99 Superhawk binds on turn over

[Pohtaytoh]

Bit of a strange diagnosis I'm going through here. I have a 99 Superhawk I've been working on restoring for the better part of this year and its nearing completion. This is a fully rebuilt motor and about 2 months ago I got that ever crucial first start. Bikes only ran about a total of 10 mins on several occasions until the last one.

The last start it sounded rich and boggy almost to the point of stalling and it did followed by a sharp PING. Now when I turn the motor over there's a specific point where is gets very resistant and I hear something going on somewhere.

Now I did make a silly, rookie mistake along the way where I was going to flush the cooling system and I used tap water and I really cant explain how, and I swore I drained the cooling system, but the left radiator was FILLED with sediment. Not using distilled water, I know...believe me NOW I know. So, the question is could these sediments have found a way into the block and possibly hinder something mechanically? I know there's a small water pump chain buried in there but unsure what parts do and do not get exposed to coolant internally past the thermostat.

So far its very difficult to narrow down an internal noise without disassembling everything I can see. I've check the manual CCTs, starter, flywheel and reduction gear, all ignition components. Carb was rebuilt so its not that and it was perfectly timed prior to this gremlin.

It sounds and feels TERRIBLE like something is on the verge of breaking, however, once it gets past this strange point it turns over smooth for several cycles (crank revolutions). Appreciate any feedback as I've been wrestling with this for nearly a month and I can't stress how devastating getting to the 90% point on a project only to have a wild meteor-sized curve ball come at you.

[AMCQ46]

Hi and welcome.

I doubt very much that the sediment in the coolant is related to your binding, only the water pump impeller makes contact with the coolant and it is a very small diameter, so I can’t see it having enough resistance for you to feel over the rest of the engine friction and compression.

I have a horrible feeling that this could be the valve timing jumped and there is a valve touching a piston as it will happen once every 2 revs of the crank. I would take the cam covers off and check cam timing, cam chain slack and valve clearance.

Good luck

[tony.mon]

Hi and welcome.

I doubt very much that the sediment in the coolant is related to your binding, only the water pump impeller makes contact with the coolant and it is a very small diameter, so I can’t see it having enough resistance for you to feel over the rest of the engine friction and compression.

I have a horrible feeling that this could be the valve timing jumped and there is a valve touching a piston as it will happen once every 2 revs of the crank. I would take the cam covers off and check cam timing, cam chain slack and valve clearance.

Good luck

Agree.
It won't be the water pump. The impeller blades can't transfer enough torque.
Check valve clearances and cam timing.

[Pete.L]

Any Squeaking noise at start up?
I noticed you put manual ctt's in. If they are too tight it might be related. Check their tension whilst you have the cam covers off checking the timing.

Pete.l

[sirch345]

I can't really add much to what has already been said, although it might be worth checking the oil level at the sight-glass just to make sure it hasn’t risen from water (coolant) getting in the oil? from a possible head gasket failure,

Chris

[Pohtaytoh]

***UPDATE**

Thank you all for the feedback, it got me on the right path. The GREAT news is that both cylinders appear to still be in timing. The strange noises I was hearing was a combination of things. First, I suspect that the rear tensioner was a bit too tight and the chain guide in between the cam sprockets was getting slapped by the chain. I'm not sure if these guides are prone to failure but to be on the safe side I may simply replace both of these guides as the hardened plastic on them might be past their limits.

When slowly turning over I could see the tension on the chain get so tight that it nearly pulled the chain out of timing. I am SO lucky that this thing didn't slip timing and boy oh boy am I relieved that the PING that continues to ring in my head was, in fact, NOT valve to piston contact.

Added a few pics for those that are interested in the progress. This VTR is getting a street fighter treatment. Thanks all again, I'll keep updating this post if I find anything new or shocking.

The bike when I first got it back in February.




The bike in May after many many things

[sirch345]

I'm happy to hear you got to the bottom of the problem and it was nothing too serious

I like the gold wheels

Chris.

[fabiostar]

Great news you got to the bottom of it

[tony.mon]

You don't have to replace the top guide brackets unless the plastic section is cracked or broken, in normal use the chain doesn't touch it.
If only Honda had extended it to wrap over the top of the sprocket to stop the cam chain being able to ride up over the sprocket teeth we wouldn't have had all of these cct failure problems. Or rather, they'd still fail. But not catastrophically.

[Pohtaytoh]

***UPDATE #2***

So, after sorting out some other to-dos I found a very strange failure and likely to be the results of all the issues I was facing before. After removing the right case cover, I found a rogue spring and pin resting on my right crankcase. They were completely shattered along with the primary gear being lightly dusted with aluminum fragments from the crankcase cover.




You can see some gashes in the cover by the water pump shaft, the ignition pulse switch was scored and the pin was ejected.


One of the dampening springs was mangled, in fact, all them were warped and likely to face the same fate as this spring. Also that silver pin was ripped from that switch and twisted.

So, the primary drive gear has several components. The main gear that interfaces with the clutch outer gear, 3 dampening springs, a narrower outer gear that the springs rest in and the ignition pulse spur gear.



According to the manual, the 98 model gets a spring washer that rests between the main and narrow gears which pushes the narrow gear out by about a mil. Mine is a 99 model and is not supposed to have this spring washer installed. The result was this narrow gear was offset so much that the corners of the teeth were starting to punch a dotted line around the clutch outer assembly and barely interlocking the clutch gear like it should. That along with the failing damping springs created a domino effect of failures one after another.

Thankfully the gears are all intact and no major repairs are needed. I have a modest amount of alum. shavings to clean, replace the switch (if I can find one), replace the 3 springs, and hopefully all will be good.

If anyone has some further insight, I'd love to hear some thoughts as I figured this was a rather uncommon failure. Then again, I'm still an amateur who's learning by doing so it's to be expected on a rebuild of a bike that hasn't been on the road in nearly a decade.

[sirch345]

Wow that is not something I was expecting to see, well done in finding that now

Chris.