Ide troubles with pd50 carbs

Please post your bike pics here

Moderators: Volker_P, tidd650

my79650
Posts: 643
Joined: Tue Apr 06, 2010 11:37 am
Location: Gagetown, New Brunswick Canada

Re: Ide troubles with pd50 carbs

Postby my79650 » Wed May 29, 2013 2:52 am

Will try the no cover idea. And my battery is getting weak. Added some water to all cells; almost 4 yrs old so replacing may be needed afterall. My advancer was a little rusty, never pulled it but i did spray everything inside and let it dry while checking valves.....again. Screws wouldn't turn in the advancer or i would have pulled and cleaned it properly. Have spark to plugs also, and i have black sooty plugs so i need to readjust cause they were the light brown and running right before i cleaned the carbs and swapped timing chain. These are new NGKs and properly gapped.

my79650
Posts: 643
Joined: Tue Apr 06, 2010 11:37 am
Location: Gagetown, New Brunswick Canada

Re: Ide troubles with pd50 carbs

Postby my79650 » Fri May 31, 2013 2:53 am

Still acting up. Plan to check valves again before i pull the carburetors and clean again. When i did the cleaning i didn't use compressed air in the castings. Just used wd40 and spray carb cleaner, everything blew through with both products. If no change after valve check then i'll remove and disassemble the rack again now i got a small compressor with a small enough fitting to clear out anything in the castings. New inline filter installed as well and not lacking gas to carbs.

my79650
Posts: 643
Joined: Tue Apr 06, 2010 11:37 am
Location: Gagetown, New Brunswick Canada

Re: Ide troubles with pd50 carbs

Postby my79650 » Sat Jun 01, 2013 10:38 am

Pulled the rack and dropped the bowls. Slow jets are pretty good, only 1 out of 4 has 2 clogged holes. 3 of the 4 emulisifer tubes has some clogged small holes. Should have used compressed air to clear all the spots in the castings, know better next time.

my79650
Posts: 643
Joined: Tue Apr 06, 2010 11:37 am
Location: Gagetown, New Brunswick Canada

Re: Ide troubles with pd50 carbs

Postby my79650 » Sun Jun 02, 2013 4:46 am

I filled up with 91 octane during test drive. I want to drain the gas and check the tank, what do i use for a straining filter?

User avatar
Volker_P
Posts: 5311
Joined: Mon Mar 06, 2006 1:53 am
Location: southern Germany

Re: Ide troubles with pd50 carbs

Postby Volker_P » Tue Jun 04, 2013 2:58 am

I prefere these "gold" coffee filters.
But a piece of underwear cloth will do it, too.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

my79650
Posts: 643
Joined: Tue Apr 06, 2010 11:37 am
Location: Gagetown, New Brunswick Canada

Re: Ide troubles with pd50 carbs

Postby my79650 » Tue Jun 04, 2013 8:33 am

Used an old shirt and a large clean pail. Hardly anything came out. I cleaned out the tank with paint thinner and a few nuts and the old timing chain from the swap job. Same as when i strained the gas, very little to any debris. Then a second time with kerosene since it leaves an oily film, great to prevent flash rust. Then i reinstalled the petcock(right name?) and sloshed a gallon of gas again, this can go into lawn mower:). Added a few ounces of Seafoam then filled up with the hi-test fuel, no leaks in tank or at petcock. Now i am going to remove and boil the isolators to ease the carb install. Hopefully i won't have to pull the rack again and clean them out, wait and see what happens now.

my79650
Posts: 643
Joined: Tue Apr 06, 2010 11:37 am
Location: Gagetown, New Brunswick Canada

Re: Ide troubles with pd50 carbs

Postby my79650 » Thu Jun 06, 2013 1:40 am

Pulled the rack again. Before i blocked off the air cutoffs on the air box side the engine wouldn't idle below 1700/1800rpm but it worked great on the road, no hesitation or flat spots or acting like it's not getting enough gas. Plus it would quit every time i came to a stop. Now since i blocked them off it idles round 1200rpm no problem except it's a bit rough. No photo yet but underneath the cutoff diaphram there is a small hole at a 45 degree angle that leads to the slow jet channel in the casting. I found this when i removed a good one to check things out for the hell of it. I think all the holes need to be plugged for this bypass to work properly as the pressure isn't equalized and this may be causing my problems with flat spots when idling or when i take it to redline. Does this make sense to anyone? I got a set of 79 750 cv carbs with the cutoffs in them. I am going to check if there any good and if they're the same size, if so then i will remove my solder job and try that. This is the 3rd time i have to split these, its getting annoying. those cv carbs were given to me so i may be able to swipe the choke cable holder to the pd50s, may as well check it out while i'm at it.

User avatar
Volker_P
Posts: 5311
Joined: Mon Mar 06, 2006 1:53 am
Location: southern Germany

Re: Ide troubles with pd50 carbs

Postby Volker_P » Thu Jun 06, 2013 4:53 am

my79650 wrote:I think all the holes need to be plugged for this bypass to work properly as the pressure isn't equalized and this may be causing my problems with flat spots when idling or when i take it to redline. Does this make sense to anyone?

The carbs without cutoffs by factory do not have any drilled holes to the empty chamber. So I guess plugging all of them makes sense before one should consider additional faults.
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

my79650
Posts: 643
Joined: Tue Apr 06, 2010 11:37 am
Location: Gagetown, New Brunswick Canada

Re: Ide troubles with pd50 carbs

Postby my79650 » Thu Jun 06, 2013 10:11 am

Alright, will check the cutoffs from the cv rack first before i do anything else.

my79650
Posts: 643
Joined: Tue Apr 06, 2010 11:37 am
Location: Gagetown, New Brunswick Canada

Re: Ide troubles with pd50 carbs

Postby my79650 » Fri Jun 07, 2013 4:08 pm

The cutoffs from the cv 750 carb rack are the same size as the pd50 type. No holes in them. Before i even think bout using them i blocked the air hole to the cutoff covers with some black engine gasket silicone. I filled the channels out to the carb throat and wiped off the excess to keep the shape. Will let them set overnight to cure. I should have done that the first time but i thought with the air box side hole sealed the others would'nt matter.....not! I don't want to chance blocking the hole under the cutoffs as it may cause problems for the slow jet in the casting. If the silicone gets pulled out into the engine then i will clean it out and solder them up, as soon as pick up another roll of 50/50 metal solder. PS: i left the solder in the airbox side to see if the silicone job works, at least it's an easy removal.

my79650
Posts: 643
Joined: Tue Apr 06, 2010 11:37 am
Location: Gagetown, New Brunswick Canada

Re: Ide troubles with pd50 carbs

Postby my79650 » Sat Jun 08, 2013 5:00 am

Lets see; need to get proper o rings for fuel pipe, leaking again. Ignition troubles: misses, pull #1 plug wire and it stalls. Pulled #4 and it still runs but like crap. Pulled the plugs and all smell of gas. Going to try my spare plug wires from parts bike then go from there on the electrical, screws for advancer are seized so i got to get some easy outs for that. I am going to try my mid 70s 750 carbs again, they work so this will tell me if i have any fuel delivery issues. Shouldn't be any as i have good steady flow from drain screws. May as well get a new battery as well as i had to add some water to mine then trickle charge it, and buy a multimeter for testing.

my79650
Posts: 643
Joined: Tue Apr 06, 2010 11:37 am
Location: Gagetown, New Brunswick Canada

Re: Ide troubles with pd50 carbs

Postby my79650 » Sun Jun 09, 2013 11:30 am

Did the pulser test and then found out i had 2 bad plugs. The set was only a month old, installed and old set of ngk's that i had sitting in the shed and bang, fired right up. When i finished up the block off job i turned the air screws to 2 turns out on all 4 this time. Seemed ok idling and revved up to 6k. Going for a drive to see what happens now; will report back.

my79650
Posts: 643
Joined: Tue Apr 06, 2010 11:37 am
Location: Gagetown, New Brunswick Canada

Re: Ide troubles with pd50 carbs

Postby my79650 » Sun Jun 09, 2013 12:25 pm

For some reason the fuel pipe isn't leaking now after setting for 2 days, leave it alone! 20km drive and pushed it to 110km/70mph and it worked fine, no hesitaion and great pulling power, some good long hills round home to test it on :D . With the air screws at 2 turns out and it seemed to perform better since the blockoff and recleaning of the carbs again. Now to run this tank of gas with seafoam in it to see if it actually changes anything.

User avatar
Volker_P
Posts: 5311
Joined: Mon Mar 06, 2006 1:53 am
Location: southern Germany

Re: Ide troubles with pd50 carbs

Postby Volker_P » Tue Jun 11, 2013 2:46 am

Sounds like some progress.. :wink:
Cosky's great (free) online manual: http://cosky0.tripod.com

forum links to common technical issues

my79650
Posts: 643
Joined: Tue Apr 06, 2010 11:37 am
Location: Gagetown, New Brunswick Canada

Re: Ide troubles with pd50 carbs

Postby my79650 » Wed Jun 12, 2013 12:49 am

It's not the carburetors causing the flat spot and slight hesitation. My charging system crapped out on me. I drove it to work, flat spots. Drive home@2:30am the headlight was dim. It got brighter a few times during the run, then dimmed out again. Was like i was running a candle power light from the 70's! 10km from home i tried the signal lights and got nothing, so i pushed it hard til i got home, then it stalled out in the yard. I changed the rotor 3 yrs ago when it crapped out and used the one from the dead 650. Got a new battery ordered and going to order a new rotor. How do i know this without testing: it acted the same way on the road the 1st time it died 3 yrs ago, except this time it was intermittent.


Return to “Show it off”

Who is online

Users browsing this forum: No registered users and 11 guests