Low vacum after top end rebuild?Help!!

[Anonymous]

Hey guys,I just rebuilt the top end of my 79 GS850G{std rings,and lapped the valves due to low compression-found that exess carbon had built up on seats holding valves open}cleaned carbs new needles+seats.Now its difficult to start and when i try to synk the carbs i can only get 4-6 inches of vacum before i run out of adjustment at carb.I followed the procedure i found outlined i varius posts-9/64 throttle opening +3 turns,1 1/2 air screw,1 3/4 idle mixture screw.points and timing werent touched and were new,although to get it timed right i had to turn the points to the limit of there adjustment before i did top end-Any ideas,could i have a cam off a tooth-im pretty sure they are right but?? :?

[scotty]

Perhaps the rings are not seated yet. Or the cylinders are out of round. I fit is not done with a overbore and oversized pistons it usually wont last more than a few K miles if it works out at all.
did you mike up the jugs??

[Don Lobacz]

Recheck your cam timing and check your compression in each cylinder.

[SqDancerLynn1]

CHeck the cam timing, I'm guessing you are off a tooth

[Anonymous]

Found crank had moved i tooth,making both cams off--easy to do--it happened a second time while setting it--got it right now--got vacume--- but still missing like hell looked at brand new points and rear set sparking like crazy,must be a bad [new] condenser-just won a dyna set up on ebay got to be better in long run,point+condenser set me back nearly 40$
THanks for your help guys!!
Bob Mulligan in VA. :roll: :roll:

[SqDancerLynn1]

You do need to change the coils with the dyna or run a balist resistor. In the last 12K miles the only thing I have done to the points on my 79 GS850 is one cleaning. I do have a dyna Ign, it has been in my spare parts bin for the last year. I couldn't pass up the sale they had last year

[KEITH KRAUSE]

Lynn, the Dyna ignition will run fine with stock coils. At least the Dyna "S" will.