RILS

Yes i would say that 130 is reasonable.If you decide to go higher like 180 you will see big gains in the lowend but will lose a little on top.Im running 18cc and 180 psi and expercing some things in the transition from mid to top.Im not sure if its in the jetting or the compression is slowing my rev.Im tring to find some used 19 and 20cc domes to experment with.Im also going to try a vitos needle not sure which first just depends on how quick i find the domes.

Thanks Dave.

Do as you wish.Go ahead why stop at 160 or 180 hell run 225 or 500 or whatever run it on 87 if you want ,I was just tring to give you some advice to help you out and save your motor in the longrun.If you can run these ratios with 93 more power to you.I will be willing to bet a few years from now you will be real good at rebuilding a motor because you will have a lot of expercince with this setup.If you dont beleave me take a poll from everybody here.

180 psi is not 10;1 its more like 12.5;1 and its not allright to run a honda at225 thats over14;1 on 93 go to your nearest race track nascar dirttrack dragstrip or anything even your local grease monkey and see how many of them run 93 on a motor with that kind of compression.I didnt say it wouldnt run i said it will damage it and it will spark nock "ever heard of this".If it was ok you would see the whole nascar field filling up at the local bp instead of hauling aroun sonco and all the other expensive race fuels.

Ive never had a motocross bike with stock compression that high and ive had a few.If you choose to run 180psi on 93 good luck but i feel you will lean a lesson the hard way.I would say your buddy has been lucky to still be running.Bore size has nothing to do with compression when you here that ping its not good.

DETONATION.It will ruin your motor tell ur budd to put some 110 octane in and see if it sounds the same.Id like to see the pistons in that cr on 160 u might get by with a 50/50 93/110 mix.If you dont want to run high octane there is no need to raise the compression that high.

This is true.

In my opinion you are no offense but pissing in the wind messing with the pistons oner that clerance,I agree it could be a little tighter but,you have to have some for the ring,and if thats what they recommend you should be fine.On that same note ur rings have more to do with holding compression than your pistons,for example if your bore was exactly the same size as your pistons you would never getthe piston in, Thats where the clearance and ring come into play.If you like to have your pistons tighter than that I would take the pistons to the shop who does the bore and ge them bored maybe a little tighter,but they do expand and you can file the ring to fit.If you were at 135 and now your at 115 I say you have something else going on like a oring or something leaking.Like I said before if you want to run 160psi get a noss head with 20ccdomes if you want 170 get 19cc domes if u want 180 get 18cc domes and be done with it,you could have done this without boring proably with less money and got ur compression at what ever you want with just the change of the domes at any time.

Im going to try to anwser this.I think you are in the ball park with your clearace,you will get a better reading after your rings have seated completly.As for your compression you said yourebuilt to get it higher this is where im confused.What elevation are you at?I would guess if you shaved 30thousands off you should be between 130 and 150 depending on elavation.If you want to go higher than that the easiest and best way would be to get a aftermarket head and the domes to get you where you want to be.Keep in mind if you get around 160 or higher you will need to run atleast 106octane or better.But why would you rebuild after only 10 hours for compression reasons , at that time you were just getting it broke in good?

What size tires are u running/

too low with 18s.

That 420 sounds pretty damn high to me how do your plus look?

Im running 15/41.12/42 is low as hell I bet you do shift alot,I would say that ratio is really hindering your performance on all terrain.

Whats your gearing?

I just ordered 20x6x10 on itp t9 and 18x10x8 on itp baja wheels from yamaha of troy for 439 shipped the tires are mxr6.

I would say 280-300 main stock or 27.5 pilot 4th clip on needle and play with the airscrew 1.5 out should be pretty good.If your not running a airbox up the main to about 340 and work your way down.I would say the 280 will work pretty good with the box at your altitude. As your elivation goes up the air is thiner meaning less oxegen so you have to run less fuel "smaller jets" to compensate.At 8500ft I wound not be suprised if you end up as small as 260 on your main and you might want to leave your needle in the stock clip to begin with,but I would not start at less than a 280main because you dont want to end up too lean and burn your pistons up.

Im experiecing something like this also.Mine is not a bog or hesitation its very hard to explain,it pulls hard from the bottom but like u say when i get in 4th or above the mid is strong but its long so long that when you have almost decided its time to shift the top hits so hard your like dam whered that come from.But the top is so strong that it makes me think the mid may be weak.This is the setup im running trinity pipes stagelv,k&n pods 340main,27.5 pilot airscrew 1.5 out with stock needles on 4th clip from top,noss head 18cc domes at 180psi.Im goig to try some toomey needles and if that dont work im going to try some 19 or 20 cc domes to see if that high compression is slowing my rev down.Im also running 15 41 gears but it totes the front thourgh 3rd with nothing but gas so I dont think its the gearing.Any susgestions would be apprecitated.

You would lose width withose wheels 4stands for inside and 1 backspace giving u a total of5.

Ok smply said go get you a noss head throw on some 18 or 19cc domes and some race gas,come back and say you lost power.If you do this I doubt we will here you arguing that low compression is better.There is a middle factor but its not at 125psi.If you go real high say 185psi you will see some good gains low but it will not rev on top like it will with say 160psi but either of these will perform better than stock compression.

Gas and oil will seperate over time.I rebuilt my yz125 top and lowend and suspension,it set for about a month i guess and did not think about it when i turned the fuel on but nothing but oil ran into carbs.I had to take them off and clean them.This was with maxima927.

That a crazy question,but here u go.I dont mix the gas until I use it.If you let it sit the oil will settle to the bottom so shake it up before pouring.I would not recomwnnd 20:1 more like32:1 would be plenyt of oil.I usually mix 2 gallons at the time put 1 in pour the oil in andput the other gallon in the can.

I am looking into putting a cub on my bike.My questions are will it kill my lowend?The one im looking at is set up for a stock stroke,if I decide to go with a 4mill later will i just be able to run a spacer plate?I can get the cub for a little more than a good port job cost,but i do alot of diffrent types riding.Can the cub be tuned to many diffrent setups or is it all about topend?Lets face it banshees shine from mid to top like most 2strokes I just dont want to lose what little bottom i have.?

With the box I would start at 300main 4thclip on needle 27.5pilots airscrew 1.5 out and cheak the plugs should be close but cheak the plugs and go from there.

oring