Author Topic: So, just when I thought I had all my problems fixed......video (Read 28038 times)

Jimbo45 · « **on:** March 10, 2015, 08:49:58 PM »

So I finally got my electrical gremlin, and jetting pretty well figured out (although I still think there is something defective on the idle circuit on this brand new Airstriker), I put my plastics back on today, after completely making a new wiring harness, so I can have lights. I fired it up to test out the lighting, and tune the airscrew, since it was 20 degrees warmer today, since the last time I fired it up. Keep in mind, I have yet to take this R on a ride, only short test runs, near my house.

So, I fire it up, and what is odd, is that when engine is cold, it always fires up first or second kick, WITHOUT the choke, and idles strong and fast, as if the choke was on!? Then, after a minute, it will settle into a normal idle. I have never needed choke on this 38PWK for some reason. Then, I fine tuned the airscrew (which is difficult, because it doesn't seem to make much difference where I set it. It will slow the idle at anything less than 1.75 turns out, but at that setting, and even turning it all the way out, doesn't seem to make a difference in idle speed. Also, after warming up, if i rev it, the idle will hang high a bit somtimes for a few seconds, sometimes hang until I back out the idle speed screw.? As I said, I think the new carb has something wonky in the idle circuit. It seems to defy logic that I can run a #40 pilot, even when its 10 degrees outside, and it still seems a bit rich at 1.5 turns out on the airscrew. ?

ANyway, the purpose for this post......steam/pressure coming out the coolant overflow tank vent. I had noticed my overflow tank coolant level always seemed to rise after even short runnings of the motor. I replaced the rad cap, thinking maybe it was bad. Fired it up today and warmed it up for the previous mentioned reasons, and happened to look at the coolant reservoir vent tube. It was constantly putting off steam, and when looking at the coolant tank where the overflow hose connects, I could see a constant stream of bubbles coming in. DAM! It was not overheating.....I checked the head temp with my laser thermometer multiple times, and it was always right at 150 degrees. It did not seem to expel gas faster as I revved it for some reason. WHAT the heck? I am assuming that I have a head gasket problem, in that some combustion gases are being pushed into the coolant passages at the head gasket. Am I right? This is not normal, right?

*sigh* I just want to get all the bugs worked out and be able to ride this thing!

Video:

[video]http://vidmg.photobucket.com/albums/v163/jimbo45/20150310_175156_zpsvmq5ei2n.mp4[/video]

dirtyd · « **Reply #1 on:** March 10, 2015, 09:45:31 PM »

sounds like you have a head gasket problem if your getting those bubbles

Pumashine · « **Reply #2 on:** March 10, 2015, 10:35:18 PM »

Thats one of the funniest video's I have ever seen. Never seen that in all my years. Good thing its just the head gasket. I will send you a new one priority mail free of charge other than shipping.

Jimbo45 · « **Reply #3 on:** March 11, 2015, 01:59:35 AM »

Quote from: Pumashine;51323

Thats one of the funniest video's I have ever seen. Never seen that in all my years. Good thing its just the head gasket. I will send you a new one priority mail free of charge other than shipping.

Wow, thanks Tony. Just trying to reason this out in my head though....why is this happening? I used a brand new thick 3 piece oem head gasket, ground for a 69mm bore, when I put this together. Do you have a different kind of gasket that will cure this? If so, tell me when and where to send the money! Thank you sir!

Pumashine · « **Reply #4 on:** March 11, 2015, 09:02:39 AM »

Have been through the head gasket nightmare myself. 2 things come to mind. #1 you cannot re use a head gasket. #2 Even if you use a new head gasket a warped head will always leak no matter how many times you have replaced the gasket. Did you re torque the head after break in? If your water pump was out and no coolant was getting to the head it could have easily warped.

Jerry Hall · « **Reply #5 on:** March 11, 2015, 10:34:27 AM »

Quote from: Jimbo45;51332

Wow, thanks Tony. Just trying to reason this out in my head though....why is this happening? I used a brand new thick 3 piece oem head gasket, ground for a 69mm bore, when I put this together. Do you have a different kind of gasket that will cure this? If so, tell me when and where to send the money! Thank you sir!

You cannot usually grind a head gasket for a large bore. Grinding a head gasket gets into or too close to the stamped ridge in the gasket that seals the high combustion pressure. Look at the gasket and see how close your grinding came to this ridge in the gasket.

Like mentioned earlier, make sure the head and top of the cylinder are flat and without ANY imperfections on the gasket sealing surfaces.

Jimbo45 · « **Reply #6 on:** March 11, 2015, 10:40:32 AM »

Tony, it was a new oem head gasket, and yes I retorqued it to 22 ft lbs. The gasket surfaces were surgically clean. This is the third gasket I have tried. The first two were wiseco, and leaked coolant outside the cylinder. This is also the second head I have tried. I think the problem could also be the cyl deck....it has a super thick sleeve installed that comes really close to the water jackets. Well, I guess I will have to scrap this top end (sucks, it has 180 psi compression), and start over. I Don't even want to try a cool head on this cylinder to find it leaks too. Guess I will have my original ported 86 cylinder bored and decked, and the other head I have cut and checked. I wonder what all that will cost. Guess my riding season is not gonna happen until I save up more money. Frustrating!!!

Here is pics of the deck, head, and gasket right before installation.....

Ugh! This is getting old! It's my birthday today, and my goal was to take the bike out for the first time today! Welp, that's not gonna happen.

Jimbo45 · « **Reply #7 on:** March 11, 2015, 10:42:52 AM »

Quote from: Jerry Hall;51355

You cannot usually grind a head gasket for a large bore. Grinding a head gasket gets into or too close to the stamped ridge in the gasket that seals the high combustion pressure. Look at the gasket and see how close your grinding came to this ridge in the gasket.

Like mentioned earlier, make sure the head and top of the cylinder are flat and without ANY imperfections on the gasket sealing surfaces.

Thanks Jerry. What gasket do you recommend I use for a 69 mm bore? The first two wiseco ones I tried, coolant seeped outside the head.

JesseA420 · « **Reply #8 on:** March 11, 2015, 10:52:20 AM »

bike will still run with a slightly leaking head gasket, go rip that sucker for ur birthday

also u can have the surface ground on the cylinder no biggie, or u can have it cut for o-rings for a coolhead also no biggie.

Jerry Hall · « **Reply #9 on:** March 11, 2015, 10:57:43 AM »

Quote from: JesseA420;51359

bike will still run with a slightly leaking head gasket, go rip that sucker for ur birthday

..................as long as the engine stays full of coolant you will be ok............but if the engine gets low on coolant you may fry the top end.

dem3500 · « **Reply #10 on:** March 11, 2015, 11:01:16 AM »

Have it lapped and also cut for o-rings. That should solve your problem

JesseA420 · « **Reply #11 on:** March 11, 2015, 11:05:58 AM »

of course, just keep the radiator topped off

Happy b-day btw

Pumashine · « **Reply #12 on:** March 11, 2015, 11:11:34 AM »

Sorry, I don't have the 69mm gaskets. Mine are all clearanced for the 67mm. When you pull the head look to see where the leak is at. Check the head and cylinder top for flatness with a straight edge. The cylinder should have been cut flat after the sleeve was installed. The sleeve may have dropped creating a step right next to the coolant passage. Still sounds like the head may be warped which is the easiest to fix.

rk88r · « **Reply #13 on:** March 11, 2015, 11:29:09 AM »

Shouldn't the sleeve be a hair proud of the jug?

Jimbo45 · « **Reply #14 on:** March 11, 2015, 11:38:06 AM »

Quote from: Pumashine;51366

Sorry, I don't have the 69mm gaskets. Mine are all clearanced for the 67mm. When you pull the head look to see where the leak is at. Check the head and cylinder top for flatness with a straight edge. The cylinder should have been cut flat after the sleeve was installed. The sleeve may have dropped creating a step right next to the coolant passage. Still sounds like the head may be warped which is the easiest to fix.

I think there is a step at the sleeve. I noticed it when cleaning the old gasket off.

I would like to just send off the other head I have, to someone that can lap it, cut it for a 69mm bore, and shape the squish properly. Problem is, I don't know where to send it, and can't spend a ton on it. The other part of me just wants to scrap this whole top end, and just have the one that came on this bike bored (if its possible, the one has a 68mm now), trued and the head worked to match.

This top end was bought used, with said to have only 5 hours on it. That was probably true, since the piston looked good and it has good compression. But, I suspect the previous owner had the same gasket issue. I don't know that for sure, but can't imagine it didn't have the problem before. The sleeve job was bad.....the bottom wasn't even blended to the ports, and no chamfer was cut on the bottom, to help insert the piston and rings. :upset: