82 Maxim 400 Build

[dgb3]

New to the site, been poking around the last few days trying to get some info and decided to become a member.

I've got an '82 Maxim 400. All original, low miles. I've had it for about 4 years now and have never had problems with it, until now.

I didn't get to ride much last year and it sat a lot although I did start it up every week. So I've got a few problems that I know what I need to do to fix but I'm kind of at a cross road because I kind of want to chop/bob this bike. So this will be a build thread/repair thread.

Anyways, so it ended up with a full tank of fuel in the engine with the oil. It's been drained and new filter put in, I have a new drain plug on order bc the old one broke the head off it was on so tight. I need to get the air box out to clean it and get all the fuel out that ended up in it. I have the bike tore down a bit but can seem to figure out how to get it out. The only thing I can think of is the engine has to get dropped to get it out, which is more then I want to do. Is there something I'm missing?

 

[dgb3]

Quick update.
After reading a bunch of threads that said you had to either unbolt the engine and tilt it or remove the swing arm but no one had confirmed it, I decided to just jump in. Ended up removing the swing arm and LOTS of other parts to wiggle the air box out.

I've decided it's not gonna go back in and I'm just gonna run pods after I rebuild the carbs. Too much work if you have to clean it out like I had to. I'll try to get photos up shortly.

Anybody have suggestions on what pods to run and a good carb rebuild kit and what jets to use?

 

[BBS360]

Dunno about dohc jets but I'd track down Dave's thread about his diy h-pipe and apply it to the dohc carbs. Same theory applies.

 

[dgb3]

You wouldnt happen to have a link? The search doesn't seem to be working. No matter what I type it gives me no results.

 

[BBS360]

The new forum software is a bit quirky: http://www.xs400.com/threads/diy-modded-stubby-h-pipe.12406/

 

[dgb3]

thanks!

 

[dgb3]

Had some unexpected expenses come up last couple months so nothing got done on the bike. However I did order a few things last night on eBay.

I'm looking for anyone who has done what I'm about to do before. Or if anyone knows of a step by step guide for rebuilding the carbs and adjusting them and what size jets and whatnot to use for my bike. I have removed the stock air box and its not going back on. I'm gonna run pods. Most of what I have found is for the older SOHC bikes and possibly different carbs. My bike has the Mikuni carbs. Any input would be great! I'm not the greatest with carbs, I've hardly worked on them, I'm used to newer vehicles.

 

[dgb3]

Also, how do I tell, or does any body know, exactly which model Mikuni Carbs I have? If i'm gonna take them apart to clean them I want to replace every piece of rubber and seal the things have. Where is the best and most complete kit to get?

 

[DynaGlide]

I think you have the BS34 CV carbs. I have a Maxim DOHC engine torn down in my garage now, just took the carbs apart last night (as well as heads, needs new seals and some other stuff). I think you're going to run into problems finding one 'kit' to do everything. From what I've read you don't really replace everything just what's needed. This is my first time working on a carb and after watching a couple of this guys videos it wasn't too bad to take apart except half the screws were so rusted I had to use the Dremel to remove them:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwiw0eXWs5jNAhUL9IMKHadCD8QQtwIIHjAA&url=https://www.youtube.com/watch?v=dD3UWtLfzX4&usg=AFQjCNHrvVC3zyYuXeTHKDi3eEOh9drtrg&sig2=j6QakEb6PnIM7E-3mxO7vQ

If you need new diaphragms I found this company:

http://jbmindustries.com/Yamaha650.html he sells the 73mm OD for our bike.

Gaskets I'm not finding a whole lot so far. .there's some kits that have the float bowl gasket like this one but I'm not sure you'd need everything in it:

http://www.mikesxs.net/parts/carbur...1GXyGTK_Ngnkb5DpCjSdAviFiofqNh2yn8aAuWH8P8HAQ

I'm kind of flying in the dark at the moment and just taking things apart. The engine is in bad shape and the manual I have isn't much help. I just want to get it running again. Watch all of that guys videos I linked to related to carbs and you should be in a lot better shape figuring out what needs done.

 

[dgb3]

Thanks DynaGlide. I've been watching a lot of videos and while most of what I'm seeing seems fairly simple and straight forward I just don't want to screw anything up because I know how hard it is to find parts for these bikes. When I first got the bike I did an oil change right away and it ended up being down for 2 months because I needed a new oil filter cover because mine had a crack in it and when it put it back on and tightened it down it split in half. Idk about your bike but mine has the filter cover that sits flush on the bottom of the engine. Just this year when I first started all this work the oil drain plug head snapped off when I went to loosen it. Took 3 weeks to find a new used one. One thing I have noticed from all this is that there looks to have been a lot of little air bubbles when things were cast.

Another question, I get the basics of the jets and things and that I'll need to change them out for pods. Are all jets the same size? Will they fit any carb? Or do I need to find ones specifically for my carbs? Is there a way to tell exactly which carbs I have? Where is the marking located on the carbs to find out?