Topic: 750K2 Hot Rod Revival - Early Christmas

[PeWe]

I edited my post sept 04 2019 about carb jettings that were wrong, now much better. The last weeks Oct 2019 verified what to change.

[PeWe]

Drop our resident master head porting and tuning expert Mike R and HondaMan a PM or email to see if they might have a moment to consider chiming in on the sudden appearance of smoke and this change.
Probably an electrical problem... . Humor...

I think it is a good idea to go back in time and verify what has changed/happened after last non smoking rides.

Oil smoke when accelerate or after a throttle off deceleration?
Smoke even when engines has idled for several minutes?

In this situation easier with 4-4 that will show which cylinder that smokes.
Head gasket in need of re-torque should leak outside too, right?

EDIT:
I had to verify the oil returns question. Went into my garage.

- Cylinder oil return  dia: 10.75mm
- HD stud dia: 8mm
- MLS gasket holes: 9.5mm!
- Cometic fiber has 11mm that match the cylinder!

There are thin slits for oil returns: 9.5-8=1.5
1.5/2=0.75mm slit for oil to return between stud and gasket.

I had also a strange oil smoke I never found out earlier on my 900 cylinder that could have been explained by this. Double checked rings etc. Head no problems since next was billet block that got the later style MLS with wider holes and no smoke nor leaks at all.

I'll grind the MLS gasket(s) from 9.5 to 11mm for my ongoing K2 900cc (67.5mm bores) build.

I'll look for a conical stone for my drilling machine and grind from both sides to 11mm holes all thru the 3 layers of steel.

One thing though.
My 836 did not smoke despite, HD studs, MLS with small holes and piston bore clearance of 0.2mm!!! Maybe too short time in use.
 I changed oil pump to one with half milage that got new gaskets, oil seal after 836 to the 900cc build. Maybe an explanation?

[CBJoe]

Hi Pewe....

This is what is driving me crazy....I had a great 1st season ride with zero smoke last weekend. 

Until yesterday, I did not do anything to the engine since the Dyno run last fall.  Probably have done maybe 40 miles on bike since Dyno run.

Last weekend I changed main jets to 125s from 120s and did a 20 minute ride.  This was the only change since last year besides cleaning up headlight wiring. No smoke after ride.

I had a re-occurrence of the starter gear issue so I quickly pulled cover and replaced Starter Gear and Rollers yesterday.  Torqued rotor bolt down and installed cover and bam...smoke.

I will double check for fuel issues...but that smoke in video sure appears to be oil burning. I can’t imagine how changing starter gear could cause damage.


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[PeWe]

I looked at the video again.
Did it smell burned oil?

If cold outside, it will smoke. Condense look like that too

[CBJoe]

Not water vapor...smelled like burning oil, but I will check again this afternoon.  It was smoking a LOT almost right after startup.  I’ll grab another video.

I am hoping I come back and magically it will just be fine again.  I’ll check the carbs again ....maybe I’m jumping to wrong conclusion and it is fuel related.


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[CBJoe]

I'm open to suggestions here.  I drained carbs and double-checked the main jets...I had this thought that maybe one of the jets didn't get tightened and fell out.  Nope...all the jets look good.  It smokes immediately on startup....does not smell like fuel.  I would think it if was a fueling issue with that much smoke it would smell intensely of rich fuel.

I just cant imagine i could have damaged something on the top end by replacing the starter clutch and torquing the rotor bolt down. 

[Jerry Rxman Griffin aka MuthaF'er]

Take it out for a good ride Joe. If this persists check your compression. Ring?

[PeWe]

+1 for a ride.
My K2 smoked like Bob Marley and friends at start-up earlier. Rich fuel mix that took some oil at the same time. Stopped smoke after 30 sec idle with reduced choke.

[MCRider]

Take it out for a good ride Joe. If this persists check your compression. Ring?

Yeah, do that. "What are you going to do?
Just a little dark humor. You know I feel for ya.

[CBJoe]

Haha Ron...I know you feel my pain. Good thing is that since we've done so much work on your engine I can probably take the top end off in my sleep

Plan of attack...

- Take it out for a ride and hope that I don't kill too many mosquitoes with the Fog
If that doesnt work
- Check Compression / Do Leak down test and go from there. 

If the head/cylinders come off, I'm going to take it as a sign that fate wants me to send it back to Mike for further upgrades

[Jerry Rxman Griffin aka MuthaF'er]

I guess that B in CBJoe could stand for Billet

[CBJoe]

I guess that B in CBJoe could stand for Billet

Dont even think it Jerry....but if you're buying then ok...I wont argue

[scottly]

Until yesterday, I did not do anything to the engine since the Dyno run last fall.  Probably have done maybe 40 miles on bike since Dyno run.

Last weekend I changed main jets to 125s from 120s and did a 20 minute ride. 
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Did you leave the petcock on after the ride last weekend? Does the oil smell like gas?

[andy750]

Id check the plugs after a ride and see how they look. If oily then that would indicate a valve/seal issue - which I very much doubt.
Good luck Joe! 

[CBJoe]

Until yesterday, I did not do anything to the engine since the Dyno run last fall.  Probably have done maybe 40 miles on bike since Dyno run.

Last weekend I changed main jets to 125s from 120s and did a 20 minute ride. 
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Did you leave the petcock on after the ride last weekend? Does the oil smell like gas?

Hey Scott...I did not.  However i went ahead and drained the oil yesterday in case there was fuel contamination at some point.  Oil didn't smell like fuel.

I'm planning to do as other suggested and take for a ride later this week if the weather holds.  If that doesn't work i'll narrow down rings/valves

[CBJoe]

Well...I finally had some time to take the Honda out and slog it a bit.....after a 25 minute ride things seem promising.  Was like a mosquito fogger at stoplights for the first 10 minutes or so...then smoke dwindled down to essentially zero.

I installed a remote Idle Adjuster on the RS Carbs which made setting the idle after warmup a cinch.  I'm going to let it sit for a while and cool down and then i'll start it up again to see if the smoke is gone for good.

Still a few issues to sort out...I'm still having the starter clatter at times...I've done the following:

- Installed a Starter Gear from Scottly that had the contact face machined smooth
- Installed a Starter Gear from Bill Bentons Stash
- Installed New Rollers and Springs

Can a bad starter cause the same symptoms?  Or am I just unlucky with starter gears?  The rotor bolt is still plenty tight

Cheers, Joe

[andy750]

Good video Joe! Sounds good to me. Glad you got past the smoke issue.

cheers
Andy

[TjTalan]

I just read through most of the thread, you have an amazing machine there!


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[RAFster122s]

Glad the smoke has dissipated... would be heartbreaking to dig into it again so soon. Hope to see you in Cherokee NC this fall...

[Jerry Rxman Griffin aka MuthaF'er]

 

[CBJoe]

Good video Joe! Sounds good to me. Glad you got past the smoke issue.

cheers
Andy

Thanks Andy...i'm still so vexed about what it could have been.   I must have let it idle for 30+ minutes since it started smoking....but something about the ride made it happy again.  So strange.

[CBJoe]

I just read through most of the thread, you have an amazing machine there!


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Thank you Sir...I cannot claim credit for the original build, but I've done enough work now that Its starting to actually feel like "my" project

[PeWe]

Good news that it was no remaining problem!

Maybe you let some oil enter the cylinders with plugs off during another service you have forgotten?
Or something thru the carbs like high amount of carb cleaner?
Or oil in fuel to not allow tank to rust during the winter?

[CBJoe]

Good news that it was no remaining problem!

Maybe you let some oil enter the cylinders with plugs off during another service you have forgotten?
Or something thru the carbs like high amount of carb cleaner?
Or oil in fuel to not allow tank to rust during the winter?

I can say nope to all of that...but at this point i'm just happy its gone....I'll just pretend that the magic oil fairy got sucked into the engine and its corpse was burning off   

[TjTalan]

The engine mod list is impressive. How far are you spinning it?


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