PLEASE ADVISE - NEWBIE HERE, CLEANED MY CARBS

Hey everyone! This forum has been a huge help with the '82 Maxim 650 that I've inherited. The bike was running but I figured I should try to get it to purr before I do a long trip with it.

I took the carbs off, boiled them, went all through with carb cleaner and regapped the spark plugs to .030" (they were a bit wider). I tried a bench synch of the carbs and I've made a bottle manometer for another synch. The trouble is it's running terribly. At first it was idling at about 4k but i backed off the idle speed screw and that dropped it. Now it won't keep running at a 1k idle and when I open up the choke it suddenly jumps up to 4k again... it's like only some of the cylinders are firing and then they all kick in when i open the choke.

What could the problem be? I don't think i can synch it with the bottle manometer if it won't maintain a 1k rpm idle? How do I check that the spark plugs are firing?

Any help would be hugely appreciated

 

OK, let's back up.

Are your valve clearances in spec? If not, do that first.

You said you took the carbs off and "boiled them." Were they COMPLETELY disassembled first, as in, butterflies and throttle shafts removed? If they were still assembled, you probably killed the throttle shaft seals.

How thoroughly did you "service" the carbs? Idle mixture screws removed, and their o-rings replaced? Floats removed, float valve needles inspected and/or replaced; valve seats cleaned/polished?

Did you accurately wet-set the float levels?

Bench sync?

Quite honestly, it sounds to me like a half-arsed carb job has done you in; you're going to have to go back and do it right if you didn't to begin with.

And you can't sync anything if the valves aren't in spec.

 

I figure the valve clearance must be passable because it was being ridden regularly last summer. It's true I only did a cleaning and not a rebuild of the carbs... I didn't separate the four of them but I took all the needles and jets out.

As far as the idle mixture screws... everything I read seems to say to not touch them. I'm already afraid that the bench synch adjustments i did threw it all off. although it does seem to be running lean.

I might be in a different situation than most people on here because I'm trying to get it running decently in time for a road trip without waiting for little parts to come in the mail. I don't really have the budget to replace everything.

shouldn't it be possible to get it running smoothly even if it's not as efficient as it would be with all the valve adjustment, replacement seals everywhere, etc??

 

No. With these bikes, if you don't do the complete job, you are wasting your time. Your bike will never ever ever run right until you do it right. Don't make the same mistakes I made. Once I gave in and listened to everyone on here, my bike has been running beautifully.

 

Umm... nope. Valve clearances are paramount, unless you want to kill the motor halfway through your road trip.

Again, if you BOILED the carbs, you submerged them. You have probably killed the throttle shaft seals; which means you'll need to replace them.

You CANNOT go halfway and expect positive results; all you will end up doing is costing yourself way more time and money than if you'd done it right.

You NEED to put the valves in spec, properly service and adjust the carbs and sync the motor. Period.

Then you can ride the bike as far and for as long as you can imagine. But until you do, it's just not happening. The bike is 30 years old; it is totally possible to resurrect it, a lot of us have.

But not by doing it halfway. It just won't work.

You said "please advise." We're advising. Sorry it wasn't what you wanted to hear. Listen to the voices of experience...

 

Ok thanks you guys. I believe you. I guess I didn't know what I was getting into with this but I'm kind of in too deep to back out now!

 

Yeah half ass don't cut it dude, Valves are important before going forward you must you must do them then on to carbs, big fitz knows what hes talking bout . I'm an impatient s.o.b tried half ass, cause wanted bike to go well after taking the carbs apart for the 6th time you bet I wised up and listened, that's to fitz & hog fiddles I have brought back my 85 xj 700 I'm glad I listened. Took the time to do so it taught me alot about this bike and sense I listen I have gotten tags on this bike and have put on about 1400 miles on it in 2 weeks. Haven't driven my truck, bikes more fun. Good luck!

 

Helps here my freind. And I cant help but feel I owe the community thanks to these cats. When you think you have enough information, believe me there's more, get all you can you will be glad, you did. And nobody here is ragging on you, you said it best newbie you are in a month you will be helping others and will feel good because you can.

 

I thought the same thing when I joined the group year and a half ago. Mine is not even close to road ready but when it is it will sure take me wherever I wish to go (and back).

Recommissioning these bikes is like dieting, if you do it right it will work, if you kinda do it, kinda works.

 

So when I'm checking the float bowl levels, the bike is on its center stand and thus the carbs are tipped forward and the gas is relatively higher at the front of the bowl. Am i supposed to just do 3mm at the back so that it is at or above the gasket in the front?

 

You have to remove build a level stand and wetset off the bike.

 

thanks donovan.

ok i think i will dive in and check the valve clearances. where can i get the shims for those? are they specific to these engines or available at napa?

 

Speffic to the engine there is a chart to follow in service book will tell you what shims u need. You will have to check them first, markem then contact chacal on this site to order the ones you need. Fortunatly I live in California and alot of these parts were on shelfs. Made it easier for me. But chacal can get you whats needed, I cant remember the link but at maxim4ever.com I beleive it is will lead you to a group in canada more like a shim pool, but you send him shims dont work for you and will send you shims u need just pay shipping. Thats another way. Check with local yamaha dealers as well never hurts.

 

Also dont boil the carbs again go and get a can of parts cleaner comes in 1gal size paint can Soak them ounce stripped and use your air compressor and blow out every nook and cranny, every passage you can see, where eye protection and really old cloths. This time around, and pay close attention to detail, you tube has a multi step video on complete rebuild watch it twice. In you tubes search type mikuni carb rebuild and you will find alot look for the 40 min plus videos there are 4 or 3 cant rember but extremely helpful and extremely detailed. You will be glad, kinda do and dont do and if you f#$& up how to repair screws, make sure you visit harbor freight tools and get a jap screwu driver set, so much easier. Good luck! Cant wait to hear how it turns out.

 

where can you find these kind of things on the shelves? i can't believe chacal has all that stuff for these old bikes.

 

Oh he does beleive me find him on a post and pm him he will send you parts info prices how to thing, the shelfs I found were several yamaha dealers thru out southern ca lot of shops had after market parts that were discontinued. They simply ordered in I picked up next day, ebay has quite a bit of things to. Goggle man every thought pops into your head favorite web sites as you will find information overload will happen.

 

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