RIDICULOUS squish. as always!

stainlesscycle

stainlesscycle

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well, got around to checking squish on my 07 300 - i knew it was loose, i could see at least 3 gaskets on the base. i measured it and my thickest solder (.125") doesn't even squish. that's more than 3mm. why does gasgas set these up with such a giant squish? i've gotta pull the cylinder to see how many gaskets i can remove and still not kill the port timing.
 
Assuming the exhaust port timing can take it...what squish will you shoot for ?
Something at, or just above, .020" ? That's what I've done on some chainsaws. Often no base gasket to get there. Just Yamabond 4.
 
i shoot for anywhere in between 1.2mm and 1.6mm. i have learned that 1.2mm needs at least 50% 112 octane. i don't think i can even achieve 1.5mm on this one. still scraping old gasket to measure it try to figure out what gaskets they had and do a little math. if my squish is still obnoxious i'll send it out to rb after november....
 
at least 3 gaskets. green/grey/green = 1.1mm of gaskets. mic'ing the gaskets at several points gets me about 1.15 mm. if i run just 1 thin one (.15mm gasket) i will end up in the 1.95mm range. better than 3mm, but still not great. what will port raising of 1mm get me? i'm assuming i'll lose some top end. how much i don't know....



i have to run at least 1 gasket. it's hard to get a good seal with the .15mm gasket, but i've been sucesful in the past.... just running yamabond only is too risky...
 
yes, it worked fine. but there's always better. there are some plusses to having a big squish.. but i'd like to unlock some hp...
 
Stainless, as you may remember, I redid the base gaskets a few weeks ago. I had the two green gaskets, 2.5+mm of squish. I used only one dark green gasket to reassemble, resulting in the 1.67mm of squish, or .066"

My bike runs soooo much better, more snap, pull, better cleaner running, wheelie power is fantastic!
 
yep, my other 300 had 1.2 squish when i was done with it. it's a world of difference. better fuel economy, and better power right now. i'm going to end up close to 2mm, there's not much more room to move, unlesss i deck head/reshape squish...


and since it's apart i might have time to do some port matching/knife edge transfers/etc...
 
Its more than just the squish clearance at one point, its the consistency across the band. An RBD head will actually have a more narrow band than stock, but be perfectly matched to the piston so the effective squish is much tighter.

If you drop the cyl too much it might get a nasty bark off idle and then go flat early, like putting an old gnarly pipe on one.

I've run 1.1 - 1.2mm @ 190+ PSI compression in two different 250s, RBD mods. Runs fine on pump gas but its probably at the limit. I think 300 compression is a bit less.
 
i had pinging issues at 1.2 on my other motor. i even retarded timing a degree... coulda been the pipe contributing (messico)


anyways, this motor still has an obnoxious squish. i just put it back together with .3 and got 2.15mm squish. didn't want to mess with port timing too much. looks like i gotta send it out. didn't match ports - just modified gasket a bit so it didn't interfere. and cut someof the center case gasket back - there was a big piece hanging in the intake.



oh and now i gotta change the preload on pv. forgot about that. it's totally changed.
 
I didn't mess with the powervalve preload after getting rid of the thick base gaskets. There was not much slop to begin with, still only a few mm of slop now.

Should I pull the case cover and tighten it up? I have two sets of gaskets!
 
a few mm of slop is alot...

you shouldn't blow a gasket when you do pv. drain fluids. pull the 3 long bolts (2 in clutch cover, one in water pump cover), remove inner clutch cover screws, remove kicker, remove right pv cover. remove inner clutch cover (you might blow this gasket - i've never replaced one - and i take it off and on all the time - just be gentle.) . no need to pull water pump impeller - but you might wanna remove wp cover to line up gear when it goes back together... then do pv preload etc. i leave no freeplay. i despise that rattle, it's so distracting. takes maybe 45 minutes - i just did it between posts.... i also dissasembled the governor for no good reason. just for the hell of it i guess...
 
300s have so much snot off the bottom they still run hard despite all the production tolerances. Before widebear got banned, he was messing with a cyl spacer plate to further raise the cyl, and cut the head to suit. That sounds like it would be nice, not excessive low end, but a lot everywhere when you twist it.
 
I can only hang on to my 300 some of the time as it is. I didn't realize widebear got banned, I have wanted to go up to Kamloops and chase him around his own turf sometime. ANyone know how to get ahold of him?
 
Allright then, that will be this weekend's project. Powervalve slop adjusting.

I do get the rattle when in the lower rpm range well before it comes on the pipe.

I hope to pick up even more low end doing this. I ride a gear or two high most of the time, and would love more low end power. :D
 
Bailey28 said:
Allright then, that will be this weekend's project. Powervalve slop adjusting.

I do get the rattle when in the lower rpm range well before it comes on the pipe.

I hope to pick up even more low end doing this. I ride a gear or two high most of the time, and would love more low end power. :D
Click to expand...

it doesn't take long. you'll have time to do other projects :)

for more low end - how are you geared? and do you have a oversize pv cover?
 
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