Questions about valve clearances.

[Flyingpony]

Last weekend resulted in the careful removal of the valve cover on my FXR and from that virginity busting experience I've got some questions!

Valve clearance figures for a 2001 Suzuki FXR150 are:
Inlet: 0.10 to 0.20
Outlet: 0.20 to 0.30

From memory inlet measurements were: Left = 0.15, Right = 0.13. Outlets were respectively the same.

This means they're fine and still within the range specified by Suzuki.
Other info: cam chain runs on the left hand side and left is viewed as if you're sitting on the bike.

Here are my questions:

Given both valves were equal in the factory, why is one clearance gap bigger than the other?
They've both operated under the same conditions and mileage so should be equal.

In reference to the 0.02 difference, why are both the left inlet and left outlet valve clearances larger than their respective right counter-part by the same amount?
Is it because they're both closest to the cam chain end of the cam shaft?

In which direction of the range i.e. 0.10-0.20, will the valve clearance gap travel as more mileage is put on?
I'm guessing towards the greater figure. Can it go in either direction?

Thanks.

[Ixion]

Your outlet clearances are too tight.

Clearances for outlets are greater because the outlet(exhaust) valve gets hotter , so it expands more and takes up more clearance.

I'm guessing here, but the reason the lefts are more worn is probably indirectly related to being on the side with the chain tunnel. The chain tunnel means the cooling on that side is not as good as the unobstructed side. So it runs hotter, which means the valve pockets into the head a bit more. Or it's just a coincidence.

On your bike the valve clearances will probably close up (only an owner can tell you for certain). Most DOHC engines the cleances reduce . But older pushrod bikes they often increased.

[imdying]

They weren't necessarily the same when they left the factory.

[Ixion]

True. That's why the standard has a range. And shims only come in certain sizes

[Bonez]

Last weekend resulted in the careful removal of the valve cover on my FXR and from that virginity busting experience I've got some questions!

Valve clearance figures for a 2001 Suzuki FXR150 are:
Inlet: 0.10 to 0.20
Outlet: 0.20 to 0.30

From memory inlet measurements were: Left = 0.15, Right = 0.13. Outlets were respectively the same.

.
If the exhaust/outlet where the same as the inlet wouldn't they be out of tolerance? IE- too little cleanance.

[Motu]

The imbalance per side is because you are doing more left hand corners than right hand,to balance this out you will have to do 30,00km doing more right hand corners - when you check your clearances again you should find them even.It would pay to keep a log book of corners turned so you can be aware if you are getting an imbalance again.It's these little things that make the difference you know....

[Ixion]

Could he not just ride round and round a car park in half circles until the balance out ?

[Bonez]

Could he not just ride round and round a car park in half circles until the balance out ?Gyros are getting dizzy with all this roundandabout stuff. Flatspining like crazy :spudflip:

[Flyingpony]

Your outlet clearances are too tight.

Clearances for outlets are greater because the outlet(exhaust) valve gets hotter , so it expands more and takes up more clearance.

The outlet clearances fell within the range 0.20-0.30. Think their measurements were 0.23 and 0.25 hence, respectively they're the same as inlet. Maybe I wasn't quite clear enough.


On your bike the valve clearances will probably close up (only an owner can tell you for certain). Most DOHC engines the cleances reduce . But older pushrod bikes they often increased.
Rang Suzuki and yes they do tighten up, as in, clearance gets smaller for engines with DOHC & Shim valves :eek5:
In 6000km (18-24months away) I'll be clearfully checking the clearances again. If they appear to need adjustment, I'll delegate this task out to the bike shop. Looks like a complex task replacing shims and something with heaps of potential error.



The imbalance per side is because you are doing more left hand corners than right hand ...
ha ha ha ha *has a quick look around encase people are watching me laugh*

[Bonez]

In 6000km (18-24months away) I'll be clearfully checking the clearances again. If they appear to need adjustment, I'll delegate this task out to the bike shop. Looks like a complex task replacing shims and something with heaps of potential error.
Try 16 of the buggers. Last check I did on the Cb750f only two needed changing. Now this was 30 odd thousand kms since I last checked them.

[Pixie]

The imbalance per side is because you are doing more left hand corners than right hand,to balance this out you will have to do 30,00km doing more right hand corners - when you check your clearances again you should find them even.It would pay to keep a log book of corners turned so you can be aware if you are getting an imbalance again.It's these little things that make the difference you know....
Booollshit!
It's because the bike was on the side stand.