I finally did a compression test on the old vision this evening. Both cylinders were about 110 psi, this is not good. I squirted some oil in each hole and they bumped up to about 120 psi. Needless to say I was not happy. I have always had good luck with an oil adative called RESTORE, it comes in a silver can. Has anyone ever used this in their own motorcycle or will I destroy the clutch plates?
I haven't used it, but I'd be leary to use it in a wet clutch unless you have spare money for new plates...
Not exactly sure where to go on this one. Looks like your problem is stuck compression rings and I really don't know if an oil additive will unstick them. How many miles on your bike and did it set unused very long before you got it? See if you can get 1000 or so more miles on it and try the compression test again.
I believe that the motor has between 16k to 30k on it. I put this bike together from 2 none running bikes and who knows what someone did to it before. I have watched the bike go from friend to friend for 8 years. I know that it would run for a short time with each person, it just never ran on more than 1 cylinder. I have put almost 400 hundred miles on it and it seems to run ok so far, I just cant seem to get it synched. I think I will hold off on the RESTORE for now and just run it for a while and see.
Thanks for the info.
Jim
If you're having problems synching the carbs, the vacuum on one may be low to non-existent. On my Vision, I found this was caused by worn second rings.
I don' know if this stuff really works but I have heard that it does. It's not cheap but if it does the trick it'll be worth it.
http://www.yamaha-motor.com/accessories/apscitemdetail/3/122/346/All/1/detail.aspx
Good Luck,
-=[Joe Vacc]=-
George,
That is the exact problem that I have. I get very little vacume from cylinder number 2, making synching next to impossible. Did you do a ring job on yours?
Joe,
I will look into that additive, if yamaha sells it, it is probably safe for my clutch.
Thanks for the info guys,
Jim
No Prob Jim...
This stuff is a fuel additive so no worries about the clutch. The mechanic that told me about it owns the local Yamaha shop and says that he has good luck with it on boat motors that have sat for a long time. So good luck.
-=[Joe Vacc]=-
QuoteGeorge,
That is the exact problem that I have. I get very little vacume from cylinder number 2, making synching next to impossible. Did you do a ring job on yours?
Yes, I replaced the rings and had the cylinders honed at around 80000 km.
The top ring produces compression. The second ring is chamfered smaller at the top, larger at the bottom. It produces the vacuum at low throttle that sucks the gas thru the low speed jets. The sides of mine were worn to almost vertical.
At higher throttle openings, the air flowing thru the carb creates its own vacuum (venturi effect) to suck the gas thru the main jets.
The 'ring-free' fuel additive is what I was thinking about. It does wonders for 2 stroke outboard motors and should work here. You don't have enough miles for wear to be the problem.
What should the compression be?
I'm shopping for a vision and would like to know.
Thanks
:-/
According to the book i have the standard compression should come in at 142 psi, minimum of 128 psi and a maximum of 156 psi. The maximum difference between cylinders of 14 psi.
I was buying the restore additive for another car , so I just bought the big can and added some to the vision. We will see what happens.
Jim