timing on the cub

[sheerider1026]

checked the timing on my cub motor tonight, i thought it was on 4, come to find out is was only on +2.. i bumped it up just a hair pas 4. what do you guys think?? will it make that much difference?? i have heard that they like a lot of timing.. its a stock stroke 68m, 33mm pwk's, vforce, and 20cc domes, 93 octane.. i also have it jetted a little rich , ..

[wesw]

15hp easy

[sheerider1026]

15hp?? no way man, surely not that much with just a timing bump.. is it true that the cubs like a lot of timing?

[badassbanshee479]

the little cubs love timing, I have a buddy who was running a stock stroke cub with a +4 key and a +10 timing plate maxed! thing screamed!

 

I run my 4 mill at +11

[sheerider1026]

so what do u think i should run on it?? i am running 93 octane with 20cc domes

[sheerider1026]

?

[sheerider1026]

bump

[91banshee]

i ran +8 on 421 20cc domes ran like a raped ape

[sheerider1026]

what kind of fuel??

[Dave I.]

same motor, 19cc domes, +7 timing, vp 110. You wanting to run pump gas is limiting what you are able to do with timing.

 

put some b9es plugs in it and try running it at +6......its cold now and might do ok, keep an eye on your plugs. in summer you probably wont be able to get away with it.

[dajogejr]

What is your current compression?

What is your squish, what is the squish amount/% (In other words, measure how flat the solder is, and how long the solder is flat)

 

Jetting a little on the fat side, nothing wrong with that...but there are more factors to what octane you need to run and what timing it will run best at.

 

When I ran my cub on race gas, 4 mil, I had 185PSI, .045 squish (don't remember squish band length) I ran 8 or 9 on my plate PLUS the Dyna on the most advanced curve. Ran great all year like that, track and dunes.

 

Without knowing anything else, play with 4 to 6, but listen to the motor and check plugs often.

[brian]

dave,

just wondering what info you can get from knowing the squish

and the squish band.

 

for example :

my 4mil is 150 comp. the squish is .040 and the band is .200

(the cut there is a little tapered but that info is pretty close). i

run about 103 octane race fuel.

what does that mean as to how i should set the timing etc.......

keeping in mind that i can run higher octane if needed.

 

oh yeah, these are stock cylinders not cubs. i assume that those

measurements tell you the same things regardless of which cylinders

you are running, true ?

 

 

Sorry sheerider, dont mean to hijack the post just figured this is a good thread

to get more info.

[dajogejr]

Aside from the squish itself, which I like to keep at .040 to .050 for 68mm cubs and smaller, you want to stay less than 55% of your bore for the band. You're safely below that....

 

when you start running near 55%, then crank the timing, smaller cc domes (more compression) that's when you get the detonation issues cubs can be known for....

[sheerider1026]

kool. i thought that 2 was pretty low, it did run good though, although this is my first cub motor, i bumped it up to about 4 1/2, so maybe that will also bring me a little more bottom end?? and also topend? from what i am seing form the plugs i am far away from detonation demons, i will play with the timing a little at a time and keep an eye on it..