New to forum

[Relic]

Hello I'm a new (old) 1988 Vmax owner.
Always wanted one. Working my way thru a lot of little problems with a 34 year old bike. I appreciate this forum and all the knowledgeable and experienced people contributing to it. The discussed topics have already assisted me with solving many issues with the bike. Thanks again!
Relic

 

[Marauder03]

Hello, welcome aboard. This is a wonderful forum with extremely knowledgeable people.

 

[Relic]

Glad to be here. Thanks ! Yep, I've seen the great answers and solutions you all have provided. It's incredibly helpful.

 

[Marauder03]

By the way I forgot to mention you have a great looking bike! Good luck with it!

 

[Relic]

Thanks, I love it. I put the bar on the back to keep the wife from flying off...

 

[gentsvmax]

Hey hello
Another good lookin machine! Welcome to the forum.

 

[Relic]

Thank you much !
Looks like you have quite a sharp and unique machine from your picture.

 

[Fire-medic]

I suggest you moderate your throttle use with The Wife on the back. You want her to enjoy the ride without scaring her.

My experience is riding with a passenger, I don't use the throttle too-hard in 1st or 2nd, and that limits the lurid wheelies, and the passenger grabbing me to hold-on. Yes to a sissybar for the passengers.



If you like the bike now, swap-out your Cobra 4-into-4 exhausts for almost anything else, even a OEM megaphone system with the resonator as part of the megaphones, and be prepared (returned to OEM jetting, if it's been changed for the Cobras) to have the VBoost and throttle response bring you to another level of VMax performance!

If you think that's exaggeration, ask Sean Morley.

I agree the bike is very clean. I like the engine case covers in a mill-finish. Are they polished?

 

[Relic]

Thanks for writing. I believe the cases are highly buffed then clear coated. I did also receive the original exhaust system with the bike. I like the looks of the cobras but had no idea they might hinder performance. I'm kind of learning on the fly here, and appreciate the input. Carburetors are my next project. Clean and sync or rebuild? . I haven't decided yet.They seem a little stumbly at idle. But ok as it accelerates.
The previous owner took great care of the exterior outside. But maintenance wise there are a lot of issues I'm working through to get it like new.
Comfort and the fear of an inadvertant blip of the throttle due to road conditions and the passenger goes bye bye was the reason for the bar

 

[Fire-medic]

I like the looks of the cobras but had no idea they might hinder performance.

Oh boy, are you in for a shock! There is a huge difference in power output and throttle response between the Cobras 4-into-4 system and the OEM or any slip-on like Supertrapps, F1, or Vance & Hines. OEM and the slip-ons of any brand have comparable levels of performance.That is to say, slip-ons don't add performance compared to the OEM double megaphone/resonator box. Remember that the prior owner may have done sone rejetting to the carburetors for the non-power output-friendly Cobras.

Put it this way: on a performance bike, why would you want to reduce power? The only reason I can fathom is 'because they're purty.' OK, I accept there are a few people who like the looks, and are willing to forego stock levels of performance, but as for me, I'll take the stock level of performance and throttle response. Once you re-install the OEM megaphones, and have the bike returned to OEM jetting (or you can reduce the main jet from a Yamaha/Mikuni 152.5 to a 150 or a 147.5, and get better performance on nearly all cases) and take it for a ride, you'll find out what VBoost is all-about. Look for the red lamp on the tachometer panel to flicker briefly as you sweep through RPM's of VBoost, which is roughly 5750-redline. That's what VBoost is all-about!


About doing the carbs, if you plan on owning the bike for years, and riding it, you're going to want to learn how to care for them on your own. If you're not mechanically-inclined, members here like dannymax, CaptainKyle, and Sean Morley will do a great job of rebuilding your carburetors so they work as-designed. However, contaminated fuel (debris, water, gas tank rust scale, deteriorated gas lines shedding bits of rubber, etc) will soon plug your pilot jets, and though some recommend the use of techniques such as the shotgun (you can look it up using the search function) I just yank the carbs, split them into two pairs, and remove the fuel bowls to access the jet blocks, where the #42 pilot jets and the #44 main bleed pipes are located. If you remove the jet block, order four of the #35 jet block gaskets. They frequently tear upon removal.
https://www.ronayers.com/oemparts/a/yam/500456a5f8700209bc79313a/carburetor
Before removing the carburetors, drain them individually into a container to see what is in the float bowls, to give you an ideal of what needs cleaning. My general rule of thumb is, 'if the carbs come-off, the fuel filter gets replaced.' A check of the appearance of the gas tank is always a good idea. Cleaning your carburetors and neglecting a rusty gas tank is going to result in plugged pilot jets, and soon.

I recently posted about using K&L carburetor parts as a less-expensive alternative to OEM. The parent company is a Japanese OEM supplier, and you can get a kit per carburetor which has the jet block gasket, float needle valve and seat, float bowl gasket, the enrichener gasket, and the O-rings used in the carbs. Buying those separately through the Yamaha dealer is more-expensive, significantly. Do a search for K&L on a post by me, and you can find the part # for the per-carburetor kit.

 

[Relic]

Wow, thanks you're a wealth of knowledge! When I do the carbs I'll get a rebuild kit with the standard original spec jets, etc. And throw the stock exhaust system back on. Pretty easy job on the pipes I think. Yes, I put in some redline fuel system cleaner and Poof! the fuel filter immediately clogged up almost solid. Replaced it and bought a few extras tucked them in the tailpiece until I go after the carb fix. That's another needy job is cleaning and sealing the fuel tank. And my charging voltage is lower than I think it should be.
I think the bike sat for several years so I'm working my way through about every system on it to make sure it's up to snuff with nothing going unchecked.
Thank you much for your advice and help.

 

[Fire-medic]

Just wondering, where are you in MI? I used to be in SW MI, and bought my first new Yamaha there 50 years ago.

Exhaust replacement:
Follow the instructions, it should help you be successful without too-much frustration. Assemble everything loose, and then start securing things a bit at a time. Don't forget the bracket on top of the resonator that gets a nut & bolt. Be careful with the fiber header gaskets, you can ruin them if you just try to 'ram' the header pipes and the resonator/megaphone assembly on.

Here's a thread on replacing your OEM exhaust:
https://www.vmaxforum.net/threads/stock-exhaust-replacement.23592/
Charging issues:
https://www.vmaxforum.net/threads/how-to-fix-your-vmaxs-low-voltage-or-charging-problems.19108/
The 'crimp fix' which is free, you just solder the wires instead of relying upon a multiple-wire brass crimp.



Get the 150 Mikuni and the 147.5 Mikuni main jets too, the bike runs better for almost everyone using one of these two, on a stock powerplant & exhaust.

Plenty of threads on cleaning your gas tank. I use 6% vinegar, tank off the bike, and remove the fuel level electrical switch from the bottom of the gas tank or the potmetal it's made-of will dissolve. Part of the gas tank cap is potmetal, so don't put that in the vinegar either. Home Depot sells 30% vinegar in 1 gal. bottles, $20. A 1 gallon bottle of that and 3 gallons of water, you have a 7-1/2% solution, not too-far from the 6% I recommended. This is NOT a case of "if a little (%) is good, more is better!"



I made a blank-off plate for where the fuel sender unit bolts-in, so I can place the tank in a containment basin, hold it in-place with some bricks on the sides of the tank, and fill the tank with 6% vinegar. The containment basin is in-case the tank is rusted-through, and it leaks. I recommend checking things every 12 hours until it's shiny clean. When you're done, empty the vinegar, rinse the gas tank, and run some-sort of air to thoroughly-dry the entire gas tank. It will flash-rust in a half-hour if you don't! Throw some oil in there and coat the entire tank, and make sure it's sealed-closed. Come time to re-fill the tank, empty it of oil, throw a half-gallon of gas in there, and rinse the tank well, and you could probably use that gas in your lawnmower.

Other ways are Evaporust (pretty-expensive, compared to cleaning vinegar), pool acid (sodium hypochlorite), which will be a disposal problem, and for the adventuresome, electrolysis. Don't do that inside anywhere you could start a fire! Also, I wouldn't do it unless I was continually monitoring it.

 

[Relic]

I live SW Mi. by Niles, about 30 minutes from the big lake. Where did you live around here?
I don't have the bike apart at the moment but that crimp looks like it's on the load side of the main fuse? Reaching it from under the seat. So soldering that eh? I know I've had little electrical problems, lights etc. that I've replaced the bullet connectors on, that were loose now they're working. I'll probably keep working through all the connections as the bike is 34 years old and i don't know if its ever been done before. I got the bike for $2500 which I thought was a ridiculously low price for how clean it is. The previous owner (a nice guy) couldn't get it to start. I negotiated the price over the phone and drove 6 hours the next day to pick it up. I bought a jump starter with me shorted the solenoid and it fired right up. Later I found the coil wire to the solenoid wasn't plugged in.
But really, if someone were to do all the little repairs/ replacements through a mechanic it probably would have been a couple grand worth. Replaced the battery, clutch, rebuilt both clutch cylinders, all new brake rotors, rebuilt all the calipers. Reterminated the ignition coil high voltage connections Etc. Etc. Etc.
Again, you are a wealth of knowledge. And I appreciate the advice. I was looking over posts on removal of the tank. It looks a little involved, but I'll get it. I was a mechanic when younger, and the balance of my career I was an electrician/contractor for the last 30 or so years.Thank you for all the tips. May look into that Por 15 to coat it inside after cleaning. Probably should do that first before I attack the carbs...

 

[Fire-medic]

Good for you, sounds like you're well on the way to having a reliable bike.

Take a look at the wires under the seat and the pic, and you'll see where the crimp is, yes, you need to remove some of the wire loom tape, and replace it when done.

If you come across some particularly gnarly mechanicals to repair, take pics, do a write-up, and now you're a resource, helping others who aren't as-savvy mechanically as you.

Have you unplugged the alternator (stator) three wires running from the front-left, back to the regulator/rectifier? The three M-F plugs often overheat, given enough time, and a build-up of corrosion at the plugs. On a bike, it's not uncommon to have the M-F plug for each pair of wires crumble-apart when you manipulate them. You may already be aware of this, but the three wires from the stator can be connected in any order, as long as a front lead attaches to a rear lead to the R/R.

I bought my new '72 Yamaha 360 Enduro in Kalamazoo at M & M Cycles. They are still in business. I still have the 360, but it got stripped of lights before the year was out, as I rode it at Buchanan MI, Mt Garfield MI, and other hare scrambles and enduro events. I never won a class, but I had a lot of fun.

 

[VMAXer]

Again, you are a wealth of knowledge. And I appreciate the advice. I was looking over posts on removal of the tank. It looks a little involved, but I'll get it. I was a mechanic when younger, and the balance of my career I was an electrician/contractor for the last 30 or so years.Thank you for all the tips. May look into that Por 15 to coat it inside after cleaning. Probably should do that first before I attack the carbs...

Hi Relic, sounds like everything's under control. Have fun.

Welcome to the forum.

 

[Relic]

Hi, yes still learning more about it everyday. But tips from people with the know how are priceless. Thanks, you too

 

[Relic]

Good for you, sounds like you're well on the way to having a reliable bike.

Take a look at the wires under the seat and the pic, and you'll see where the crimp is, yes, you need to remove some of the wire loom tape, and replace it when done.

If you come across some particularly gnarly mechanicals to repair, take pics, do a write-up, and now you're a resource, helping others who aren't as-savvy mechanically as you.

Have you unplugged the alternator (stator) three wires running from the front-left, back to the regulator/rectifier? The three M-F plugs often overheat, given enough time, and a build-up of corrosion at the plugs. On a bike, it's not uncommon to have the M-F plug for each pair of wires crumble-apart when you manipulate them. You may already be aware of this, but the three wires from the stator can be connected in any order, as long as a front lead attaches to a rear lead to the R/R.

I bought my new '72 Yamaha 360 Enduro in Kalamazoo at M & M Cycles. They are still in business. I still have the 360, but it got stripped of lights before the year was out, as I rode it at Buchanan MI, Mt Garfield MI, and other hare scrambles and enduro events. I never won a class, but I had a lot of fun.

That's wild. My first bike was a 73 MX 360 in 1975. Silver with a red stripe. Bought in South Bend Indiana. A lot to handle for a skinny kid. Wish I still had it.
I should have checked those stator wires when I had the drive cover off. I'll go back in and go through it, thanks. I did clean up and ground the rtr well.
If I come up a good solution with something in my repairs not already covered I'll certainly post it. I see that you guys have got many of these issues down to a science. Some is a little over my head without studying it, but I'll learn.
Good talking to you.