Bomber640
26-09-2006, 01:09 PM
Hi,
I'm new to this site, and to internet forums altogether. By way of introduction I thought I'd post a list of what I've done to my '99 LC4 to get it to run like it should have from the factory (strictly for off road use of course...). Nothing fancy, just standard setup tips that cost next to nothing. Most of you have probably done similar things, but it might be of use to someone. My bike is an LC4E, I bought it a couple of months ago bog standard, 14000k's with a new piston and rings at 10000k's.
Breathing;
Got a hole-saw and removed the bung from the end of the standard exhaust (with a fair bit of strong-arming and foul language). Much nicer exhaust note.
The standard airbox has a snorkel that had been removed when I got my bike. I made the hole a little larger (which probably wasn't that clever; given the vagueries of constant pressure carb/tuned airbox relationships). I use standard twin air filters, but given that its mainly used on the road I oil them very lightly. I mix a bit of engine oil with turps, work it through the filter and then let the turps evaporate.
Carb;
There's an emission control device on the right hand side of the carb that opens a port at the top of the diaphragm when 2nd or 3rd gears are engaged. This allows the pressure to equillibrate with the atmosphere and retards opening of the slide. Removing this device and blanking off the port (with a 3/8th's vacuum cap, if my memory serves me correctly) improves throttle response in 2nd and 3rd.
I'm in Melbourne, close to sea level. The standard main jet is a 142.5. I tried a 150, and currently have a 155 which seems fine (from plug chops). The BST40 is also used on DR650's, so I got the jets from Mick Hone Suzuki, $9 a pop, genuine Mikuni. The carb doesn't have to be removed to change the main jet; just loosen the clamps and rotate it a bit to the side. Removing the carb is a real nightmare.
I also raised the needle 1 position; this got rid of the lean condition at approx. 1/4 throttle.
In addition, I enrichened the idle circuit 3/4 of a turn. The main effect of this was to reduce the amount of popping and farting on the overrun. To assist with this I've also set the idle speed a little higher than standard.
I haven't touched the pilot circuit, (mainly because I can't be arsed), but it could probably be a little richer.
I also put an NGK iridium plug in. Probably makes no difference, but on other dirt bikes I've had it seemed to make hot-starts a bit easier.
Suspension;
I weigh about 95 kg's.
Front; Changed the fork oil, standard weight and volume. Bleed the air out of the forks every time you ride (or at least frequently). I've got the rebound damping standard and 2 clicks more compression damping than standard. Just as a general note, the bolts on the fork clamps and the axle pinch bolts are easy to overtighten. It's a good idea to check them with a torque wrench.
Rear; The most important thing is to get the spring preload right. 15-20 mm static sag and 80-90 mm with rider and gear. I've got 1 click more rebound damping than standard and (off the top of my head) 2 clicks more compression.
Misc.
I removed everything I could find that might rattle (chainguards, horn, pathetic toolbox etc.) and put it in a box in the corner of the shed. On such a high vibration bike its a good idea to keep an eye on the torque of the engine mounting bolts and anything thats holding stuff on that you want to stay on. Judicious use of Loctite 243 is also warranted. I also fitted sintered, higher friction-rated front brake pads. Better stopping power, but they're fairly hard on the disk and they squeal at low speed.
2003 onwards bikes have the 'hi-flow' head, and bigger jets to suit. All of the above tips are applicable to these bikes, but the jet sizes will be larger (I think 162.5 standard main? maybe try a 170 to start with?)
These few simple adjustments have transformed the bike. I hope someone can get some use out of these tips.
Cheers
I'm new to this site, and to internet forums altogether. By way of introduction I thought I'd post a list of what I've done to my '99 LC4 to get it to run like it should have from the factory (strictly for off road use of course...). Nothing fancy, just standard setup tips that cost next to nothing. Most of you have probably done similar things, but it might be of use to someone. My bike is an LC4E, I bought it a couple of months ago bog standard, 14000k's with a new piston and rings at 10000k's.
Breathing;
Got a hole-saw and removed the bung from the end of the standard exhaust (with a fair bit of strong-arming and foul language). Much nicer exhaust note.
The standard airbox has a snorkel that had been removed when I got my bike. I made the hole a little larger (which probably wasn't that clever; given the vagueries of constant pressure carb/tuned airbox relationships). I use standard twin air filters, but given that its mainly used on the road I oil them very lightly. I mix a bit of engine oil with turps, work it through the filter and then let the turps evaporate.
Carb;
There's an emission control device on the right hand side of the carb that opens a port at the top of the diaphragm when 2nd or 3rd gears are engaged. This allows the pressure to equillibrate with the atmosphere and retards opening of the slide. Removing this device and blanking off the port (with a 3/8th's vacuum cap, if my memory serves me correctly) improves throttle response in 2nd and 3rd.
I'm in Melbourne, close to sea level. The standard main jet is a 142.5. I tried a 150, and currently have a 155 which seems fine (from plug chops). The BST40 is also used on DR650's, so I got the jets from Mick Hone Suzuki, $9 a pop, genuine Mikuni. The carb doesn't have to be removed to change the main jet; just loosen the clamps and rotate it a bit to the side. Removing the carb is a real nightmare.
I also raised the needle 1 position; this got rid of the lean condition at approx. 1/4 throttle.
In addition, I enrichened the idle circuit 3/4 of a turn. The main effect of this was to reduce the amount of popping and farting on the overrun. To assist with this I've also set the idle speed a little higher than standard.
I haven't touched the pilot circuit, (mainly because I can't be arsed), but it could probably be a little richer.
I also put an NGK iridium plug in. Probably makes no difference, but on other dirt bikes I've had it seemed to make hot-starts a bit easier.
Suspension;
I weigh about 95 kg's.
Front; Changed the fork oil, standard weight and volume. Bleed the air out of the forks every time you ride (or at least frequently). I've got the rebound damping standard and 2 clicks more compression damping than standard. Just as a general note, the bolts on the fork clamps and the axle pinch bolts are easy to overtighten. It's a good idea to check them with a torque wrench.
Rear; The most important thing is to get the spring preload right. 15-20 mm static sag and 80-90 mm with rider and gear. I've got 1 click more rebound damping than standard and (off the top of my head) 2 clicks more compression.
Misc.
I removed everything I could find that might rattle (chainguards, horn, pathetic toolbox etc.) and put it in a box in the corner of the shed. On such a high vibration bike its a good idea to keep an eye on the torque of the engine mounting bolts and anything thats holding stuff on that you want to stay on. Judicious use of Loctite 243 is also warranted. I also fitted sintered, higher friction-rated front brake pads. Better stopping power, but they're fairly hard on the disk and they squeal at low speed.
2003 onwards bikes have the 'hi-flow' head, and bigger jets to suit. All of the above tips are applicable to these bikes, but the jet sizes will be larger (I think 162.5 standard main? maybe try a 170 to start with?)
These few simple adjustments have transformed the bike. I hope someone can get some use out of these tips.
Cheers