Carb Fine tuning

Helo you knowlegeable people!

I’ve just bought a new engine from fleabay, and I should be getting it by the weekend…

How do you fine tune carbs? Infact…do you have to time the carbs when you install the new engine? If so…how do you do that?

You replies are much apreciacted…


What bike is it on Mole?

The only thing you can really do is to balance them.

to get the fuelling right you really need to have the carbs set up on a dyno.

depending on what bike / engine it is, i’d also do the valve clearances before bolting it in. (this will be much easier to do with the engine out of the frame whilst you have it in that state) unless of course you know the history of the engine / sewrvicing it recieved!

So it need to have valves done before carbs? New engine will be out of frame so thanx for that tip.

Laura, you read that! :stuck_out_tongue:

You are supposed to have the engine serviced first eg, new oil, filters, plugs. Checking shims is a bit OTT but I suppose if you don’t know its history is sensible.

You didn’t say if you are taking the carbs from your bike and putting on new engine. If you are then they might need a tweek as they are set up slightly differently in the factory. It will still work, it will just not be quite right.

If using the carbs that came with the engine they might have been sat around for a while so could need a bit of running in to get the gunk out of them. You don’t want to fiddle around with them now and have to do it again in a couple of weeks after they has bedded in so to speak. I’d say stick it in, run it for a while then have them done. My bro has a carb tune thingy if you need one.

If the bike is running stock exhaust and air filter it shouldn’t need a dyno to set it up.You should be able to find the settings for mixture screws (usually 1 1/4 turns out from fully in).

If its a multi cylinder bike the carbs will no doubt require balancing though (synchronizing):)A drop of carb cleaner never goes amiss either

PaVeLBlueBaNdiT (26/09/2007)

not a necessity but if you dont know the history of the engine its worth doing and its much easier to do with the engine out of the frame!

Hey!Thanks for all those replies, they’ve helped loads!

It’s a suzuki gs500e, and I bought it off ebay last night. It’s done just over 13,000 miles, and I don’t think it comes with carbs, so I’ll be using my own.

I read that post Pavel!;):smiley:

It is a twin cylinder engine. I think I’ll be ok with balancing the carbs, I skim-read through that section a couple of weeks ago, and I’ll re-read it.I forgot to add, it’s got really shiney downpipes, but no end can, and I can transfere my downpipes from my bike, but it’s a onepiece downpipes and can (if you get what I mean). So I might see if I can transfere my pipes on it now, and then get a nice can in a couple of weeks.

this is the item…

Why did you need a new lump?

I’m curious to know why the breaker says the downpipes are hard to remove:crazy:

Well, yesterday my output shaft died, and it’s got a bit of piston slap, and it’s done 65000km, so I thought I’d get a new one to get back on the road and then either recon the engine or take it apart and keep it for spares.

I don’t know why they can’t be bothered to take the pipes off. You’ve got me starting to worry now…

Sorry to cause you any worry but I would ask them the question if it was me.It’s probably only held on by 4 nuts and prevents the engine from sitting on the floor squarely. Its more of a pain to leave on than take off as a rule.

Quite simple really, the header bolts are the first thing to go rusty and they obviously don’t want to risk breaking a stud off.

If it is a 93 bike and only done 13k I’d be surprised. You’ve not seen the bike so it is difficult to confirm that. Less then 1k miles per year hmm…

Good luck, hope it works.

I’ve seen headers welded on before now because the studs have sheared:crazy:

Olrighty then…anyone got a blowtorch I could potencially borrow? Locally heating it up should help, shouldn’t it?Otherwise, the shop I’m picking it up from is a breakers aswell, so they might have a decent can lying around for not too many greens. Or I could see how loud it is as a bare tube…moohahahahhaahahaaaaaaaa:DThanks for the good luck btw :slight_smile:

I bought a spare engine for my CB600 Hornet. It was going cheap on eBay, I only paid about £40. I think no one else really bid on it because it was pick up only and the guy I got it from had cut the downpipes off with a blow torch :rolleyes:

I just wanted the carbs off it, then the engine sat in my garage for about two years just in case I needed a spare.

There was still enough of the studs left to get them out with a stud extractor but really you need a mechanic or workshop to do it, so I never bothered.

Eventaully after I’d sold my bike I got rid of the engine to another guy for £50 :stuck_out_tongue:

was ther anything wrong with the carbs in the first place…if not dont touch them tel you get them on the engine.might run ok:)