Cylinder studs for minarelli

[kevin55950]

I'll install the MVT when I'll get the exhaust so I have time to look at little things like this...

I will need studs for this engine, stock 50cc length. I need good ones, I broke SOO much OEM ones while torquing them... a very little over tightened and BAM, they break. I was looking for long bolts but I can't find any... The Kymco I rebuilt last week was having long bolts, not studs and I like those long screws because it's easier to take the cylinder out when the engine is on the frame ( the 100cc cylinder is kinda hard to take out of my zuma if I don't take out the studs)

Did you have a link for good studs and nuts? Or if you know somewhere I can find long bolts (Allen or hex). I think threads are 7X1mm.

If I can't find long bolts, will these fit without breaking ?
www.ebay.ca/itm/CYLINDER-STUDS-and-BOLT-KIT-for-YAMAHA-Vino-Neos-Breeze-Zuma-Zest-50cc-/280834447286?pt=UK_Motorcycle_Parts&hash=item41630997b6&_uhb=1#ht_2467wt_1002
I like these taller nuts, they are less prone to get loose over time.

If you have another link for similar studs nearer from US/canada send it to me, thank you !

Kevin

[90GTVert]

I have never broken 1 cylinder stud on a 2T. How much torque are you using?

[rupert]

Honda Dio/Aero

[aznatama]

I think 12-15 ft-lb is the torque setting per the minarelli maintenance manual. how are you breaking those bolts??

[kevin55950]

I tighten them at 10-12NM as it should (from my CY50 manual), but they break when I tighten them OR they break when I crank the engine, I hear pressure escaping from the cyl. head ( engine at idle) and when I re-torque them, one has broken...

I've seen Kymco, Aprilia etc. where the cyl. head bolts were tightened far over this and the studs/bolts don't break ( I had to take 2 wrench together to loosen them). It looks like they get weaker after some time... I really don't want this to happen on the LC. I only have studs that were on 30K+ km engines. I need new ones, and I don't want to buy cheap studs that break easily.

[90GTVert]

I see why you're looking for better studs now. That's just less than 2/3 the torque I put on mine. Might wanna get your tq wrench re-calibrated. I'm just using stock CPI studs (Keeway, Vento) on the 50-70cc and I buy stock replacement studs from 90cc ATVs from kaseaparts.com for the strokers.

[aznatama]

These tq setting are really low... I can pretty much tq them w/ a 1/4" tiny rachet.

Not sure how under-torquing it would cause them to break. I can understand overtorquing them, but will undertorquing them break them too?

[kevin55950]

They break if I over-torque them a little. As I told they come from kinda high mileage engines so it might be the cause, I just don't want to buy studs that will do the same lol.

[190mech]

Ive never had studs break either!Use the proper torque for your engine with a GOOD torque wrench!!I have found that 90cc plus builds do tend to leak at the head some,but I think its due to the very weak crankcase design our scooters have..

[kevin55950]

I ordered the studs I sent the link on the first post. I hope they'll last lol.
I'll try to find a good torque wrench, at local stores they are only 40 NM+ models.