idle and sync issues?

[cowpuc]

Could running seafoam through the intake ports get rid of some of that carbonation? Or even pouring some down the intake side of the carbs.

 

This is probably gonna sound nuts (again) but many many years ago when I was just a kid I landed a Honda 305. It was before before kids were allowed to drive, even mopeds,, so the only place I could ride it was round and round the parking lot of the high school which was right next door to our house (unless my dad - who was a Cop - was gone,, then I could ride any where I wanted ). One day,,, while out going round and round in circles my 305 started missing. Similar to present day, I had no clue so I started rippin and tearin it apart... Nothing helped. Dad came home and asked why my bike was scattered all over the school parking lot. I told him what it was doing. He said "put it back together and I'll go fix it for ya"... He took off and about a 1/2 hour later he came back with my little 305 purring like a kitten.. Apparently wide open for 10 miles on the highway was all it needed to clean out the carbon that my dad figured was causing the problems.. Now I am no smart mechanic by any stretch of the word but I can tell you this,,, from that day to present time,,,, none of my bikes have ever suffered again from carbon collecting on the pistons or heads!!!!!! Lawn Mowers? Yes.. MOTORCYCLES - NOT:big-grin-emoticon:

[Chaharly]

I remember from back in the 60's an old trick for decarbonizing old car engines was to keep the rpm's up there and with an eyedropper slowly drop water through the carb throat. The water, through compression, would literally send shock waves in the combustion chamber and bust loose the carbon! No, I am not recommending this procedure, I'm just reminiscing!

 

So far I see two possibilities, an exhaust leak, and excessive raw gas coming from the engine, both are very plausible! I am leaning towards the exhaust leak as the primary culprit as even with some raw gas/unexploded vapors with no source of oxygen they would possibly not ignite, and the only way to get oxygen to them before they exit the exhaust is from a leak.

 

Now, as far as the intermittent stumble, where do you want to look first? Valve adjustment? An intermittent ignition failure? A partially plugged orifice somewhere? A vacuum leak somewhere? Speaking of that, are you still using your plastic YCIS box?? Although in theory, they do help balance the vacuum, they also develop a crack on the seam of the body and can (and do) develop a vacuum leak. All that YCIS box does is to form a collector tank for all 4 carburetor vacuums to balance out. In reality, the gain of the system is pretty much insignificant and many people eliminate them! To properly test them, submerge the tank in a bucket of water, plug off 3 of the 4 ports, and apply air pressure to the 4th port and watch for bubbling for several minutes. You can sometimes fix them by applying a bead of glue or sealer to the seam which is where they usually leak. Just something else to check out...

 

The MKIIs don't have the YICS box right?

[Chaharly]

This is probably gonna sound nuts (again) but many many years ago when I was just a kid I landed a Honda 305. It was before before kids were allowed to drive, even mopeds,, so the only place I could ride it was round and round the parking lot of the high school which was right next door to our house (unless my dad - who was a Cop - was gone,, then I could ride any where I wanted ). One day,,, while out going round and round in circles my 305 started missing. Similar to present day, I had no clue so I started rippin and tearin it apart... Nothing helped. Dad came home and asked why my bike was scattered all over the school parking lot. I told him what it was doing. He said "put it back together and I'll go fix it for ya"... He took off and about a 1/2 hour later he came back with my little 305 purring like a kitten.. Apparently wide open for 10 miles on the highway was all it needed to clean out the carbon that my dad figured was causing the problems.. Now I am no smart mechanic by any stretch of the word but I can tell you this,,, from that day to present time,,,, none of my bikes have ever suffered again from carbon collecting on the pistons or heads!!!!!! Lawn Mowers? Yes.. MOTORCYCLES - NOT:big-grin-emoticon:

 

Don't the old school boys call that "blowin the cobwebs out"??

 

Plus i don't know how well the police are gonna like Luv doing 125 on that venture. Especially when they ask him why he was speeding and he replies with, "well sir, I'm Just cleaning out my carbon deposits"!!

 

Kinda neat that your dads a cop, my old man's one too!

[videoarizona]

Don't the old school boys call that "blowin the cobwebs out"??

 

Plus i don't know how well the police are gonna like Luv doing 125 on that venture. Especially when they ask him why he was speeding and he replies with, "well sir, I'm Just cleaning out my carbon deposits"!!

 

Kinda neat that your dads a cop, my old man's one too!

 

I had a Chrysler Cordoba with the lean burn V8. I floored it going up a hill, crested the hill and a cop was sitting at the bottom with radar. That was the excuse I gave him. It was the truth. That engine needed some high speed burn to run right. I still got the ticket.

 

Now back to our program...

 

My vote is for exhaust leak for the popping.

In my book, those plugs need replacing.... way to lean... gotta solve the excessive popping.

[Patch]

Sorry guys I Had needed to shut down for a while.

 

The compression numbers were very much on my mind so I just looked them up.

 

Now I get why there are so many who swear by these bikes.

Amazing how tough a build it is, for it to not show signs or blow gaskets with a limit of 156 lbs that's 44 lbs over WOW.

Could these numbers be wrong?

[videoarizona]

Sorry guys I Had needed to shut down for a while.

 

The compression numbers were very much on my mind so I just looked them up.

 

Now I get why there are so many who swear by these bikes.

Amazing how tough a build it is, for it to not show signs or blow gaskets with a limit of 156 lbs that's 44 lbs over WOW.

Could these numbers be wrong?

 

 

Maybe that's a question to ask the group, like survey.

[Patch]

Please pardon my interuption here Steven but I am a bone head and gotta ask,,, where exactly should 45 be "blowing it out" at to decarbonize the heads/pistons during this process and exactly what "nozzle" should be covered to catch debris.. If you would not mind, please clairify for an old slowpoke.

Thanks

 

 

Sorry Puc I must be missing something?

 

The bit of carbon can fly with the pressurized air as can the chemical used to soften. If we don't blow out the chamber one she will be hard to start after testing and 2 you could plug the compression tester up!

 

True I haven't had the pleasure of working on the 1200 so what am I missing?

[Patch]

Could running seafoam through the intake ports get rid of some of that carbonation? Or even pouring some down the intake side of the carbs.

 

Hey Chaharley, good question dude. Carbon is a problem because we can break it up, we can also say we dissolved it but that isn't really the case. The problem I see with this much carbon is what happens after it becomes free to move!

 

If when writing I knew the limit was 156 hmm not sure if I would have forwarded the suggestion.

 

We or I would rather see the carbon leave through exhaust.

 

So if anybody is interested there are cleaning chemicals such as may be used on engines with plenums. I thought about it in the wee hours, I suppose one could try through the the crankcase ventilation at the bottom of the air box? Again haven't worked on the 1200 so am not familiar with the air box set up!

Edited July 14, 2018 by Patch

[Patch]

I remember from back in the 60's an old trick for decarbonizing old car engines was to keep the rpm's up there and with an eyedropper slowly drop water through the carb throat. The water, through compression, would literally send shock waves in the combustion chamber and bust loose the carbon! No, I am not recommending this procedure, I'm just reminiscing!

Yah man, the thing again is we had plenums and would anticipated steam but the practice I remember was misting water to reduce knock after all the bad anti pollution junk came out and, we still had engine designs around leaded gas. Truth is we found that we were beating the valves and pistons with deposits in the water.

 

So far I see two possibilities, an exhaust leak, and excessive raw gas coming from the engine, both are very plausible! I am leaning towards the exhaust leak as the primary culprit as even with some raw gas/unexploded vapors with no source of oxygen they would possibly not ignite, and the only way to get oxygen to them before they exit the exhaust is from a leak. You know Bongo I wrote this up at least my theory, I mentioned our conversation yesterday with 14:1 as ideal in theory but that I suspect this puppy was running 10 or worse. I didn't include it in the post as I thought Luv had enough to deal with as is.

[Chaharly]

Hey Chaharley, good question dude. Carbon is a problem because we can break it up, we can also say, we dissolved it but that isn't really the case. The problem I see with suspecting this much is what happens after it becomes free to move!

 

If when writing I knew the limit was 156 hmm not sure if I would have forwarded the suggestion.

 

We or I would rather see the carbon leave through exhaust.

 

So if anybody is interest they have cleaning as is used on engines with plenums. I thought about it in the wee hours, I suppose one could try through the the crankcase ventilation at the bottom of the air box? Again have worked on the 1200 and am not familiar with the set up!

 

I wonder if they maybe got their conversion wrong when making the switch from whatever the metric version of pounds per square inch. I'm at work so i don't have the time to convert the numbers or even look it up in the book until later

[Chaharly]

According to the manual the minimum spec is 149psi and the mac is 199psi give or take. It seems compression is not the issue. Especially since all 4 cylinders are running about the same compression

[Patch]

According to the manual the minimum spec is 149psi and the mac is 199psi give or take. It seems compression is not the issue. Especially since all 4 cylinders are running about the same compression

 

 

Interesting the manual I am looking at is standard is 142 minimum is 128 and max is 156 psi.

[luvmy40]

Yep, My manual matches Steven's.

 

Bongobobny, No YICS chamber. It was cracked so I just took it off and capped the ports. It is possible that the caps have developed leaks since I last checked, so I'll check that again as well.

 

I got new plugs today and will run another comp test and install the plugs gaped at .032". I had been setting the gap to factor spec of .036".

 

I do alternate running Lucas fuel additive, Sea Foam and Star Tron enzyme. Not every tank but fairly regularly. My current tank is treated with the Lucas.

 

I'll try to dig up a bore scope and see if I can get a look at the piston heads and valves.

[Chaharly]

Interesting the manual I am looking at is standard is 142 minimum is 128 and max is 156 psi.

 

You are right sir, i was looking at the 1300 manual! Sorry about that!

[Patch]

Yep, My manual matches Steven's.

 

Bongobobny, No YICS chamber. It was cracked so I just took it off and capped the ports. It is possible that the caps have developed leaks since I last checked, so I'll check that again as well.

 

I got new plugs today and will run another comp test and install the plugs gaped at .032". I had been setting the gap to factor spec of .036".

 

I do alternate running Lucas fuel additive, Sea Foam and Star Tron enzyme. Not every tank but fairly regularly. My current tank is treated with the Lucas.

 

I'll try to dig up a bore scope and see if I can get a look at the piston heads and valves.

 

 

I know it seems a lot to absorb or the disappointment of it but, addressing it head on is the better approach in my experience.

 

There are ways to knock compression down quickly if you choose an aggressive approach which is what I would do if it were in my shop.

 

Regarding the plugs: my read is they aren't running hot enough to self clean, so all the problems will stay in play.

 

Regarding vacuum leaks: there may be some but, that would mean lean and that would also mean excess heat, which you don't have!

 

Anyways young fellow let me know if I can help further.

 

Patch

[bongobobny]

The MKIIs don't have the YICS box right?

You are correct! The system was something that worked in theory but not necessarily in real life, so with the MK2 they scrapped it which also cut production costs and raised profits...

[luvmy40]

Compression test results:

Cyl. #1 165psi

Cyl. #2 160psi

Cyl. #3 170psi

Cyl. #4 140psi

 

Test parameters:

All plugs removed

CDI unplugged

Battery charger connected on boost mode

Throttle wide open

4 cycles repeated 4 times

Numbers are averaged

 

The differences between the way I tested today and the last time are may be quite significant. Last time the air box and carburetors were removed and I let the engine chug until there was no increase in pressure on the gauge.

 

I installed new plugs, DPR8EA-9 gap set at .032"(.81mm)

 

The old plugs still looked way too lean for my taste so I connected up the Carb Tune and fiddled with the mixture a good bit. Going by ear and keeping an eye on the manometer, I got the highest rpm and vacuum I could on each cylinder. I started with #1 and went around the bike 4 times then I set the synchronization. I have to admit that I am one of those guys that can let the pursuit of perfection get in the way of good enough so I forced my self to only run the sync procedure 3 times! Once again, all cylinders are richer than they were before the tweaks.

 

I then ran to the local Dollar General for a BBQ lighter as I could not find any of the dozen or so that I know are in this house.

 

Lighter in hand I immediately found a pretty severe exhaust leak at the #1 header. I could not determine exactly where because I couldn't keep the lighter lit. It's somewhere after the EGA port, maybe under the heat shield. Or, it could be the gasketed, clamped connection. All I know for sure is that it blew the flame out when I got close.

 

No other exhaust leaks found.

 

I think I'll go hit the freeway for a a 20 mile High rev run. How's 7K rpm sound? That might blow the cobwebs out, huh?

Edited July 1, 2018 by luvmy40

[Freebird]

I'm certainly no expert on it but I thought that when you did a compression test, you were supposed to leave the plugs in the cylinders that weren't being tested. Maybe I'm thinking about something else. By the way, I have a "colortune" if you ever want to give it a try.

[luvmy40]

Thanks Don, I have a color tune and have had limited success with it on the Venture. It does great on my XJs and was totally useless on my Suzuki GS bikes.

 

I forgot to mention that I did test for vac leaks and found none. I used starting fluid and sprayed it around the intake rubbers and vac ports.

 

So, I buttoned everything back up and went out to "blow the cobwebs out". About 15 miles on the freeway at 6500rpm. Everything was nice and smooth and when I twister her tail she instantly jumped. Extremely responsive at the higher rpms.

 

When I got back, I let her idle at 1000 rpm for a minute or two and the stumble at idle is gone.

 

I'll take a look at sealing up the exhaust when I park her for the winter.

 

Oh yeah, I forgot to mention that while not completely gone, the popping is much less severe after this round of adjustments.

 

 

BTW, According to the Yamaha Factory Service Manual, you are supposed to chug the engine until the pressure stops rising with all plugs removed and grounded for the compression check.

[Patch]

Regarding compression testing the idea is to get the crank to as high a speed as possible.

So no plugs helps this potential.

Hard to fill the cylinders faster when the carbs are off making this a preferred way. However if you are just monitoring for records then of course keep them on.

 

So the most recent test posted do not reflect true readings.

 

Deceleration provides best results for shaking off carbon, also helps the ring landings providing they are not already packed.

 

I think you may be chasing the wrong tune for the bike. Time will show you other options that work better engine to engine. Books, articles, posts and a like are knowledge based, how you implement or understand the results is what matters because, that will determine what the fix is.

[luvmy40]

Well, she's running great and I now Know the popping is due to, or at least most likely due to the exhaust leak. I'll leave things alone until I can fix the exhaust leak.

[cowpuc]

Well, she's running great and I now Know the popping is due to, or at least most likely due to the exhaust leak. I'll leave things alone until I can fix the exhaust leak.

 

OUTSTANDING 40!!!!!!!:thumbsup:

Glad to hear you figured it out brother,,, now get out there and let er buck with some good ol CTFW!!!!!

[luvmy40]

I don't know if I ever mentioned this anywhere in the forums before.

 

The PO I picked The Beast up from gave me the standard story with some ridiculous embellishments. You know, garage kept, never ran in the rain, the odometer is actual. Blah, blah, blah. He also made the ridiculous comment that he had had a "racing cam" installed. I let it all go in one ear and out the other as I have dealt with the type on many occasions.

 

As I have stated in other threads, she was in pretty bad shape as far as running goes. Only hitting on 3, sometimes two cylinders, but she still idled steady and ran down the road with authority.

 

She had 26,248 miles on the odometer when I took possession. Now according to everyone I've ever talked to who knows these bikes even slightly, that would barely be past break in and certainly would not need valve adjustments yet. So why were all the valve clearances tight? Obviously the odometer had rolled over and she had 126,248 on the clock.

 

I'm extremely happy that I have not had any more major issues than carb rebuilds, some new(to me) coils and plugs and wires to deal with. The exhaust leak is nothing really. Just a PITA at this point.

[luvmy40]

The exhaust leak is "fixed" and the popping is gone.

 

After determining that the entire exhaust system needed to be removed to replace the leaky gasket, I made a command decision.

 

Seeing as how the old girl is nearly 36 years old with 130K+ miles on the odometer, I decide to "fix" the gasket with high temp liquid metal and it worked like a charm. Now, I may be cursing this decision if I ever do have to remove that header for any reason, but I doubt that is likely to happen. I'd more likely replace The Beast with a slightly newer Venture project before doing any real deep dive mechanical work and relegate her to a parts doner.

 

So, now the search for the elusive "Perfect Tune" continues.

[Patch]

I don't know if I ever mentioned this anywhere in the forums before.

 

The PO I picked The Beast up from gave me the standard story with some ridiculous embellishments. You know, garage kept, never ran in the rain, the odometer is actual. Blah, blah, blah. He also made the ridiculous comment that he had had a "racing cam" installed. I let it all go in one ear and out the other as I have dealt with the type on many occasions.

 

As I have stated in other threads, she was in pretty bad shape as far as running goes. Only hitting on 3, sometimes two cylinders, but she still idled steady and ran down the road with authority.

 

She had 26,248 miles on the odometer when I took possession. Now according to everyone I've ever talked to who knows these bikes even slightly, that would barely be past break in and certainly would not need valve adjustments yet. So why were all the valve clearances tight? Obviously the odometer had rolled over and she had 126,248 on the clock.

 

I'm extremely happy that I have not had any more major issues than carb rebuilds, some new(to me) coils and plugs and wires to deal with. The exhaust leak is nothing really. Just a PITA at this point.

 

 

I can't believe he lied to you? I'd rather believe he bedded the cam in fertilizer for a month during rainy season and therefore growing the lobes, increasing both lift and duration! That would also explain the tight lash! He may have likely set the enrichers to spill a little extra gas down instead of re jetting to compensate for the extra airflow?

 

It is so much fun searching for the truth

 

These bikes should run well in to the high mileage range with fare maintenance schedules. The Cavalcade's we often saw them for sale with 500K (klm) of course you can't really find parts for them so good thing they were built to last;)

 

Cheers Dude