Where can I find documentation on Setting a carb?

I'd like to learn before I start posting like crazy.

Here's my issue. I have a 1980 KZ750LTD. I'm running 4 pods with 140 Main jets. I'm finding some recent weird issues, (For example, bike stalls after idling for 20 seconds or so, Bike doesn't idle with Choke on when cold, etc.) and I'd like to read up on how to properly adjust carbs, what tools to get, and a troubleshooting process for adjusting etc.

I could surf all the posts and slowly piece it together, but I find that becomes confusing as so many people have different mods.

What I'd like to find is kind of an idiot's guide to motorcycle carb maintenance. (Mulitple carb installations.)

I'm hoping to learn how to balance, synchronize, properly determine whether I need to rejet or or adjust air screws. which screw does what etc.

I'm not a mechanic, I'm a geek. I can hold my own when it comes to the mechanics if I have the reference material to leanr first.

Any resources, links etc would be most helpful. If I still end up hopelessly stuck, I know there's lots of knowledge here, but I want to try to figure this out on my own first.

Thanks.

Regarding links Dans motorcycle course is usefull and you can find the carb section here www.dansmc.com/carbs.htm

mbsween who is a member here has a shop manual for the 750/4 on his site www.mbsween.com but it appears to be down at the moment. Maybe check later.

I'm assuming your carbs are Keihins. With pods you should be fine with the 140 which I think is actually a secondary main. I have pods and 135s. I believe wiredgeorge recommends 140. for the primary main air jet I have 62s - see pic below and others may recommend going as high as 70 - if you can get them.

I find Keihin carbs are a bit different. I need full choke to get the bike started from cold but once running I need to gradually let off the choke or the engine will bog or "choke". Over the course of about two minutes I can take the choke down to 1/4 and ride it from there. No way though will it idle on full choke... so your experience sounds about normal to me.

The mixture screw are top front (assuming Keihins). Colour of the spark plugs and how the bike runs will indicate if you need to make any adjustments - and this only after you have done everything else like valves.
If you can get the bike to properly warmed up and then it stalls then perhaps your problem is valves. Carbs are usually the last thing one should do in a tune up situation.
For synchronising I use a Morgan Carbtune and follow the makers instructions.

Good luck and dont hesitate to ask questions and post.

Post edited by: JR, at: 2007/07/03 15:33

Post edited by: JR, at: 2007/07/03 15:34

Here's that pic I was looking for