hotter spark plug with the uncorked mod?

10 replies to this topic
  • Hondathumper450

Posted February 09, 2007 - 05:25 PM


Does anyone know if you have to get the next step hotter plug after you do the uncorked mods? My 2000 XR650R has been uncorked with the honda power up kit and the plug is really dark as in black. Do you need to get a hotter plug because of the richer jetting? I know there is more air coming in as well compensating for the richer jetting but it seems to me more fuel a hotter plug may be needed?????

  • creeky

Posted February 09, 2007 - 06:21 PM


I would suspect that the jetting is a little rich. Take a look here on spark plug heat range.

  • Hondathumper450

Posted February 09, 2007 - 06:55 PM


ok, will try this again. It has the power up kit which includes of course a RICHER main jet but I do understand it also includes a air boot that allows more air in the system as well. I use to ride and race 2 smokers in my younger days and know how to check plug heat ranges by color and tip status. and yes of course it is a richer fuel mixture because of the bigger main jet. I am surprised though that the original main jet that was in the bike was a 125??? and the power up kit from honda which inludes the pilot 68s jet, the needle and the 175 main jet. Did they actually use that small 125 jet installed from the factory? Big jump for sure.
SO now we have the yes I know it has a richer fuel mixture now because of the richer main jet. My question is does anybody use a hotter plug or recommend a hotter plug because fo the power up kit and the richer settings that come with the power up kit????

  • rebelventurer

Posted February 09, 2007 - 07:30 PM


I thought the power up kit came with an iridium plug that has a shorter electrode and was indeed a hotter plug. Please by all means correct me if I am wrong. :censored:

  • motopsycho650

Posted February 10, 2007 - 05:33 AM


I have not done the full power-up kit, just the uncorking mods. I also have a cut out side panel for much better air-flow.

It's been my experience that the XR650R likes to run just a tad rich. I have messed with the stock carb A LOT!! I got it to where the plug was burning perfect color, and it actually seemed a touch less responsive, and it lost 2-3 mph of top speed. When I went up one size main jet, and richened to pilot adjustment a 1/4 turn, it seemed to run better. As long as your spark plug does not collect deposits, (i.e. the black layer stays really thin & dry), It's not a big deal.

A touch rich won't hurt anything, but stay away from a touch lean.

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  • Hondathumper450

Posted February 10, 2007 - 05:35 AM


how many are using stock plug and how many are using a hotter plug and what type with the power up kit?

  • cleonard

Posted February 10, 2007 - 08:47 AM


I don't have any experience with the HRC kit, but generally I do know that the HRC kit makes for a hotter running engine. That would indicate a colder plug not a hotter one. Usually when the performance of an engine is increased with higher compression that makes it hotter. It might be too hot with the standard plug.

I think that it depends on your intended use. For trail use I bet the normal plug is good. If you are going to do some more wide open type of high speed riding a one hear range colder plug might be good.

The stock XR600 plug is a bit of an unusual one with the projected electrode. The NGK number is DPR8EA-9. The "P" is for projected electrode. It sticks out a couple of mm further than the more standard D8EA. I think that the the recommended HRC plug is a racing style that does not have this extra projection.

  • Hondathumper450

Posted February 10, 2007 - 11:39 AM


When I say the power up kit I am talking about the jet switch, the carb manifold that is opened up. My stock plug is black but not caked just black. seems a bit cold to me. does the normal kit, not the pistion upgrade kit need a hotter plug?

  • rebelventurer

Posted February 10, 2007 - 05:44 PM


I would say no it shouldnt need a hotter plug, however if you are lugging the engine (low RPM's) a lot a hotter plug may be in order. If you are desert type riding wot for long periods a colder plug would be reccomended.
The proper spark plug would be NGK-BKR7E-11

  • Hondathumper450

Posted February 11, 2007 - 06:28 AM


is that the original plug? which one would be the next hotter?

  • rebelventurer

Posted February 11, 2007 - 08:06 AM


NGK-BKR7E-11/ I believe some one please correct me if I am in error, a hotter plug would be NGK-BKR6E-11/ Colder would be NGK-BKR8E-11 :censored:

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