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Replacing diaphrgam

Started by Old Rider, December 04, 2020, 10:09:25 AM

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Old Rider

Her is my road to replacing the carburetor diaphragm . This is a poor mans DIY and of course the quality of the diaphragm i bought from eBay cant stand up to
original quality that can and should be bought from RPM.But i needed to fix mine because i discovered that the repair i did with plastidip a couple of years ago
after seeing a video on youtube did not work.I found that replacing them was not so easy as i first taught because the slot where they sit is very narrow so i did some mistakes
first time around and teared 2 of them but i found a fix to make it easier so here is a write up

Old Rider


T Legg

Nice work. Your persistence in completing repairs shows again. Your wife is kind to let her kitchen be your maintenance shop.With all of the extreme wear your bike has accumulated you might buy a whole non running bike for four hundred and slide your motor into it. I bought my last set of OEM carbs from Woodcreek Pete for $150.00 US. They had even been sent through his ultrasonic cleaner. I had them apart a couple weeks ago and they still look spotless inside.
T Legg

Old Rider

Quote from: T Legg on December 05, 2020, 09:13:42 AM
Nice work. Your persistence in completing repairs shows again. Your wife is kind to let her kitchen be your maintenance shop.With all of the extreme wear your bike has accumulated you might buy a whole non running bike for four hundred and slide your motor into it. I bought my last set of OEM carbs from Woodcreek Pete for $150.00 US. They had even been sent through his ultrasonic cleaner. I had them apart a couple weeks ago and they still look spotless inside.

Most of the times i do some engine cooking in the kitchen she is not home so she does not know .I just have to work fast and clean up before she comes home.  :good:
The bike is still good because i have replaced all serviceable parts i can think of except the rear svingarm bushings they are next,but not sure if i need to replace them because when i bought the bike it included a workshop manual and in the manual PO had marked the bushings with red rings and calculated some prices.I have tested them for play and cant find any signs of wear.
I wonder how long these cheap rubber diaphragms will last cant find out until March because there is snow here now.

fj1289

Just be very aware of what the engine is doing at WOT.  There is some concern over the thicker diaphragms not allowing the slide to fully rise to full travel. 

http://www.fjowners.com/index.php?topic=5340.msg88442#msg88442

Old Rider

Quote from: fj1289 on December 05, 2020, 04:09:04 PM
Just be very aware of what the engine is doing at WOT.  There is some concern over the thicker diaphragms not allowing the slide to fully rise to full travel. 

http://www.fjowners.com/index.php?topic=5340.msg88442#msg88442

Thanks for the link and telling me about that fj1289. i have never read it before .I have now checked if the slides can rise to full travel open and they can.
The diaphragm i used is another type than jbm they talk about in the tread.Maybe it is the thick rubber ring in the middle that is stopping the full travel on the JBM combined with them swelling
Today i have investigated a little more here are some pictures.

Old Rider

Just a little uppdate on the diaghprams i mounted  desember 2020 .The bike runs with no problems no jerking when accelerating no hickups on full throttle
and smoth on low speed.I was thinking it may run jerky because of the rubberdiaghprams  with no fabric inside maybe making a rubberbandeffect ,but it runs smoth.I have not opened the lids to take a look at them but since bike runs well i think they are still in good shape.