My turn

VMAX  Forum

Help Support VMAX Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Looks like it happens just about when the V boost starts kicking in. Is all good with the v-boost unit and cable. Is it opening all the way. I had a similar problem and found the boost had a sticking spot when opening. Just my two cents. :confused2:
 
Looks like it happens just about when the V boost starts kicking in. Is all good with the v-boost unit and cable. Is it opening all the way. I had a similar problem and found the boost had a sticking spot when opening. Just my two cents. :confused2:
Boost seems good. cycles good , and It feels great coming in. I'll have to check if there opening all the way if and when I change jets.
 
I'm wanting to say that Rusty (in Texas) was at 147's and then went to 145's and was surprised at how well the bike ran. He left it that way for a while....but eventually went back to 147's.
 
Rusty had 145s for a trip to Colorado, but returned to Texas that way with no issues. I believe he is back at 147.5 now. You'll be fine.
 
Rusty had 145s for a trip to Colorado, but returned to Texas that way with no issues. I believe he is back at 147.5 now. You'll be fine.


Yes, I had to put 145's in it when motor was stock to get it to act right at 8,000-11,000 ft while working a project in Utah....it had DJ 165's and wouldn't pull a greasy string out of a gooses ass at that elevation cause it went pig rich.

Trailered it home (Houston area) and was amazed how well it liked them at practically sea level. I then put 147.5's in it just to be conservative since I was a little worried that 145 was too lean a jet for sea level. In retrospect though I think it would have been just fine leaving the 145's

It has 180 Mikunis in it now.
1540cc
 
Ready for the dyno one more time. Put in 145 mains today. Dropped the needles a half a clip to the 3rd. I went lower, but it ran poorly. and turned the A/F in a 1/4 turn. Runs good and strong. It had a slight smell of gas at a stop light, that's why I turned the a/f in. I should be able to get there this week. I have a few days off for the holiday.
 
A bit of a new twist today. I haven't been back to the dyno yet but I needed to get the bike Inspected. While I was there I asked if he could do a compression test.


Cly 2- 180
cyl 4- 175
cyl 1- 185
cyl 3- 145

He sprayed oil in number 3 and it came up to 160. They suggested a valve adjustment. I haven't been impressed with my dyno numbers. When I dynoed the A/F was still pretty rich, but I wonder how much horsepower I'm also losing with low compression on #3. Is a valve adjustment also what you guys would suggest.
 
I wonder if there's a way to pressurize the cylinder? On aircraft we pressurize the cylinder then you can hear where the air is escaping. Intake, exhaust, crankcase.. I cant imagine one cylinder wearing down the rings that much more than the rest. Off them numbers I would try valve adjustment also. Unless like I said you pressurize it and know forsure. If you do it. Go to TDC on compression stroke and make sure someone is on the BRAKE and in gear so the bike don't end up lunging FWD
 
Spraying a little oil in the cylinders and the compression raising as a result usually means a piston ring issue, but checking the valve lash can't hurt.
 
Leak down tester. I bought mine on Amazon for $50-60.
Hook it to your air compressor and go. If you open the oil fill cap and hear a hiss, it's rings. If it hisses out the adjacent plug hole it's head gasket. I'm pretty sure that's what the old thread said.
 

Latest posts

Back
Top