Jump to content

Bought a 99 yz400f, have a few questions

Recommended Posts

So, a little background about my self. Im almost 29 years old now but from when i was 4 until 14 i raced motocross. Then i jumped on streetbikes so ive been out of the dirt world for some time so forgive my stupidity. Recently, i got a stupid good deal on a 99 yz400f. I just wanted something to toy with and have fun on may it be hitting trails or the occassional mx track again. So, ive heard moxed reviews about the 400f but as a general consensus people seem pretty happy with them. Anyways, so i have a few questions.

1. I want to change the sprockets and chain. I want to buy something that will last and apparentlt ironmans are the way to go. However, everything ive seen says ironmans work on yz450f's but i dont see anything about the 400f. Would the 450f sprocket work on my 99 400?

 

2. Best oil to use on this bike and how often would you change it?

 

3. The starting up of these bikes are quite ridiculous, any strategies on making this easier?

 

4. Any mods you all think are must haves or must do's?

Thanks everyone and remember im new to this site so be gentle lol.

Share this post


Link to post
Share on other sites

Hey man I an brand new to the dirt scene. I bought one (a yz400f) last fall for supermoto. I have learned a few things. You can install hot cams for auto decompression. I don't have that but i have the hang of it now it's not so bad. They say change oil every 5 hours. I have 3 suzuki street bikes so I buy suzuki oil by the case so I use it. I love this thing. I put a wr stator and flywheel on mine and a baja light kit with a rectifier so I run lights. I bought a sunstar sprocket off this site's store and a rk oring chain for mine a 42 rear and 15 front for my 17 inch wheel setup (supermoto road course setup.) She'll do 100! I hope this is helpful

  • Like 1

Share this post


Link to post
Share on other sites
Hey man I an brand new to the dirt scene. I bought one (a yz400f) last fall for supermoto. I have learned a few things. You can install hot cams for auto decompression. I don't have that but i have the hang of it now it's not so bad. They say change oil every 5 hours. I have 3 suzuki street bikes so I buy suzuki oil by the case so I use it. I love this thing. I put a wr stator and flywheel on mine and a baja light kit with a rectifier so I run lights. I bought a sunstar sprocket off this site's store and a rk oring chain for mine a 42 rear and 15 front for my 17 inch wheel setup (supermoto road course setup.) She'll do 100! I hope this is helpful


Thanks a lot! Truly appreciated. Ill look into what youve said and see what i can find out as well. I, too, have a 07 suzuki gsxr 1k. I use mobil 1 for that though. Anyways, i appreciate the insight.
  • Like 1

Share this post


Link to post
Share on other sites

My track bike is a 05 gsxr750! I put my takeoffs on my sv1000. I would suggest checking your cake clearances so you can see where its at. I did mine shortly after getting it and they were way out of spec. That is one of the best ways to maintain the engine longevity other than changing the oil often. The checking the oil procedure is also interesting on this model.

Share this post


Link to post
Share on other sites

1)Sprockets and chains are the same for '99-'09 at least.  Pretty sure it goes to current models, but either way, you're covered.  The key to making the sprockets last is not so much buying steel sprockets as it is in getting a chain the won't "stretch' right away.  A chain that runs beyond 1.5 - 2% longer than new will eat just about any kind of sprocket regardless.

2) High quality oil, preferably a good true synthetic in 10w-40 viscosity, or 20w-50 if the outside temperature will be around 95 or higher most of the time. Change it every third ride day, or every 6-8 hours actual run time.  Oil is worse than politics; everyone has something to say about it.  I prefer Mobil1 Racing 4T or Mobil1 V-Twin (two different weights).  If the bike has a BRASS mesh filter, throw it away immediately and replace it with one listed to service an '03 or later YZ450F instead.  You can purchase a stainless steel mesh filter that can be reused almost indefinitely, but either way, clean or replace the filter with every oil change.  Keep the air filter cleaned and oiled too.  That may be necessary for every ride day.

3) There are two keys to starting the older YZF's: First, the idle mixture and speed has to be correctly set.  Second, it's "the drill".  Watch these two vids:

Cold Start

Hot start

4) Your starting drill can be nearly eliminated by the one mod I would recommend, which is to purchase an aftermarket exhaust cam with an automatic decompression system built in.  If the carb gives you any grief, swapping it out for one from an '05-'09 YZ450 is a great step up.  Otherwise, the bike is frankly too old to do too much mod work with because most of the stuff you would want is no longer available.

 

  • Like 2

Share this post


Link to post
Share on other sites
1)Sprockets and chains are the same for '99-'09 at least.  Pretty sure it goes to current models, but either way, you're covered.  The key to making the sprockets last is not so much buying steel sprockets as it is in getting a chain the won't "stretch' right away.  A chain that runs beyond 1.5 - 2% longer than new will eat just about any kind of sprocket regardless.
2) High quality oil, preferably a good true synthetic in 10w-40 viscosity, or 20w-50 if the outside temperature will be around 95 or higher most of the time. Change it every third ride day, or every 6-8 hours actual run time.  Oil is worse than politics; everyone has something to say about it.  I prefer Mobil1 Racing 4T or Mobil1 V-Twin (two different weights).  If the bike has a BRASS mesh filter, throw it away immediately and replace it with one listed to service an '03 or later YZ450F instead.  You can purchase a stainless steel mesh filter that can be reused almost indefinitely, but either way, clean or replace the filter with every oil change.  Keep the air filter cleaned and oiled too.  That may be necessary for every ride day.
3) There are two keys to starting the older YZF's: First, the idle mixture and speed has to be correctly set.  Second, it's "the drill".  Watch these two vids:
Cold Start
Hot start
4) Your starting drill can be nearly eliminated by the one mod I would recommend, which is to purchase an aftermarket exhaust cam with an automatic decompression system built in.  If the carb gives you any grief, swapping it out for one from an '05-'09 YZ450 is a great step up.  Otherwise, the bike is frankly too old to do too much mod work with because most of the stuff you would want is no longer available.
 

Gray, youre the man. Looking into Hot Cams and a 450f carb asap.

As for sprocket and chain, whats a good combo? As in decent brand name of each? Back in the day when i used to race, renthal was the brand to have but after reading reviews today, i see lots of mixed feelings. So, based off what you said, i should put my money into the chain. Whats the best chain (bang for your buck) should i get? Lastly, im going to be doing a mix of trail riding and mx (a little bit more trail though). What gear combo would you recommend. I was thinking 14/51 but id love to hear your input.

Seriously, thanks again Gray!
  • Like 1

Share this post


Link to post
Share on other sites

Gray is the man! Such a plethora of knowledge! One thing you might consider is leaving the manual decompression in place and no one's going to take off with your bike! When I got a hold of my 400 , it was in running condition but the carburetor did leak little bit but after a few tweaks and seals and a couple Jets, my carb's pretty happy. If you're going to do trail riding and one a lot you can pick up a stator and flywheel from Ricky Stator and a Baja kit and you have lights. The heavier flywheel will also help you keep from stalling when you are releasing the clutch on the trails I could see it probably being somewhat of an advantage to keep from spinning tire than with the YZ flywheel. As long as you're components are in good working conditions that bike is a beast, the more modern bikes are stronger and lighter but this one will get the job done!

Share this post


Link to post
Share on other sites
19 minutes ago, Sgprelude711 said:

As for sprocket and chain, whats a good combo? As in decent brand name of each?

I use mid-priced, reputable brand front sprockets like Pro-Circuit or similar.  Not too fussy about them. (BTW, if the sprocket has one undercut side, it goes IN, toward the engine).  I like TAG Metals hard anodized rears.  They give much longer service than the untreated aluminum stuff like Renthals.  My favorite chain is a Regina ORN6 O-ring chain.  Run them with a non tacky chain lube applied the night before a ride (Maxima Synthetic Chain Guard is one) and never pressure wash the chain or wire brush the top and bottom sides.  If you absolutely have to power wash it, do it only from the sides, and no closer than a foot away.  You'll blow water and crap under the O-rings and wash out the factory lube.  They're also sold under the MSR label with the same ORN6 model name.

Share this post


Link to post
Share on other sites

Thank you both very much. Like i stated above, ive been out of the dirt game for some time now so you two are doing wonders for me. Much much appreciated.

Share this post


Link to post
Share on other sites

Did you two have any recommendations on tooth count i should do for my type of riding? (Both trails and mx. 65% trails 35% mx) also, a buddy of mine was saying that gytr rear sprockets were decent. But id love to hear you alls input on those compared to TAG

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×