused one.

[LovingOffroadPain]

Replace the Ti valves with stainless, stick with a lower compression piston, if you have a carb jet it a little fat to make it run cooler, high flow water pump impeller (probably no real help), and external oil cooler are the first things I would do to increase reliability. As said before, solid maintenance, not hitting the rev limiter all the time, and keeping you engine from overheating probably will do more for reliability than building a "mild" engine.

CoKTM

 

^^ This guy stole my comments!! 

 

Overheating the motor and revving the piss out of it are the worst things you can do while riding it.. aside from crashing on a colossal king size jump, but that's not really riding.

 

Neglecting the air filter and oil changes are the worst things you can do while working on it.. aside from improper assembly installing the air filter wrong/not tightening down the oil fill plug.

Edited November 14, 2014 by LovingOffroadPain

[LovingOffroadPain]

Aside from maintaining it. Don't fix it unless it's broke. Modern 4t will surprise you on how long it will last even a abused one.

 

My buddy has a 2008 KTM 450 with almost 500 hours on it.  Original top and bottom end.  Now granted he's an older guy and not too fast, just putts around, but holy cow that's a lot of riding!

[Wild Alaskan]

put restrictor plates in the exhaust and intake, will keep you in the low revs ?

[Doggitter]

If any of you have had the 500exc apart have you noticed if a piston with longer piston skirts  and 3 rings will clear the crank? Or is it cut to the max as it is?

[The Inquisitor]

IMO......... and I'm drinking beer and watching nascar truck racing ?

hour meter and log your ride hours, fluid changes, etc. this is an old pic and my writing sucks....

throw in a magnetic engine oil drain bolt cus it's nice so see NOT metal on it when you drain your oil

use the best the engine oil, filter and tranny oil you can afford.

check engine oil every ride and if it starts looking dark, change oil and filter.

I change my engine oil/filter and tranny oil MAX 10 engine hrs.

I've got a 05 crf250r I bought used in the spring of 2010. Did new values and piston in the winter of 2010. I ride the crap out of my bike....

After rebuild = approx. 50 engine hrs before I put on the hour meter

Since the hour meter = 174.7 engine hours