Simon Davey Posted March 28 Share Posted March 28 So, it's no good us pretending we're all 30 years old, I know most of you, like me, are old enough to have had your mitts on a set of carb's at one point. I'm used to cleaning out the winter crap left in the bowls etc, but I've never cleaned out the jets. Are jets adjustable, or do they just screw out, get cleaned, and get screwed (ehem) back in again? I'm convinced the idle jets are clogged. My concern is messing up the sync and balance that's just been done. Cheers Quote Link to comment Share on other sites More sharing options...
husoi Posted March 28 Share Posted March 28 From time to time you will need to replace them. Mostly if second hand bike old enough and previous owner(s) were a bell end and messed with it. Usually jets are fairly cheap. Mods to exhaust or a different air filter will usually result in the need to different jets. Quote Link to comment Share on other sites More sharing options...
husoi Posted March 28 Share Posted March 28 Unless you mean the idle jet. Then yes they are adjustable Plenty of fun syncing dual carbs Not impossible or too difficult, just one of those precision jobs you want to get right first time. 1 Quote Link to comment Share on other sites More sharing options...
Simon Davey Posted March 28 Author Share Posted March 28 Many thanks @husoi It's the idle jets I want to look at. It's a 4 cylinder, so I'm nervous about messing around with it. 1 Quote Link to comment Share on other sites More sharing options...
Tinkicker Posted March 28 Share Posted March 28 (edited) 44 minutes ago, Simon Davey said: So, it's no good us pretending we're all 30 years old, I know most of you, like me, are old enough to have had your mitts on a set of carb's at one point. I'm used to cleaning out the winter crap left in the bowls etc, but I've never cleaned out the jets. Are jets adjustable, or do they just screw out, get cleaned, and get screwed (ehem) back in again? I'm convinced the idle jets are clogged. My concern is messing up the sync and balance that's just been done. Cheers Three removable jets in a carb that flow fuel. Starter enrichment jet (choke). Primary jet (idle to around 25% throttle when its flow rate is maxxed out) Main jet (upwards of 25% throttle to wide open depending on needle position. Needle controls up to around 75 to 80% throttle) All jets can usually be unscrewed and cleaned out with care. Do jot poke sharp steel stuff down them, the brass is easily damaged and you could destroy the calibration. Then we have the idle circuit that is controlled by the airscrew. Not removable, just carb drillings. Edited March 28 by Tinkicker 2 Quote Link to comment Share on other sites More sharing options...
husoi Posted March 28 Share Posted March 28 Before starting to strip everything. Have you tried adding some seafoam additive to the fuel? It does wonders. SeaFoam Petrol & Diesel Fuel Treatment 473ml (force4.co.uk) 1 Quote Link to comment Share on other sites More sharing options...
Simon Davey Posted March 28 Author Share Posted March 28 (edited) @Tinkicker OK, this is something I hope to start next week. Two mechanics have said they'd clean the carb's, but all they did was use an ultrasonic cleaner,and not actually remove the idle jets fir cleaning. Edited March 28 by Simon Davey Quote Link to comment Share on other sites More sharing options...
Simon Davey Posted March 28 Author Share Posted March 28 2 minutes ago, husoi said: Before starting to strip everything. Have you tried adding some seafoam additive to the fuel? It does wonders. SeaFoam Petrol & Diesel Fuel Treatment 473ml (force4.co.uk) Oh blimey, that does look good. I've tried additive preserver, but maybe I'll try Seafoam first, thanks 1 Quote Link to comment Share on other sites More sharing options...
Mississippi Bullfrog Posted March 28 Share Posted March 28 Another suggestion for cleaning carbs is stuff used for marine engines. QuikSilver Power tune. It is like a carb cleaner on steroids. I've had a few carbs that were giving trouble and before taking them to bits I used the above on them. Most of the time it did the trick without needing to take the carbs to bits. I buy it via ebay if I'm not near a boatyard. 2 Quote Link to comment Share on other sites More sharing options...
Simon Davey Posted March 28 Author Share Posted March 28 8 minutes ago, Mississippi Bullfrog said: Another suggestion for cleaning carbs is stuff used for marine engines. QuikSilver Power tune. It is like a carb cleaner on steroids. I've had a few carbs that were giving trouble and before taking them to bits I used the above on them. Most of the time it did the trick without needing to take the carbs to bits. I buy it via ebay if I'm not near a boatyard. Many thanks, wonder if that's similar to the Seafoam which is a marine fuel cleaner too. I'll have a look on eBay, cheers. Quote Link to comment Share on other sites More sharing options...
Nick the wanderer Posted March 28 Share Posted March 28 You have a few options to be going on with, not tried the additives myself but defo worth a go. Plus giving the bike a good run out to get all the juices flowing, so to speak, run a full tank of fuel through it. If the shop you took the bike to did a ultrasonic clean they would have taken the carbs off to do that, maybe they didn't want to take the bowls off to have look. At least they come on and off ok. I'd be asking exactly what they did. No air leaks anywhere? If you get no joy from the additives and want to take the carbs to pieces and want to do a proper job get a rebuild kit. Allens Performance are recommended. https://www.allensperformance.co.uk/ 2 Quote Link to comment Share on other sites More sharing options...
Tinkicker Posted March 28 Share Posted March 28 (edited) 1 hour ago, Simon Davey said: @Tinkicker OK, this is something I hope to start next week. Two mechanics have said they'd clean the carb's, but all they did was use an ultrasonic cleaner,and not actually remove the idle jets fir cleaning. When you are removing them, the primary jets will look like this: Mains like this. Edited March 28 by Tinkicker 2 Quote Link to comment Share on other sites More sharing options...
Simon Davey Posted March 28 Author Share Posted March 28 27 minutes ago, Nick the wanderer said: You have a few options to be going on with, not tried the additives myself but defo worth a go. Plus giving the bike a good run out to get all the juices flowing, so to speak, run a full tank of fuel through it. If the shop you took the bike to did a ultrasonic clean they would have taken the carbs off to do that, maybe they didn't want to take the bowls off to have look. At least they come on and off ok. I'd be asking exactly what they did. No air leaks anywhere? If you get no joy from the additives and want to take the carbs to pieces and want to do a proper job get a rebuild kit. Allens Performance are recommended. https://www.allensperformance.co.uk/ Cheers Nick, that madness sense whilst it's all apart. Quote Link to comment Share on other sites More sharing options...
Simon Davey Posted March 28 Author Share Posted March 28 6 minutes ago, Tinkicker said: When you are removing them, the primary jets will look like this: Useful thanks. Quote Link to comment Share on other sites More sharing options...
Stu Posted March 28 Share Posted March 28 Don't forget the diaphragm's and the needs too! making sure to check them diaphragms for splits and ensure they are seated properly Just to add more anxiety in the mix just removing and cleaning all the bits you want to do won't mess up the balance The balance is just ensuring each carb is drawing the same amount of air Some have air screws that can be adjusted and moving these or the butterfly valve screws will bugger things up a little 2 Quote Link to comment Share on other sites More sharing options...
Simon Davey Posted March 28 Author Share Posted March 28 Cheers @Stu much appreciated. I'm actually looking forward to it. Quote Link to comment Share on other sites More sharing options...
curlylegend Posted March 28 Share Posted March 28 1 hour ago, Simon Davey said: I'm actually looking forward to it. You're going to love it. At our age getting a set of carbs finely tuned is better than sex .... so I'm told ! 4 Quote Link to comment Share on other sites More sharing options...
Fender1515 Posted March 28 Share Posted March 28 I am sure you already know this, but I am going to put it out there in case, you can get hold of carb jet cleaning tools for square root of bugger all, from, £2 to £7, some thing like : CARB JET CLEANING TOOL - Matt Pope Motorcycles Have fun 2 Quote Link to comment Share on other sites More sharing options...
Simon Davey Posted March 28 Author Share Posted March 28 3 minutes ago, Fender1515 said: I am sure you already know this, but I am going to put it out there in case, you can get hold of carb jet cleaning tools for square root of bugger all, from, £2 to £7, some thing like : CARB JET CLEANING TOOL - Matt Pope Motorcycles Have fun Very handy, and I didn't know such a thing existed, cheers Quote Link to comment Share on other sites More sharing options...
S-Westerly Posted March 29 Share Posted March 29 Glad I don't do spannering. Sounds like an open invitation to buggeruppery to me. Or at least for me. 1 Quote Link to comment Share on other sites More sharing options...
Nick the wanderer Posted March 29 Share Posted March 29 If you are ok with slow meticulous processes it's not that bad. Keep each carb separate from it's neighbour, in 4 tubs if you like, some folks just do one at a time so you don't mix them up. Getting the carbs on and off with the rubbers can be a challenge, and often the rubbers themselves harden over time being a bit of a pain, you can soften them if you need to. Be prepared for skinning your knuckles and get a swear jar ready! 1 Quote Link to comment Share on other sites More sharing options...
husoi Posted March 29 Share Posted March 29 To soften the rubber use either a heat gun if you have one or hairdryer. It works really well 1 Quote Link to comment Share on other sites More sharing options...
Bianco2564 Posted March 29 Share Posted March 29 14 hours ago, Simon Davey said: Very handy, and I didn't know such a thing existed, cheers General rule of thumb is don’t poke anything like wire etc into a carb jet, I’d only use compressed air, carb cleaner or ultrasonic cleaning to break down any blockage. 1 Quote Link to comment Share on other sites More sharing options...
Simon Davey Posted March 29 Author Share Posted March 29 (edited) I've ordered some SeaFoam, it would be great if it works, if it doesn't, then I'll whip the carb's off. Edited March 29 by Simon Davey Bad Grandma 2 Quote Link to comment Share on other sites More sharing options...
curlylegend Posted March 29 Share Posted March 29 6 hours ago, Simon Davey said: I've ordered some SeaFoam, it would be great if it works, if it doesn't, then I'll whip the carb's off. Post a report on the SeaFoam. I'm sure quite a lot of us would be interested. 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.