1st Gen V-Max 89 VMAX

[UncleBran]

VMax Year

1989

Hey guys, took an $1,800 gamble on a 34k mile auction bike this last November with the notorious "ran when parked," asterisk on it.


I've since:

- Rebuilt clutch slave & master, didn't replace the clutch but probably should have.
- Cleaned, rebuilt, and sync'd the carbs.
- Cleaned and sealed the tank.
- C.O.P. mod (thanks to this forum for all that info)



I'm getting 17-20mpg and definitely have a cylinder that isn't doing anything at less than WOT and >5K RPM for some reason.

Figuring that out is next up along with both brake master rebuilds.

 

[Radioguylogs]

You're getting there.

You'll figure it out sooner or later.

 

[Fire-medic]

With that kind of mileage, those carbs need another go-'round. Buy an ultrasonic tank and re-do the carbs. They aren't clean, the float level is 'way-off, or you have a fundamental failure to perform somehow in the induction system. You should be getting 30+ MPG. I ride mine pretty-hard and I get about 32-33 MPG, and have a full exhaust and Dynojet Stage 7.

 

[UncleBran]

With that kind of mileage, those carbs need another go-'round. Buy an ultrasonic tank and re-do the carbs. They aren't clean, the float level is 'way-off, or you have a fundamental failure to perform somehow in the induction system. You should be getting 30+ MPG. I ride mine pretty-hard and I get about 332-33 MPG, and have a full exhaust and Dynojet Stage 7.

I cleaned em with an ultrasonic but I'm positive I need to do it again because I ran it before cleaning and sealing the tank.

Already tested for compression and spark so I'm pretty positive you're right.

 

[Fire-medic]

Yeah, the gas tank has to be shiny-clean. If you use a sealer, you have to follow the instructions exactly! Lazy people fail to follow the directions, and then have issues with the sealer causing problems because it doesn't bond properly, and the carburetors fill up with the failing sealer.

 

[UncleBran]

Yeah, the gas tank has to be shiny-clean. If you use a sealer, you have to follow the instructions exactly! Lazy people fail to follow the directions, and then have issues with the sealer causing problems because it doesn't bond properly, and the carburetors fill up with the failing sealer.

That surprises me, I'd expect shedding tank sealer would come off in big enough chunks that the filter would catch it, but then I guess filters don't seem to stop anything else that constantly plugs these carbs up based on the TON of "HELP. BIKE RUN BAD." threads I've looked through on here.

Here's what the underside of the filter looked like post-carb rebuild, but pre-tank clean...Real bad.
I knew I was going to have to pull and clean them again, but was hoping--delusionally--I wouldn't lol.



Possibly stupid question: Think I can get another use out of the gaskets or should I just eat it and get another set of kits?

 

[Fire-medic]

Possibly stupid question: Think I can get another use out of the gaskets or should I just eat it and get another set of kits?

Nah, nothing 'stupid' about that. I think if you're referring to the disassembly & cleaning of the carburetors. If you just recently did the carbs tear-down, with new gaskets & O-rings you can probably re-use them. The one that seems to have a short life upon disassembly is the jet block gasket. I use a thin 90 degree SS pick to gently separate the jet block from the gasket, and if it doesn't tear, I re-use it. On the assembly of a new gasket, I may use a water-soluble lubricant, K-Y or similar, which helps to be able to disassemble things should you need to do it, and it also helps things stay in-place during reassembly.

I don't re-use gas filters. They're cheap, and you can find one very similar in size at your local auto parts store. You should consider just discarding them when you see an accumulation of crud.

 

[UncleBran]

Possibly stupid question: Think I can get another use out of the gaskets or should I just eat it and get another set of kits?

Nah, nothing 'stupid' about that. I think if you're referring to the disassembly & cleaning of the carburetors. If you just recently did the carbs tear-down, with new gaskets & O-rings you can probably re-use them. The one that seems to have a short life upon disassembly is the jet block gasket. I use a thin 90 degree SS pick to gently separate the jet block from the gasket, and if it doesn't tear, I re-use it. On the assembly of a new gasket, I may use a water-soluble lubricant, K-Y or similar, which helps to be able to disassemble things should you need to do it, and it also helps things stay in-place during reassembly.

I don't re-use gas filters. They're cheap, and you can find one very similar in size at your local auto parts store. You should consider just discarding them when you see an accumulation of crud.

Yeah, I was referring to the carb gaskets. That's good to know. I'll hope I don't tear the jet block gasket getting it off.

I bought two filters, so that one got trashed when I pulled the tank. New one's crystal clear.

I might make a new thread for it, but something is also up with my instrument cluster: Neutral light and Oil Level lights are backwards but the wiring in the panel seems right. Guessing something's wonky further down the harness. It doesn't seem affect anything other than lights indicating the wrong things, and the bike won't let me start it with the kickstand down. (Presumably because it doesn't know it's in neutral?)

 

[Fire-medic]

Try using a shot or two of PB Blaster on the brass shaft of the sidestand switch, & make sure that it readily extends and contracts. If you put the bike on the centerstand, it should be easy to service that switch. With the bike running and the sidestand down, if you pull-in the clutch & click it into gear that should
kill the engine. Yes to the sidestand has to be retracted into its 'ready to ride' position for the engine to keep running.

Yes that gas filter is much-more-clean!

The 1985-'89 wire schematic:


How does your wiring compare to this? Looks like the neutral switch hot is robin's egg blue (light blue) and the oil level hot is black and what looks like orange? In one wire.

You can save this page and enlarge it, and put it into a plastic sleeve after enlarging it.

 

[UncleBran]

Try using a shot or two of PB Blaster on the brass shaft of the sidestand switch, & make sure that it readily extends and contracts. If you put the bike on the centerstand, it should be easy to service that switch. With the bike running and the sidestand down, if you pull-in the clutch & click it into gear that should
kill the engine. Yes to the sidestand has to be retracted into its 'ready to ride' position for the engine to keep running.

Yes that gas filter is much-more-clean!

The 1985-'89 wire schematic:
View attachment 94246

How does your wiring compare to this? Looks like the neutral switch hot is robin's egg blue (light blue) and the oil level hot is black and what looks like orange? In one wire.

You can save this page and enlarge it, and put it into a plastic sleeve after enlarging it.

Thank you for the schematic! My side stand switch definitely works because the bike always thinks it's in gear (even in neutral) and dies/won't start with the stand down.

Oil level light is on if the bike is in neutral, and the green neutral light comes on if I get real twisty with the throttle. I'll recheck that wiring when I get home.

Edit: found it. Wiring at cluster was good, wiring at sensors was good...bullet connectors connecting each of those ends? Backwards.

I also discovered today I have non-oem jet needles. I didn't take those apart and inspect them on the first rebuild. Diaphragms weren't torn so I went with it. I looked up the comparison photos, but they all look pretty similar to my newbie self. Any ideas which these are?

 

[Fire-medic]

The Factory Pro look closest-to yours. Maybe not the same color, but the taper shape is very similar. http://www.factorypro.com/prod_pages/prody11.html

diagram courtesy of Sean Morley

 

[UncleBran]

View attachment 94248View attachment 94251
View attachment 94250


The Factory Pro look closest-to yours. Maybe not the same color, but the taper shape is very similar. http://www.factorypro.com/prod_pages/prody11.html

diagram courtesy of Sean Morley

That was what I was guessing, but like I said: I'm real new to these bikes, so I appreciate the 2nd opinion.
If it is FactoryPro that would maybe explain the word "FACTORY," stamped on PAJ2.
PAJ1 is the stock "100," PAJ2 is "???" says FACTORY and 162K. Main is "155."

So, needle...richer than stock? (the diagram labels "leanest clip line," and the previous owner had it 2 notches up from that so I'm making an assumption there), a bigger-than-OEM main, and an unknown PAJ2--Thinking I'm going to throw the money at going back to the stock setup I thought I had lol.

 

[Fire-medic]

Well, that's helpful, if you had mentioned the information about the jets inscriptions earlier. It seems you have the Factory Pro kit, they have a 1.0 Supersport jet kit and another kit with titanium needles as shown in Sean's picture previously mentioned. The Dynojet Stage 1 and Stage 7 are probably in the USA/Canada market the most-popular. Factory Pro was started by a guy who was able to determine why a very-special Yamaha from the early 1980's didn't perform as it should-have, since it was a very-advanced bike for its time. It was introduced in 1982. As a water-cooled bike, with a DOHC cylinder head, and a 70 degree V-twin arrangement, shaft-drive, double front disc brakes, rear monoshock, cast aluminum wheels, a 3/4 fairing, available, and styling like much-bigger displacement bikes, it was about as technically-advanced as Japan Inc. was offering at the time, with the exception of no fuel injection, and no turbo, though its big brother the Seca 650 Turbo, a transverse, inline-4 was available at the same time.

The Vision 550 was like a slice-off of the Ford-Cosworth DFV F1 engine, a V-8 that has been called the most successful F1 engine of all-time. The founder of Factory Pro worked-out a carb problem solving a rideability issue with the Yamaha 550 Vision, and that was one of their first products. Now for the Gen. 1 VMax, Factory Pro offers several kits, a 1.0 Supersport drop-in kit, to the 1.1 TiProKit (with titanium needles).


The 550 Vision DOHC V-twin

Going back to stock is always a decent starting point, and going to a 150 from the USA 152.5 stock, or below the 150 to a 147.5 main jet, can make the bike work a bit better.


https://ia800204.us.archive.org/14/...ice-manual/yamahavmaxvmx12-service-manual.pdf

 

[UncleBran]

Well, that's helpful, if you had mentioned the information about the jets inscriptions earlier. It seems you have the Factory Pro kit, they have a 1.0 Supersport jet kit and another kit with titanium needles as shown in Sean's picture previously mentioned. The Dynojet Stage 1 and Stage 7 are probably in the USA/Canada market the most-popular. Factory Pro was started by a guy who was able to determine why a very-special Yamaha from the early 1980's didn't perform as it should-have, since it was a very-advanced bike for its time. It was introduced in 1982. As a water-cooled bike, with a DOHC cylinder head, and a 70 degree V-twin arrangement, shaft-drive, double front disc brakes, rear monoshock, cast aluminum wheels, a 3/4 fairing, available, and styling like much-bigger displacement bikes, it was about as technically-advanced as Japan Inc. was offering at the time, with the exception of no fuel injection, and no turbo, though its big brother the Seca 650 Turbo, a transverse, inline-4 was available at the same time.

The Vision 550 was like a slice-off of the Ford-Cosworth DFV F1 engine, a V-8 that has been called the most successful F1 engine of all-time. The founder of Factory Pro worked-out a carb problem solving a rideability issue with the Yamaha 550 Vision, and that was one of their first products. Now for the Gen. 1 VMax, Factory Pro offers several kits, a 1.0 Supersport drop-in kit, to the 1.1 TiProKit (with titanium needles).

View attachment 94263
The 550 Vision DOHC V-twin

Going back to stock is always a decent starting point, and going to a 150 from the USA 152.5 stock, or below the 150 to a 147.5 main jet, can make the bike work a bit better.

View attachment 94262
https://ia800204.us.archive.org/14/...ice-manual/yamahavmaxvmx12-service-manual.pdf

I should have noticed them in the first place, let alone mentioned 'em.
Honestly it took finding that needle on this second go at the carburetors with way more forum lurking under my belt vs the first time to clock "...OH THEY'VE BEEN MESSED WITH." I was naively assuming it was all as it should be in there the first time round lol.

Knowing what I do now I should look up what all is in those kits because ONLY the needle and PAJ2 weren't OEM (or at least stock size)

Funny you mention the Seca Turbo; there was one at the auction I got the VMAX at. Interesting bike. Family friend got that one.--I was actually only there for an XS650 Special but that same friend was proxy bidding for someone with more dollars than sense that wanted it waaaay more than me so I kind of 'accidentally on purpose,' ended up with the VMAX.

I'll try a 150 and the stock size PAJ2 and see how she do.

 

[Fire-medic]

I'll try a 150 and the stock size PAJ2

I think you will be happy.

Buying used VMaxes and other bikes, I've found all-sorts of ham-fisted 'repairs' and 'improvements.' That includes parts loose in the carburetor float bowls, rattling-around, and needles not any-longer being held in-place.

 

[UncleBran]

Got everything cleaned out, back together and re-synchronized today.
Perfect excuse for a test ride, and to re-fill the tank to see if my economy gets better this week.

150 main, 170 PAJ2, and reused the FactoryPro needles from the previous owner left at the notch pictured above.

Made a world of difference. It didn't fix all of its weirdness but it doesn't reek of fuel and fall on its face for a second every time I roll on the throttle now.

It does still slightly hesitate/give me the lightswitch treatment at certain RPM/loads.

Timing of "The Weirdness" seems related to those points when VBoost would be partially doing its thing, but once I'm at the RPM or throttle input where it would be 'fully-actuated' it pulls smooth and hard. (Unless I'm misunderstanding how VBoost works, I'm under the impression it actuates variably/gradually based on certain factors.)

 

[Fire-medic]

See the Service manual chapter 7 page 59 (7-59) or page 362 of 405 pages in the .pdf counter, at the top-middle of the page when you access the online service manual.

https://ia800204.us.archive.org/14/...ice-manual/yamahavmaxvmx12-service-manual.pdf

 

[UncleBran]

My last fill up, after the 2nd cleaning (and before the messing with the needles I mention below,) I got a whole 19MPG. (Up 2! ) So something is still funky.

Made a little float/fuel level checking tool out of some fuel line and I'll have to get around to using it at some point this week.
I'm know I'm probably going to have to mess with them, but they seemed fine compared to the "proper level," photo I've seen in here a bunch. I suppose I'll have to actually measure rather than eyeballing the 'little circle.'

Based on the RPMs shown in the screencaps of the FSM you shared, Firemedic, the issue wasn't the VBoost. It was doing it~4k-5.5k RPM.
I took the needles out and moved them back a notch and that seems to have solved it? I'll readily admit that I can't tell you why that seems to have fixed it, so I very likely either got lucky or band-aided a different issue, but I'll take it for now until I get around to checking my float levels and what not.

Side note: is it bad form to post these as replies, and bump the thread? Should I be adding this stuff as an edit to my first post?

 

[Radioguylogs]

You are posting in the ideal fashion, posting updates as "replies". If you edit the orignal post, the story becomes confused. What you are doing is the normal way.

 

[Fire-medic]

The mileage should be nearly double that, so something is still out of sorts.

Yes to how you posted, same thread, but another entry or post, separate from the 1st, as radioguylog said.