Standard transfer Port height and squish clearance '2005 200
Posted: 01:59 am Aug 24 2021
Hi Guys
Think I previously posted on the wrong thread.
I am busy helping a Bud do a rebuild on a 2005 200 and on the point of finishing off the cylinder and piston installation when I saw some (possibly) strange things which I need to confirm :
1. With the piston at BDC , the top edge of the piston is STILL approx 1,4mm above the bottom edge of the transfers and in fact also just above the lowest portion of the exhaust port. Is this standard ? Most previous MX bikes I worked on the top edge of the piston was 100% in line with the bottom of the transfers at BDC ?
The cylinder measures 105mm from base gasket surface to headgasket surface which as I can ascertain is correct and I checked that the port heights do match a previous posting measurement given on the group.
Piston is a new ProX "C" standard diameter - I do see that the cylinder bore was re-plated locally at some time by a reputable company in SA - although they confirmed that they would not have done any mods to the cylinder.
2. Using solder I measure a squish clearance of 1,8mm. Again, is this the standard gap ? This seems huge but obviously relates back to CR . The head gasket surface has a step of about 0.35mm to the squish band .
The head surface is still cast finish so no work has been done on the combustion chamber but I am trying to figure out if the head might have been machined - is the 0.35mm step standard ? Does someone have a volume measurement on the standard head please ?
I see the crank has a Hot Rods Con rod in and the Prox piston is identical to the one that came out - although I'm not sure what piston the old one was.
Bike ran ok previously- not overly strong and smoked a bit so we suspected crank seals - because every now and then it would belch smoke when under load and climbing. Cannot find anything wrong on the KIPS - the only sign of wear was on the governor engaging arm.
Other than that the motor is in really good condition internally - has not worked hard . It has an FMF pipe and muffler on and Boyeson reeds
Basically I just want to confirm that all of the above are standard and normal measurements before I put her together- any info would be much appreciated !
Think I previously posted on the wrong thread.
I am busy helping a Bud do a rebuild on a 2005 200 and on the point of finishing off the cylinder and piston installation when I saw some (possibly) strange things which I need to confirm :
1. With the piston at BDC , the top edge of the piston is STILL approx 1,4mm above the bottom edge of the transfers and in fact also just above the lowest portion of the exhaust port. Is this standard ? Most previous MX bikes I worked on the top edge of the piston was 100% in line with the bottom of the transfers at BDC ?
The cylinder measures 105mm from base gasket surface to headgasket surface which as I can ascertain is correct and I checked that the port heights do match a previous posting measurement given on the group.
Piston is a new ProX "C" standard diameter - I do see that the cylinder bore was re-plated locally at some time by a reputable company in SA - although they confirmed that they would not have done any mods to the cylinder.
2. Using solder I measure a squish clearance of 1,8mm. Again, is this the standard gap ? This seems huge but obviously relates back to CR . The head gasket surface has a step of about 0.35mm to the squish band .
The head surface is still cast finish so no work has been done on the combustion chamber but I am trying to figure out if the head might have been machined - is the 0.35mm step standard ? Does someone have a volume measurement on the standard head please ?
I see the crank has a Hot Rods Con rod in and the Prox piston is identical to the one that came out - although I'm not sure what piston the old one was.
Bike ran ok previously- not overly strong and smoked a bit so we suspected crank seals - because every now and then it would belch smoke when under load and climbing. Cannot find anything wrong on the KIPS - the only sign of wear was on the governor engaging arm.
Other than that the motor is in really good condition internally - has not worked hard . It has an FMF pipe and muffler on and Boyeson reeds
Basically I just want to confirm that all of the above are standard and normal measurements before I put her together- any info would be much appreciated !