Spark plug heat range vs. thread repair method-UPDATE sufficiently pondered

H

Hunter

Junior member
Location
Raleigh, NC USA
I neglected years ago at rebuild time to repair the spark plug hole threads on my 750. One side is pretty bad but it holds the plug OK. I feel like it may spit it out at an inopportune time and I will soon have it timeserted.
In the past I have timeserted many Guzzis and Ducs and they seemed to be ok with the stock heat range. Does anyone here have experience either way on this? I want to avoid creating a new problem if possible.
Thanks, Hunter

Modified thread title 5/10/13 as subject seems settled with thread repairs having no real affect on plug performance. Thanks to all!
 
If installed correctly, Timeserts will work perfectly for many, many years, irrespective of what you ask of the engine.

If not, you'll find out the first time you attempt to remove a plug... :D

piet
 
Hi Hunter,

Are you worried about the PLUG heat range no longer being suitable after timecerting?

I would not worry, it is unlikely to be noticeably effected. Anyway, if it is, just shift one way or the other on the plug. There is nothing sacred about the plugs heat range - whichever suits YOUR bike is the right one.

Paul
 
Haggis said:
Hi Hunter,

Are you worried about the PLUG heat range no longer being suitable after timecerting?

I would not worry, it is unlikely to be noticeably effected. Anyway, if it is, just shift one way or the other on the plug. There is nothing sacred about the plugs heat range - whichever suits YOUR bike is the right one.

Paul
Click to expand...
Thanks Paul, yes the plug heat range. I'm not married to a heat range, just wondering since I have mine dialed in pretty well. I've not noticed a particular issue but wondered if the wide and varied group here had noticed any.
Now if I can just get over the fear of having someone else wrench on my baby I will get the threads fixed! :o
 
slower dissipation of heat from the plug to the head since the insert is different material (than the head) is always the speculated, i've never seen that big of a difference and have used a lot of insert over the years (british bikes)



Tippie said:
Can anyone please enlighten me on what possible effect a new thread will have on the heat range of spark plug needed.
Click to expand...
 
I agree entirely with Mik667, but since most Laverda have an iron insert for the head/skull/valve seats and plug stub, it is still going into a broadly similar material, so it would be hard to detct a difference, especially on one of our old clunkers, I mean its not an FI engine revving to 19000RPM, and 23:1 compression and nevver droping much below 10,000RPM is it? What is and would be very worrying is something that I have seen and may have been heard of by the original poster (Hunter) triples and twins from Breganze have 3/4 inch  length plug threads, I have see a couple which have had inserts for the plugs installed for the shorter reach plugs (ie 1/2 inch) which works just fine and dandy and the bike will run well, untill the 1/4 inch of exposed plug thread cannot dissiapate the combustion heat as well as one that is 100% contacting, or gets sooted/coked up form normal use, and then when you try to remove that plug, the 1/4 inch of exposed/ cooked/ coked plug thread , rips the insert out and your getting the head off again (Thanks Baldyne Engineering)
CLEM
 
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