Jump to content

B12 DOT Head Overheating/Won't Start


Recommended Posts

So yesterday I installed a DOT head onto my 2003 b12s. I'm running a dale walker stage 2 kit, k & n pods, yoshimura can/mid pipe ( the midpipe leaks at the connection with the headers possibly causing a lean fuel mixture). No advance on ignition. Valve clearances are set to spec. PAIR system removed.  I have low octain gas in the tank at the moment and I just did an oil change. It's 90+ degrees here and above 85% humidity.   When the bike warms up the oil starts to steam from the crankcase breather and the oil fill hole (when I remove plug). It also will not start. The motor turns over really slowly in a chugging fashion. The more I try to start it the slower it chugs until it just stops. The battery is just above 12 volts. I'm also getting some pre ignition or detonation ( I'm not sure which one) when it's hot and under heavy load.   Any ideas? Am I running too lean and overheating? Is it my starter overheating? Is 11:1 too high for such hot weather? I'm guessing the low octain fuel is the source of my ignition issues. 

Thank you in advance! This is the first time I've needed to post anything but I have always found a ton of useful and well thought out info here. 

Link to comment

Sounds like the battery is low on charge too, the solenoid clicking means there's not enough charge to engage starter. Low octane fuel can cause pre-detonation and excess heat. 11:1 comp. ratio isn't a problem - there's 1000's of oil cooled engines running well with 11:1 and 12:1, but you do need to put half decent fuel in your tank.. It takes a lot to kill one of our engines.

Link to comment

A fresh charged battery will show 13.2v and should sit at about 12.7-12.8v. What ignition are you using - blandit or GSXR? There are likely to be timing / advance differences which won't help pinking issues. You've increased the combustion efficiency significantly with the compression increase - that needs more fuel just to keep up - don't second guess fueling, if you haven't got a wideband lambda, get it on a dyno asap! An exhaust leak won't significantly affect in-cylinder mixture just after its out - popping is the usual symptom on decel. Sometimes high comp. and slow starter speed bumps the starter clutch enough to undo the retaining bolt so starter will just spin and can't turn the engine. Sounds like a combination of lots of small issues that need to be addressed on at a time!

Link to comment

Gizzer1460- thank you very much for the response. I am using the bandit ignition and I had the timing advanced to about 5 degrees but I was under the impression the advance would have a negative effect with the higher compression. Working through some of these issues it seems that I do have a few different smaller, unconnected issues that need to be addressed. I'll post back as I figure them out. 

Please continue to throw your ideas at me while I'm working through all of this. 

Link to comment

So I finally got my other battery fully charged/installed yesterday and the starter is still having a hard time turning the motor over. This leads me to believe it's the starter itself that is faulty. I'm replacing it with my spare tonight and hopefully going on a very long ride. 

Link to comment

Ok. So I just replaced the starter and it didn't fix my issue. So I did some more trouble shooting and gixer1460 was spot on. Clutch retaining bolt had come loose. I just took it for a short ride to get some higher octane fuel and it is still running really hot. Hot enough to make the oil smoke out the crankcase breather again. It ran fine, but now I have to address the mildly lean fuel mixture. Could this be causing my heat issue?

Thanks again gixer1460 for the spot on advice and gixerjonah for pointing it out again for me. 

Link to comment

This is a problem using a std ignition system with a radically different configuration of engine! The Blandit ign curve is designed to suit a 'low' comp engine so will probably be a bit retarded around idle and more advanced higher up to compensate. This sounds opposite to what you need! Adding the advancer may help low end but will smoke the engine at high rpm's IMO. So unless you swop out to a Dyna 2000i or similar where you can tailor a better ignition curve, you'll always have to suffer a compromise set-up!

Link to comment

hmm. That makes sense. So much for a cheap compression increase.

Today I fooled around with different degrees of timing advance and carb tuning. Throughout it still ran too hot and even loosened the clutch retaining bolt again. This is not normal. I believe I may have higher compression than 11:1 somehow. I'm going to double check cam timing and that the cam chain is not too tight. If I am still having problems I will just go back to the stock head. 

I'm confused that through all of my research on this conversion I never found someone with a similar problem. I am either missing something or people don't run there 11:1 bandits with stock ignition in 95+ degree weather.

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...