hawfunk

After a front CCT failure/replacement, I've been trying like crazy to get the hawk running again, to no avail. My front cylinder just won't work for me; the rear is running like a champ.

Things I did:
1. Took off both heads and built back up from there. (new gaskets, obv)
2. Front CCT replacement
3. Full carb teardown and rebuild
4. PVLIR
5. Replaced plugs
6. Set timing 180-out
7. Verified spark
8. Verified fuel getting to the carbs
9. Oil/Filter change
10. Coolant change
11. Tore hair out
12. Set timing to the correct stroke
13. Vacuum leak test with spray can of starter fluid, while running

Things I didn't do (that seem relevant) yet:
1. Valve clearance check
2. Vaccum measurement

Symptoms:
1. Feels like good compression out of tailpipe, but no heat from right side (front). Left side has heat.
2. Slight spitting of fuel into the airbox from the front carb while running.
3. Timing appears to be possibly retarded 1/2 gear-tooth (pictured below) with tensioner engaged, and on the FT mark. The dental floss is right on the gears, so there shouldn't be any parallax error.



Any help is appreciated.

nath981

welcome aboard hawfunk, albeit under these circumstances.

You are running a bike that is out of time and you haven't checked the valves????
doesn't seem like the right thing to do.

GTS

The cams look like they are timed to each other properly but not sure about the crank. Did you go through the shop manual on the proper timing proceedure? As I recall it starts by checking the rear cam timing, then depending on where it's at rotating the crank X° or Y° to the front timing mark. If this is 180° out it won't fire properly.

hawfunk

For the timing, the following draws a pretty clear picture, I think:
6. Set timing 180-out (using the shop manual, but misunderstanding)
11. Tore hair out
12. Set timing to the correct stroke

I am 100% convinced through various methods that the timing is on the correct stroke now. If the cams look right to you guys, then the timing is spot on.

For the valves, they are so far out that I can't measure them. As in, instead of .012 for the exhaust it's about .375 (3/8"). I can almost get my finger in there. If it was this way when I installed the cams, I couldn't tell...it seemed to rest up against the lifters when I laid them in.

8541Hawk

With clearances like that I can pretty much assure you that you have bent valves...

hawfunk

Looks like I'm going back into the head.

Thanks for taking a look guys.

RCVTR

Are you F'n kidding? Because surely you can't be serious.

Your description of the all the work you have done leads one to believe that you are being fairly methodical, except I have to wonder why you would rebuild your carbs, to fix a broke cam chain tensioner.

So, you had the heads off. This would be a very good time to check whether bent valve stems were holding the valves off the seats by a country mile. You also could have checked whether the valves were well seated by spraying contact cleaner in the combustion chambers and blowing compressed air into the ports.

Then you put it all together and set the timing. The rear cylinder fires 270 degrees after the front cylinder. So you set the front cylinder cams, with the front piston at top-center. It doesn't matter if it's top center, or 360 degrees after top center. then you rotate the crank 270 degrees (3/4 turn until the timing mark shows top-center in the rear) and set the rear cams.

All well and good. Not necessarily intuitive, but fairly straightforward, once you understand it.

But then, you can't figure out why it won't start with bent valves???

Hard to believe.

GTS

Yeah if there is that much clearance definitely bent valves. If you look at the pic in my avitar you'll notice that the two upper valves aren't seated. This is exactly what happened to mine.

Though he was a bit harsh I have to agree with RCVTR in that you didn't notice the valves were bent when you had the heads off?

E.Marquez

Yes it would lead one to think you bent the valves.. it is an interference engine, they do not tolerate out of time cams.. Bending valves is always the result.

RCVTR

I'm sorry. Yeah that was a pretty harsh reaction. I had a frustrating day on a job site 3 timezones from home. Been here for more than a week.

I'm sure this thing is stressful enough without my input. Engine work looks simple enough, but an engine is an extremely precise machine and every detail is important.

I think the most important thing to take away from this is that you simply cannot be in a hurry doing engine work. If you feel rushed, put down the wrenches and walk away, because doing it wrong is very costly.

Good luck.

hawfunk

I appreciate the feedback, and I'm pretty thick-skinned from my years in the Navy as an Electronics Tech, so no worries about that

I'm learning as I go here, working on this in my driveway, with my dad helping as he can, though his eyesight is pretty terrible, so I just describe everything and bounce ideas off of him.

A lot of this is foreign to me, so things like noticing that the valves aren't seated (which I did notice when I had the front head off) aren't necessarily significant to me yet. It will be now, heh.

E.Marquez

Where are you at? There may be a SH forum member experienced with this task willing to help.

hawfunk

Charlotte, NC

I snapped photos when I had the head off, so I looked back and BAM! there it was. It just plain didn't connect with me at the time.

Wicky

Ouch! Same as what what happened to mine many moons ago before the wonderful world of manual CCTs. See if fleabay has any front heads/engines breaking so you can simply transplant a head over and get back on the road.

get some Krieger or APE MCCTs for peace of mind.

GTS

Looks like at least 3 or the 4 are bent for sure. Kind of hard to tell in the pic on the lower left. Once you get the head off pull the buckets out and take the springs off the valves. The easiest way is to take a socket that's large enough to fit on top of but around the outer edge of the retainer and give it a good smack with a hammer. This will compress the spring and generally pop the keepers out. It'll probably take a couple of smacks to get them both to pop out.

Then pull the valves out and take a look at the guides. If they are cracked at the ends then they need to be replaced. The guides aren't super expensive, just getting them pressed in and reemed and the seats recut is the more expensive part.

zxbud