Smoke on startup - Kawasaki KLR 650 Forum
2008+ KLR650 Wrenching & Mod Questions For repair, maintaining or modifying discussions related to the newly updated 2008 and beyond, Generation 2 KLR650 Motorcycle.

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post #1 of 46 Old 09-25-2019, 12:53 AM Thread Starter
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Smoke on startup

2008, 685 (supposedly), new to me. On startup, with choke on (toward rider), smoke billows up from the engine (haven't determined an exact location/source). Smoke goes away when choke lever gets pushed back. Any ideas why?
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post #2 of 46 Old 09-25-2019, 10:12 AM
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I'll take a guess of possible oil leakage from the top valve cover drooling on to the exhaust header pipe when parked for a while & especially over night.

The exhaust header heats up pretty quickly, smoking the oil film. The thin film may just coincidentally be burned off by the time the engine is warm enough to idle without choke.

I'll strongly urge you to NOT simply try to tighten valve cover bolts to stop an oil leak. Too Many people strip the threads or twist off the bolts. This may already be the case & why it may be leaking from there! The bolts are only 6mm thread, with a stepped shoulder and an OVERLY Large 12mm head which encourages people to over-tighten, 12mm head is usually on a 8mm shank.
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pdwestman
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post #3 of 46 Old 09-25-2019, 01:14 PM
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Quote:
Originally Posted by pdwestman View Post
I'll strongly urge you to NOT simply try to tighten valve cover bolts to stop an oil leak. Too Many people strip the threads or twist off the bolts. This may already be the case & why it may be leaking from there! The bolts are only 6mm thread, with a stepped shoulder and an OVERLY Large 12mm head which encourages people to over-tighten, 12mm head is usually on a 8mm shank.
I'll echo Paul's suggestion regarding the valve cover bolts. It is super easy to strip these dinky fasteners, even with a torque wrench!

Jason
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post #4 of 46 Old 09-25-2019, 04:05 PM Thread Starter
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Thanks for replies/thoughts. The previous owner has silicone glue running a circumference around the valve cover gasket edge and the other gasket edge below (said he had a little oil seepage after the 685 upgrade). So you all may be on to something. Assuming I choose to pull the top off and install new gaskets and retorque, do I need to pull the motor out, or can it be done in the frame without an inordinate amount of trouble?
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post #5 of 46 Old 09-25-2019, 05:40 PM
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Quote:
Originally Posted by Schoen View Post
Thanks for replies/thoughts. The previous owner has silicone glue running a circumference around the valve cover gasket edge and the other gasket edge below (said he had a little oil seepage after the 685 upgrade). So you all may be on to something. Assuming I choose to pull the top off and install new gaskets and retorque, do I need to pull the motor out, or can it be done in the frame without an inordinate amount of trouble?
The Best Thing that you can do for your bike & yourself is to Purchase a Clymer or OEM service Manual. (But not a slightly used oem 99924-1384-01 OEM service manual off any net site. Too Many ERRORS in 1st printing)

Yes, the top-end can be serviced in-frame.

pdwestman
Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 85,000+ miles & counting

Last edited by pdwestman; 09-25-2019 at 05:42 PM.
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post #6 of 46 Old 09-25-2019, 07:13 PM
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Quote:
Originally Posted by Schoen View Post
Thanks for replies/thoughts. The previous owner has silicone glue running a circumference around the valve cover gasket edge and the other gasket edge below (said he had a little oil seepage after the 685 upgrade). So you all may be on to something. Assuming I choose to pull the top off and install new gaskets and retorque, do I need to pull the motor out, or can it be done in the frame without an inordinate amount of trouble?
As Paul said, no need to pull the motor out of the frame.

If you do have stripped threads in the cam caps, they can be repaired via Helicoil.

I do not recommend using a torque wrench for installing the valve cover bolts. Torque is not a very accurate means of preloading a fastener, as small variations in friction translate into big changes in preload. Instead, I would torque the valve cover bolts by feel. Slowly tighten the bolts in a cross-pattern. You will fee the gasket compressing as you turn the wrench. The moment you feel that the gasket has stopped compressing and you feel metal-to-meal contact as the bolt torque shoulder makes contact with the cam caps, STOP tightening.

And lastly, get a workshop manual--if you don't already have one.

Jason

Last edited by Norton 850; 09-26-2019 at 08:13 AM.
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post #7 of 46 Old 09-25-2019, 09:00 PM Thread Starter
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This is the first I've heard of Helicoil. So I searched it, watched a couple videos, and found a thread or two here where it seemed to solve the stripped thread problem (don't know if they experienced leaking). Assuming I have stripped internal threads:
1. Is the purpose of the Helicoil so you can reuse of the stock bolts? If so, why would you want to reuse the stock bolts if they are "dinky"?
2. Is there any benefit in using the Helicoil instead of just drilling/tapping to the next size up which, I would think, would get me a better/stronger bolt than those "dinky fasteners"? I already had to do this with the rear brake lever pinch bolt (previous owner overtightened it and stripped the internal threads). Tapping to a slight oversize worked fine for securing the brake lever but, then again, it's not being used to make a seal and keep oil inside. Does the Helicoil insert allow you to tighten more confidently (without the worry of stripping)? I found an opinion in one of the threads that there might not be enough metal for drilling/tapping...Has anyone confirmed this? But, if you're having to drill for the Helicoil...?
3. Does anyone make better/stronger/larger valve cover bolts to deal with what is starting to sound like a common problem? The sub-frame bolts were deficient, so there's an upgrade for that. The front brake reservoir Philips head screws get stripped out so Eagle Mike makes replacement hex-head screws. But, from looking at his website, it don't see anything for this problem.

For a failed Helicoil report, go to the advrider.com forum and search for KLR 650 Valve Cover bolt - New Threat! Has good pics of the fix (stud implantation). Hope I don't have to go to that extent.

My bike came with an old Clymer manual. When I get home, I'll look and see which edition it is.

Last edited by Schoen; 09-25-2019 at 09:49 PM.
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post #8 of 46 Old 09-26-2019, 08:11 AM
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Quote:
Originally Posted by Schoen View Post
This is the first I've heard of Helicoil. So I searched it, watched a couple videos, and found a thread or two here where it seemed to solve the stripped thread problem (don't know if they experienced leaking). Assuming I have stripped internal threads:
1. Is the purpose of the Helicoil so you can reuse of the stock bolts? If so, why would you want to reuse the stock bolts if they are "dinky"?
2. Is there any benefit in using the Helicoil instead of just drilling/tapping to the next size up which, I would think, would get me a better/stronger bolt than those "dinky fasteners"? I already had to do this with the rear brake lever pinch bolt (previous owner overtightened it and stripped the internal threads). Tapping to a slight oversize worked fine for securing the brake lever but, then again, it's not being used to make a seal and keep oil inside. Does the Helicoil insert allow you to tighten more confidently (without the worry of stripping)? I found an opinion in one of the threads that there might not be enough metal for drilling/tapping...Has anyone confirmed this? But, if you're having to drill for the Helicoil...?
3. Does anyone make better/stronger/larger valve cover bolts to deal with what is starting to sound like a common problem? The sub-frame bolts were deficient, so there's an upgrade for that. The front brake reservoir Philips head screws get stripped out so Eagle Mike makes replacement hex-head screws. But, from looking at his website, it don't see anything for this problem.

For a failed Helicoil report, go to the advrider.com forum and search for KLR 650 Valve Cover bolt - New Threat! Has good pics of the fix (stud implantation). Hope I don't have to go to that extent.

My bike came with an old Clymer manual. When I get home, I'll look and see which edition it is.
The dinky bolt doesn't fail, the aluminum female thread does.

The Helicoil repair will accommodate slightly higher tension loads. The Helicoil does this by providing slightly greater shear area in the aluminum base material and the Helicoil's stainless steel material has greater yield strength than aluminum.

A larger diameter bolt would make for a stronger connection. But, the larger bolt would have to have a unique geometry similar to the stock bolt, as the stock bolt has several upset diameters that are not found on hardware-store-type bolts.

So, I recommend a Helicoil repair instead of trying to use an oversized bolt.

Of course all this assumes that the threads used to secure the valve cover bolts are stripped. Have you investigated the root cause of your smoky startup?

Jason
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post #9 of 46 Old 09-26-2019, 09:46 AM
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The dinky bolt doesn't fail, the aluminum female thread does.

The Helicoil repair will accommodate slightly higher tension loads. The Helicoil does this by providing slightly greater shear area in the aluminum base material and the Helicoil's stainless steel material has greater yield strength than aluminum.

A larger diameter bolt would make for a stronger connection. But, the larger bolt would have to have a unique geometry similar to the stock bolt, as the stock bolt has several upset diameters that are not found on hardware-store-type bolts.

So, I recommend a Helicoil repair instead of trying to use an oversized bolt.

Of course all this assumes that the threads used to secure the valve cover bolts are stripped. Have you investigated the root cause of your smoky startup?

Jason
Excellent explanation. Simple answer; you can't use generic bolts for this application, the valve cover bolts are unique.

Dave
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post #10 of 46 Old 09-26-2019, 11:33 AM Thread Starter
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Just figured out I need 15 posts before I can post pics of what appears to be the problem.
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