RIDICULOUS squish. as always!

[Jakobi]

When I rebuilt mine I made sure not to sacrifice any top end by keeping the port timing (top of piston with base of exh) at BDC. Combo'd up with a 13-50 sprocket combo its smooth on the bottom end and builds up quickly. I found adding the extra couple teeth on the rear makes it heaps easier to keep the engine in the meat (on the pipe).

This is using a base gasket stack of 1.3mm, s3 high high (black) comp insert, and results in a squish of 1.8mm.

 

[GMP]

I'd do a 300 like that too if I had one. Make a spacer plate though, and hope the head can be cut as much as needed.

 

[Jakobi]

I was hoping the S3 head would bring my squish back into the 1.4mm range. May look at having some machine work done to it next time around.

Have to decide if I want a 2012 250/300 and alot of that decision will depend on if the s3 head will still fit the new cylinder.

 

[Bailey28]

I did a PV chamber when the bike was newer. I didn't like it, it seemed to delay when it would come on pipe. Low end was a *tad* stronger, mabye 5% or so. I wound up selling it.

Still stock 13/48 gearing. I can live with 1st in the woods. I have been using the Honda racing 80/85 wt. gear oil and I haven't heard a peep from the clutch. Just this past weekend I was in really tight trails, the kind where you don't know if there is a trail or not... 1st/2nd slipping through sugar sand... not a peep!!

I'll do the cover this weekend and report back with the results. Should I be removing or adding any shims to the PV governor assembly?

 

[stainlesscycle]

no need to change shims unless you want to adjust when the hit comes in. just get rid of the slack.


i like 13/51 and rarely use 1st gear. there's no sand here, thank god

 

[Bailey28]

If I wanted it to hit lower, sooner, would I add or subtract shims?

I came off of a 450XC, honestly, I got really lazy riding it and do miss some of the brute off the bottom strength. The 300 is great, smooth, but some more low/mid in the deep sugar sand hills and bogs here would be great.

 

[swazi_matt]

I did a PV chamber when the bike was newer. I didn't like it, it seemed to delay when it would come on pipe. Low end was a *tad* stronger, mabye 5% or so. I wound up selling it.

Still stock 13/48 gearing. I can live with 1st in the woods. I have been using the Honda racing 80/85 wt. gear oil and I haven't heard a peep from the clutch. Just this past weekend I was in really tight trails, the kind where you don't know if there is a trail or not... 1st/2nd slipping through sugar sand... not a peep!!

I'll do the cover this weekend and report back with the results. Should I be removing or adding any shims to the PV governor assembly?

was this one of the retail large PV covers, or did you manufacture one yourself?

how would you rate one of these mods for an extreme enduro?

 

[stainlesscycle]

If I wanted it to hit lower, sooner, would I add or subtract shims?

removing shims makes the pv open earlier.

 

[Bailey28]

For extreme enduro, I couldn't say one way or the other. I tried the cover before I did the base gasket squish mod so maybe the large squish clearance had something to do with the sag I was getting before it came on the pipe.

I also moto the bike, so I do need some snap. I felt the cover reduced and delayed the snap. However, I felt there was more net torque from the bottom up to the sag. Then the hit came, but it came in later. Go figure I did try different needles bit ultimately my bike responded better with the stock finned cover.

I bought the cover from gofasters.

 

[stainlesscycle]

how would you rate one of these mods for an extreme enduro?

the big problem for setting up extreme enduro i would think is this: you need big fast power off the bottom to loft the wheel at anytime. most of the lofting is clutch release speed, but a power wheelie is necessary when you're moving along... then you need big grunt for when you get stuck/in wrong gear.

i would probably gear like 13/52 and actually use first gear occasionally... i don't think top speed is so much an issue...

on a side note - i set this up in my yard yesterday.

i have about a face cord of old firewood i'm gonna build a log pit about 20' before the approach of the telephone poles. i also gotta find some more poles, although it looked ok, i just zipped right over it. i had to remove the bottom log to make it a little tougher to get on it... and i'm going to need to remove some transition logs to make it harder...i also staked it so i didn't shoot poles everywhere - i also think i finally have a use for the stacks of old tires i've been accumulating - thank god i don't have neighbors ...

 

[stainlesscycle]

quick test run today - i had to go 1 leaner on the main jet, and turned a/s out about 1/2 turn after the squish mod. with previous jetting it refused to rev out, it would get to the top and break up/not overrev. so the tighter squish made it more efficient. now it's more of a rocketship. the squish at 2mm REALLY smoothed the power out - it has a very minor hit at the top, but it's very trials like. just with a whole bunch more juice than a trials bike. i'll have to ride it a bit more to see what it will really do..