Bike hesitant?

[beemer]

Been out for a ride this morning,bike is hesitant between 60 to 70mph,keep twisting the throttle but no increase in speed?in line fuel filter is full,ive recently adjusted the carbs and it's pulling like a train till you reach 60mph,air cleaner ok,choke not sticking,float bowls full,valve clearances all ok,changed coil,all seems fine,this is a 83 R65LS with electronic ignition,help please!!!thanks,Julian.

[montmil]

Done anything with the diaphragms lately? Several recent posts by riders with oh so similar problems have traced the issue to using heavier than stock replacement diaphragms. The fix is going back to the lighter rubber bits and/or raising the needle one notch.

"ive (sic) recently adjusted the carbs."  That would be a starting point to find your problem. Did it pull past 60 before the carb work? Did you use a manometer for balancing? What adjustments were made?

Can be frustrating. The fix is usually something very simple. Finding it is the challenge. Luck to you...      Monte

[beemer]

Done anything with the diaphragms lately? Several recent posts by riders with oh so similar problems have traced the issue to using heavier than stock replacement diaphragms. The fix is going back to the lighter rubber bits and/or raising the needle one notch.

"ive (sic) recently adjusted the carbs."  That would be a starting point to find your problem. Did it pull past 60 before the carb work? Did you use a manometer for balancing? What adjustments were made?

Cab be frustrating. The fix is usually something very simple. Finding it is the challenge. Luck to you...      Monte

Mixture and balance was done to the carbs,it was slightly hesitant before,but has got worse now,no didn't use a monometer,i did it by ear this time,but iv'e just come indoors after another check and monometer tune,and it's still the same.plugs are a nice grey colour,so mixture seems ok.

[larstorders]

If it revs up ok when in neutral, then, this sounds very 'carby' to me.  If you just did a carb rebuild all those pesky tight screws n nuts should be loose enough to allow for a quick re-strip to check all is as it should be or, hopefully discover the problem.

[beemer]

I want to check the diaphrams tomorrow,how do i go about it?and what am i looking for?thanks,Julian

[montmil]

The domed tops of the carbs must come off. Simple, as long as the cross-point screws have not bonded themselves to the carb body. [smiley=angry.gif] Be sure the screws can be removed before proceeding further.

You'll need to detach the throttle and choke cables. Here's a way to do it without messing up four cable adjustments...

1. Disconnect fuel lines at the carbs;
2. Loosen the clamps holding both ends of the carbs to the rubber      connectors and air box;
3. Slide the rear rubber connector tube down onto the hard plastic elbow;
4. Gently rotate the carbs to permit releasing the cables at the carb connections;
5. Removing the top cover will take away the cables and retain the current slack adjustment positions.

Diaphragms may develop tiny almost invisible tears. Also, be sure the locating tabs on the diaphragms perimeter are returned to the small notch in the carb body. Too, the metal "caps" in the top of the domes can develop leaks. I've seen black RTV, epoxy, dimes and BMW roundels glued on as leak stoppers.

I you have not done so, buy a manual for your own peace of mind

Monte  -Guys. What have I forgotten to tell Julian?

[beemer]

I took the left hand carb cover off this morning and found a small tear in the diaphram,so i removed both carbs,the right hand carb is fine,but i have orderd 2 new diaphram's and will replace them both,one screw in each cover was buggered!!!!the crosshead was chewed up,i managed to get the one from the left hand carb off tapping round gently with a small chisel,the right hand one had to be drilled out!!!i have also ordered a set of 4 stainless screws for the rebuild,SO!!!just have to wait till the new parts come,maybe tomorrow?i can't see how you remove the needle,if for instance if i was going to replace it in another position?will keep you updated as soon as the job is done,fingers crossed it will run ok after that,by the way,how can you tell if the dome on the top cover is leaking air?think i should run a bead of epoxy round it just in case?Julian.

[montmil]

Following edited info is credited to the Snowbum site:
"LEAKY TOP PLUGS
Some carburetors have had leaky steel plugs on the domes. You can easily test the plugs for leaks when the domes are off for servicing the carburetors. DO NOT allow any leaks; it will act like a torn diaphragm. They can be crimped or epoxied. There is a BMW Roundel that can be epoxied to the top of the carburetors."

Julian, grab the fatter part of the needle where it exits the vacuum slide using some thin leather and needlenosed pliers to turn the needle 90 degrees. Pull on it and it should move to the next notch. Now, turn it 90 degrees to the next notch, etc. Do not mess up the needle.

[beemer]

Following edited info is credited to the Snowbum site:
"LEAKY TOP PLUGS
Some carburetors have had leaky steel plugs on the domes. You can easily test the plugs for leaks when the domes are off for servicing the carburetors. DO NOT allow any leaks; it will act like a torn diaphragm. They can be crimped or epoxied. There is a BMW Roundel that can be epoxied to the top of the carburetors."

Julian, grab the fatter part of the needle where it exits the vacuum slide using some thin leather and needlenosed pliers to turn the needle 90 degrees. Pull on it and it should move to the next notch. Now, turn it 90 degrees to the next notch, etc. Do not mess up the needle.

Thanks Mont,iv'e just put some epoxy on the domes,a thin smear,so if there is a leak it should seal it up,fingers crossed!!!thanks for the needle tip,i don't want to mess with it(yet),but it's good to know how to do it,i ordered the diaphrams from motorworks,they had 2 types,a european type,and the bings,i got the bings,he said they are much softer and plyable,so,will wait for them to arrive,and take my time and re-assemble them,i hope it's going to be a success,Julian.

[montmil]

You did good, Julian. The non-Bing diaphragms sold by several outfits have caused multiple tuning, synch'ing and various driveability problems after the rebuilds. Right choice, eh, Lucky Lou?         Monte

[beemer]

You did good, Julian. The non-Bing diaphragms sold by several outfits have caused multiple tuning, synch'ing and various driveability problems after the rebuilds. Right choice, eh, Lucky Lou?         Monte

I remember the threads Monte on the problems with non bing units so i didn't want to go over it again if i didn't have too,iv'e just measured the length of the needles,they are both the same,i just wanted to know!julian.As a matter of interest,what is the metrail Hydrin?look here,
http://www.motobins.co.uk/displayfinal.php?function=show&subs=084&title=DIAPHRAGMS+%26+GASKETS

[larstorders]

While you're waiting for that replacement diaphragm SUPERGLUE will provide an effective temporary fix.
 After carefully glueing, I managed to get about 1,500 miles from an R100RS carb diaphragm, before replacement. Meaning not a single day of dry sunny riding weather was missed. So a valuable repair for us in northern Europe.

[Lucky_Lou]

You did good, Julian. The non-Bing diaphragms sold by several outfits have caused multiple tuning, synch'ing and various driveability problems after the rebuilds. Right choice, eh, Lucky Lou?         Monte

spot on spare yourself all the greif ive had with the generic ones BTW are you useing any fuel addative?
Lou

[beemer]

You did good, Julian. The non-Bing diaphragms sold by several outfits have caused multiple tuning, synch'ing and various driveability problems after the rebuilds. Right choice, eh, Lucky Lou?         Monte

spot on spare yourself all the greif ive had with the generic ones BTW are you useing any fuel addative?
Lou

I use a drop in the tank unit,Julian.

[montmil]

As a matter of interest,what is the metrail Hydrin?

Those are the thicker, aftermarket, non-Bing diaphragms. Half the Bing price with twice the tuning issues.
Monte