14 replies to this topic

[CaRnI026]

hellow folks,

i got this montesa cota 315r, they gave me this huge tank of BLUE GAS, i was told it was mixed with oil already (the front of the thank has a VP sticker). a friend of mine told me it was race fuel, and im about to finish it, im not sure what fuel to use, i dont consider race fuel an option but i could try getting it if nessesary. another important observation, i dont think my bike its running well, it feels ok at high revs, but otherwise it feels like its pushing and pushing and pushing every half/second, i heard it could be that this fuel its too old..... could it have something to do?

so my options are:

* VP (if nessesary, but tell me which one, cause i know there is vp2 and vp4 or something like that)
* 93 octane <----(super unleaded??? is it???)
* 89 octane
* 87 octane,

the other important thing would be what oil will i mix it with, and at what quantities, some say 80:1, but others say 70:1 will work better,

anyone has try all of these fuel mixes?

Edited by CaRnI026, 21 October 2009 - 12:40 AM.

[Neil King]

I use VP110 which is 104 octane. Sounds like your pilot jet is clogged. If you use lower octane fuel in it it will knock like its trying to break the door down.

[CaRnI026]

well i cleaned the carb not too long ago, but i could take a look at it if your sure of this, otherwise i would blame the gas im using, i sure its super old, just like the bike
i just hope the problem is the gas not the bike,

and.... so how's vp11o working on your bike? its it great, good, average, has it been better before? is it the best you've tried? convince me i should use it!!!

thanks

[Neil King]

Well, I used VP Red for a good while and it seemed to be a little better. They told me that the 110 is the same except the die is different and is $.50 a gallon cheaper. So I started using it and have adjusted to it. When I first got my 315R the pilot jet clogged almost every day. I drilled it out till it quit doing that, it has never clogged again. No need for me to convince you, your bike will do it for you.

[Wherry]

Neil King, on Oct 21 2009, 03:57 AM, said:

When I first got my 315R the pilot jet clogged almost every day. I drilled it out till it quit doing that, it has never clogged again.

Hmmm. That's an interesting train of thought.

[Wherry]

Oh yes and to get back to the question.
Here in the UK I use 97RON Super Unleaded at 80:1. Standard Unleaded here is 93RON.

[CaRnI026]

Wherry, on Oct 21 2009, 07:09 AM, said:

Oh yes and to get back to the question.
Here in the UK I use 97RON Super Unleaded at 80:1. Standard Unleaded here is 93RON.

ok, ok, that's why i typed the question marks (???), cause i was not sure if it was the super unleaded, i believe thats about the highest u can get here in south texas, or north of mexico, i will look for a shell gas station, they should have a better gas there. and my next gas option would be VP...but.. if i try the VP red, will my pilot get clogged???, in that case i might just go for the highest octane gas i can get at a pump or a shell gas station.

before getting my gas, let me refresh your minds, WHAT IS THE BEST FUEL FOR A 315R?
VP
97 (super unleaded)
93
89
87
HAS ANYONE TRIED THEM ALL? OR A COUPLE OF THEM... WAS THERE ANY DIFFERENCE?

[DGShannon]

CaRnI026, on Oct 20 2009, 07:30 PM, said:

hellow folks,

i got this montesa cota 315r, they gave me this huge tank of BLUE GAS, i was told it was mixed with oil already (the front of the thank has a VP sticker). a friend of mine told me it was race fuel, and im about to finish it, im not sure what fuel to use, i dont consider race fuel an option but i could try getting it if nessesary. another important observation, i dont think my bike its running well, it feels ok at high revs, but otherwise it feels like its pushing and pushing and pushing every half/second, i heard it could be that this fuel its too old..... could it have something to do?

so my options are:

* VP (if nessesary, but tell me which one, cause i know there is vp2 and vp4 or something like that)
* 93 octane <----(super unleaded??? is it???)
* 89 octane
* 87 octane,

the other important thing would be what oil will i mix it with, and at what quantities, some say 80:1, but others say 70:1 will work better,

anyone has try all of these fuel mixes?

Owned a fair number of 315's, as have my riding buddies. They will knock like crazy on straight pump gas, and don't much like pure race fuel either. In the end, we all ran the highest octane pump gas mixed 50:50 with race fuel. The race fuel is not so critical, as long as it is 108 or 110 octane. If you can get leaded racing fuel, then even better. Mix that at 80:1 with a quality full synthetic oil, and the bike will love you for it.

Edited by DGShannon, 21 October 2009 - 06:21 PM.

[CaRnI026]

ohhh, i see, i will try getting some of that race fuel then, mix it with the best pump gas i can get, and see the results,

Thanks man, ill check back soon, and see if anyone has any other opinios

[Neil King]

No the VPred won't clog your jet anymore than any other fuel. It is leaded, so you need to clean your sparkplug every once in a while. My bike had sat idle for several years before I bought it. I should have had the carb ultrasonicly cleaned. The drilled pilot is still within adjustment range of the air screw. I use the 104 octane so I don't have to worry about mixing, it doesn't save all that much money to mix.

[samandkimberly]

Keep in mind that US Octane measures are RON/MON, whereas most Euro measures are straight MON. Check out http://en.wikipedia....i/Octane_rating for more explanation.

I ran super (US 93 octane, ~97 Euro octane) with no problems on me 315 for some time, but I do find it runs more crisply with a 50/50 mix of VP C12 and super. I've been thinking about running an avgas 100 low lead/super mix, purely for convenience, but I seem to always have a little race gas kicking around.

Sam

[tt5th]

Mine runs fine on either UK pump petrol - 93 or 97. I usually use 97 but can't say I notice much of a difference. I mix it at 80:1 with a fully synthetic oil.

With the running well at high revs but feeling like its pushing at low revs - Obviously I'm not sure its the same experience but I think mine was doing something similar, at low revs it was jumpy and I ended up using a kind of all or nothing style of throttle control. Reminded me a bit of a motocross bike. After much carb cleaning it turned out it was the baffles and packing in the mid-box of the exhaust had gone completely. A local motorbike guy cut it open, packed it and welded it, made a world of difference. Loads smoother bottom end and more power lower down in the rev range so I don't have to cane it so often.

Worth checking - just pop off the silencer and stick a torchlight into the mid box. With the age of these bikes if its not been changed or repacked its likely a lot of them have mush for baffles!

[CaRnI026]

.... i've been trying several deferent oils, with the same gas, V-power from shell, 93 octane, and i believe i was using VP before, but it was 3-4 months old. anyways even with this different gas, i still feel the push, push, push on low revs, although i have to say it has decreased. i will give a try to some new VP, then a 50:50 VP and shell gas mix, if still no results, then i will take the silencer, or midbox? to someone who can do the job.

thanks for the advice !!!

Edited by CaRnI026, 29 October 2009 - 02:30 AM.

[fastducs]

I've tried 50/50 mix of 93-octane pump gas and VP C12.
I've tried 50/50 mix of 93-octane pump gas and CAM2 110 octane.
I wasn't very happy with any leaded race fuel options.

After doing some research I currently run pure Sunoco 260 GT-100. It is 100-octane Unleaded street-legal race fuel (RON 105, MON 95). I run it straight, and I mix it 80:1 with Motul 710 or Motul 800 full synthetic oil (whichever is available). My 315r really likes this Sunoco fuel, and I really like NOT breathing leaded exhaust. I pay $8 USD / gallon, so running this fuel straight costs me about as much as 50/50 mix of pump93 with VP C12. I keep it in a sealed metal container and it seems to stay good for several months. Another nice thing about it being unleaded is that at the end of the season I can pour leftovers into my car without worrying about damaging catalytic converter.

Here are the fuel specs:
http://www.sunocoinc.com/Site/Consumer/Rac...Sunoco260GT.htm

You can find retailers here:
http://www.sunocoinc.com/site/Consumer/Rac...GT100Locations/

Sunoco also makes 260 GTX, which is not street-legal (harder to find and more expensive) but has no ethanol whatsoever, and presumably very long shelf life. I haven't tried it yet.

[Neil King]

Unleaded fuel is designed to run through a catalytic converter and is probably more poisonous than leaded fuel exaust fumes. I've read articles on this subject, I'm no expert but they made sense. Oh, and they are on the Web so they must be true.