turbowrenchhead

When I get my clutch gasket I'll get the motor together and install it in the bike and re test cranking compression

I tested my gauge on another machine. It read 120psi on a stock warrior. Seems about right

I didn't want to put an impact to crank nut.

If you look at my other post about higher exhaust port effecting cranking compression you'll see that I'm scratching for answers. If you crank over an engine with a 1/2' ratchet on the crank gear nut and spin it over by hand will you get a good psi reading? Does the kick start spin the crank several times faster then doing it manually with a ratchet?

I've had my craftsman gauge for a long time and its been really good for several years. I've compared reading to snap on's and mac's and it was accurate. It's not the gauge. The next thing I'm going to try and putting the old cylinders and piston back on and see what I get for cranking compression on the bench using the same method I did today.

Ok, so I pulled the head back off and the cylinders. I checked the ring gap. They are between .003 & .004. Piston/cylinder wall clearance is .003. I compared the old cylinder and new cylinder deck height. Old ones are at 102.37, new ones at 102.36. I had the new pair decked .004 because there was a nick in one of them. I measured how much I raised the exhaust port and I raised it 1.6mm over the old pair. So I'm really at a loss why compression is so low. Is it just because of trying to crank it over on the bench? Does the kick start actuate the piston's that much faster that you get higher cranking compression?

Because the exhaust had no where to go? It is trapped in the head port? It probably doesn't work that way, who knows. I'm just thinking out loud. I'm really boggled why the compression is so low

I understand how it works. However I'm kinda boggled how only 2mm would effect cranking compression that much

For shits and giggles I tried blocking off the exhaust and seeing if the compression would go up. Now I get 90psi with a blocked exhaust. So that shoots down the theory that the exhaust porting is effecting the compression.

Thats what I'm thinking. How can it be so low?

Typo: Its suppose to be 21cc domes not 20's

I have a .045 squish and 20cc domes. The last pair of cylinders were ported the same way except I didn't raise the exhaust port. Those made 150psi with the 20 domes.

I thought I would do a little experimenting on this last pair of cylinders since I got them cheap. I raised the exhaust port up 2mm. I did a cranking compression test with it on the bench and cranked it over with a large ratchet and socket off the crank gear nut. I also tried with a cordless and that was a bit faster, regardless I got the same reading on the both cylinders, 60psi. So is this normal when you raise the exhaust ports?

It seems I can't get it to seal up with just the gaskets in this area. I have to apply Yamahabond to both sides of the gaskets and then it will pass the leak down.

I haven't had one seal up with just gaskets yet! I always have to silicone both side of the gasket with Yamahabond.

google "how to build a leak down tester" Once you have it built then you apply 7psi to the crank case. It should hold that pressure for 20 mins. If it doesn't then you know you have a leak. You spray the seals and gaskets with a soapy water mix. The leak will create bubbles. Whala! there is your leak. I have had leaks between the case halfs and the reed/intake boot gaskets.

Exhaust port is radius-ed well. My machinist champhered the ports and did a nice job when he bored the cylinders.

Do a leak down test

I have a the biggest trip of the year on March 30th. There will be around 10 other big sport bikes riding with me. Last year I discovered that one of my cylinders had a chuck of metal missing between the intake and boost ports. It still ran great, however I knew that I needed to replace my cylinders. I was going to send them to Cam at redline. He didn't have any good used cylinders in stock so I had to find a pair. I bought a pair advertising a 64.50mm bore size. I got them and powder coated them red. Machinist states that they will need a 66.00 piston. Now I'm stuck with them because I can't return them because they are not in the condition that they were when I bought them. The seller gave me a round around as well. I decide to port them myself like the last pair but leave more room between the boost and intakes. Ordered 66mm wiseco pro lites and some V4's. All my parts, gaskets and misc showed up. Tonight I thought perhaps I should pull the motor and go through everything to make sure all is well. First discovery I found was the lower case was cracked by the rear sprocket. I poped a chain last year and it hit is so hard it put a 1 1/2" crack in the case in a non oil cavity. It also bent one of the chain guard bolts. So I need to get it welded so the crack doesn't spread to an oil cavity. Drained the oil and it had excessive amounts of fine aluminum flakes. Pulled the case half's apart and I can't see any damage anywhere. Only thing I can think is the the billet aluminum water pump gear if the source. The gear looks fine though, so again more weird. I measured up the new cylinders versus the old ones. My intakes are 6mm longer then the last pair. And exhaust is 4mm wider then last pair. I wonder how much this will effect my jetting/performance? I also roughed up the trench and did some case porting. Brought the transfer opening on the outside to 4mm wide on both the jugs and case.

Sounds like the biz is going to stay closed.

You have to start with the basics again. Check spark then check fuel. No spark then you need your volt meter to run ohm tests.

I wrote back to Brandon that I was sorry for his loss and that no one should out live their parents. He responded and apologized for "being a jerk". He said that he would ship me a spring or any other parts that may be in stock that I need.

I found out the hard way how expensive it is to restore and modify a beat bike. I thought I got a great deal for $900 running banshee, ha ha ha

If I could go back and do it over that's what I would of done

I could of bought an elka for the money I'll have into two stockers