Leak Down Test Results

[Honda 250r 001]

Finally got my leak down tester made and tested my engine. The base gasket was leaking so much, it wouldnt hold 6 pounds of pressure for 30-45 seconds, and i ran it this way for a whole afternoon!!!

So i sealed that up with gasket sealer, and now it holds 6 pounds forever, but i pumped it up to 10 and it leaked ever so slightly under the base gasket still, so i let the pressure off and pumped back up to 6, and it held again for 3 hours. Is this good enough for a race this weekend?

I dont have any more base gaskets so im kinda screwed if this isint good enough. Im hoping this will solve my engine over heating troubles.

Any input would be appreciated.
Thanks

[latheboy]

If you are looking for an opinion.....
I think it will be fine, but not ideal. I had a monster base gasket leak (wouldn't hold any psi for anytime) and it caused the motor to run hot. But I unknowingly ran it for a long time that way, searching for the reason it was running hot. After all that, I will always use the leakdown tester now!

[Grande Huevos]

im not 100% but i pretty sure it only has to hold for like 5 min to call good. this is what i have been told by multiple people

[Honda 250r 001]

I figured it wasnt ideal, Im just looking for oppinions.

Its suppose to hold 6 pounds for atleast 6 minutes which it passes, but I think after this next race, when i have new base gaskets, I will have the cases decked and see if the cylinder is warped.

[wilkin250r]

10psi is actually pretty high pressure for a leak-down test.

It's your engine, but if it was mine, I wouldn't even worry about further inspection of the base gaskets down the road. If it holds 6psi for 3 hours, you're fine.

[jcs003]

they all leak no matter what you do. but to what degree is that case and point.

i read an article years ago about team kawasaki doing everything possible to seal the engine completely air tight. they even went as far as welding on it. i wish i still had the magazine so i could be more specific.

[Honda 250r 001]

Do you guys think a leak like i had before i sealed it up would cause my motor to run upwards of 200 degrees? 225-250?

I have been running my cylinder like this forever and couldnt figure out why it was running so hot. Hopefully this fixes it, i havnt got it back together to test it. But i have had nothing but trouble with my motor and overheating. Pistons would just literally melt away at the exhaust port. Jetting showed rich as the plug and top of piston was dark brown to black, coolant system was functioning well.

[latheboy]

Absolutly. My engine ran hot when it had a massive base gasket leak.

[86 Quad R]

Originally posted by Honda 250r 001
Do you guys think a leak like i had before i sealed it up would cause my motor to run upwards of 200 degrees? 225-250?

I have been running my cylinder like this forever and couldnt figure out why it was running so hot. Hopefully this fixes it, i havnt got it back together to test it. But i have had nothing but trouble with my motor and overheating. Pistons would just literally melt away at the exhaust port. Jetting showed rich as the plug and top of piston was dark brown to black, coolant system was functioning well.


i just gotta know why is it that you've allowed youself to run this engine for sooooo long without even considering a leakdown test? even though you knew better. its not like your a newby.... so to speak.

[Honda 250r 001]

I dont know honestly. I just didnt understand how easy it was for a leak to develop through out the whole motor...

The new problem is, my cylinder is still running hot, its like 225-250 all the time. Its jetted plenty fat, 188 main, no air leaks. sealed it up again with new gaskets and it holds 6 pounds for 1 hour. Anyone have any suggestions???

Pipe is clean and free of restrictions,
Filter is clean and reeds are good
Compression is 175 running on 91
Timing is set as far retarded as it can be (although it doesnt change the temp of the cylinder no matter where its set)
has good spark
Waterpump is pumping plenty well

Radiator has plenty of bent fins, but water flows though the rad well and its clean.

[86 Quad R]

you running a mesh screened front bumpah?

[Honda 250r 001]

Originally posted by 86 Quad R
you running a mesh screened front bumpah?

Yes i sure am. I have a number plate too. The radiator seems to get plenty of flow though when i put my hand behind it when driving in 2nd, 3rd and 4th gear.

[86 Quad R]

just for shiggles..... take it off. http://forums.everything2stroke.com/images/smilies/Thumbsup2.gif

[Honda 250r 001]

Originally posted by 86 Quad R
just for shiggles..... take it off. http://forums.everything2stroke.com/images/smilies/Thumbsup2.gif

Alright. I will do that. Maybe i need to run a fan??

[jcs003]

what kind of coolant are you running?

[Honda 250r 001]

Whoops, my bad typo. dexi cool is what im running. No special wetter water or anything like that.

[jcs003]

isnt dextron transmission fluid?

[Honda 250r 001]

whoops typo, recheck last post

[jcs003]

try engine ice. great stuff.

[machwon]

How long does it take to overheat? Does it spit coolant out of the radiator cap? Where is the squish set at? How high is the exhaust port raised?

[Honda 250r 001]

It usually takes 10-15 minutes of hard riding for it to get up to its normal 225-250 degree temp, no it does not spit coolant out of the overflow, its always at the same level and never gets any lower. Squish is just over 1mm like .045, just , and I do not for sure know what the exhaust port is, its CT national porting. Its prolly nothing too radical as it has pretty dang good low end.

Ive set the squish much looser, and the compression lower, and it doesnt seem to run much cooler though.

For example, I switched from two .20 stock base gaskets to two .40 thickness base gaskets and the temps didnt change all that much, maybe 5 degrees max.

[machwon]

I would switch to Race fuel. That should take care of the piston exhaust side and could help with the heat. Also carefully look around the intake and transfer ports of the cylinder for areas that attract dust, maybe look a little darker than normal. I've had cylinders with hair line cracks that were undectable with a leak down test, but open up when hot and then create the leak.

[Honda 250r 001]

Originally posted by machwon
I would switch to Race fuel. That should take care of the piston exhaust side and could help with the heat. Also carefully look around the intake and transfer ports of the cylinder for areas that attract dust, maybe look a little darker than normal. I've had cylinders with hair line cracks that were undectable with a leak down test, but open up when hot and then create the leak.

Ok i will run straight race fuel to see if it cools it down. And thats a very good suggestion, i will look for those dark spots!
Thanks