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CB350 1971 Restoration Project
philward:
Further update Ben. Today I stripped the carbs and found a few issues! Found both floats had small amount of petrol in and R/H slow running jet blocked (hence the lack of adjustment on that air screw) - soaked in some carb cleaner but can't shift what ever is blocking it. I should of spotted it first time. Sent for some new float and slow running jets.
So maybe your lack of adjustment on your air screw is a blocked slow running jet?
philward:
--- Quote from: florence on September 27, 2023, 12:42:56 PM ---Is it worth running without air filters attached for a test just so you can see if slides are popping back down in good time and together when throttle is released?
--- End quote ---
Checked prior to carb strip and all good - thanks
Sent from my moto g(50) using Tapatalk
BenPowell:
Little update on the carbs tonight, I took them apart to inspect and found that the jet which is under the rubber bung (idle jet?) was blocked on both carbs. Must have missed it when I rebuilt them originally, because it took a fair bit of unblocking, gave everything else a thorough clean while they was apart.
Got them back on the bike with mixture screws 1 full turn out from loosely nipped up, and idle speed screws 3/4 turn from touch and the bike fired up straight away with no more popping from the right cylinder, in addition to this the idle mixture screws have a definite impact on the engine now, safe to say that was the issue there.
Before I removed the carbs I ran the bike with no air filters and could see the slides moving freely, and while off i checked the diaphragms and couldn’t see any holes, I also checked the slides and they are completely free, so I think the hanging rpm must have been caused by a lean running condition on one cylinder.
Tomorrow I’m going to spend some time getting the carbs set up, or as best I can without riding it.
Had the DVLA inspection this morning, guy was here 10 mins and took plenty of photos of the bike, hopefully I’m not waiting much longer for the V5, I just want to get out for a ride now ;D
philward:
Sounds like we are having identical issues Ben! My slow running jet just wont clear. It's been soaking in carb cleaner for 2 days. I've ordered a .35mm drill. As a back up, I've ordered some pattern jets (as genuine not available) as a back up. Also ordered some pattern floats.
Hopefully I'll have your success!
BenPowell:
--- Quote from: philward on September 29, 2023, 10:38:30 PM ---Sounds like we are having identical issues Ben! My slow running jet just wont clear. It's been soaking in carb cleaner for 2 days. I've ordered a .35mm drill. As a back up, I've ordered some pattern jets (as genuine not available) as a back up. Also ordered some pattern floats.
Hopefully I'll have your success!
--- End quote ---
The radial holes on mine were all clear, but down the bore it actually goes to a smaller diameter and it was blocked there, I bought some 3D printer nozzle cleaners, turned out to be really useful for the carb, get a load in a pack for about 3 quid.
Link: https://www.amazon.co.uk/dp/B09L86LJ81?ref=ppx_pop_mob_ap_share
Was really quite tough to break through the blockage, and just for a final check I poured a small amount of petrol through to make sure the passages through the carb body were clear.
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