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Aussie Mick
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| Joined: | Fri Oct 3rd, 2008 |
| Location: | Australia |
| Posts: | 5 |
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Posted: Fri Oct 3rd, 2008 11:54 pm |
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Hi all,
I have just bought a CB250T to eithe restore or customise. I know a lot of people hate them but I thought it looked flash. Anyway, it has been sitting out in the weather for a while and most things on the bike are rusty and is generrally a bit of a mess. I have a couple of questions on the carbs to help me get the bike running bfore I pull it apart and fix it up.
1. I have never owned a bike with multple carbs before and I understand that the carbs need to be "balanced". Can some one explain to me what this means and how is it done?
2. I have pulled the carbs off to clean them out and it seems there is a tube(s) missing that either runs between the carbs or is for overflow. I not too sure so I am hoping someone may have a picture of the original set up they could send me so I can see what it should look like.?
3. Also I was thinking of removing the airbox and running it on Pod style filers. Will this mean I need to re-jet the carbs and how do I do that?
Thanks for your help.
Mick
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hondapartsman
Member
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Posted: Sat Oct 4th, 2008 07:57 am |
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Aussie Mick wrote: Hi all,
I have just bought a CB250T to eithe restore or customise. I know a lot of people hate them but I thought it looked flash. Anyway, it has been sitting out in the weather for a while and most things on the bike are rusty and is generrally a bit of a mess. I have a couple of questions on the carbs to help me get the bike running bfore I pull it apart and fix it up.
1. I have never owned a bike with multple carbs before and I understand that the carbs need to be "balanced". Can some one explain to me what this means and how is it done?
2. I have pulled the carbs off to clean them out and it seems there is a tube(s) missing that either runs between the carbs or is for overflow. I not too sure so I am hoping someone may have a picture of the original set up they could send me so I can see what it should look like.?
3. Also I was thinking of removing the airbox and running it on Pod style filers. Will this mean I need to re-jet the carbs and how do I do that?
Thanks for your help.
Mick
Okay mate. (1) You'll need gauges and a workshop manual, I've never done it myself but I understand it's not so bad once you get going but I'd be tempted to get a bike shop to do it if you have one close enough as it saves on the initial outlay and if they mess up then at least you have some come back.
(2) If it's just an overflow tube missing then all you need is a suitable length of the right size tube, have a look at the parts list on http://www.nielsens.com/ I think they have the 250 or something like it there so you ought to be able to spot anything missing.
(3) You would be a brave man to try, I would not ditch anything but stick with standard set up, if you decide to go for it be prepared for a world of woe, not easy to get right.
Hope that helps a little, I'm just a humble parts person, nowhere near a mechanic so I expect someone else will say different, just saying what I hear through others.
____________________
Have faith but don't trust to luck.
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TheMightyGusset
Member
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Posted: Sat Oct 4th, 2008 11:12 am |
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G'day Mick !
There's no great mystery to carb balancing - basically it just means setting them so that they both provide the same mixture, at the same time, to each cylinder - in place of 'balancing' you could equally use the word 'synchronising' - it should be fairly obvious that if the carbs are set differently then each cylinder will be trying to run at a different speed - not a good scenario !
In order to set them properly you'll need a set of gauges - if you haven't got any then you might indeed be better off paying someone to do it for you.
if it's just a question of getting the bike to run first then you might be able to set them roughly by eye and ear - then once you've completed your restoration get the job done properly - I'd steer clear of pod filters on this bike, they are a sod to set up on CV carbs, and as you aren't familiar with multi carb set ups I'd get used to them on a standard set up before mucking around any further.
____________________
Gus
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Aussie Mick
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| Joined: | Fri Oct 3rd, 2008 |
| Location: | Australia |
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Posted: Mon Oct 6th, 2008 12:49 pm |
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Thnaks all,
That solves the mystery and I think I'll take the advice and get someone else to do it. I'm not that cleaver when it comes to tricky things. It also sounds like more hassell that it is worth to put the pods on, so I think I will leave that alone as well.
Thanks for the help guys 
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triumph5ta
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| Joined: | Thu Jun 26th, 2008 |
| Location: | London, United Kingdom |
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Posted: Mon Oct 6th, 2008 03:36 pm |
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A rough and ready way, good enough to get the bike running:
Im guessing the bike does not run at present? Take the air box off so you can see/feel down inside the carbs.
There will be a "butterfly" across each carb inlet, its a round disk. When you look in there you will see what I mean. You will probably need to push the slides up out of the way by hand. When you turn the throttle both those disks should move at the same time. As long as the disks seem to move at the same time you are "near enough" to get the bike running. If not you need to adjust the screws to get them in synch. Theres more to carb synch than this but it should be enough to get the bike running.
All this is ASSUMING the carbs are clean, no blocked jets or airways and no perforations in the rubber "diaphragms" in the top of the carb. Also float height OK.
Have a go, if it does not work or the bike runs rough then you are going to have to strip the carbs. Once you know carbs are clean, valve clearances etc are OK, air filter clean, ignition timing OK then its time to invest in guages to fine tune it and get it just right.
You will need to re-jet if you run pod type filters but I would just get it running standard first. Good luck.
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Aussie Mick
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Posted: Tue Oct 7th, 2008 12:08 pm |
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Ahhh, that sounds like a perfect cunning plan . If only I had asked the question before I pulled the the carbs off.
Oh well, they did need a clean out as there was a bit of muck in them. I have cleaned them out and run some air through them and there doesn't appear to be any blockages in the jets or airways. I pulled both the top and bottom of the units off but I have not come across any "diaphragms". I am yet to check the pictures in the link that Hondapartsman sent but made these ones don't have them.
It will be a little while before I can put them back on and give it a go as I need to replace the throttle and choke cables and they have coroded and ceased.
Once I have replaced those I'll put the carbs back on and go through the procedure you have out lined. It sounds easy enough.
Thanks again for the help. It has been great.
Mick
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Aussie Mick
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Posted: Tue Oct 7th, 2008 12:17 pm |
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| Just in case you were wondering what it looks like I have attcahed some oictures. His neame is "Chester" Attachment: CB250T Compressed.JPG (Downloaded 12 times)
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Aussie Mick
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| Joined: | Fri Oct 3rd, 2008 |
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Posted: Tue Oct 7th, 2008 12:18 pm |
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| Just in case you were wondering what it looks like I have attcahed some oictures. His neame is "Chester" Attachment: CB250T Compressed 2.JPG (Downloaded 11 times)
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Current time is 11:06 pm | |
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