Topic: Patina Hyena - 550/650 674cc Hybrid Cafe Build

[dave500]

once its been ridden a couple of times the clutch will settle and need re-adjusting.

[DaveBarbier]

Oh my god it fired up. I was terrified.

Started well and all 4 pipes are hot. The timing is way off and I seem to run out of room. I already set the gap to 14 thousandths and set timing statically first. I was reading about shimming the points plate so I'll try that stuff. But it also seemed that when I move the plate for 1-4 the timing lines don't really move much. But I'll see what shimming does for me.

It also smokes a lot out the tail pipe. White smoke. Could just be normal from oiling the jugs as I slid in the pistons but it wasn't going away. But something else really weird, as it was idling I heard a loud "PSSHHHHHHH!" Like pressure being released quickly. Like a loud, longer duration, blow off valve from a turbo. It happened once and the bike still ran fine. It didn't stall the bike or anything and I can't find any oil leaks. Couldn't really tell where it came from.

It idled with my hand on the throttle for about 4-5 minutes then once I couldn't get the timing I shut it off.


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1978 Honda CB550K

[Tews19]

Maybe an air leak on the boots to carbs. I bet it happened after idling for a bit then giving it gas? Smoke may be due to climate temperature change?

[DaveBarbier]

Maybe an air leak on the boots to carbs. I bet it happened after idling for a bit then giving it gas? Smoke may be due to climate temperature change?

It's possible that it was an air leak. I'll have to check for that once I do a carb sync.

As for the smoke, it is a little chilly and damp right now so that's possible too. But it seemed more smoky than that. Hard to say. Further tests need to be performed. Right now I'm focusing on the timing.

Thanks


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1978 Honda CB550K

[DaveBarbier]

May have found the pressure culprit. I had a little rubber cap on the breather cover's nipple to protect from crap getting in while the motor was out. I found it about 8 feet behind the bike...



I just simply forgot to remove it and put the hose back on. Good thing it shot it off. Could have blown a gasket because of internal pressure, no?


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1978 Honda CB550K

[calj737]

Only if it were "welded" on. Nice catch, though.

By the way, don't let your bike idle too long without a large fan blowing on the motor. Remember it's air-cooled. We tend to overlook this while we tune/tweak. And keep a battery charger handy to supplement the charging system while you dial it in.

[DaveBarbier]

Thanks Cal, and I wish I did actually "catch" it, haha.

Understood about the idling getting too hot. But I also remember Hondaman recommending to have it run without a fan if you used an OEM head gasket because it has a heat activated adhesive. But yeah, I won't let it idle longer than a couple minutes without a fan from now on. Thanks for reminding me.


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1978 Honda CB550K

[DaveBarbier]

Ok, read the shimming points posts and seemed to get it dialed in well. Gaps are .013". I had to use a .005" feeler gauge to keep the plate steady.

I was on the far end of the slot with the plate but now it's almost dead center. But I'm going to check it now dynamically with a timing light. I won't adjust it while it's running because the plate likes to vibrate around.



Now time to start it up again and possibly go for a ride then sync carbs.

Thanks guys.


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1978 Honda CB550K

[DaveBarbier]

Timing is a lot better. 1-4 is dead on but 2-3 is not perfect, although both 1-4 and 2-3 advance is perfect. Since these bikes usually run normally over 2k RPM am I right in think that the advance is more important?

Also, after I shut it off there was smoke coming out of the number 4 pod filter. Went away in about a minute.



Still smoking out the tail pipe and when I rev it to about 4k a little black smoke comes out too.




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1978 Honda CB550K

[calj737]

Wait until after the carb vacuum synch to fret over the smoke.

[DaveBarbier]

Ok, "synced" the carbs and got them to this point:


I only put quotes around it because it was weirdly very close. Only the #4 had to be brought up. I was expecting much more tuning. So I think there is a problem of some kind. When I was adjusting the #4 it feels like I turned the adjuster screw a lot for the little movement it did. And it still smokes a bit, although after a 15 minute ride to get gas and back home it was reduced a lot. But still the bit of black smoke at high RPMs. Also the idle all day today has been slightly sporadic. Reminds me of when I had my old rack of carbs with my other "hanging idle" post earlier this spring. I checked for air leaks with a propane torch and no change. (But weirdly when I put the nozzle right on one of the pod filters there's still no change in idle.)

In case this makes a difference, here is my carb info:
IMS-1.5
Main Jet-110
Slow Jet-42
Float Height-12.5mm
Needle Setting-3rd from top

Mac 4-1 headers with muffler
UNI foam pod filters



Where do you guys think I should start now? I already did timing, valve clearance and cam chain and there are new plugs gapped according to the OM.

Thanks


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1978 Honda CB550K

[calj737]

Freshly oiled pods could easily contribute to your smoking and slightly irregular idle. Smoke could also be from any paint being burned off/cured on inside.

I wouldn't get too concerned until you get some miles on the motor. Keep a close eye on oil consumption and level as you break it in.

[DaveBarbier]

Freshly oiled pods could easily contribute to your smoking and slightly irregular idle. Smoke could also be from any paint being burned off/cured on inside.

I wouldn't get too concerned until you get some miles on the motor. Keep a close eye on oil consumption and level as you break it in.

Ok, that makes me a little more relieved that you're not thinking the smoke is a serious issue yet. Right now the oil is a little high. It's covering both marks on the dip stick. Actually pretty much past the lower flat part and a little on the round part. Too much? I put in a little less than the recommended amount because I poured in a good amount before buttoning it up.

What about the idle issue? Think I just need to put more miles on it before anything? It'll hang up at about 3k but then drop to 1k. When it drops it'll stall if I don't give it a little gas. It also feels a little rough at the 1k mark. But it's weird because my nanometer says it's synced well.

Thanks for the help, everyone.


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1978 Honda CB550K

[calj737]

Classic description of a vacuum leak. Have thou tested this bike for those leaks? I know you dealt with the issue on your other bike. Especially check the pod connections. May have forgotten to snug up the inner boots or pods (seem to recall you recently forgot another ventilation port  )

[calj737]

One more thought: I've always looked for a wee bit of condensation from the exhaust after initial start up, before engine comes up to temp. I was always mentored that to be signs of a well sealed engine, essentially solid vacuum pressure. Since our motors are air pumps, you want the "cold" air driven out the exhaust promptly.


I have no clue whether the liquid level of your synch gauges is relevant, but they seem a bit low to my "expectations". Certainly, equal is the most important factor, but is there a scale on them to provide some idea of how much pressure you're generating? And what rpm did you synch at?

[DaveBarbier]

In an above post I mention that today I did check for an air leak with a propane torch...off...with no change in RPM. But weirdly when I push it into the foam on a pod the RPM doesn't change either. I put new o-rings on the intake manifold during the rebuild, too. It's possible that there IS an air leak but the propane didn't find it. I remember tightening down the clamps on the rubbers pretty good so I may have tightened them down too much and they could be warping. I'll go back, loosen them and then re-cinch them down.

Now if you remember my carb post, with the horribly rebuilt carbs by a person who is only fit for bagging up hammers in a burlap sack, one of the carb mouths is bent a bit. Might not provide a good seal. Might put a tiny bead of non-hardening sealant on that before putting on the pod.

I put my hand at the end of the muffler today and I remember feeling condensation. So that's good I guess.

On these gauges the level isn't important, just the equality across them. This is the new MotionPro Sync Pro and before you use it you calibrate the device on the master carb and the user sets the level wherever he/she wants. I just set it a little low but could have just as easily set it half way or 3/4 up the scale. Makes no difference. Doesn't actually measure cm/Hg or psi. I synced them at about 2k, but since the idle was a little wonky it fluctuated from 1-3k.


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1978 Honda CB550K

[calj737]

Now if you remember my carb post... Your'e kidding right? But I' do now that you mention it...

I put my hand at the end of the muffler today and I remember feeling condensation. So that's good I guess.  I think that's good.

On these gauges the level isn't important, just the equality across them. This is the new MotionPro Sync Pro and before you use it you calibrate the device on the master carb and the user sets the level wherever he/she wants. I just set it a little low but could have just as easily set it half way or 3/4 up the scale. Makes no difference. Doesn't actually measure cm/Hg or psi. I synced them at about 2k, but since the idle was a little wonky it fluctuated from 1-3k. Gotcha. Thought as much, just checking.

[DaveBarbier]

Now if you remember my carb post... Your'e kidding right? But I' do now that you mention it...

Haha, that's funny. I can't tell if the first part is sarcastic or not, haha. I know you have seen many many posts but that guy who rebuilt my carbs was...memorable...in my eye.

I'll report back after I thoroughly check for an air leak. Since I just painted my motor anything I can spray on the boots to check? I'd rather not use carb cleaner or acetone since that eats paint. WD40? Although only the propellant is flammable. Is propane good enough?


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1978 Honda CB550K

[calj737]

First part was sarcastic, but I do remember the carbs you bought from a "rebuilder".

Propane will work fine. Could even spray some soapy water to check for extra bubbling if the leak is bad enough.

[dave500]

strobe time to full advance,its the only way,forget where it ends up idling,get some miles on it,dont baby it.

[DaveBarbier]

Cal: I'll stick with the propane for now. I'd really love for this to be a horrible air leak.

Dave: Ok great, advance is almost exactly between the two lines. I'd say I'm good for now. Shimming really seemed to help. Yeah saw on the forums a lot of people saying to really give it the beans. So I've been having fun, ha. Worst part is that's it's almost November so I'm going to have to put it away soon.

Will report back hopefully on Saturday.


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1978 Honda CB550K

[dave500]

depending on your fuel you can even set to the right hand mark or just beyond it if your not pinging.

[DaveBarbier]

depending on your fuel you can even set to the right hand mark or just beyond it if your not pinging.

Oh ok, so it seems like there is some leeway. I just use 89. I'll probably replace my points plate screws with allen heads eventually so I'll keep that in mind.


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1978 Honda CB550K

[DaveBarbier]

Currently 45° F and raining here in southern CT. Out in my shed trying to find a crack in the rubber carb insulators. They look in great shape actually. Which way are these supposed to go? Does the double ribbed part face the head or carb? I just forget but I'm pretty sure I had them correct before I just removed them. Or does it not matter?





Also, PLEASE tell me there is supposed to be an o-ring in the vacuum gauge hole. I remember my old carbs didn't have them either so it probably doesn't need one but it would explain a lot. It's also hard to tell from the parts fiche.



Would it be a good idea to replace the band clamps? Are the worm gear type better?



I also feel like I should remedy this bent mouth somehow. Thoughts? It can't be good but it actually doesn't seem like it's blocking that air jet much. I may be reaching now.




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1978 Honda CB550K

[dave500]

theres generally an aluminium washer on those plugs,you can put copper washers on them,bending that mouth back will have to done very gingerly its likely to crack?id try gently tapping it back placed on wood with a lump of brass?