On disassembling the carb i found the diaphragm fully intact with no tears and sealing well but it is kind of symmetrically wrinkled. I saw a suggestion in this forum about soaking in dot 4 brake fluid? or is it ok to run as is?
In my experience, the older the diaphragm, the more likely that it will be wrinkled. I don't think the wrinkles are going to affect performance. Soaking shrunken rubber parts in oil of wintergreen or brake fluid will soften and expand them. If your diaphragm seals well, I'd leave it alone.
The alcohol in the gas cause the diaphragm to wrinkle some diaphragm materials are alcohol resistant. Many replacement rubber parts are alcohol resistant and usually indicate so on the kit. I have a box of old fuel pumps that used alcohol gas and they were all completely destroyed, the replacements parts were alcohol resistant materials. Replace it as it will only get worse.
Thanx much! I tried to replace it but I cannot find one anywhere for a 1st Gen Rebel. 2nd Gen are to small. I soaked it and managed to get a good seal when I put it together.. Seems the only alternative would be to switch to 2nd gen carb and manifold.. pricey.
Just looked back to this thread, the old diaphragm is working ok BUT Ist and 2nd gen diaphragms are NOT INTERCHANGEABLE. The 2nd gen are smaller, I bought one and I cant return it, anyone need one ? Jus thot I should let folks know this case they read this thread.
AFAIK, the diaphragms are interchangeable between generations. If we can get someone with a first generation diaphragm and another with a second, measure their diaphragm tubes (diameter and height to the bottom lip of the diaphragm on the tube) we would know for sure. I just sold my only spare second gen carb, but pretty sure I have a first gen around here somewhere. Will try to measure in the morning and post the dimensions here.
About 99% sure those are Chinese knock-off diaphragms, so they may or may not actually fit Rebel carbs. I bought one when I first came across them, but haven't needed to install it yet. Mine may be the wrong size too!
Yup.. gotta wonder.. the pics above are of the original 1st gen and the knock off (2nd gen?), the micrometers in the pics. the smaller one is the knock off.. the old ones workin OK for me but would be good for other folks to know one way or the other : )
I just measured a second generation diaphragm and the replacement bought on ebay. They are essentially the same with the exception of the needle that came with the replacement diaphragm; it's slightly different, but that may not be a problem. So the inexpensive ebay diaphragms should work. Not sure how long the diaphragm rubber will last compared to OEM, but certainly looks like a bargain.
I think they are different. Just got a first generation used carb and I'll measure the diaphragm tomorrow. Just eyeballing it in the carb, it looks bigger than the second generation, which is what you observed.