Author Topic: crank work  (Read 3762 times)

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Offline cappra

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crank work
« on: September 17, 2015, 06:01:08 am »
I have a friend in New Zealand that is trying to get a VF 414 crank rebuilt. Shop he took it to has already ruined the new crankpin. Anyone know of a competent shop in NZ or Australia that can rebuild a Montesa crank? He is lucky they didn't mess up one of the crank halves! Yet...

Offline Lozza

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Re: crank work
« Reply #1 on: September 17, 2015, 06:40:19 pm »
I know several.
Jesus only loves two strokes

Offline cappra

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Re: crank work
« Reply #2 on: September 18, 2015, 03:12:39 am »
Links or addresses?

                                                              Thanks, Jared

Offline OverTheHill

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Re: crank work
« Reply #3 on: September 18, 2015, 09:35:54 am »
Shouldn't show up my [lack of] ability lol--but had a "75 Mk8 Pursang new but in 1976 & it was in bits for something every other week, mostly gearbox by memory but came apart easy--undo screws then shake it. Had the crank apart too a few times & in the end the pin was too loose a fit to be safe, so not knowing what to do other than an expensive cure, i went around town with a micrometer & ended up using a volkswagen king pin [true], was a couple of thou bigger [or something]. Got the rod honed a bit for the rollers to fit good & carried on. Loved the Bully though, best failsafe airfilter & easy to service. Quiet exhaust, handled great & was quicker than i realised as had an MX250B 1975 which blasted off with a hiss & a roar but Bully was still on the shop floor in "76 so boss said use 'that' for a while--actualy fell in love with it. Useless brakes though--Chrome on aluminium. Funny thing is, thinking back & hope i'm not contradicting myself above but i took the Yam & the Bully out to our track in "75 & thought the Bully was slow but was a Yamy fan anyway so went with that again as changed every year. Sorry, getting off subject. Got a 36 Bing on my RT2 Yam off a Monty though lol.

HeavenVMX

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Re: crank work
« Reply #4 on: September 18, 2015, 02:16:10 pm »
Jared I have had several Montesa cranks (6 from memory) rebuilt and never had a problem with any of them. I use a couple of different shops in the Hunter Valley NSW. I always mention to the shop that Montesa cranks do need an unusually high pressure to part and reassemble and check that the shop does have a high quality crank building rig other than that they are reasonably straight forward.

New Zealand have a lot a very high quality machine and engine shops so I feel your friend has been very unlucky or has chosen poorly. Maybe Bill can make a recommendation. The cranks are a bit like the rebores for Monties as the liner material is very hard the machinist needs to know that before they start.
« Last Edit: September 18, 2015, 02:20:00 pm by HeavenVMX »

Offline Lozza

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Re: crank work
« Reply #5 on: September 18, 2015, 06:47:50 pm »
Links or addresses?

                                                              Thanks, Jared

The fellow can always go to the Kiwibiker forum and ask but I'll have an answer tomorrow
Jesus only loves two strokes