QuestionHey there!
Recently acquired an 82 Maxim 750, it runs great when it is running but the thing is horrible to try and get started. Having gone over all possible problems, all seems okay, yet it gives unimmaginable greif starting. I hear that this is a common problem with Maxims. Is there any way to get the bike to fire and run like most do?
I'd appreciate any feedback whatsoever,
Chris
AnswerHi Chris,
The problem is associated with aging and worn parts and how cold engine surfaces causes air-fuel vapor to reform into liquid droplets. This is a result of cold natured engines and hard starting problems.
I'm referring you to the below listed website and article for more details on things you may do to help the problem.
Respectfully,
Mark Shively
http://www.skylinc.net/~hap/maxim-x/index.html
"Easy to Start"
People who have difficulty starting their Maxim-X have often asked me how to improve starting, so I decided to add this section.
First, everyone should know that when it's setup right, the Maxim-X engine has no trouble starting, even in sub-zero weather. When the carbs are out of tune, the ignition system isn't up to par and the battery has one foot in the grave, there can definitely be difficulty starting - especially in sub-zero weather.
Naturally, starting is easiest whith a healthy battery, a perfect igntion system and well-tuned carburetors. Each of those areas can effect starting in the following ways:
Battery: While other bikes might kick into action even with an ailing battery, that's not true of the Maxim-X. Due to some weaknesses and common issues in the ignition system, it's genuinely difficult to start the X with a battery that isn't perfect or at least close to perfect. A sign of a less-than-perfect battery is that the bike won't start while cranking but tends to start just as you release the starter button. That bass-ackwards functionality is because the battery voltage drops too low to facilitate ignition while the starter is robbing it of voltage. Then, in that brief moment just after you release the starter button, battery voltage climbs again which suddenly becomes enough for ignition while the engine is still spinning due to momentum. In most cases, starting can be improved by installing a new battery. A new battery wouldn't experience the same voltage drop and would recover more quickly so it might resolve battery-related starting difficulty... but that may only be a patch for other problems.
Spark Plugs: To most people it's obvious that fouled spark plugs can make it difficult to start anything, and that's no different for the Maxim-X. Without going into reasons why plugs may have become fouled, replacing them is essential for easier starting. Naturally, correctly gapping plugs, whether old or new, will also improve starting. That's all pretty obvious but what many people don't know is that spark plugs can be bad even when they look good. For that reason, if you're having trouble starting your X, it's often a good idea to replace the spark plugs regardless of how good you think they might be. Sometimes, X owners believe they have new plugs and on that basis they'll ignore the spark plugs as a potential cause of difficult starting... but they may be the wrong plugs. The Maxim-X uses either D8EA (1985) or DR8ES-L (1986) spark plugs but sometimes availability problems cause people to install different spark plugs. Doing so could inadvertently introduce starting problems under the wrong set of circumstances. There is, however, one type of non-stock spark plug that will almost certainly improve Maxim-X starting. From first-hand experience and from the reports of many other Maxim-X owners, it's clear that NGK Hyper Iridium DR8EIX spark plugs are the ultimate choice for the Maxim-X. Even when other issues continue to make starting difficult, if you can afford them, Iridium plugs will improve the situation dramatically.
Spark Plug Caps: Many X owners don't give spark plug caps a second thought but they can easily be the root of hard starting problems. The stock T-140 caps are 5 k resistor caps which often corrode both internally and externally and thereby introduce unexpected resistance to ignition spark. Spark plug caps essentially look the same when working properly as they do when they're not so it requires a multimeter and some resistance testing to discover whether they are a problem. If they are, rebuilding the stock plug caps is difficult, so most X owners will simply buy replacements and be done with it. However the problem is solved, a set of good plug caps will almost certainly make starting your X easier.
Ignition Coils: The Maxim-X coils weren't that good to start with and after 20 years they can contribute significantly to hard starting. The stock coils aren't very powerful and respond poorly at low RPMs and after they've had a chance to degrade and have corroded internally, they can often have difficulty delivering a good spark. If starting your X is difficult, a good place to begin looking for problems is by testing the primary and secondary coil resistances to see whetehr they're still within specification. If they're not, it may be possible to rebuild them to improve performance but they'd still be relatively low voltage coils. If coils are indeed the reason for hard starting, replacing them with high power after-market coils, like Dyna Coils, would be a massive improvement.
Petcock: Depending on how long your bike has been parked, it may be necessary to switch the petcock to PRI (prime). The Maxim-X doesn't have a fuel pump but employs a gravity-fed fuel system instead. That has its benefits and its drawbacks. Where starting is concerned, it means that fuel might not be immediately available because a good engine vacuum is required to first open the petcock. When switched to PRI, however, fuel flows freely from the tank to the carburetor float bowls so you can be certain you have sufficient fuel for starting.
Enrichment (choke): The Maxim-X doesn't have what people commonly refer to as a choke. A typical choke is designed to restrict air by closing choke plates while leaving the fuel supply unchanged thereby making the fuel:air mixture richer. For the Maxim-X, however, there is an enrichment circuit instead of a choke. When the so called choke lever is moved, a carburetor component known as a starter plunger is adjusted on each carburetor, which introduces more fuel to the same flow of intake air thereby making the fuel:air mixture richer. If that wasn't clear - a choke reduces air but an enrichment circuit adds fuel. Either way, the result is a richer mixture. To start the Maxim-X cold, it's necessary to enrich the mixture but that enrichment has its limits. Depending on the tune of your carburetors, it may not be necessary to swing the choke lever all the way over and if the carbs are tuned properly, it shouldn't be necessary to move the choke lever at all when the engine is already warm. If you're having a hard time starting your X even when you use the enrichment circuit, it may be because there is too much or too little enrichment. It's all a matter of degree. You might find that you improve starting simply by moving the choke lever less or more - try several positions.
Carburetor Mixture: The fuel mixture settings of the carburetors are very much tied to the description of the enrichment circuit above and have a similar effect on starting. If your carburetor mixtures are already set too high or if they're artificially high by some other means like leaking float valves, then you might find it fairly easy to start your X when it's cold but more difficult when it's already warmed up. If the mixtures are high and you add to that by engaging the enrichment circuit, you might create a situation where your mixtures are so high that the engine doesn't want to run at all. If the carb mixtures are set too lean then swinging the choke lever over might only enrich enough for normal operation but not enough for cold starts. It's a fine balance. If mixture settings are too far off in either direction, starting can be a problem. You can get a very rough idea about your mixture settings by turning in your mixture screws and counting the number of turns until they seat lightly (return them to the same point you started from after you're done). For the Maxim-X Mikuni carburetors, the specifications show 2½ +/- ½ turns out. If you're far off from spec, it's probably time to tune your carbs. Doing so will undoubtedly improve starting.
Carburetor Synchronization: Arguably, the most valuable change you can make to your X to improve starting (and performance) is to have the carburetors synchronized. Quite often, carbs are horribly out of synch and that imbalance makes it very difficult for the carburetors to work as they should. A carburetor imbalance can make starting difficult for some and almost impossible for others. Carburetor synchronization will definitely help improve starting.
Air Filter: A clogged air filter may also make it harder to start your bike. If your engine can't breathe and operate correctly then it might be more difficult to achieve the conditions needed for starting. It's not the first thing I'd look after if starting was difficult but it's not something I'd ignore either
Essentially, everything that contributes to the ease or difficulty of starting your Maxim-X is covered under the heading of "A Tuneup". With a proper tunep, there shouldn't be any reason left for starting to be difficult.
If a tuneup won't happen any time soon but difficult starting is making you crazy, then there may be a technique that could help you get your X started more easily. In cold weather or after long periods of storage, you might find that the X will start for a moment but then die out. After that point, you'll probably find yourself cranking endlessly to no avail. Some Maxim-X owners solve this problem by removing the seat and using a puff of Quick Start spray but that can be awkward and it shouldn't be necessary. If you're successful in getting it started at all, the trick is to "get over the hump", as I call it. If you rev the engine up over 2500 rpm and keep it there to give it some momentum to get past the spot where it would normally die, then the engine will usually spin long enough for the carburetors to provide a fresh source of fuel/air for combustion just before the engine tries to stop again. After that, it should keep running.
This isn't something I'd recommend because most engine wear happens immediately after starting, before oil can circulate thoroughly through the engine. It's just not wise to spike rpms so soon and it's certainly not advised in cold weather when oil circulation isn't what it should be for a longer period of time. Pushing the engine "over the hump" isn't something I'd want to do on a regular basis but it may get you on the road while you make plans for that tuneup I mentioned .
Most of the time, however, if your X is tuned as it should be, you'll find it incredibly easy to start, so easy in fact that it's almost enough just to tap the Starter button quickly (okay, maybe a little more than that). I don't believe I've ever owned a motorcycle that was quite as easy to start as the Maxim-X.
