Squish standards

S

stian

New member
Just wondering, since ive got a problem finding 2,5mm solder/tin wire, im looking at decent numbers for squish and what gaskets are used.

Ive got :
0,15mm - squish? = under 1mm
0,30mm - squish? = 1,2mm
0,50mm - squish? = over 1.6mm

I just put in a new piston, and running a single 0,30 with the head untouched.
Seems to me that the squish is over 1mm, due to not touching the 1mm diameter solder ive got.

Anyone knows what squish you have with one 0,15? or one 0,50?
 
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stian said:
Just wondering, since ive got a problem finding 2,5mm solder/tin wire, im looking at decent numbers for squish and what gaskets are used.

Ive got :
0,15mm - squish?
0,30mm - squish?
0,50mm - squish?

I just put in a new piston, and running a single 0,30 with the head untouched.
Seems to me that the squish is over 1mm, due to not touching the 1mm diameter solder ive got.

Anyone knows what squish you have with one 0,15? or one 0,50?
Click to expand...

It could be variable depending on your engine but 1mm would be pretty ideal as a final number. the problem is that if you shave the head & I think I had to do mine 1.3mm to get a 1mm squish you will end up with a compression ratio way too high.

You have to commit to doing the head mod properly or not at all really. Try a plumbing shop or area of your hardware to get some fat resin cored solder rather than electronic solder. Do a search on my thread about head mods for more reading, but it seems RB is the easy way to get the job done for not much money, but you do need a measurement.
 
(F5) said:
It could be variable depending on your engine but 1mm would be pretty ideal as a final number. the problem is that if you shave the head & I think I had to do mine 1.3mm to get a 1mm squish you will end up with a compression ratio way too high.

You have to commit to doing the head mod properly or not at all really. Try a plumbing shop or area of your hardware to get some fat resin cored solder rather than electronic solder. Do a search on my thread about head mods for more reading, but it seems RB is the easy way to get the job done for not much money, but you do need a measurement.
Click to expand...

Yeah, ive done the squish a 10-15 times on other engines, but squish has been under 1mm. Squish at 1,5-3mm is enormous.

Re-did the gasket job yesterday, took me a solid hour. Changed 0,3mm gasket against 0,5+0,15, giving a total gasket value at 0,65mm. Now the engine wont even start.

Going to put on a 0,3 again, and use a 180 mainjet, 42pilot. Want the engine to go rich, but tried with a 188, and the thing wont get on the pipe.

Note: with 0,65 and un-touched head, my squish seemed pretty well over 1.6mm. Tried with a rosin cored solder 1.6 thick. Did not touch it.
Edit Note: With a single 0,3mm bottom gasket, still not under 1.5mm squish.
 
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Engine won't start? unrelated but interesting.

Yeah crazy squish clearances are common. They run nicer when closed up & a better chamber shape/squish angle. Worth the effort or money.
 
(F5) said:
Engine won't start? unrelated but interesting.

Yeah crazy squish clearances are common. They run nicer when closed up & a better chamber shape/squish angle. Worth the effort or money.
Click to expand...

Yeah. Checked everything (and I do really mean everything.) kicked it over a thousand times, starter-gas and did emty the crankcase in case 2 times. Also changed the gear oil. After 2 days of cranking, it did start. Did spit massive oil.

In the winter time im going over the engine, new bearings and seals, clutch and going to cut down the head and raise the cylinder more.

Thanks.
 
i have two 09 engines here, both have 1.3mm of base gasket stack, this is to get the piston level with the exhaust port at BDC....(standard from factory)
both had squish readings around 2mm, as standard... one i have had machined to bring the squish down to 1.3mm the other is waiting for spair cash....
changing base gaskets changes the port timming as well as squish...
get the head machined...
as for the solder, twist 2 or more strands together to get a thicker "rope" of
solder...
 
I don't know why everyone gets so worked up about the bottom of the port lining up with the piston at BDC. It is the very least important attribute.
 
(F5) said:
I don't know why everyone gets so worked up about the bottom of the port lining up with the piston at BDC. It is the very least important attribute.
Click to expand...

It was just an easy reference point for a lot of people. Saying this, for the minimal time the engine is actually at BDC its not the be all or end all, and quite often dropping the jug can result in a much broader or more enduro specific spread of power.

I know with the 2013 model that the relationship between the transfers, boost, and exhaust ports are all different to that on my 2010 model.

What we all agree on is that having less tolerance at the head generally results in a cleaner, more efficient running engine.
 
(F5) said:
agreed and +1
Click to expand...

Agree myself.

Btw, M.O.T Dyno chart shows 21,72hp at 66 km/h with 13/40 gearing. (RWHP) (before exhaust valve opens). Thats around 16w, and that is what is allowed in the papers.
Restricted with 195 main jet, new piston (1,5h). Anyone know what rpm its in at 65kmh in last gear with 13/40? 17" with Michelin Sports

I want high peak power, since im using it on the street with SM tires and brakes. If it doesent show 45 on the rear wheel im taking it up, raising/lower cylinder, porting cylinder and head and some new pipes. Dont know about retarding the igniton or not.

 
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I don't understand.

Or maybe you have a bogus dyno sheet to get the bike approved for your road use? with PV disconnected?


my 200 did 32 at 9000. I dyno'd my 300 but never recorded it. it revved somewhat lower of course. If I remember I'm going to the dyno tonight I'll try dig it up.

There is much you'd do differently for peak power that we don't entertain as it would spoil it as a dirtbike. Depends how serious & how reliable you want it to be.
 
+1 Relatively easy to chase peak HP (at the expense of the rest of the range).

Most people will find a wider spread of less power much more enjoyable to ride than a bike with a narrower stronger power band (even on the street).

Don't under estimate the effect of the ignition curve either. TSP has been making some big gains using custom cdi maps.
 
Checked my runs but I can't rely on them as I think the PC was sticking at the time. it was indicating peak at 8000 & that equated to 60mph in 5th with a 50 rear spkt.
 
(F5) said:
I don't understand.

Or maybe you have a bogus dyno sheet to get the bike approved for your road use? with PV disconnected?


my 200 did 32 at 9000. I dyno'd my 300 but never recorded it. it revved somewhat lower of course. If I remember I'm going to the dyno tonight I'll try dig it up.

There is much you'd do differently for peak power that we don't entertain as it would spoil it as a dirtbike. Depends how serious & how reliable you want it to be.
Click to expand...

Correct. As stated, I did a mainjet at 195, the bike wouldnt og on pipe, allowing it to max-rev at around 4-5000rpm, PV not opening. Just to get it approved.

Just took a quick look at it yesterday, at this forum I think.
With porting and lowering/raising barrel 1mm, squish at <1,3 was maxing out over 50bhp, With peak Power around 7,5k if I remember correct.

Its just hard and high reving. High peak-power/mid at 5-8,5k rpms wouldnt be a problem. Could still maintain trafic at low RPMs. Nearly 10years ago, i daily drove a two stroke who had a powerband from 9-14k, so this is sweet as pie :)


But, not so much intresting pulling at 17kw, but wondering about gearbox-ratios at the 2007 EC300, 5 gears I think. Running 13/40, With 17s SM and Michelin Pilot Power.
Guessing it would be hard to determine rpm without getting the tire height. Dooh.

Jakobi: Did follow Your build thread at Dirtbiker; did you ever retard the ignition at the 2k3 ignition? Looking at Power higher up.
 
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