ktm 50 compression psi?

zobenv · 06-16-2010, 10:33 AM

i have a 03 mini adventure air cooled. anyone know what kind of compression psi i should be looking for, checking the condition of the rings

zobenv · 07-14-2010, 08:47 AM

i can answer myself approx 75 psi

dgangle · 10-25-2010, 08:24 AM

IME, anything less than ~110 psi needs rings, crank seals and maybe a piston.

When my '06 50MA was new, it measured ~130-135 psi if that is any type of a gauge for you.

zobenv · 10-25-2010, 09:04 AM

thanks,
i am almost certain the crank seal on the clutch side is bad.
can this seal be changed with the motor together?

dgangle · 10-25-2010, 09:26 AM

if one is bad they are both bad. the ingition-side is just a little easier to get to. On the clutch-side, remove the kickstarter, cover, idler gear and seal holder. To remove the seals I drill (2) 1/16" dia holes in the seal 180* apart, partially screw in a sheet-metal screw just a couple of threads, put Vise-Grips on them and hammer out against the VG's gently in an even pattern. Comes right out everytime. Becareful not to press the new seals in too far. For the ignition-side you will need the puller which is very inexpensive or make your own.

When you re-install the kick-start idler gear, buy the hardened woodruff key from 50ccparts/manga or any of the knowledgable 50cc hop-up places. use red loctite on the nut. if it has been red lock-tited before, a little heat from a propane or map torch will soften it nicely.

2.5 banana job.

zobenv · 10-25-2010, 10:29 AM

thanks, good info- i had not even looked at the job yet it's nice to have confirmation.
what does the seal puller look like? ignition side only. is that correct?

dgangle · 10-25-2010, 12:54 PM

for the ignition-side, I was saying you will need a puller to remove the stator. No way around that. It is 'easier' from the standoint of havign to remove less stuff to access the seal. The clutch-side is more work just to get to the seal.

For the seal puller, you will need it for bother sides. here's a tool you can buy or make your own as I described

You Tube

zobenv · 10-25-2010, 01:05 PM

thanks again

ktmmom · 10-25-2011, 02:23 PM

Does anyone have a pattern to use for a 2001 min adventure? We are used to a sr 50sx using 15 washers but when we opened the mini it only had 8 washers? It starts but won't go anywhere. Any ideas?

dgangle · 10-25-2011, 02:36 PM

I thought were were talking about compression and crank seals...

Plenty of read about clutch shim stacks. This is not an easy question to answer based on many factors such as the kid's skill level as these can be set up from mild to wild, engaging early and easy to late and hard.

Mini Adventures aren't set up new with bevel washers (some call 'shims') but with springs. Unless your 50MA is hopped up with a carb/pipe and your kid is seriously fast and aggressive there is really no reason to go with bevel washers. They are significantly more maintenance/cleaning and expense. If he/she needs these then they really need to be on a 50SX as they are probably bottoming the heck out of the limitted suspension travel and stopping ability of drum brakes.