Honda Magna Problems: 3 Known Issues (Explained)

There’s never been a bike quite like the Honda Magna.

Its liquid-cooled, 748cc V-4 engine’s cylinders puff into four valves conducted by overhead cams. It revs to 9700 rpm, which is unheard of in a medium cruiser.

The Magna is known not just for power but for reliability, so it’s no wonder that the bike has such a dedicated cult following.

Still, these bikes are getting up there in age, so if you’re in the market for one, you’re probably wondering what common issues other Honda Magna owners have had. Read on to find out.

1. Dry Rotted Fuel Lines

Like I alluded to above, Magnas have been around since the 80s.

While collectors and enthusiasts finally recognize them as the force the Magna’s been since its release, many of the original owners didn’t appreciate what they had, and a lot of these bikes have been sitting for a long time.

One issue to look for when scouting out a used Magna, or any bike that’s been sitting for an exceptional amount of time, is dry rotted fuel lines.

A bike with dry rotted fuel lines will have difficulty running, as a limited amount of fuel will probably make it to the carbs because of blockage caused by deteriorating fuel lines.

On a bike that’s been sitting, it’s easy to assume a bad fuel pump may the culprit for the lack of fuel. For some riders, that was the case too.

But after installing their new fuel pump and verifying that it’s pumping more than enough fuel even at wide-open throttle, the bike would still die in idle if they barely tapped the throttle.

In some cases, the wiring to the new fuel pump was incorrect, and in others, the fuel filter was gunked up, so the owner replaced that and still had issues.

If you let the pump fill the bowls, cut it off, hit the starter, and the Magna fired up, but the bike still dies once the choke is pushed in.

You’re still not getting enough fuel, and on an old bike like a Magna, that could be due to a piece of the dry rotted fuel lines blocking the fuel’s flow.

Replace the fuel lines along with the pump and filter, and your Magna should be ready to rip.

If you’re still having issues, check Magna’s carb—there’s a chance that a piece of rubber from the inside of the old fuel line split off and shoved itself into the carburetor.

It’s not always guaranteed, but if the bike is idling before you hit the throttle, you may be able to clear the carbs by flushing a heavy dose of Seafoam or another carb cleaner through the fuel lines.

Still, there’s a good chance you’ll need to clean or rebuild your carbs, and we’ve included a guide to doing so in section 3.

Please also read our article about how long Honda Magnas last.

2. Poorly Adjusted Float Needles

The float needle is a component in a bike’s carburetor that floats up and down in the needle seat, enabling the float bowl to maintain suitable fuel height. While seated or closed, the needle should seal on the seat and not permit fuel flow. 

As a bike sits, things get hot and change shape and become unaligned, and if you take home a used Honda Magna that’s been sitting for a while, you may find fuel coming out of all four of your Magma’s heads.

The bike could’ve been running just fine for a couple of miles when you tested it, but then the cylinders get full of fuel. If you keep riding it past the point of where the float should’ve seated and sealed, you’ll flood the chamber and wet your spark plugs.

If you try to start again in severe cases, fuel might even splash out of the cylinder, and eventually, fuel/oil mixture can make its way through your exhaust system and out of your pipes.

Like I already mentioned, this is no defect with the Magna, but an issue with many old bikes that have been sitting unkept for decades; either their float needles aren’t seating, or they could be defective, or the float heights could be set wrong.

There’s a chance that the previous owner installed an aftermarket fuel pump that works at a higher pressure, and its pressure is blowing fuel past the sealing float, needle, and seat.

If that’s not the case, then there’s nothing left to do but

• Pull out your carbs.
• Remove the float bowls.
• Inspect the action of the floats and needles.
• Inspect the float heights as specified in the Service Manual.

Float height is significant.

The float doesn’t just block the overflow of gas, but the depth of the fuel permitted in the bowl affects the air-fuel mixture and jetting.

Think of it as a toilet tank; you don’t want the tank overflowing, but you need a certain amount of water in there to flush.

Also read our article about common problems with the Honda Fury.

3. Clogged Jets and Dirty Carbs

Here’s the big one. When in the market for a Honda Magma, or any old carburetted motorcycle, check the condition of the carbs.

The most common issue owners find on their used Honda Magna is dirty carbs or clogged jets.

The first telltale sign of this is backfiring since the clog is causing your motorcycle to run lean.

A lean running bike motor is a decent sign of clogged jets inside the carburetor. Clogged jets restrict fuel delivery, causing a lean air: fuel mixture.

There isn’t one clear culprit behind a clogged jet, but it usually has something to do with a bike that’s been sitting uncared for.

For example, if the fuel tank was full of rust and then the owners fired the bike up, that rust would travel with the fuel through the lines into the jets and clog them.

You can always start by running Seafoam or Carb Cleaner through the tank to break up the gunk, but something like rust or gunk past a certain point warrants dissembling the carbs and cleaning them.

Cleaning the Carbs

Follow these steps to clean the carburetor:

•  Buy a gallon of carb cleaner and get a basket or strainer handy in which to soak your carbs.
• Carbs must be thoroughly dismantled for maximum cleaning. DO NOT use liquid carb cleaner on rubber, plastic, or felt carb parts—this can damage these components.
• Keep the components for each carb together to reassemble the same parts back into the same carb when you’re finished.
• The carbs in the first generation Magna V45 are different, and their internal components are not interchangeable, so clean each dismantled carb separately.
• Dip all the metal parts for one carb together for 1-24 hours, then rinse them with water.
• Dry with compressed air.
• Once the carbs are cleaned, inspect to verify that the passages are open by peering through every jet hole.
• Inspect carb passages further by blowing air or spray cleaner through them.
• Fish the washers and o-rings from the strainer.
• Reassemble carbs.

Make sure to also read our article about common problems with Honda Rebels.

General Pros and Cons of the Honda Magna

Below, I summarize the merits and demerits of the Honda Magna:

Pros

Like I mentioned earlier, the Honda Magna came equipped with a liquid-cooled, 748cc V-4 that pushes 9700 RPMs.

Couple that intense motor-power with the Magna’s weight of 538 pounds and boom—a medium cruiser willing and able to beat big twins out of the block.

The Magna achieves its power with RPMs, so it runs and accelerates as smoothly as it gets at as low as 1500 rpm.

Performance packed and nimble, the Honda Magna is also reliable. If you notice, all the major complaints are about Magnas that have been sitting without maintenance.

There are many well-kept Magna’s that have clocked over 100,000 miles and are still running flawlessly. 

Cons

1.  Dry Rotted Fuel Lines
2.  Poorly Adjusted Float Needles
3. Clogged Jets and Dirty Carbs

What Do the Reviews Say?

“The Magna leaps ahead of those other middleweight cruisers and will quickly vanish up the road if it becomes an all-out race. It is geared a bit lower than other 800s, which means it has plenty of power in hand on the highway, allowing quick passes even if you don’t downshift. If you do, it jumps past laggardly four-wheelers. Around town it rewards those willing to stir the five-speed gearbox, which is nicely staged and shifts positively.

You can feel that middleweight stature in the Magna’s handling, however. The steering is light, steady and precise; more responsive than what is found on V-twins. The well-sorted suspension and chassis also make Honda’s V-4 cruiser steady, whether heeled over in a bumpy corner or cutting through truck wakes on the interstate. Like the suspension, the tires also offer better performance than those found on most cruisers, during braking and cornering. However, that long, low profile does mean the Magna is easier to drag in corners.”

Source: motorcyclecruiser.com

What’s the Resale Value on a Honda Magna?

Year	Mileage	Price
1987	6,138	$3,995
1988	22,513	$3,000
1997	40,005	$3,990
2000	41,401	$4,499

Sources

https://www.motorcyclecruiser.com/

ⓘ  The information in this article is based on data from National Highway Traffic Safety Administration (NHTSA) recall reports, consumer complaints submitted to the NHTSA, reliability ratings from J.D. Power, auto review and rating sites such as Edmunds, specialist forums, etc. We analyzed this data to provide insights into the best and worst years for these vehicle models.

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