Crappy Gas Mileage

[Micksan]

I just got off the phone with the Bosh Tech rep. They have discontinued the +4 plugs. No reason given. Some are still in a few stores Their crossover to our stock plug would be the XR4CS which is their coldest plug. the XR5Cs would be one colder. The more I am looking into it the stronger my belief is that as we modified our bikes with the TORS, K&N, and Maps we changed the dynamics that were used to assign a spark plug. So with the changes that help our performance a lot of gas goes out the tail pipe.

 

[Jarrod83]

Bosch plugs are a joke, especially the plus4 . I tried using them in several cars I have owned and my mileage always seemed to suffer. I also would hook up a vac gauge before and after switching and my vacuum at idle would be lower even compared to NKG. A good platinum or irridium plug its your best bet. And NEVER use a bosch in a forced induction motor the electrode posts tend to break off.

 

[Jarrod83]

How did your plugs look when you switched them out? I had a situation once where a little mazda hatch I had started using a lot of extra fuel, but nothing felt different. I checked everything and the only thing I noticed was that the plugs looked extremely wet. Turned out I had a winding broke in the fuel pump so it still worked but wasn't putting out adequate pressure. The ECU compensated by putting even more fuel in, more like a squirt of liquid than an atomized mist. Just a shot in the dark but I hope you figure it out.

 

[Rocket Scientist]

EVERY single time I've tried Bosch plugs, starting with snowmobiles in the 70's, they have been a complete POS ! The last thing I tried them in was my supercharged Buick Riviera. Ran way worse than the 100,000 miles plugs I took out. Took them back. The guy at the parts store wasn't surprised. He said they get a lot of them back !

 

[ROCKETHEAD]

How did your plugs look when you switched them out? I had a situation once where a little mazda hatch I had started using a lot of extra fuel, but nothing felt different. I checked everything and the only thing I noticed was that the plugs looked extremely wet. Turned out I had a winding broke in the fuel pump so it still worked but wasn't putting out adequate pressure. The ECU compensated by putting even more fuel in, more like a squirt of liquid than an atomized mist. Just a shot in the dark but I hope you figure it out.

Twice had bad mpg's on two different rockets and one was fuel filter and the other was fuel filter and pump both times due to junk fuel...

 

[Jarrod83]

EVERY single time I've tried Bosch plugs, starting with snowmobiles in the 70's, they have been a complete POS ! The last thing I tried them in was my supercharged Buick Riviera. Ran way worse than the 100,000 miles plugs I took out. Took them back. The guy at the parts store wasn't surprised. He said they get a lot of them back !

Bosch plugs are just like fishing lures, before they ever catch a fish they have to catch a fisherman.

 

[kblahetka]

I'm replacing plugs soon, should I go with the DPR7EA9? I have pipes and the under the claw triple filters.

 

[Gregger]

Fellows. Don't replace plugs just because Triumph recommends a change. Take them out and look at them. If the electrode looks fine, verify the gap clean if necessary and reinstall.

 

[Micksan]

Fellows. Don't replace plugs just because Triumph recommends a change. Take them out and look at them. If the electrode looks fine, verify the gap clean if necessary and reinstall.

Along that lines the color can tell you a lot about what is going on , with your engine.

 

[zenbiker]

It's not the plugs. If the plugs fire and the A/F mixture ignites, that's all a plug can do. If the heat range was too cold, you'd be fouling and running rough with power loss.
If the bike is pulling strong as always, changing the plugs will not make a difference of the magnitude you are talking!
Just what changes have you made in the intake and exhausts?..Much more likely culprits...JMHO