? its back

Discuss all things 1970 & later Airheads right here.
Post Reply
Motorhead
Posts: 391
Joined: Mon Aug 09, 2010 8:30 pm

? its back

Post by Motorhead »

well after a week of rideing a few laps around palos verdies where there are switch backs and roads with surface repairs I like to test my suspension all in all about 30 miles of ride and trips to work
...... I hoped the 5 hours of lapping my heads and checking the timeing was gona be the last of this puzzle and maybe if I rode it some the clear it maybe a hope for a higher PSI

today I have 120PSI on both cylinders, a little lower than when I finished the work last sunday

a few drops of oil didn't help and also it burns NO oil or loses oil or pushes out out the breather ??????? valves are stable

What if I have Ted Porter. Ed Corn... or other guru rebuild my heads and maybe a rebore and a set of new pistions with rings other than Hastings which I always trusted?????

Is the Californa gas killing my Bike?????
Major Softie
Posts: 8900
Joined: Tue Aug 03, 2010 1:46 pm

Re: ? its back

Post by Major Softie »

Edit: Oops, I mixed this up with the Krauser 4v bike.
MS - out
Kurt in S.A.
Posts: 1657
Joined: Tue Aug 03, 2010 12:08 pm

Re: ? its back

Post by Kurt in S.A. »

I don't understand what the issue is...what does "?" in the subject mean?? Makes it kind of hard to know what's going on... Maybe it's just me...

Kurt in S.A.
User avatar
George Ryals
Posts: 510
Joined: Tue Aug 03, 2010 10:22 am
Location: Stone Mountain, GA

Re: ? its back

Post by George Ryals »

Motorhead, 30 miles in one trip is barely enough to get the engine fully warmed up, forget seating the rings that fast. Put 2500 miles on it (in at least 50 mile incremente) then check the compression
Smile it's contagious!
'74 R90S, '67 /2 Conv w/sc, '66 R50/2
'74 Harley FXE, '72 Harley FLH w/HD sc
'69 BSA 441 Victor Special, '74 R90/6 Basket case
'85 R80RT wreck for parts
Motorhead
Posts: 391
Joined: Mon Aug 09, 2010 8:30 pm

Re: ? its back

Post by Motorhead »

the bike has 25,000 after a rebuild, the rebuild compression was 135 psi the bike ran strong and wondeful until last year I ride to sturgis and thats when I noticed the miles on the tank didn't last as I expected

I been blameing the Californa fuel for 4 years especally after the sturgis ride with my faithful BMW especally after use after the Sturgis ride when I got 35 MPG with the 37/11

I changed my rear drive for a better MPG Like my first BMW with 32/11 that got me 50 MPG. with the Texas run got me 25 MPG????????

so as I surched my problem I came to a 110 on riight and 95 left all other stuff like I said seems stable and right on time tappets and oil use is not suspect and stable

I spent 5 hours lapping the valves and after I put the heads back on and a trip around the hill seemed better

the trip around the hill is 30 miles and I actually ran the road 2X each time so 60 miles actually 2 times this last week

to work before the event so milage covered is ok the problem still exists
Motorhead
Posts: 391
Joined: Mon Aug 09, 2010 8:30 pm

Re: ? its back

Post by Motorhead »

Oh to hear the bike it sounds normal and nothing other than a poor MPG says anything is wrong
Kurt in S.A.
Posts: 1657
Joined: Tue Aug 03, 2010 12:08 pm

Re: ? its back

Post by Kurt in S.A. »

What is your procedure for checking compression? And for the unread, what bike model/year do you have? Carb types?

Kurt in S.A.
Motorhead
Posts: 391
Joined: Mon Aug 09, 2010 8:30 pm

Re: ? its back

Post by Motorhead »

the major part of year is a matching frame and motor case 1973 R75/5 after 87,000 the motor suffered a valve recession
I knew the history of this bike from the first owner...... I'm the 4th and last owner, the bike had Leaded fuel, then had first mix unleaded fuel, when I got it the fuel was 91 MBTE Unleaded , it seemed to like that gas..... then fuel changes again to 91 gasahol....

so when I rebuilt it I went to 1974 spec 900cc with stock bore used cylinders and matching pistions, with new rings and rebuilt R90 heads

Rings used were Hastings, heads rebuilt in National city

I used these rings before with my First BMW and had no trouble and the buyer that I sold to had no trouble, even when we we met again... after 4 years and over 40,000 miles after I built that one so as I had sucess before I retraced my build before I didn't account for a problem

the only thing diffrent now is I used heads I had rebuilt from Luftmeister........

I found last weekend the leaks are from the exhaust valve a sorta film burned on them like oil on a fry pan that coats the valve ruining the seal I lapped all valves

yesterday I checked my effort and I heard the same hiss that came last time as the cylinder comes to compression
Motorhead
Posts: 391
Joined: Mon Aug 09, 2010 8:30 pm

Re: ? its back

Post by Motorhead »

Method is Mickuni carbs locked open and bike starter is used, if compression is in range( 125+) after 4 pumps of piston Grand if 5 to 6 Ok more is poor PSI range is 125 to 140 PSI full compression now is 120 after 5 pumps on top......

the guage is certified and I've use it for years as I'm a builder, I have a simler guage certified for leak down and again the leak is in the valves
Post Reply