SX/SXi/SXi Pro 750 sxi question

[Captain PegLeg]

I can ride it all day long no problems. But when i go to start it up the next time i go ride, i have to put new plugs in it to get it running. Then it will run fine all day, with numerous starts and stops. But it seems like after a week of sitting it needs new plugs. What could be causing this?

 

[Hirschfelt]

I would do a leak down test. I had a similar problem hard to start initially but once I got it going It was fine for the day. I never had to put new plugs in I just would clean them up real good.

 

[madscientist]

whats the plug color look like?

 

[Waternut]

I'm going to go out on a limb and guess some fairly random stuff here but all are possibilities. My guess is your engine has a leak in the crankcase, your piston rings are shot and only seal when everything warm, your plug wires are corroded and can't fire through cold fuel, and/or you aren't using a primer and the engine isn't getting fuel at the beginning of the day.

 

[Captain PegLeg]

Plugs look perfect when i remove them. Top end is brand new, with good compression. Just put brand new main seals. And i also put gasket maker on entire crankcase halfs when i put them together. I am not running a primer, just the choke.

 

[Waternut]

Have you ever done a pressure check on the engine though? Every engine I've put together has been pulled back apart due to a small leak. I've also had an engine test perfect and then 2 months later develope 2-3 leaks.

 

[nokfir]

do a compression check, and def add a primer!!!!!!!!!!

 

[Captain PegLeg]

compression is right at 140 with a stock head.

 

[Captain PegLeg]

Have you ever done a pressure check on the engine though? Every engine I've put together has been pulled back apart due to a small leak. I've also had an engine test perfect and then 2 months later develope 2-3 leaks.

How do i check this? Only reason i am trying to see if anything is wrong is because i do now want to have keep putting plugs in it. It runs absolutely fine!!

 

[Captain PegLeg]

Also.. will you have to change anything on the carbs to swap to a primer? Like jets, pop off, ect...

 

[jondotcom]

Why not put irdium plugs in it. They last "forever" and are foul resistant. BR8EIX if I recall correctly. www.sparkplugs.com

 

[Waternut]

Here is a good write up I did a while back on how to pressure test your engine. It's completely different from getting compression numbers in the cylinder. A few dollars at Lowes and you'll have a tool you can use any time you think something might be up.

http://pwctoday.com/f64/how-pressure-test-your-engine-166854.html

I would pass on the iridium plugs. At $12-$20 each plus shipping because no local stores have them, I think you could afford enough BR8ES at $2 each to last quite a while. Plus you aren't fouling plugs because everything is running perfect either.

 

[Captain PegLeg]

I had a bad splice in the stop button. It would barely sputter like it was starting then it's shut off. I checked compression again, then put new plugs in, and it didn't change anything, so i started searching more and found the bad splice. F-in salt water will eat away wires within weeks. Thanks for the help again x family!

 

[gabe1986]

hey im having the same problem on a stock93 750sx the plugs r nast black at the nd of the day and when i go to ride next i clean them and it goes allday any ideas??

 

[customride0105]

running to rich..