How often do you rebuild?

**icarus1859** · 02-04-12, 18:26

My bike broke on Sunday, 4th gear was slipping and was obviously knackered so I packed up and went home.

The mender split the engine today and it turns out that four gears are knackered, plus a broken fork and the selector drum is knackered.
He reckons about £600, the gears are about £90 each.

I was going to get the engine rebuilt at the end of the season but never bothered because it seemed to be fine.

He did say there was no point in replacing the piston as it appeared brand new.
Clutch looks ok too.

I reckon I did about 15-18 races last year, plus about half a dozen practise days.
So in terms of hours of actual use I'd say altogether its done about 30-35hrs of use.
Admittedly hard use as its been raced for most of those hours, but it still seems a lot of wear.

I reckon I broke the selector fork when I tried to drop into 4th and gas it but it felt like it hadn't located, so I stamped it down, the torque on the engine probably meant the gear wouldn't slide properly and against that and my boot stamping it down it probably snapped.
But I didn't think I was that much of a butcher than I'd do 4 gears in 30hrs of use.

**NigelBates** · 02-04-12, 20:47

35 hours is not a lot but if you know you stamped on the gear lever and broke it what do you expect. May have lasted much longer maybe not. KTM's are not as strong as some other brands, ive had most brands and admit my current bike (ktm 300) is not as well made as my previous suzuki or yamaha but neither of those make a modern enduro two stroke or i would have got one over a Keep Taking Money! Looking on the bright side at least ktm spares are cheap compared to jap bikes.

**Julian_Boolean** · 03-04-12, 09:00

My Husky 610 could probably do with a new cam chain - but it has done 20,0000 kms.

**icarus1859** · 03-04-12, 11:39

Originally Posted by NigelBates

35 hours is not a lot but if you know you stamped on the gear lever and broke it what do you expect.

Thats what I *think* may have broken the selector fork, but I knew 4th gear was gone by then anyway.
I suspected the others might be a bit dodgy because it occasionally slipped out of gear or felt like it hadn't gone in properly.
But I was surprised at the amount of damage in there.

And personally I will not own a Jap motocrosser because they are too unreliable.
All my mates now ride Jap bikes and every single one has been dogged by problems, I have 4 mates with 2012 CR450's and EVERY single one has gone bang.
I have two mates with 2012 Kawasakis (250 & 450) and both have gone bang.
And my mates Suzuki let go - which is why he bought the CR450 - which let go within 5hrs

I took possession of my KTM 350sxf in May last year, it had 6hrs on the clock.
The only problem I had was the EFI, which is a known fault and KTM did piss me off by not helping with it.
But other than that its been bob on.

Prior to that I had a 450sx which never gave me a hint of trouble.
And prior to that I had a 300exc which was the same.

The last Jap bike that I owned that was any good was a 1996 CR250.

**NigelBates** · 03-04-12, 14:13

All fair points. Some people seem to be lucky with KTM's some not. Dont know why, doesnt seem to be down the the maintainance as the highest hour KTM i know of was abused but kept going while other keen mechanics had their bike explode in no time. Anyway, 35 hours is not much for any gearbox.

**icarus1859** · 03-04-12, 15:29

Originally Posted by NigelBates

All fair points. Some people seem to be lucky with KTM's some not. Dont know why, doesnt seem to be down the the maintainance as the highest hour KTM i know of was abused but kept going while other keen mechanics had their bike explode in no time. Anyway, 35 hours is not much for any gearbox.

I think if they are going to go then they go early on, perhaps their QC isn't as good as it was.
I've known one or two go pop early on.

But as I said the Jap bikes seem to be made of cheese just lately, the CR450's all seem to be going bang and the clutch is a well known failure point.
There have been some very good deals on offer for CRF's this year and I know four people well that took advantage, and as I said all of them have gone bang inside of 6hrs.

**scud** · 03-04-12, 16:21

Surely an engine rebuild wouldn't necessarily looked at the gearbox anyway, usually piston and valves with a check on bearings.

Gearboxes tend to last well, unless the get a small bit of swarf grinding them down.

I like my Hondas, but admittedly mine are always older models as I just don't use them enough to buy new one, but surely 6 hours use before a break down would be covered under the sale of goods even if it is a race machine??

**icarus1859** · 03-04-12, 16:42

Originally Posted by scud

Surely an engine rebuild wouldn't necessarily looked at the gearbox anyway, usually piston and valves with a check on bearings.

For a race engine I'd usually have it split and checked at the end of every season.
I would imagine at higher levels it happens more often.

If the big end/crank needs doing then its got to come apart anyway and the gears will be taken out and checked as part of the job.

**scud** · 03-04-12, 16:52

My bike never really gets enough use, or hard use for it to become too much of an issue. Regular oil changes and valve clearance checks/adjustment where necessary.

The beauty with Honda's is the seperate engine and gearbox oils, a pain in the arse when changing them, but can be a god send when something goes wrong as it does not take the other with it.

**icarus1859** · 03-04-12, 17:06

Originally Posted by scud

My bike never really gets enough use, or hard use for it to become too much of an issue.

The bloke who's fixing it sponsors a few top level riders and he said he wouldn't have been that surprised if it had needed a piston and even maybe a crank if its been hammered but none of his riders have ever done that to a gearbox.
FWIW neither have I.
I've ridden this bike exactly the same as my others but this is the first gearbox I've buggered.

**scud** · 03-04-12, 17:14

I had a customer (died last week sadly) who owned a company called Nova Engineering, they build gears and gearbox components for mototcycles upto the WSB level. He told me motocross gearboxes aren't built to last as the factories tend to build the bikes purely for approx 2 seasons racing use and that is all they design them to last.
He built a mate some new gears for his YZ250, they were things of beauty and about as expensive as an original Hirst.

**icarus1859** · 03-04-12, 17:24

Originally Posted by scud

I had a customer (died last week sadly) who owned a company called Nova Engineering, they build gears and gearbox components for mototcycles upto the WSB level. He told me motocross gearboxes aren't built to last as the factories tend to build the bikes purely for approx 2 seasons racing use and that is all they design them to last.
He built a mate some new gears for his YZ250, they were things of beauty and about as expensive as an original Hirst.

Well...

There is a story to my bike.
It was bought new by a bloke that owns a suspension and engine tuning firm (RSS).
He buys new bikes and tests suspension until he's got all the figures he needs, then sells them on, always at a big loss but he makes it back on the tuning and suspension work he does once he's worked out exactly what each model needs.
I bought the 350 off him, with pretty much every gucci part you can buy on it.

Anyway, the story behind the bike is that his test rider (top level bloke) took it out and after 4hrs it went bang.
KTM didn't want to know, so he rebuilt it himself using top quality components (i.e. better than OEM)...and yesterday he told me that he replaced the 2nd gear when he did this as it looked a bit suspect, even after only 4hrs.
The ONLY gear that isn't fucked now is the 2nd gear that he replaced. Which might lead one to conclude that the original OEM gears were a bit shite.

**scud** · 03-04-12, 17:30

I find it outragous that these companies can sell these bikes at top dollar, know what they will be used for, but still they make them fragile and offer no assistance when they go pop after a few hours use.

I always pay for them on a credit card and then pay that bill, I believe you can get some sort of recompense through the CC company for a fair length of time after purchase.

**Tomcat** · 03-04-12, 17:36

I bought our 2005 YZ250F from a chap on the other forum who'd used it for practice riding for a year. JJ raced it for 3 years and I had the odd play on it too. In 2009(?) we sold it to Lily and Ryan who I believe are still using it.

It's never needed a rebuild though I did give it a precautionary piston and cam chain in 2008 (the shop - Yamaha offroad specialist - said it didn't need them but since we were in there as a precaution we did it anyway).

Yeah, dead unreliable these Jap bikes

**icarus1859** · 03-04-12, 18:28

Originally Posted by Tomcat

I bought our 2005 YZ250F from a chap on the other forum who'd used it for practice riding for a year. JJ raced it for 3 years and I had the odd play on it too. In 2009(?) we sold it to Lily and Ryan who I believe are still using it.

It's never needed a rebuild though I did give it a precautionary piston and cam chain in 2008 (the shop - Yamaha offroad specialist - said it didn't need them but since we were in there as a precaution we did it anyway).

Yeah, dead unreliable these Jap bikes

One of the lads has had his YZ250 destroy itself last weekend, he's currently crying on Facebook about it.

My CR250 ran for two seasons without as much as a spark plug, just an oil change every few meetings.
But my four mates have had their 2012 450's blow up.