misssing at low speeds

[Big Auggie]

My bike started to miss/pop on the tail end of a short run. I initially thought a vacuum cap had came off but it still misses after I replaced all 3. I took the plugs out and found the back right plug was not firing. First thing I'm checking will be the plug then the wire. If it isn't the wire then I'm thinking coil.

 

Question 1: Does this have two coils and do they run left bank/right bank or front/rear bank?

 

Question 2: How important are those plastic shields that sit on the valve covers? The front one is a royal pain in the @$$ to get in

and out when you need to change plugs and I'd like to leave them off!

[Venturous Randy]

You need to check the spark plug cap as there is a built in resistor that can get corroded. Had this happen on a friends bike with the same symptoms. Take the cap off and there is a screwdriver slot to disassemble it. Be careful as there may be a spring in there.

Randy

[Marcarl]

Ditto on that.

The plastic cover you speak of is land fill material. very few are being used for anything else.

Each plug has it's own separate coil, not a real common issue, but has happened.

[Karaboo]

I don't think you need to take the plastic cover off to change plugs. It may depend on the type of socket, though. Also check the plug wire ends (unscrewed from caps) and cut back 1/4" or so if not clean.

[Donvito]

Ditto on that.

The plastic cover you speak of is land fill material. very few are being used for anything else.

Each plug has it's own separate coil, not a real common issue, but has happened.

 

In the 28 years I've owned my bike, I wondered if leaving the plastic covers off would cause some drastic consequence but never had the nerve to try so I have always reinstalled them. I guessed they were there for some reason possibly air flow or insulation. So, maybe, the next time I have to remove them, I may leave them off. Nahhh, probably not. I don't remove mattress tags either.

[Prairiehammer]

In the 28 years I've owned my bike, I wondered if leaving the plastic covers off would cause some drastic consequence but never had the nerve to try so I have always reinstalled them. I guessed they were there for some reason possibly air flow or insulation. So, maybe, the next time I have to remove them, I may leave them off. Nahhh, probably not. I don't remove mattress tags either.

 

I agree. Yama Mama would not have spent the yen to produce and install those shields if they were not needed. I believe those shields are heat shields, protecting sensitive components (TCI, coils, fuel filler neck, rider's balls, etc.)

[Venturous Randy]

They also help a little on reducing engine noise.

Randy

[Big Auggie]

When I took the plug cap apart there was a small brass(?) disc that came out. I didn't notice it at first so don't know where it goes in the line up. I'm guessing it protects the resistor from abrasion by the spring. Took the other back cylinder plug cap apart but didn't see that small disc right away either. Thoughts?

[flyday58]

I agree. Yama Mama would not have spent the yen to produce and install those shields if they were not needed. I believe those shields are heat shields, protecting sensitive components (TCI, coils, fuel filler neck, rider's balls, etc.)

Went to 3 different Yamaha parts sites, could not find "rider's balls" on any of them. Is that the Yamaha name or a colloquialism?

[cowpuc]

Went to 3 different Yamaha parts sites, could not find "rider's balls" on any of them. Is that the Yamaha name or a colloquialism?

 

Not for sure Flyed Lice but I think those parts have something to do with the special California models.. I know that part name was mentioned to me several times while out there by other riders and even by LEO's.. I only say that cause they (the people I am talking about) mentioned Tweeks not having any a couple times but the Officer in mention said something along the line of having my bike and I right by "them" after pointing some funny looking plastic x-ray gun with a big lense attached to it at Tweeks..

Now that I think about it, I should have asked the officer if he would mind x-raying her carbs and crank bearings for me while he had me stopped - check float levels and crank tolerances and all that..

I also think its closer to provincialism than colloquialism.. As Curly Howard would say Flyday, "your murdering the Kings English" nuck nuck..

[flyday58]

Ya, my engrish not so good, from the DEEP south ya know. Lived next to FSU for my first 19 years, musta rooned me.

 

:sign back to topic:Meanwhile, back to the disc question...if I remember not all my caps had the disc, either.

[Big Auggie]

The back two plug caps which have the springs have the discs. My thinking is that it is a buffer between the spring and resistor to avoid abrasion to the resistor.