Valve clearance checks

Moderator: Moderators

H2rider
Posts: 16
Joined: Mon Sep 24, 2018 11:01 am
My Bike: Zxr400h2

Valve clearance checks

Post by H2rider » Mon Oct 08, 2018 7:02 pm

I'm doing a valve clearance on my h model . I just tried it and wrote down the gap sizes , I don't think iv done it correctly . I followed the manual but how can I tell when it's the #1 on tdc and when it's the #4 on tdc. One of my gaps I got was less than 0.05 which is completely off . Also do you have to change the shims if the gap is off? Is there any way of adjusting the lobs instead ? And what is the best gap size to have for a bike running stock . Inlets are 0.12 - 0.17 would it be best at 0.15 ?

User avatar
Miles
zxr400 oc member
zxr400 oc member
Posts: 455
Joined: Wed Apr 30, 2008 11:00 pm
My Bike: ZXR 400 L3
Location: Bangor, Northern Ireland

Re: Valve clearance checks

Post by Miles » Mon Oct 08, 2018 9:09 pm

#1 tdc will be when the lobes are pointing away from each other

User avatar
banner001
Track day God
Track day God
Posts: 2269
Joined: Sat Sep 24, 2011 3:27 pm
My Bike: ZXR400 L4
Location: Nuneaton

Re: Valve clearance checks

Post by banner001 » Mon Oct 08, 2018 11:25 pm

#1 and #4 will always be atdc simultaneously...whats needed is to make sure that #1 is atdc at the end of the compression stroke (i.e. the lobes are pointing away from each other), you then spin the engine 360 degrees so that now #4 is atdc at the end of the compression stroke.
UK ZXR 400 L4
UK ZXR 400 L3 track bike
1989 FZR 1000 EXUP-R streetfighter

User avatar
banner001
Track day God
Track day God
Posts: 2269
Joined: Sat Sep 24, 2011 3:27 pm
My Bike: ZXR400 L4
Location: Nuneaton

Re: Valve clearance checks

Post by banner001 » Mon Oct 08, 2018 11:27 pm

as for the gaps, the only way to change them is to change shims.

if your gap is too small then you need to fit smaller shims, and vice versa.

as for the gaps, its more important to make them consistent, a bike thats got all the inlets bang on 0.13mm will run better than one where half are 0.12 and the other half are 0.17.

remember that tighter is not always better, if you intend to rag your bike and always have it running hot then a bigger gap will be better for you.
UK ZXR 400 L4
UK ZXR 400 L3 track bike
1989 FZR 1000 EXUP-R streetfighter

H2rider
Posts: 16
Joined: Mon Sep 24, 2018 11:01 am
My Bike: Zxr400h2

Re: Valve clearance checks

Post by H2rider » Tue Oct 09, 2018 11:44 am

Thanks for that Im not planning on racing the bike, I'm getting it ready for road use . I'm in London so mostly slow moving , but of course I'd want to blow down the m roads . What size would you think is the best , at the moment I don't think any clearances are consistent.
There's two T marks on the cam , both opposite each other , is one for #1 and the other for #2 at tdc end of compression stroke ?

User avatar
banner001
Track day God
Track day God
Posts: 2269
Joined: Sat Sep 24, 2011 3:27 pm
My Bike: ZXR400 L4
Location: Nuneaton

Re: Valve clearance checks

Post by banner001 » Tue Oct 09, 2018 2:35 pm

I can tell you, but I suggest you give the manual a damn good read before starting this, messing it up is a good way to detonate your engine.
UK ZXR 400 L4
UK ZXR 400 L3 track bike
1989 FZR 1000 EXUP-R streetfighter

User avatar
banner001
Track day God
Track day God
Posts: 2269
Joined: Sat Sep 24, 2011 3:27 pm
My Bike: ZXR400 L4
Location: Nuneaton

Re: Valve clearance checks

Post by banner001 » Tue Oct 09, 2018 2:37 pm

I only mention this as the T marks are on the timing plate that's attached to the crank, not the cams, I want to be sure that you know what you are doing and that you know all of the terminology.
UK ZXR 400 L4
UK ZXR 400 L3 track bike
1989 FZR 1000 EXUP-R streetfighter

H2rider
Posts: 16
Joined: Mon Sep 24, 2018 11:01 am
My Bike: Zxr400h2

Re: Valve clearance checks

Post by H2rider » Tue Oct 09, 2018 3:28 pm

Hi sorry my mistake , is the manual wich is available on this forum , the full manual ? Iv read through that and understand which valves to check when each cylinder is at tdc . I was wondering if there was another manual which goes into more detail on how to do valve clearances . The one online is not very detailed ( for the h model )

User avatar
banner001
Track day God
Track day God
Posts: 2269
Joined: Sat Sep 24, 2011 3:27 pm
My Bike: ZXR400 L4
Location: Nuneaton

Re: Valve clearance checks

Post by banner001 » Tue Oct 09, 2018 11:52 pm

UK ZXR 400 L4
UK ZXR 400 L3 track bike
1989 FZR 1000 EXUP-R streetfighter

H2rider
Posts: 16
Joined: Mon Sep 24, 2018 11:01 am
My Bike: Zxr400h2

Re: Valve clearance checks

Post by H2rider » Wed Oct 10, 2018 4:00 pm

Banner001 very very helpful . Especially the cam chain guide . I'll be checking if my sprockets are aligned using a mirror . One more thing viewtopic.php?f=117&t=13871 in this topic there's 2 pictures showing the cam chain tensioner . Mine is fully extended as shown in the first of the 2 pictures , is this an issue

User avatar
banner001
Track day God
Track day God
Posts: 2269
Joined: Sat Sep 24, 2011 3:27 pm
My Bike: ZXR400 L4
Location: Nuneaton

Re: Valve clearance checks

Post by banner001 » Wed Oct 10, 2018 4:57 pm

if its extended to the point that its touching, or almost touching the metal engine casing then your cam chain is most likely knackered and needs replacing as this will affect the cam timing to a small degree

it could also be severely damaged/work chain guides as well, you will need to investigate more
UK ZXR 400 L4
UK ZXR 400 L3 track bike
1989 FZR 1000 EXUP-R streetfighter

H2rider
Posts: 16
Joined: Mon Sep 24, 2018 11:01 am
My Bike: Zxr400h2

Re: Valve clearance checks

Post by H2rider » Thu Oct 11, 2018 4:55 pm

Banner001 , opened up the crank casing and did a quick check . There a plastic peice above the cam chain guide which was very loose . I removed the tensioner and done a check up and it seems ok . It's very tight and hard to press down ( even when pressing the taper part ). I put it back in according to the manual . The small plastic peice was much tighter when I put the tensioner back in but still moves a bit . ALeo is the cam chain supposed to be very tight on is there ment to be a very small amount of slack ?
I removed the top to check if the exhaust / inlet sprockets where aligned , they seem to be . I took a picture of the lobes of the first cylinder and that's how they look at tdc
You do not have the required permissions to view the files attached to this post.

User avatar
banner001
Track day God
Track day God
Posts: 2269
Joined: Sat Sep 24, 2011 3:27 pm
My Bike: ZXR400 L4
Location: Nuneaton

Re: Valve clearance checks

Post by banner001 » Thu Oct 11, 2018 8:30 pm

How exactly did you replace the tensioner, you didn't just take it off and then put it back on did you?

Did you fully reset it or did you put it back in fully extended?
UK ZXR 400 L4
UK ZXR 400 L3 track bike
1989 FZR 1000 EXUP-R streetfighter

H2rider
Posts: 16
Joined: Mon Sep 24, 2018 11:01 am
My Bike: Zxr400h2

Re: Valve clearance checks

Post by H2rider » Thu Oct 11, 2018 8:48 pm

I removed the bolt . Pushed the push rod down and put a pin in the spring to hold it down . I moved the rod holding the cam chain guide so the chair went loose . Then I put the tensioner back in and removed the pin . The manual states to remove the rod holding the cam guide but I only moved it down .

User avatar
banner001
Track day God
Track day God
Posts: 2269
Joined: Sat Sep 24, 2011 3:27 pm
My Bike: ZXR400 L4
Location: Nuneaton

Re: Valve clearance checks

Post by banner001 » Fri Oct 12, 2018 8:30 am

That's correct, I thought for a moment you had put the tensioner back in whilst fully extended.

Can you take a picture of the inside of your pulsar cover so I can see if you need a new cam chain, you need to take a picture of the rod that is pushed up by the tensioner
UK ZXR 400 L4
UK ZXR 400 L3 track bike
1989 FZR 1000 EXUP-R streetfighter

Post Reply