Hitchcocks Forum

Hi,
Stripped my engine down today suspecting a big end problem but I've found play in the timing side main bearing.
Ive ordered some new bearings for both sides. The timing side one looks very flimsy compared to the primary side.
I've not seen many issues on the forum re main bearings. Am I just unlucky or is this something others have had.
I'm pondering the Carberry vibration plate to support the flimsy needle bearing. What do others think?
What should have been done in a day is now stretching out.
Cheers

I had a similar experience recently; I stripped the engine on my C5 to investigate the cause of increased vibration and noise, fearing big-end failure. In the event, the big-end was ok. Whilst it had a fair degree of side-play it had no up and down play. I sought the opinion of an engineer friend of mine who concurred that it was fine. I replaced the timing side main, together with all the needle roller gearbox shaft bearings and the sleeve gear bearing, which had a distinct rough spot. On my engine there was evidence that the rotor had been rubbing against the generator stator in that some of the segments had worn on the outside. This was with a Carberry plate fitted and I have to say that when I carry out the first service after the rebuild I’m removing mine. It didn’t stop the weak timing side main bearing lunching itself and might even have caused it by holding the shaft firmly in one position. I’m thinking here of how back in the day some manufacturers of vertical twins put in a central main bearing in an effort to cure the vibration apparent on Triumph twins. This didn’t do much good and crankshaft whip turned out to be better than trying to restrain it given that Triumphs seemed to withstand being thrashed better than most. In my opinion the Carberry won’t improve a shaker; at best it’ll shift the vibration of an already smooth (for a 500 single) up the rev range and the owner will mention a small improvement. I’ve never come across anyone who has said that the plate transformed the smoothness of their engine....
Sadly my engine still vibrates, though the tapping/knocking noise has gone. I’m afraid that, whilst probably not that common an issue, the earlier ones (pre Euro IV?) can have inferior bearings fitted. Apparently there are a lot of fake bearings in India and although the timing-side main bearing in mine has INA on it (a decent make), it could be a copy. Maybe that’s what RE mean when they say quality control has improved? Who knows...
You will no doubt have noticed that our host sells improved bearings for these bikes, usually with an A suffix. Hopefully the replacement bearing , which looks very like the original but is a different make, will last longer (I did the rebuild at 6,500 miles). I’m not convinced that the bearing is under-specced as timing side bearings don’t have the load to withstand that the double bearings on the drive side need (I left mine alone). BTW, don’t worry about the end float when you bolt the crankcase together, it will disappear when you tighten the crankshaft nut outboard of the sprag clutch. Just don’t forget the thrust washer on the drive side before joining the crankcase.
FWIW while I was at it (and because it kept me busy during lockdown) I fitted a new piston and rings - the engine had gradually lost its sparkle because of worn rings. I also fitted a Hitchcocks replacement exhaust valve. The originals have been known to drop their head if the engine is run at high speed for a while because, like small block Moto Guzzis that suffer the same issue after around 30,000 miles, the valve head is welded to the stem. On mine I reckon an apprentice did the job as there is a pronounced bulge at the join. The inlet valve is much better. Apparently the Hitchcocks valves have a better profile to aid gas flow, though without tuning the engine I doubt that matters much, but it is clearly better made.
You must be a lot more proficient at stripping and rebuilding engines than I am ( not difficult) if you can do it in a day. Getting the gearbox shafts and change mechanism back in place was a challenge (euphemism) but refitting the kickstart spring was a real PITA, though once I’d borrowed some longer fine nose pliers it was easier.
Good luck.

Hi Rattle battle,. I've ordered SKF bearings as I live near a bearing supplier. I'm pondering doing the rest of the needle bearings while in in there as it seems a false economy not to.
Forgive my ignorance whatbis a sleeve bearing?
I had the gearbox appart last year so I'm quite adept at getting the cluster back in. How easy is it to do the bearing behind the gearbox sprocket as that is probably under quite a load.

The sleeve gear bearing is the one behind the gearbox sprocket. I’m no mechanic but I believe that’s what the one in which the output shaft runs; if not, apologies. As you say, it’s under some load. I found that there was a lot of slop on the shafts on mine and had thought that it was the shaft needle roller bearings but when I had replaced these some play remained and I traced this to the big sleeve bearing. It’s easy enough to replace, just heat locally and knock it out with a suitable socket. I put the replacement in the freezer, heated the housing and gently tapped it home. You’ll need a new seal. There is a bit more dismantling needed to access the bearing, including removal of the k/s spring, best replaced when the partly-assembled engine is back in the frame.
In my opinion the kickstart shaft, not fitted to the 2009/10 models and introduced on the 2011 B5, lacks support. Mine felt quite rough where the gear engages with the gear on the gearbox shaft. I do wonder if the use of the kickstart is what caused a rough spot on the bearing. I don’t use it now, the electric start works really well anyway.
Just curious: how many miles has yours done and why did you need to attend to the gearbox - I agree, having now done the job getting the cluster back in is straightforward.
To put this in perspective, I don’t recall anyone else disassembling an engine for repair on this forum. Plenty of Indians doing so; I think that one might occasionally be unlucky and get one with duff or poorly fitted bearings. Hope it goes well; you sound like you know what you’re doing.

Thanks. Re gearbox,. After returning from 2.5k mile trip across Europe to Auschwitz I changed the oil and found the broken end of a circlip on the magnet. Not knowing where it came from, I left well alone. About 6k later having done the NC500 and other long runs I lost 4th gear. Big neutral where it should have been. Strip down revealed rest of a very worn circlip and no bushing left on 4th gear. I bought a 2nd hand complete cluster from Mr H. Whilst in there I had the barrel honed and replaced the rings as the bore was a bit glazed and I had high oil consumption. Bike has 27 k on it. It is a home market 2010 C5 and I don't treat it gently. Quite enjoyed pulling the engine appart the 1st time. Nothing too technical and it all worked when back together with nothing left over. Haynes was very useful.

Thanks for that. The gearbox seems pretty substantial to me but I guess these things happen. Decent mileage on your one too. As you say, the engines do come apart and go back together quite easily, though I did a bit each day being in no hurry during lockdown. The job would be a lot easier next time. What was your t/s main bearing like? The followers in mine seemed loose but there were to some extent in the new one too, as were all the new gearbox ones. Before she letting the cases there was no detectable play on either side of the crank.

Nothing obvious on the bearing, just a good bit of play. As with you i expected a problem with the big end and when I tried the piston there seemed to be some play. A friend with me questioned the play which made me try the alternator spindle and found quite a bit of play.
BTW alternator stator doesn't seem to be as magnetic as others I had stuck screwdrivers to. What is yours like?
Why do you think magnetic particles stick to the sump magnet and not the alternator?
Also. Quite a bit of side to side movement on the con rod

Interesting. I took my engine to pieces because I thought the big end had gone. There was more vibration than it used to have and a pronounced tapping noise. Like you, I found a lot of sideways play at the big end but no up and down play. The tapping turned out to be the inlet cam backlash. Although none was apparent with the cylinder head un disturbed, when I rechecked after relieving the pressure on the rocker shafts there was a fair bit of backlash on the inlet cam.
It’s funny you should mention the alternator magnets. When I fitted a bigger gearbox sprocket earlier on there was a lot of resistance when removing the outer timing cover, as expected. That seems to have gone now, though the charge is still healthy. I took the crankshaft to an engineer friend of mine, who pronounced it sound. One of the members of an American forum on these bikes, who modified them for racing, reckons a lot of cranks come from the factory with side play outside of their own specified limits...It doesn’t seem detrimental. I have a feeling that something still isn’t right in my engine because there is a whining noise - I’m hoping it’s the Carberry bearing; I’m going to remove this when I do the service. Another possibility is that the end of the crank is slightly off-centre - this would explain the worn segments on the generator...

Sorry, reread your post. Not clear what you mean by alternator spindle? I’ve no idea why iron particles don’t stick to the magnets on the alternator, except that I don’t think there’s much oil flow there, at least as long as the o ring seal is good. A bit weird really. Could centripetal force prevent it? Dunno.