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Old 07-25-2013, 07:35 PM   #1
Beezer Josh OP
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Starting

Back in late January I picked up an R75/5. I really like the bike. It runs well once it's started and it's way smoother than my BSA, especially at higher speeds! However, I've always had a problem starting it even with the enrichener and the problem gets much worse in lower temperatures. With that in mind, I rebuilt and rebalanced the carbs. I replaced all the jets, making sure all circuits were open. I balanced them with a TwinMax, tuning the idle mixture in the middle of the mixture screw's very narrow in/out range. I also checked the valve adjustment. The left intake and right exhaust were slightly off, but only by very little-about a thousandth. I also replaced the battery.

Next I went to adjust the points. Lo and behold, the PO replaced those with a Dyna III. The timing was off-too advanced at idle, too retarded at 3k. So I replaced the advance springs, which fixed the problem. Timing is almost spot on, with a little ghosting.

The idle was still off so I added the springs to the slides as Snowbum suggests. No difference, so I took them out. A few weekends ago I replaced the timing chain, tensioner, tensioner spring, and crankshaft and camshaft sprockets and re-timed the bike. No change. I figure the ghosting I should be able to adjust out by moving one of the pickups on the Dyna III. Argh! I think the starter also needs to be rebuilt, but, taking the starter out of the equation, it's still a bear to start with the kickstart. I'm not sure if this is normal, but it seems like it wants to fire on one cylinder while starting it. Kinda like a whir-whir-whir-boom-whir-whir-whir-boom. So, I'm now begging you guys to give me some more ideas on what else to check.

Beezer Josh screwed with this post 07-25-2013 at 07:42 PM
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Old 07-25-2013, 08:14 PM   #2
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Assuming you have torqued the heads and set the valves properly, I would verify the state of the coils, wires and caps. New plugs may help too.
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Old 07-25-2013, 09:23 PM   #3
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Carb starter circuit? One working the other not.

------------
For better battery start up performance an odessy battery would be good. But it is an add on.
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Old 07-26-2013, 03:27 AM   #4
Bill Harris
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That is what I'm thinking. Especially the little jet in the bowl and the pickup tube. And make sure that the enrichener discs are correct R and L.

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Old 07-26-2013, 03:50 AM   #5
Beezer Josh OP
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Thanks guys! Just to add to the list, one of the first things I did was change the plugs.

When I cleaned out the carbs, I made sure that the jet in the bowl and the pickup tubes were clear. In fact, I thought that might have been an issue, so I cleaned the carbs out again. At that point, I also verified the enricher discs were on the correct sides (I only did one at a time, anyway) and that the jets drilled in the discs were clear and operated in the correct positions.

On maybe a related note, once the bike warms up, idle varies by about 100-150 rpm. Sometimes I'll pull up to a stoplight and the idle will be very slightly faster than at the previous stoplight. I have also checked for air leaks around the flanges and that came up negative. All o-rings are also brand new.

Beezer Josh screwed with this post 07-26-2013 at 03:56 AM
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Old 07-26-2013, 04:32 AM   #6
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Did you set the idle mix screws with the engine hot? I can't see why it would want to hunt by 150RPM when hot if you set it while hot.

Sounds like you've done all of the right carb stuff. Have you done a leakdown or compression test?

That bike should start like a dream.
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Old 07-26-2013, 02:56 PM   #7
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Don't need resistance plugs. You have resistance caps. But this may have zero effect.

Immediate and energetic starting is something I have insisted on for several years. I always set the enrichners to full on, unless the bike is already warm, and crank the throttle open about 1/3rd. This time of year the enrichners come off right away, when colder out they come off slower, but I still use full enrichner in the Summer. I don't spend a lot of time warming the bike before riding but I do spend some time warming the bike. Minimum I'd say a minute. Maximum 2. Warm up is held on by the throttle cruise control screw. I set to a comfortable 1500 to 2000. I have to control the idle with the throttle for the first 5 minutes or more.

I do have problems with idle once my bike is warm but it has very little to do with starting the bike.
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Old 07-26-2013, 03:56 PM   #8
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Somehow mine has good and bad days. Most of the time I set the enricheners to half and the bike starts right up. Then on other days I have to play with the enricheners and / or the throttle to get it started. Once it has started it runs like a charm... Typically I take the enricheners off as soon as I am on my way and accelerate easy to warm the engine up first. To me it seems kinda odd that it so inconsistent.
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Old 07-26-2013, 04:28 PM   #9
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It may pay for you guys with problems to check the enrichner gaskets. Not uncommon for them to succumb to vacuum forces, and once that happens all kinds of mystery problems occur.
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Old 07-26-2013, 06:58 PM   #10
Bill Harris
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Yeah, the Enrichener gaskets do suck some times.

But you don't have it bad. Here is the Enrichener-less old 600cc /5 owners starting drill:

First shalt thou Depress the Holy Tickler Pin until fuel dribbles out the overflow tube in the bottom of the float bowl. Then, shalt thou Pump the throttle seven times. No more. No less. Seven shalt be the number thou shalt count, and the number of the counting shall be seven. Eight shalt thou not count, nor either count thou six, excepting that thou then proceed to seven. Ten is right out. Once the number seven, being the seventh number, be reached, then crack the throttle by one-in-eight and hit the starter button. And the engine will start, and the people will feast upon the lambs and sloths and carp and anchovies and orangutans and breakfast cereals and fruit bats and large chu--

(Skip a bit, Brother)

After 20-30 seconds, if the engine starts to bog, hit the tickler again...

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Bill Harris screwed with this post 07-27-2013 at 01:39 AM
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Old 07-26-2013, 08:26 PM   #11
Mista Vern
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Quote:
Originally Posted by Bill Harris View Post
Yeah, the Enrichener gaskets do such some times.

But you don't have it bad. Here is the Enrichener-less old 600cc /5 owners starting drill:

First shalt thou Depress the Holy Tickler Pin until fuel dribbles out the overflow tube in the bottom of the float bowl. Then, shalt thou Pump the throttle seven times. No more. No less. Seven shalt be the number thou shalt count, and the number of the counting shall be seven. Eight shalt thou not count, nor either count thou six, excepting that thou then proceed to seven. Ten is right out. Once the number seven, being the seventh number, be reached, then crack the throttle by one-in-eight and hit the starter button. And the engine will start, and the people will feast upon the lambs and sloths and carp and anchovies and orangutans and breakfast cereals and fruit bats and large chu--



--Bill




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Old 07-26-2013, 08:44 PM   #12
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Ensure the float bowl gaskets are in good condition. If not, air can enter the starting circuit diluting the expected rich starting mix. Click to enlarge.



I'm in the full choke crowd, no throttle until the engine catches. I start the bike whilst seated and ready to ride, minimal stationary warmup. Idle won't be independant until it's a bit warm. Upon starting half choke is almost immediate, then it's off within 2-3 kms.
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Old 07-28-2013, 11:01 AM   #13
Beezer Josh OP
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Quote:
Originally Posted by Bill Harris View Post
First shalt thou Depress the Holy Tickler Pin until fuel dribbles out the overflow tube in the bottom of the float bowl. Then, shalt thou Pump the throttle seven times. No more. No less. Seven shalt be the number thou shalt count, and the number of the counting shall be seven. Eight shalt thou not count, nor either count thou six, excepting that thou then proceed to seven. Ten is right out. Once the number seven, being the seventh number, be reached, then crack the throttle by one-in-eight and hit the starter button. And the engine will start, and the people will feast upon the lambs and sloths and carp and anchovies and orangutans and breakfast cereals and fruit bats and large chu--
Haha! Awesome Bill! I just checked on this thread and it made me laugh. I offered to help a friend move a deceased sister's house this weekend, so haven't had the opportunity to install the new spark plugs and ride.

As for sucking in the gasket, it's not. I changed it out, had the same problems, and pulled it apart to verify it was in the correct location-no sucked in gasket. Anyone tried anaerobic gasket maker in this application? I've used it on oil pumps-where you definitely don't want globs clogging the lubrication system-with great success.

On a different note, and one to which this thread has shifted, I love the extended ticklers on my old Amal carbs. My BSA starts up MUCH better in the cold (or any time for that matter) than the BMW and I don't get gasoline on my hands. The only downside is that the area just under the ticklers is gas stained...it comes off with a bit of carb cleaner though. However, I rebuilt that bike not for show, but to be ridden!
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Old 07-27-2013, 12:01 PM   #14
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There were some differences in the Bing CV enricher operation over the years. Early ones like my 79 flat tops originally had only one fuel hole in the disc which explains why it's all or nothing in operation. I don't know when they changed but later models have several fuel holes of varying size to provide a progressive action.

There was service bulletin S1300179 100R issued in Jan 79 for the R45/65's with flat top Bings. It describes modifying the disc by enlarging each of the 4 drilled recesses to 2.5mm and drilling a 0.6mm hole in the 4th position. The bulletin also states that spare parts are already modified and any carbs updated by the dealer will have a spot of red paint on the enricher housing.

Next time I have the carbs of I'm going to give this a try.


Ticklers if they could have left out the mess was a brilliantly simple automatic choke that provided enrichment that diminished as the fuel level fell. SU did it much better by lowering the needle jet to achieve the same result.

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Old 07-28-2013, 07:00 PM   #15
bmwrench
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Make sure the choke discs are on the correct side and that they are oriented correctly. Also, make sure that the choke jet in the bowl is clear.
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