Plug chop test results...

[Shuriken]

02 model. UNI air filter. OEM exhaust. 5700ft elevation. 150 main jets.

I have this color at idle, mid, and full.

Are we going for the light tan or the light gray?

 

[Fire-medic]

I think you may get an improvement in operation with 147.5 Mikuni mains.

 

[Shuriken]

I think you may get an improvement in operation with 147.5 Mikuni mains.

Funny you mention that. I put 147.5s in my 85 many years ago....

I have some 147.5s on the way. It will be nice to have 152.5, 150, and 147.5 to experiment with.

 

[Aquamax]

To me, that's not a bad color. I think you may find the 150's will be golden to your altitude...especially with OE exhaust. Is it a single UNI filter in the stock air box? If you had a Kerker system, I would definitely say you need to get into the 147.5 range.

 

[maleko89]

I agree. I'd be ok with the look of those plugs.

Mark

 

[Shuriken]

To me, that's not a bad color. I think you may find the 150's will be golden to your altitude...especially with OE exhaust. Is it a single UNI filter in the stock air box? If you had a Kerker system, I would definitely say you need to get into the 147.5 range.

It is a single filter. I've used K&N before and have one of those in my 85. This UNI came installed in the bike.

I might be splitting hairs.... but my 85 feels slightly stronger. It has the same OEM configuration, but uses a single K&N with the OEM exhaust, and 147.5 main jets.

I have some 147.5s coming. I do need to remove the carbs one more time to replace the right rear carb body. The PO effed up the idle mix screw threads. I tapped out the body to m7x1 and made my own bolt, which works, but it looks hokey and isn't as easily adjustable. So I need to decide if I want to keep these 150s installed or try the leaner mains.

The difficulty is that I sometimes ride at lower elevation (around 2800) and sometimes ride at higher elevation (over 8500). But in the current state of tune, which looks and feels pretty decent, I have to have my mix screws out beyond 5 turns. I have not gone a step down on pilot fuel jets.

I really wish I could find my Colortune plug that I bought 20 years ago. They are like $200 now. I used it on my old XS1100s to really see what was going on. I use the "ear method" in general but the XS1100s preferred a slightly rich idle. For example, bunson blue flame at idle on my XS1100s just wouldn't quite hold the idle, while slight orange flame would; but it was real easy to get all 4 pretty close with the Colortune plug, combined with the ear method.