How can I tell if all my cylinders are firing correctly?

I have a 1997 royal star deluxe. Not sure if I have a problem or not. I haven’t had this bike real long so I am not familiar with how it is supposed to run. Now for what I am experiencing. Through the gears and especially in 4th and overdrive I feel a vibration on exceleration, especially when you lug it alittle. At first I thought I was running to high of gear but even when running in 5 th it vibrates almost like a miss. I pulled the plugs and they are all a nice even tan exactly the same. The one thing that concerns me is when I used a inferred on start pointing at the base of the exhaust port the front 2 cylinders are running about 125 deg’s cooler than the back cylinders. Is that normal with these motors? Also what are the correct spark plugs for this motor? Any help would be great

I have a 1997 royal star deluxe. Not sure if I have a problem or not. I haven’t had this bike real long so I am not familiar with how it is supposed to run. Now for what I am experiencing. Through the gears and especially in 4th and overdrive I feel a vibration on exceleration, especially when you lug it alittle. At first I thought I was running to high of gear but even when running in 5 th it vibrates almost like a miss. I pulled the plugs and they are all a nice even tan exactly the same. The one thing that concerns me is when I used a inferred on start pointing at the base of the exhaust port the front 2 cylinders are running about 125 deg’s cooler than the back cylinders. Is that normal with these motors? Also what are the correct spark plugs for this motor? Any help would be great

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Sounds like a sync issue...

 

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How do I go about syncing the carbs? Is it hard?

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Same concept on 2nd gen

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I'm sure a carb sync will help but keep in mind these bikes LOVE RPM's. Don't let them lug, down shift and crank the throttle for the best performance. There is a built in rev. limiter, you won't hurt the engine. Some would say "Drive it like you stole it!" Not me, just be a little more aggressive with the throttle. I'm a couple of hours away but willing to help with a carb sync if you wish. Keep it cranked up!!!

Thanks for the reply. I think I may be shifting to soon. But that doesn’t explain the temp difference between the front and back banks. If I can ask where are you located? The site will not let me access your profile

With these bike if you are in 5th at under 60 MPH you are lugging the engine. Many of us will not use 5th until 65. That will give you an idea of the RPMs that these like to run at. If you are coming from a V twin, a V twin red lines close to where these V4s like to cruise at.

As for the temp difference.

With the engine completely cold, start it and let it idle and using your wet fingers see if the pipes all come up in temp at the same rate. the cool ones are the ones that are having an issue.

If 2 are not heating up, it could be sync, it could be an ignition issue, or it could be a carb issue.

When you said that you checked the temps with a heat gun and the front 2 were cooler, was that at idle or right after a run? The front 2 do get much better airflow so they may run a bit cooler under power.

Syncing carbs is very easy to do, once you have seen it done once. That is why some dealers get big $$$ for it. By asking for a sync you are telling them you do not know a lot about the bike. That is why most members here will do it for the refreshments needed for the visit and then you will know how to be able to pay it forward and help the next person that needs a sync.

Thanks I check with the gun at idle right at start up and after a short run and the front was alway quite a bit cooler.

I am going shoot cha another quick vid here of my wife, Tip and I on our fully loaded Tweeks, our 83, running it down in 5th gear to 2 grand on the tach/35 mph and then leaving it there = no down shifting and opening the throttle and letting it climb to highway speed before letting up (I reopen the throttle briefly with still no down shift after making sure that wasnt a Police Officer sitting in the opening on the highway ).

I did this video as a comparison challenge to someone testing the new V-Twin Venture to establish some kind of scientific low speed pulling power comparison between the two but,, for what we are talking about here - I think the vid may be useful, at about .20 in the video is where we let er buck.

I ride these old Ventures at what a lot of folks consider a "lug" a lot.. I have found them (and ONLY speaking of 1st Gens) to be very very worthy scoots in low R's.. They pull very strong right off the bottom BUT,, their REAL performance potential doesn't start (IMHO), as mentioned, until ya get above 4500 R's = thats when they start to really come alive (you gotta get above 5250 RPM on ANY motor before horsepower goes above torque).. That said though,, they do pull plenty hard to that point when compared to other scoots of their size IF in proper tune, again,, IMHO..

Now,, all that said,,, I have never owned or ridden any of the early "Star" V-4's like you are riding.. I do know that I read somewhere that those scoots were majorly detuned (even to the point that I believe Star dropped the balance shaft in them because they were not allowing the motor to spin up like our 83 so they didnt need it).. Reading about all the other stuff Star to in detuning made me think they probably did so in search of a stronger torque curve because of all the hype happening concerning the higher torque that HD was stating on their V-Twins (and HD has been selling a LOT of bikes on that hype). Fact is,, again IMHO, chasing that rabbit was a fool's errand cause the original V-4 Venture, set up just like it was, pulled just fine..

All that stated,, I have a sneaking hunch that the answer to your question will actually be found in a good tune up..

Gotta remember,, these scoots are 4 cylinders and therefore, if one jug drags or decides to not carry its load its not like a 2 cylinder scoot = you dont 50% you lose only lose 25% of your power.. Again,, I am no real Yamaha mechanic or engineer, but to my pea brain this SCREAMS as an answer as to why these scoots can run so good on 3 cylinders (and they do,, and they dont perform that bad on 3 either)..

Part of a good tune is making sure your carbs are in sync = very very easy to do if ya got the tools.. I strongly suggest anyone seriously wanting to ride any multi carbed scoot learn to sync their own carbs.. These Yamaha's have linked carbs and the linkages like to crawl over a very short period of time = especially when they get a few miles on them.. Learn to sync em and you will find yourself taking 5 minutes every oil change to resync = probably not totally necessary but syncing is that much fun IMHO..

From what I am reading here, I think a good pre op to syncing would be a very close examine of the slide diaphrams in all four carbs on your scoot. The reason I say that is because if those diaphrams have holes in them, the very very best carb syncing mechanic (and trust me - there are a number of them around this joint) giving you the how to's of it is actually going to do you no good..

I run NGK DRP8EA-9's in my 1st Gens and would not be surprised that that is exactly what your scoot specs out.. Thru the years I have tried many other types and brands but have had my very best of luck with the stock OEM plugs,, besides,, they are cheap.. The Auto shop where I get my plugs from didnt have any last time I dropped plugs in the old gal so I just dropped in a set of NGK D8ES's and they have been worthy - if you vary from OEM always make sure and check the length of the plug compared to OEM.. I didnt do that one time on a Honda 125 and end up bumping a valve and bending it cause the plug was 10 thousands to long !! Not that big of a job sticking a new valve in a single cylinder Honda but THAT would be a chore on a bike like yours..

Getting long here and I gotta scoot.. Hope ya find something in all this that helps somehow..

Oh,, before I forget =

Puc

Thanks for the reply. I think I may be shifting to soon. But that doesn’t explain the temp difference between the front and back banks. If I can ask where are you located? The site will not let me access your profile

I'm in Chambersburg, go ahead and sign up as a member of this great group. Best 12 bucks you'll ever spend. My contact info is in my profile. Ride safe!

Find a Hardley at stoplight!! If you have to struggle to get to next light before he does its probally only running on 3. Or maybe two!!

I would like to jump on the "it should be syncbed" bandwagon. Its just that important, especially for idle and low rpm behavior. Its not uncommon for the fronts to run a little cooler, although Im not sure about 125. I do the downpipe spit sizzle test and its hard to distinguish. I have read about a few guys on the Vmax side that actually run slightly fatter jets in the rear two but like most, I just run it and enjoy.unlike the Vmax, the venture seems fine with OEM jetting. Synch it and dial it in and ride! Like Puc, I dont need to do much downshifting but its really happier after 3000 rpm in the top gears. It really starts to pull at about 4000rpm. I can cruise and gradually accelerate from under 2500 but her powerband would be around 3500 up.. If you tend to short shift, as I do, sometimes well under 2500rpm then it really needs to be kept in synch or it may buck and fuss. There will be some performance differences between gen1 and gen2, never ridden the later so I cant elaborate much.

One noteworthy tidbit, these V4s run surprisingly well on only 3 pots, other than being down on power it might not be immediately obvious. This is why the DP temp test is valuable.

Find a Hardley at stoplight!! If you have to struggle to get to next light before he does its probally only running on 3. Or maybe two!!

:crackup:,, ,, :rotfl:

Ever had a buddy that you wish you could just fold up and put in your pocket and be able to pull him out at just the right moments in time... IMHO,, that Yammer Dan is exactly THAT kind of friend :guitarist 2:!!!!!

DanL',, I hope you know that it's off the wall little comments just like the one above that make spending time with you on club probation so relentlessly doable..

:crackup:,, ,, :rotfl:

 

Ever had a buddy that you wish you could just fold up and put in your pocket and be able to pull him out at just the right moments in time... IMHO,, that Yammer Dan is exactly THAT kind of friend :guitarist 2:!!!!!

 

DanL',, I hope you know that it's off the wall little comments just like the one above that make spending time with you on club probation so relentlessly doable..

Yeah I picked the lock on the Door to that corner!!! I ment to add "SYNC THEM" to my post but was Dreaming of Busting Hardley's!! Get those carbs pulling togather will Amaze you!!

:crackup:,, ,, :rotfl:

 

Ever had a buddy that you wish you could just fold up and put in your pocket and be able to pull him out at just the right moments in time... IMHO,, that Yammer Dan is exactly THAT kind of friend :guitarist 2:!!!!!

 

DanL',, I hope you know that it's off the wall little comments just like the one above that make spending time with you on club probation so relentlessly doable..

But tell me I ain't Right???

But tell me I ain't Right???

You ever see that king of the Hill episode where Hank says of Bobby

Find a Hardley at stoplight!! If you have to struggle to get to next light before he does its probally only running on 3. Or maybe two!!

WHAT HE SAID:smile5:

WHAT HE SAID:smile5:

YEAH!!!! What I said. Er What did I say?? Oh Yeah I was right..... I think!!!

YEAH!!!! What I said. Er What did I say?? Oh Yeah I was right..... I think!!!

Yes,, you are him and Yes,, you were right... We are in agreement,,,, at least until the Fried Chicken runs out,, then we may have to go back to

Ya might wanna consider the source though cause I still think Mom Yam screwed up by not stickin that new V-Max motor in a shaft driven, REAL game changing new VENTURE of a touring scoot!!

Yes,, you are him and Yes,, you were right... We are in agreement,,,, at least until the Fried Chicken runs out,, then we may have to go back to

 

Ya might wanna consider the source though cause I still think Mom Yam screwed up by not stickin that new V-Max motor in a shaft driven, REAL game changing new VENTURE of a touring scoot!!

I fully agree with that one Puc!! I was really expecting that V-Max engine at least!!!