Z250SL muffler replacement

As the owner of what is surely the most abused and neglected Z250SL in the British Isles I feel I should report about the stonkingly poor build quality of the exhaust. Here is how it looked not long after I bought it:

And here is how it looked after 18574 miles and another crash:

It had been noisy for at least a couple of months previous to this but the crash really finished it off. The noise was tiresome and the bike's first MOT was drawing near so I figured I had to fix it. What I really wanted was an Ixil can but these require real money to be spent so instead I bought a very-slightly-used original exhaust from ebay for £36.01, I can only thank the vain person who thought it was wise to fit something aftermarket. So, remove the bolt from the passenger footpeg hanger and remove the muffler..

I had to giggle.

In the interest of science I tried to get some pictures of inside the can but my phone insisted on focusing on the grass instead, when will technology allow us to manually operate the focus??

Not a lot to it really, why are they so expensive? It was also well on its way to rotting in other places too:

The next step was to get what was left of the muffler section off the stainless downpipe. I like that at least some of the exhaust is stainless but why not make it all stainless?? Anyway, it is held on with a clamp which I thought was going to be a nightmare to get off - not so! I hammered a socket on to what was left of the bolt head, gave it a good twist and the whole clamp tore off! Result.

Happily the new exhaust came with its clamp so this was no loss at all. Also if this is supposed to happen by design then it's brilliant.

So, twist and heave on the remains until it comes off.

It wasn't too difficult to remove, and the remains of the gasket were quite easily removed with a wire brush. I did consider fitting a new gasket but the one left in the new exhaust still looked fine (it wasn't torn up) and have you seen the price of them?? So on it went.

Upon starting it sounded very much like a sewing machine, only slightly less embarrassing but much less offensive. Overall a good job but a shame I had to do it so soon. Also the footpeg hanger is bent after the crashes which means the bolt hole isn't quite where it should be any more, I did consider bending it back but if it snaps off then I'm in deep doo-dah so I left it. An insurance person would probably write it off because the frame is bent, oh well..

Super professional crash fixes

Back on the 4th of July this year (it was raining and I still had to wear my heated gloves!) I chucked the Z250SL up the road on its right side after locking the front on some patches of road that were worn smooth and polling the rain water. It was only at about 15MPH or so but the usual damage was done - bent handlebars and a bent brake lever. This also finished off the exhaust but that was already well rotten so never mind. So, here is a guide on how to enact super mega professional back street mechanic type fixes to your freshly rashed machine!

Step 1 - Bend the bars back to where they were with a big bar.

The lock stops and top clamps can take it, they bent the bars in the first place anyway. This is actually really easy if you have a bar long enough, I used some aluminium scaffolding pipe which was brilliant for this job. Result:

I went a little too far the other way but I'm sure the next crash will sort that out for me. Next problem - bent brake lever:

For this job you will need the hallowed pump pliers on scrunchiness..

Scrunch, twist, grab, bend..

There, good as new. Sadly the exhaust is more difficult to fix, so I set up an ebay search - that'll be a separate post!

JT Z3 chain review

Back in December 2017 I fitted a 520 Z3 "Black Steel" chain made by JT, a company who are well regarded for their sprockets but not their chains. The Z3 looks to be an attempt to change that with JT boasting X rings and an average tensile strength of 4240kgf (41.6kN) which is very high for a 520 chain. The "Black Steel" version is the standard plain steel, you can also get "All Silver" which is nickel plated to combat corrosion and now "Gold & Silver" which is nickel inner plates and gold coloured outer plates. So, when first fitted it looked like any other standard chain:

As it was fitted in December it wasn't on for long before the bike stopped moving due to work shutting down for 2 weeks for Christmas. When I came back to it the half underneath the swingarm had corroded quite badly, leaving half the chain tight and half loose! Not a great start.

I carried on regardless, with the chain always a little on the loose side to accommodate the tighter half and after around 2000 miles it seemed to stop stretching and settled down, just like most chains. I was quite pleased with this as I'd paid £45 for the privilege of being JT's tester which is not far off decent D.I.D money. The chain also felt the full force of some unusual weather we received here in the UK, the so called "Beast From The East" which bought freezing temperatures and therefore huge amounts of salt on the roads for around a month. This did the chain no good at all but I wouldn't expect it to be wrecked, especially since the bike was used every day. At around 8000 miles it started to stretch a little more, until by 9500 it was stretching an unbelievable amount. At 9700 miles I tightened it again, and at 10,000 (exactly!) it was again hanging off the sprockets:

It had stretched so much I was starting to run out of adjuster.

JT also boast about the width of the side plates, as you can see they really are quite thick:

I don't doubt the chains are indeed very strong, but that apparently doesn't guarantee them a long life.

Upon splitting the chain the cause of demise became clear, no grease:

Given the way the plates had corroded it's little wonder the seals no longer worked well enough to hold the grease in, probably only helping hold water in there instead. As always, bend the chain sideways for a visual display of wear:

Not quite the full 180 degrees but not far off! For a chain that has done 10K I find this quite pathetic but it may be that the Kawasaki Z250SL destroys chains so I can't quite call it just yet.

So, thoughts - probably a really good chain in the coated versions, not so good in the basic Black Steel version because the steel JT have used is far too prone to rust and ruins the seals. Problem is, at the time of writing the coated versions are priced well into X-ring D.I.D territory so why bother?

Avon AV83 Streetrunner review

With the happy demise of the horrible Mitas MC25 I was in need of yet another 130/70-17 rear tyre. There's plenty of choice from the likes of Duro and Vee Rubber but I am now put off from third/fourth tier manufacturers somewhat and decided to treat myself to a European tyre. In fact to heck with it, I work in British manufacturing and should support it! Also there are precisely no reviews for this tyre from Avon so that'll be interesting. £55 later I had one in my possession, ahh feel the quality of this fine thing. "Made in England" it will surely say..

Oh, okay then. The Mitas/Sava was also made in Slovenia so alarm bells were ringing.. Loud alarm bells. The tyre is also really stiff to handle it I would put it on par with the Metzeler Sportec Klassik - if this tyre is for 125s then why make it this stiff? Turns out it does indeed have all the plies:

At least it shouldn't struggle to keep the bike in line. More pictures for your delectation, this is a review after all..

After some faff the tyre was fitted to my Z250SL:

And it seems to have quite a lot of tread depth, which is marvellous:

So, what's it like? First impressions are that it is indeed really very stiff, I wouldn't mind putting one on the back of my K100 let alone a 125. Letting the pressure down to 15PSI still didn't have the tyre squishing at all when I bounced up and down on the seat, it's almost like a run-flat.

At an initial pressure of 32PSI (as per Kawasaki's recommendation for the original Dunlop TT900) I set about testing and found it to be a great improvement over the Mitas, wet roads are no longer a test of Speedway skills and dry grip is even more plentiful. It has behaved impeccably on the frosty roads that we lucky Brits get to use in Winter and wet weather grip is perfectly adequate if not astounding - if really "making progress" on slightly wet roads the tyre can slide a bit on corners (particularly if you hit a polished surface at the same time), but stick to normal speeds and it's absolutely fine. In the first 500 miles it also seems to have softened up a touch, it's not as chattery now but I would still say it's a very stiff tyre.

Wear updates will of course come in time, stay posted.

**UPDATE**

I ended up running this tyre at 28PSI, it's so stiff that it still doesn't wobble all over the place at this pressure but it at least isn't too hard and chattery. As far as wear rate goes, well, at 3110 miles I can only describe it as disappointing..

You can also see how it has squared off, it wasn't bad at all until the tyre saw some motorway miles and after a few trips up and down, well..

I'm also sad to say that after around 2000 miles the tyre became really quite slippery in the wet and I can spin the rear up in 4th gear, yes it's better than that awful Mitas MC25 but not by a lot. Given the not-too-cheap price of these I'm really struggling to find any reason to recommend them to anyone right now. Further updates to come..

**FINAL UPDATE**

At last I can get rid of this thing, 5685 miles sees it down to the wear markers:

After around 4K it became really very slippery in the wet, the lack of grip actually starting to rival the Mitas MC25 - I really do suspect these tyres are closely related. It constantly threatened to let go if a damp patch of road was touched, full wet weather was very precarious indeed. Dry grip was always fine, the tyre was always incredibly stiff giving a harsh ride even though I ended up running it at about 26 PSI and even let it drop to 12 before feeling the need to blow it up again! Overall I couldn't wait to get rid of it, this tyre is a liability.

At the time of finishing this review these are selling for £70.50 on https://www.moto-tyres.co.uk/ which makes them more expensive than a Dunlop TT900 (£62.10, excellent and longer lived) or a Pirelli Angel City (£63.70 with glowing reviews from many real people) and even the Pirelli Diablo Rosso II (£67.80 sporty radial loved by Americans). Sadly I see no reason why you should bother with this Avon at all.