head job

[vmeyer]

I lost a belt several years ago. all seemed ok when I got it back together, but I didn't ride much(Less Than 1000mi.) The bike sat in the barn for 2 years then last spring I went throught the carbs and did several other much needed refreshes and ugrades. The bike ran better than it had in years. I had the radiator out last summer so I checked the belts and renewed the tensioners. During that time I looked and felt that the belt on the left (2/4) was 1 tooth behind. So I corrected it. Then the bike really ran nice!! Fired up this spring everything seemed great, but I had nagging feeling that the right side may be off too and I hadn't checked it when I had the front off. So now that I had help I made absolutely sure that both sides were dead on. After that it seems to have a miss. The plugs all look normal as far a color and deposits, but you can feel a definite vibration and loss of power. I checked compression tonight 1@156 2@135 3@160 4@129???? If I had bent valves from lossing the belt why would it run good a tooth behind but miss when correct? I thought I could hear a slight knocking on the right which is why I wanted to make doubly sure that it was on the correct tooth on the belt

[Whiskerfish]

Having a cylinder advanced or retarded can mask other issues for sure. The key with the belts is to get your head down to level when lining up the index point on the front of the cylinder head.

I would run those numbers again then try to do a leak down test to try and determine the exact reason for the split. A 30 pound split is pretty significant.

[jdvorchak]

Don't beat yourself up over those compression numbers. It if ran fine a year ago but now has a miss I suspect that your carbs need freshing/cleaning. Yes do a compression test again and yes do a leak down. If the leak down shows no definite problem suspect your carb idle circuits or a sticky slide or sticking float/float valve.

[vmeyer]

If I pull the carbs apart again do you normally just order the gaskets. They came out great for a first time carb job for me.... All Raddaks kit.

[vmeyer]

btw THANK YOU Whiskerfish for all you do here!!

[Whiskerfish]

[jdvorchak]

No if the gaskets are still good you can reuse them

[vmeyer]

Or another solution..... Do not let the teenager help.. As when he let it roll past the T1 mark then went to the next T1 the right cam ends up 180 out. Causing several nights loss of sleep and this thread. Whicj you find out after tediously removing the belt covers w/o the factory spanner wrench.

[vmeyer]

Any suggestions on how to shpre up tje low compression though.

[Whiskerfish]

In the event that the cause is the Valves, I have seen several bikes that were run with "fouled" Carbs. That causes a incomplete burn of the fuel air mix and excessive carbon build up. Eventually that will lead to build up on the valve seats and even into the intake port of the head. So you can try a de-carbonizing treatment and see if that provides any relief. If you go that route you may want to alert the neighbors as they may think your Garage is on fire. I have done it with seafoam and with raw water. If that does not show any improvement then you probably need to remove the heads and do a Valve lap.

[jdvorchak]

You're skipping a step here. You have to run a leak down test to see where and if there is leakage. Or you can spend the weekend taking the heads off, lapping valves that didn't need it, risk tearing a gasket or two, source $100 worth of new head gaskets, hope you don't strip a bolt and put it all back together again only to find one of your carbs has a dirty pilot jet.

In my humble opinion that 30 lb split is not that bad. Since the bike has not been running those compression numbers will come up and even out. Also that 30 lb split will not cause a miss.

[vmeyer]

Very carefully re timed the belts tonight. It ran sooo smooth. I am going to re sync the carbs. Then re check the compression. I will post them here again when I get it done.