GT240 Build

[GeorgeS]

A bit more progress has been made, some good, some not so.

Towards the end of last week I fitted the crank bearing and seals and then fitted the crank. I'm using viton seals that came in the Taylor Tuning rebuild kit (great value and to my mind you get parts that he has vetted in circumstances that would exceed my usage), these type of seals are not something I've used before.

All the bearings and related stuff went in fine & so I fitted the crank which seemed on ok the drive side but the mag housing kind of sprung back a bit after I fitted it. After bolting everything up the crank was difficult to rotate by hand, no catching or grinding, just difficult and more so than I had expected. I left it for a day or so and kept turning it over but I wasn't happy with it. After a bit more fannying about I decided to open it up and straight away found the mag seal spring on the crank. The seal looks fine and the spring wasn't damaged at all so I put i back on the seal and gave it another test fit. No matter how gentle I was I couldn't get the mag seal over the 'hump' without rolling the spring off the seal.

I thought if I'd got that side wrong there's a good chance the drive-side was in the same situation, so thanks to James from round the corner paying me a visit today with the proper tools (and a decent hangover). We pushed off the crank & sure enough found the seal spring on the crank.

So then we put it back together. This time after every half turn of the crank puller we rotated the crank a few times, stuck the conrod locking tool back on and repeated. It felt good all the way this time. For the mag side the mag was lowered on (the seal goes over the bearing collar no problem) and James continually spun the crank while I applied a bit of pressure on the housing until there was a very positive feeling as it went down the lat 5mm, this time with no spring-back. These viton seal really are that much tighter, I really don't know how you'd do the mag side on your own.

Anyway, after doing it, messing it up, worrying about it, I was glad I took it apart & am sure it's now good. the crank rotates much easier this time, more in line with what you'd expect and feels silky smooth.



Gearbox is also in and I think I was very lucky to simply transfer the lose gears from my old series 2 in to this SIL casing with new SIL layshaft and find with the existing shim i have around 0.1mm of play. The only niggle I have is one of the spring washers has splayed, so I'll probably replace that.



BTW, Scooter Restorations asked me to send back the dodgy gear selector so hoping the refund or credit will work out fine, they've seemed good so far.

Thanks again James, disaster averted. Kickstart mechanism assembly is next for me, then probably the purchase of this months bits.

[eden]

Did you lube the oil seals ?

[Chris in Margate]

What really pees you off is when you can't sleep fretting about a possible problem, think it over with a yes/no a thousand times, strip it and find its all OK !!

This is my favourite thread. Real man and machines.

[GeorgeS]

The crank and seals were lubricated. When I fitted the crank to the drive-side it had come out of the freezer and the oil went a bit syrup-like when it cooled which surely didn't help things much and on reflection I didn't rotate the crank often enough.

The mag-side was a different matter though. I think if the mag studs were not fitted the extra rotation you'd get when fitting the flange might be enough to get the seal over the crank but my concern then would be getting threebond in to the threads etc. When you look at the difference between the bearing collar and the crank seal surface it's such a small difference (I did measure it, but can't remember the exact figures, but it was something like 1.5mm, so around 0.7mm 'each side', if you see what I mean), and with as much wiggling and gentle pressure I could manage on my subsequent test re-fits, I couldn't stop the spring rolling off. All good in the end of course, having the crank continually rotating certainly worked well in my case, and I'd hope the seal should do its job well.

Some of it was certainly down to my poor technique and lack of experience, but I do like a problem to solve & know better for the next time.

The 70mm GT kit is some 4+ weeks away so I think the next step for me is to get the drive chain complete.

All the best,
George.

[jonashford]

I find viton seals s**t. Basically they are too hard.

[eden]

I find viton seals s**t. Basically they are too hard.

I don't use them either!!!!!!!!!!!!!!!!!

[GeorgeS]

Well, they're in now! Let's see if they live up promise of being tolerant to modern fuels and all that.

Just tried to fit the kickstart shaft from my series 2 to the GP chaincase and it doesn't fit, I take it they're slightly different in diameter? Something else for the parts list then...

[GeorgeS]

Made some more progress recently. Other than the top end I have all the parts together and fitted, with the kit hopefully available next month.

AF clutch and X44 tensioner fitted.


I have a 1.2mm shim fitted as with the 0.8 the chain was grazing the endplate bearing holder. I could go down to 1.1mm but nothing less than that, after checking with feeler gauges.

I have a couple of issues with the kickstart shaft. First, it's rubbing on the clutch, second is that it won't fully retract in to the ramp. The rubbing on the clutch seems only slight, see pictures below where the white paint had been rubbed off, I can just grind that down, but what do you think about not retracting all the way? I guess I could solve both problems by machining the inside shoulder of the chaincase down & fitting a larger kickstart shim (would also need to trim the shaft under the plunger circlip to stop it fouling the ramp bolts)? Or should I grind some of the ramp away instead, but it seems a long way off?

[HxPaul]

Have you got the kickstart fitted ? If so the kickstart lever stop may be against the crankcase side cover stop.Remove the kickstart and see if the shaft and reference pin moves further into the ramp.You can then adjust the ramp by moving it once the three bolts have been slackened.

[GeorgeS]

There's no kickstart fitted. The reference pin is at the bottom of its travel and won't go any lower.