Idling problems after some time

[Screwloose]

But i agree with Zeus36 that could be ignition coils starting to fail when they get hot....or something about the ignition componets-parts.

I agree, also I put two household fans near the engine while fault finding on this issue. The resistances of the leads, caps, coils, everything changes drastically when you overheat the engine above the 3/4 mark. I noticed that although the manual elec spec's testing on my parts at ambient temp showed within limits, overheating showed up some faulty equipment such as the spark plug leads arcing. The age of the coils cannot help either as nothing lasts forever in the current carrying game, especially if they have been feeding faulty worn leads and caps, been overheated and cooled many times over, causing the varnish on the internal coils to melt and crack, and hence leak current (you see this in burnt out industrial motors), and your left with a bucket of faulty parts and some headaches. In my opinion where the front two coils are placed is a naturally accumulating hot area. I'll be keeping this bike for a long time yet, hence if I go there again it's automatically COP's for me.

As for the fan not working, try testing it right to the battery, and clean the sensor (near filler cap) that switches it on, I bypassed my sensor with a simple piece of wire and put a switch in-between.

 

[02GF74]

how old/what is condition of the spark plugs? Fit oem ngk if in doubt.

 

[johnissan]

In my opinion where the front two coils are placed is a naturally accumulating hot area. I'll be keeping this bike for a long time yet, hence if I go there again it's automatically COP's for me.

That's why i've bought 4 seperate Nology Profire coils with leeds and i'm planing to put them in the air scoops away from hot areas!

 

[kjerkegaard]

how old/what is condition of the spark plugs? Fit oem ngk if in doubt.

Brand new spark plugs. Havent checkes the condition recently

 

[kjerkegaard]

Could be ignition coils starting to fail when they get hot.

Okay. In terms of buing new coils. Is there Any other great alternative to oem coils? Pretty expensive stuff.

 

[02GF74]

Yes, cop (coil on plug) - search forum ad to which bike/models to use.

 

[Zeus36]

I converted to COPs and it fixed a stumble I had at 4500 rpm. They just bypass the stock coils. I think back in 2015, it was around fifty bucks for the set from a forum member.

Highly recommend Coil over Plugs! Lots of posts here on the forum... and you may find them from members cheaper than anywhere else. There is a set on eBay for $150: 1985-2007 Yamaha Vmax Spark Plug Coils & Wires (COPS) | eBay

Here's mine with a split loom cover:

 

[kjerkegaard]

I converted to COPs and it fixed a stumble I had at 4500 rpm. They just bypass the stock coils. I think back in 2015, it was around fifty bucks for the set from a forum member.

Highly recommend Coil over Plugs! Lots of posts here on the forum... and you may find them from members cheaper than anywhere else. There is a set on eBay for $150: 1985-2007 Yamaha Vmax Spark Plug Coils & Wires (COPS) | eBay

Here's mine with a split loom cover:

Thanks for replying

Is it just a direct switch with those COPS or do I need anything Else to make it work?

How is the quality on the ones you linked?

 

[Fire-medic]

'kj,' it's a good idea to put your location below your screen name, and your year VMax in the signature line. That helps people direct you to services/parts/help by you, and it helps readers to understand issues you face. An example: the early DYNA ignition modules with dip-switches used upon the '85-'89 models, seem to be sensitive to running COP's without presenting the proper load to the ignition box. The '90-'07 models use a different DYNA box, and are not as prone to developing problems from the use of COP's. Use the 'advanced search' function to look for posts on this, look in the upper right hand corner and click on 'search,' and then 'advanced search.'

Me, I'd contact Sean Morley, [email protected] and ask him about a set for your specific model/year bike, and confirm the ignition box you have by the # of wires from the pick-up coil (5) for '85-'89; and (2) for '90-'07. Follow the wire back from the left front engine case cover, to the connector, and it will immediately be apparent which type you have. Typically, you can just go by the model year, but an early engine can fit into a late frame and vice-versa. The wire harness has to accompany the engine year. Early engine, early wire harness, late engine, late wire harness. I know, because I've put a late engine into an early frame.

A member on here, Gannon used to make the Splicker Designs COP sets, I think he sold his inventory to Sean Morley. Ideally, there's much-more to it than picking-up a random set of COP's from some parts vendor, and splicing them into your wire harness. Caveat emptor.

 

[one2dmax]

We don't have COP adapter harnesses anymore though I have some of the coil connector parts on hand, new coils, and even some upper support brackets.

 

[Zeus36]

Thanks for replying

Is it just a direct switch with those COPS or do I need anything Else to make it work?

How is the quality on the ones you linked?

The ones I linked to are on ebay, so I have no idea as to the quality. The ones I bought from a forum member were built for 1990 to 2007 years. I have a 1997. Just unplug the stock coil connectors and pull the plug wires. Plug in the COP harness and connect the COPs plug wires to the plugs. My stock coils are still mounted in case I needed to troubleshoot the new COPs. But they've been great and I've never looked back.

 

[kjerkegaard]

UPDATE:
Talked to Sean for some weeks ago Who adviced me to replace caps and wires. So i did but it still seems to have some hesitation when hot. Like one of the Cylinders not firing? Seems to run reasonable when "cold". Today when idling it kind of popped through the air filter box like it didnt fire some times?

Sean Morley do not sell the COPS anymore. Anyone selling them og know which one is working and where to buy them. I think that would be the next step.

 

[Fire-medic]

Again, the year bike you have, can affect the longevity of your ignition box, if you decide to run COP's. The resistance presented to the ignition box seems to be a critical factor in the early ignition box's lifespan. The Denso coil-over-plug pieces are supposed to be better-than the Mitsubishi COP's, from anecdotal reports. Using resistors of the proper value is what's necessary, so the ignition box operates properly, for the long-run in the case of the early bike (1985-1989) component. Look in the factory service manual, and compare that to the resistance you measure with the COP's you get, and decide what value resistor you use, on each COP 'stick.' Again, many people use COP's without resistors, on the later model digital ignitions (1990-2007) but I make no recommendation on what resistor to use, or on not using any resistors. Proceed at your own risk. FYI, I use COP's with resistors, made by Gannon VMX12.