Arrrrgggggg mystery rattle in top end...........

[badgerkdd]

My GSXR750 WR has developed this rattly noise at the top end. It's one of those annoying ones that comes and goes, but mostly as the bike gets warmer it sounds clearer. It seems to sound like its on cylinder 1 or 2. I did a compression test, cylinder 1 @‌ 140 psi, 2 @‌ 130 psi, 3 @‌ 150psi and 4 at 140 psi. Ahhh methinks, best dribble a little oil down cylinder 2 just to check rings or valves. Did that and the compression tester just read off the scale?? Maybe oil in the tester, not sure. So thinks next job lets get the cam cover off and check clearances. Long story short, took engine out now checked clearances and all within tolerance.

So I'm now confused? Cam chain is tense and within wear limits, clearances are good so its not that. I did read in the manual that 'if a valve spring is weak this can be the cause of chattering noise from the valves', but wouldn't that also affect the valve clearance readings? I'm prepared to take the head off and start removing valve springs etc if necessary but I don't want to do a full strip if I don't have to? Just as another check the cam lobes all look to be in good condition, clean, no pitting and sharp edges. This is on a 45,000 mile engine by the way.

Sooooo, what do you guys reckon, best take the head off and take a look at the valve faces and piston crowns? Then attack the valve springs etc. or does anyone have any experience of something similar and can offer a different direction of exploration to take?

One final point, after putting some oil down cylinder 2 there appears that oil came out of a small hole below the exhaust port and spread along the gasket line, is this normal? I'm hoping so, but if I have to take the head off I'll be replacing the head gasket anyway, so it is more for my information than a panic question. Also ( yeah sorry lot of questions, is an egg cup of oil in and around the rotor arm normal? when I took the cover off it dribbled over my foot, so I'm guessing an egg cup full!

I've taken a few pics if this helps too.

Thanks guys.

 

[badgerkdd]

Here's some pics, mostly showing the oil around the exhaust port and the rotor arm, with one of the cam lobe.

 

 

 

 

 

apologies for the quality of the close ups, my old work camera is getting a bit tired these days

 

[Jaydee]

I try to aim for the biggest clearance available when do the valves. The valve springs might be a little tired. No harm checking them to make sure they're the right length as stated in the manual. 

You poured oil down the bores. There's a drain hole in front of the sparkplug mating surface. Just some oil just dripped it's way out the exit holes. And yes, there is a light pulse of oil at the rotor as the crank spins so nothing to worry about there. 

Edited September 19, 2015 by Jaydee

[badgerkdd]

brilliant , I can relax about the extra oil running around!

 

So that's it then, cam shafts off and remove the head then! I've not done this before so its easy does it and probably a whole load more questions later!

One quick question and its more of a cheapskate query, can you re use the head gasket if you are careful when taking the head off? I'll replace it if necessary but at 50 odd quid it would be nice to save it if possible.

[Jaydee]

Think @fatblokeonbandit reuses his old gaskets. After they're cleaned up, he gives it a coat or two of primer. Don't think he's had any bother with his oil cooled gaskets. Don't know if he's done water cooled gaskets though 

[badgerkdd]

I'll ask him when I get five minutes, home from the workshop now and no chance to tinker tomorrow so I've got until Monday to ponder.............

[Fula28]

Just thought I'd ask but have you got stock cam chain tensioner? As there getting pretty old now maybe an idea to swap for manual one? Well before you strip the top end.

[kja.busa]

I'd be looking to the cam chain tensioner before I took the head off too. Regarding the gasket, purely from a personal point of view, I'd be using a new oem head gasket.

[bluedog59]

You can pull the tensioner out and inspect it. Measure the free length of the spring against spec.

[badgerkdd]

I've now discovered what I hope is the source of the problem. The back cam chain guide has been broken where the chain tensioner strikes it, only on the plastic lump not the actual guide face. I've removed the head but not the barrels yet and I'm wondering if its necessary to remove the crankshaft, when its open from the bottom, to take out the guide? If it can, that will save me from removing barrels, pistons etc. and save time, effort and also of course bloody GASKETS!! .

Any advice before I turn and strip the lower engine half would be great!

Cheers, Badger.

 

[badgerkdd]

You can pull the tensioner out and inspect it. Measure the free length of the spring against spec.

Can't find the free length spec of the spring, manual just says if the tensioner arm doesn't move freely then replace. It does move freely .

Anyhoo, I've bitten the bullet and I'm sending my head down to a local engineers to have it skimmed and the valves re lapped. They will then rebuild the head including any shim adjustments due to re lapping. All this for roughly £100. As far as I'm aware this is a good price and I know the guys do a good job as they are well recommended. Seeing as I'm getting all that done it would be pointless skimping on gaskets so I've bought an OEM head gasket online.

Cam chain guides are in the post, so when they arrive I'll finish the engine strip down and replace the rear guide.

 

[Fula28]

Bin the in the tensioner treat her to a new manual one fit an forget.Simples.

 

Edited September 25, 2015 by Fula28

[badgerkdd]

would love to, but finances are already being stretched getting the head done professionally, so its clean and use the original again!

[bluedog59]

If you're going to reuse the tensioner, put a new spring in it. They're cheap and mine was about 20% shorter than a new one when I replaced it. 

[badgerkdd]

If you're going to reuse the tensioner, put a new spring in it. They're cheap and mine was about 20% shorter than a new one when I replaced it. 

 

without sounding stupid (  ) where did you get one from, local dealer or online site?

[Gixer1460]

 

 

without sounding stupid (  ) where did you get one from, local dealer or online site?

http://www.robinsonsfoundry.co.uk/content/pages/shop/parts/Suzuki/GSX-R/GSX-R1100/K L 1989-1990/gsxr1100klcamchain.htm

Item #16 - needs back-ordering .........assuming you have an 1100 GSXR? - Quote OSS and you'll get an extra 10% discount

 

[badgerkdd]

http://www.robinsonsfoundry.co.uk/content/pages/shop/parts/Suzuki/GSX-R/GSX-R1100/K L 1989-1990/gsxr1100klcamchain.htm

Item #16 - needs back-ordering .........assuming you have an 1100 GSXR? - Quote OSS and you'll get an extra 10% discount

 

Its the 750 not the 1100, but I'll give them a call today thanks

 

[badgerkdd]

phoned, in stock, on its way! Cheers ‌@Gixer1460 

[badgerkdd]

well thought I'd better re visit this thread as things have moved on.

 

Once the engine was stripped down, the head was sent to a local motor engineers for a skim, valve check etc.

and the problem was revealed to be a broken cam chain guide. This meant a full engine strip as it was the rear guide, which is fixed under the camshaft.

This is what was retrieved from the lower cases...

And the cam guide looks like this.....

Well a replacement guide was sourced, as was a new chain tensioner spring and the engine was rebuilt. I also took this opportunity to replace the clutch springs as the old ones were well out of spec.

The head came back from the Engineers, who commented on the overall good condition of valves, springs, seats etc. Good news but at least its now had a 40 odd thousand mile refresh.

I also took the opportunity to clean and re paint some engine parts and cases, so the engine is looking tidy again...

 

 

 

 

So with a few niggles here and there, sorted with time and patience ( and a few choice words) the engine is back in the frame and a few evenings in the workshop the bike is back together and running again.

BUT!!!!!! After a few test rides and allowing for everything bedding back in, I still have BLOODY CAM CHAIN NOISE!! ARRRGGGGGGG!

I've taken the advice given on here and I'm now awaiting the immanent arrival of an Ape Manual Cam chain Tensioner from GrumpySpares! Hopefully this will sort the last problem and I can get back to riding the bike.

 

 

 

Edited November 14, 2015 by badgerkdd
better pics added

[Kristjan]

MCCT needs checking every now and then. Are you sure that it is chain noise and not valve lash and how is it when properly warmed up? These can't be made dead quiet anyway.

[badgerkdd]

It's definitely not its normal running noise.It's fairly much the same noise if its cold or warm, possibly more noise when under acceleration though, not loud like the cam chains real loose, just more noise than I would expect, or what it was making before the cam guide got mashed. I'll have to be honest I don't know what valve lash sounds like ( haven't had it before ) so I couldn't say if it is that?

The cam chain seemed ok tension wise before I put the rocker cover back on, and the cams etc. were in the correct position as described in the manual.

[FJD]

following this i´m curious if the manual cam chain tenisoner solves your rattle.

I have a bike in me shed, that´s rattling like hell as well, afaik these engines are known to have valvetrain problems.

[Fula28]

Well it's a process sorting these issues, at least motors all fresh an sweet now that's a bonus! as for tensioner the ratchet mechs are know weak point!  So once you have slipped the manual tensioner in set it up nice and Don't over tighten it (broken blades)! Will happen  I've seen a few wreaks the motor. 

Sure it will be sweet and purring like Gsxr should.

[badgerkdd]

Fingers crossed ,

 

I'll be sure to update on progress.

[badgerkdd]

Ok so last night I got the rocker cover back off, checked the cam chain and it has 1/2" of movement up and down. Took out the standard Chain tensioner and there's plenty of adjustability left on the rachet, so I am fairly certain its not operating properly. I would only expect a maximum of 1/4" deflection if the chain was properly tensioned, according to what I can find on the web, anyway, but double checking my manual today ( didn't have it with me last night ). Just waiting for the Ape to arrive now!