gombur
Velociraptor
Posts: 29 
Bikes: -98 Bandit 1216, -83 Moto Guzzi V35 MKII
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Post by gombur on Jan 6, 2014 11:19:14 GMT
I can't calculate the actual compression ratio and that's what worried me yes but given that it generates 200psi it should be fine? Pistons are actually high comp busa pistons. Got them cheap'ish' What's the problem with calculating compression ratio? 200psi (~13.5bar?) sounds pretty much all right. All right, if the pistons are made for Busa then compression probably isn't that high. As far as I know Busa pistons have lower compression height so they result lower compression ratio if installed in oil cooled engines. But then combustion chamber shape may get less optimal. What was the deck height with these pistons? I don't have a dial gauge so I can't measure the exact piston deck height but it seems to be around 0.7mm E: Stripped the frame off of previous owners stone guard films. Uh ohh.. How did I miss that?   |
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Post by arttu on Jan 6, 2014 17:38:53 GMT
I don't have a dial gauge so I can't measure the exact piston deck height but it seems to be around 0.7mm So if the head gasket is about 1mm then squish band clearance would be 1.7mm. A bit on large side but not completely wrong. |
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Deleted
Posts: 0
Reg: Apr 27, 2024 15:06:03 GMT
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Post by Deleted on Jan 6, 2014 18:18:30 GMT
i think you have a problem with tin worm ? smiley-shocked003 smileyshit
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gombur
Velociraptor
Posts: 29
Bikes: -98 Bandit 1216, -83 Moto Guzzi V35 MKII
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Post by gombur on Jan 6, 2014 19:11:27 GMT
I don't have a dial gauge so I can't measure the exact piston deck height but it seems to be around 0.7mm So if the head gasket is about 1mm then squish band clearance would be 1.7mm. A bit on large side but not completely wrong. Right. I ordered tools to measure and calculate the CR and probably have to think about changing into busa rods with correct spacer |
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Post by arttu on Jan 7, 2014 8:07:03 GMT
Right. I ordered tools to measure and calculate the CR and probably have to think about changing into busa rods with correct spacer Yes, definitely better to do it right at first time  I.e. check CR and squish clearance and adjust them if needed. Like you probably know you can also skim the block to adjust deck height. And machining the pistons is also feasible option to adjust the CR. I think 1.0-1.5mm would be good range for squish. Not sure about optimal compression ratio for oil cooled engines with pump gas, maybe around 12:1? |
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gombur
Velociraptor
Posts: 29
Bikes: -98 Bandit 1216, -83 Moto Guzzi V35 MKII
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Post by gombur on Feb 14, 2014 19:01:25 GMT
Well it's been slow build. It took more than a month to powdercoat the frame! My local paintshop uses a third party company to sandblast items and that company lost a few bits of mine.  Got the frame back today and they found the missing bits but now the owner is on vacation in Thailand for two weeks.. But the paintshop powdercoated the frame in one evening and did a top job. Starts to look like a bike again Don't mind that dirty swingarm, just wanted to put it on and see how bike looks like after a long time  Removed rear shock linkage from old shock to put into new one. No wonder I had some rear end wobbling.  No news from engine side. Got some busa connections rods and waiting few parts from dragrace.fi  I know that's not the right way to increase CR but wanted them for their durability. Calculated CR would be 12.5:1 |
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I.e. check CR and squish clearance and adjust them if needed. Like you probably know you can also skim the block to adjust deck height. And machining the pistons is also feasible option to adjust the CR. I think 1.0-1.5mm would be good range for squish. Not sure about optimal compression ratio for oil cooled engines with pump gas, maybe around 12:1?
Got the frame back today and they found the missing bits but now the owner is on vacation in Thailand for two weeks..