Some general questions - 1st gen vmax

[rlburkholder2010]

I'm new to forums, so bear with me. I do find this forum an excellent source, and I'm thankful & fortunate (we) have it.

I always wanted a vmax. Pretty expensive most often, but I picked up a 1985 that had been stored in a large bin for nearly 6 years. Pretty good shape. Approx. 23,xxx miles.

Since I've owned many motorcycles (self taught mechanics), I have got the bike running pretty good. I REALLY love this bike.

NOTE: I have put allot of time into finding answers to my questions on my own. I appreciate any help.


Anyway, to the point. My 'general' questions are:

* The needles in these carbs have only (1) setting for the c-clip. Everyone else talks as though theirs has several settings (for enriching / leaning). Any insight?

* Why no vboost for the European vmax?

* Why didn't Japan have a vmax until 1990?

* COP (coils over plug?) Is this better?

* Underneath the airbox is (2) nipple type connections for hoses. One, at the rear of the airbox, goes down to the crankcase for re-circulation purposes. But, the one at the front of the airbox (UNDERNEATH)......goes where? On mine, it's not connected to anything. I can't find if it's supposed to be connected anywhere.

* One last thing. I've never ridden one of these bikes before. I don't know anyone who has, or, who owns one (yet). So, I don't know if mine is running well? The reason I ask this, is because all 4 cylinders are showing between 90 - 100 psi on a compression check. Could it still run when 128 psi is the minimum? I understand the battery has to be fully charged, and the bike warmed up, and WOT. Anyone's take on this?

Thank you vmax forum.net for being here for me. 20 years ago, this would've been a pain in the ass without the internet & people like you.

Richard Burkholder
[email protected]
Riverside County, California

 

[one2dmax]

Compression sounds low but it's relative so as long as all cylinders read within 10% of each other you're probably fine.

Not sure why Yamaha only gave one setting on the needles for the U.S. - the other countries got adjustable needles. Most jet kits include adjustable needles with them. Stay away from the stage one kits.

Europe couldn't handle the power lol! They have a speed limit imposed but not sure why they didn't have it (since we can't get to that speed limit). Japan has had CC restrictions for years. Not sure but only those rich enough can still get them.

COP's do work well but not a mandatory upgrade by any means.

Nothing connects to that small front nipple (a drain). If you look it also has a small filter in the inside where that nipple comes into the airbox.

 

[KJShover]

I'm new to forums, so bear with me. I do find this forum an excellent source, and I'm thankful & fortunate (we) have it.

I always wanted a vmax. Pretty expensive most often, but I picked up a 1985 that had been stored in a large bin for nearly 6 years. Pretty good shape. Approx. 23,xxx miles.

Since I've owned many motorcycles (self taught mechanics), I have got the bike running pretty good. I REALLY love this bike.

NOTE: I have put allot of time into finding answers to my questions on my own. I appreciate any help.

Welcome to the forum! :clapping:

Anyway, to the point. My 'general' questions are:

* The needles in these carbs have only (1) setting for the c-clip. Everyone else talks as though theirs has several settings (for enriching / leaning). Any insight?

Canadian models and aftermarket needles can be adjusted

* Why no vboost for the European vmax?

Horsepower restrictions

* Why didn't Japan have a vmax until 1990?

Part of the deal after WWII. :biglaugh: Actually I have no idea.

* COP (coils over plug?) Is this better?

To some yes. It is a money saver vs. buying new coils.

* Underneath the airbox is (2) nipple type connections for hoses. One, at the rear of the airbox, goes down to the crankcase for re-circulation purposes. But, the one at the front of the airbox (UNDERNEATH)......goes where? On mine, it's not connected to anything. I can't find if it's supposed to be connected anywhere.

That is normal. Just the rear connects to the crankcase.

* One last thing. I've never ridden one of these bikes before. I don't know anyone who has, or, who owns one (yet). So, I don't know if mine is running well? The reason I ask this, is because all 4 cylinders are showing between 90 - 100 psi on a compression check. Could it still run when 128 psi is the minimum? I understand the battery has to be fully charged, and the bike warmed up, and WOT. Anyone's take on this?

Things will run with a lower compression, but it will be a little under powered. Plus, this might be a sign that your rings are beginning to fail, a valve is slightly hanging open, other internal issues, or just a simple sign of engine age. A good leak down test can point you in the right direction.

 

[PDWeyand]

Welcome to the forum and it looks like your answers are in the above replies

 

[rlburkholder2010]

Thanks for your feedback. I've read many things in this forum inwhich 'Sean Morley' has helped others. Much appreciated. If I check my valve clearances, do I have to purchase a whole 'shim kit'? What if the clearances are good? (my 85 vmax has 25,xxx miles on it).

 

[rlburkholder2010]

Thank you KJ.

 

[rlburkholder2010]

Thank you PD.

 

[midmoraider]

Sean is real good about loaning out his shim kit. It has everything you will need to do the job. Make sure to order new valve cover gaskets from him at the same time. And be prepared for a lot of frustration. I did mine after Christmas, first time, and it was not a lot of fun. Hit me up when you plan to do yours and I can hopefully save you some headaches. Oh, and welcome.