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Fork oil and jet size?
Posted: 01:26 am Apr 18 2019
by Hendrikder
Good Day Everyone
Can anyone please help me I have 2 questions
1 - How do I determine what size main jet I currently have in, because I want to put in a smaller jet , but I dont know what size is in it at this stage.
2 - The specs on changing the front fork oil? What oil should I use, the amount, pressure ...ex.
If anyone could please assist me.
Thank You
Re: Fork oil and jet size?
Posted: 08:24 am Apr 18 2019
by K50X200
Hendrikder wrote: 01:26 am Apr 18 2019
1 - How do I determine what size main jet I currently have in, because I want to put in a smaller jet , but I dont know what size is in it at this stage.
You'll have to pull the current jet out of the carb - the jet size should be stamped on the jet itself...
Re: Fork oil and jet size?
Posted: 09:39 am Apr 18 2019
by KDXGarage
K50X200 wrote: 08:24 am Apr 18 2019
Hendrikder wrote: 01:26 am Apr 18 2019
1 - How do I determine what size main jet I currently have in, because I want to put in a smaller jet , but I dont know what size is in it at this stage.
You'll have to pull the current jet out of the carb - the jet size should be stamped on the jet itself...
Exactly.
Take it out and read it.
Which bike is this?? The one in your signature, 2005?
Do you have the stock forks on it? What is your weight in full riding gear? Usually it is 5 weight fork oil for the cartridge forks.
Do you have the stock fork springs? What terrain do you ride? What is your skill level?
Re: Fork oil and jet size?
Posted: 04:38 am Apr 19 2019
by Hendrikder
KDXGarage wrote: 09:39 am Apr 18 2019
K50X200 wrote: 08:24 am Apr 18 2019
Hendrikder wrote: 01:26 am Apr 18 2019
1 - How do I determine what size main jet I currently have in, because I want to put in a smaller jet , but I dont know what size is in it at this stage.
You'll have to pull the current jet out of the carb - the jet size should be stamped on the jet itself...
Exactly.
Take it out and read it.
Which bike is this?? The one in your signature, 2005?
Do you have the stock forks on it? What is your weight in full riding gear? Usually it is 5 weight fork oil for the cartridge forks.
Do you have the stock fork springs? What terrain do you ride? What is your skill level?
I will pull the jet and have a look, with gear I am 240lbs, the forks are bone stock and everything in it is stock as well. I normally ride rocky and woods areas, I would say I am an average rider.
Thank you
Re: Fork oil and jet size?
Posted: 10:35 am Apr 19 2019
by KDXGarage
Unfortunately, pulling it apart is the best way. If you have a JIS compliant screwdriver, use it on the JIS screws on the float bowl. If you have an old, cheap Phillips #1 and a bench grinder, some have reported that hitting the tip just a bit will help it to settle down into the screw head better.
I am 233 all geared up. Stock fork springs and shock spring won't do for either of us. I would say somewhere around .46 fork springs and 5.4 rear shock spring. Look at what rate fork springs come on a YZ250X or YZ250FX (.44 I think). We are a good 50 pounds more than the average rider.
Re: Fork oil and jet size?
Posted: 08:35 pm Apr 19 2019
by bufftester
for the stock fork, 5W fork oil, 530 ml approx volume. With spring out and fork fully compressed the oil level should be between 85-89 mm from the top. If you're changing the oil may as well change the seals and dust sliders too. That will refresh your front end, but won't solve the problem of being woefully undersprung for your weight. Get the right springs, IMO best performance enhancing money you can spend.
Re: Fork oil and jet size?
Posted: 12:05 am Apr 20 2019
by KDXGarage
Don't forget the cartridge rod bushings, inner tube bushings and outer tube bushings.
Re: Fork oil and jet size?
Posted: 12:28 pm Apr 23 2019
by Hendrikder
KDXGarage wrote: 10:35 am Apr 19 2019
Unfortunately, pulling it apart is the best way. If you have a JIS compliant screwdriver, use it on the JIS screws on the float bowl. If you have an old, cheap Phillips #1 and a bench grinder, some have reported that hitting the tip just a bit will help it to settle down into the screw head better.
I am 233 all geared up. Stock fork springs and shock spring won't do for either of us. I would say somewhere around .46 fork springs and 5.4 rear shock spring. Look at what rate fork springs come on a YZ250X or YZ250FX (.44 I think). We are a good 50 pounds more than the average rider.
Thank you very luch for the advice will definitely be looking into get beter springs or maybe to change the front end completely.
I toom the main jet out it is a 152, what jet size would you suggest? I am riding at 5500ft, temp getting cooler now ranging between 5 - 15 Celsius.
Thank You very much for the kind help!!
Re: Fork oil and jet size?
Posted: 05:55 pm Apr 23 2019
by KDXGarage
Stock in the USA is 160.
Is there anything else going on with the bike that might cause you to run one that size?
Re: Fork oil and jet size?
Posted: 10:11 pm Apr 23 2019
by Hendrikder
KDXGarage wrote: 05:55 pm Apr 23 2019
Stock in the USA is 160.
Is there anything else going on with the bike that might cause you to run one that size?
Mods on the bike are as follows
Boysen reed valves
Fmf Gnarly Pipe
Fmf Silencer
Air Box Lid removed
That is the only stuff I can think about that might change the jet, but in my personal opinion I am running a bit rich still. Has quite a lot of spooge and it does feel like I might use a bit to much fuel.
Thank You
Re: Fork oil and jet size?
Posted: 11:18 pm Apr 23 2019
by KDXGarage
Did you dip the carb in strong cleaner?
Have you checked the fuel / float level?
How clean is the float valve? Is it worn? properly seating?
Re: Fork oil and jet size?
Posted: 11:27 pm Apr 23 2019
by Hendrikder
KDXGarage wrote: 11:18 pm Apr 23 2019
Did you dip the carb in strong cleaner?
Have you checked the fuel / float level?
How clean is the float valve? Is it worn? properly seating?
I did clean the carb yes and the float valve is in mint Condition. I have the float height set at 16mm, would you advice changing?
Re: Fork oil and jet size?
Posted: 11:44 pm Apr 23 2019
by KDXGarage
How did you clean the carb?
Re: Fork oil and jet size?
Posted: 12:13 am Apr 24 2019
by Hendrikder
KDXGarage wrote: 11:44 pm Apr 23 2019
How did you clean the carb?
I cleaned it with some good and proper carb cleaner, I've seen that some suggest to set the float height to 19mm?
Re: Fork oil and jet size?
Posted: 08:53 am Apr 24 2019
by KDXGarage
OK, on occasion, some have cleaned the carb with an aggressive dip which damages the jet block gasket.
Adjusting the float level is worth a try.
Re: Fork oil and jet size?
Posted: 12:49 pm Apr 24 2019
by Hendrikder
KDXGarage wrote: 08:53 am Apr 24 2019
OK, on occasion, some have cleaned the carb with an aggressive dip which damages the jet block gasket.
Adjusting the float level is worth a try.
I adjusted the carb and will be checking it out on my ride tomorrow.
So in your opinion you think I shouldn't go smaller on the jet?
Thank you
Re: Fork oil and jet size?
Posted: 02:10 pm Apr 24 2019
by KDXGarage
Which pilot jet do you have?
Which needle?
Which position is the needle clip?
Re: Fork oil and jet size?
Posted: 05:01 am Apr 25 2019
by Hendrikder
KDXGarage wrote: 02:10 pm Apr 24 2019
Which pilot jet do you have?
Which needle?
Which position is the needle clip?
The needle is a R1174N and it is in the first clip from the top.
I haven't had time to remove the pilot jet but I will let you know the size when I have a bit of spare time.
Regards
Re: Fork oil and jet size?
Posted: 12:42 pm May 06 2019
by Hendrikder
Okay guys this is what I got :
Main jet 152
Pilot Jet 42
Needle R1172N on first clip from the top.
I did a ride this weekend, trails with a bit of technical I only got 90km out of the tank with about 1L of reserve left when I got home.
I also pulled the spark plug todat, 13.4 hours after the last timed I cleaned it, it was very black and dirty.
I am runny Castrol racing 2T 40:1, 93 grade petrol.
Any advice please
Kind Regards Hendrik
Re: Fork oil and jet size?
Posted: 10:30 pm May 06 2019
by Hendrikder
KDXGarage wrote: 02:10 pm Apr 24 2019
Which pilot jet do you have?
Which needle?
Which position is the needle clip?
Just want to tag you to my previous post.