Niche cylinders

[toddo]

Hello 

I recently joined your forum -Thanks for accepting my request. I am in Australia and own a 1985 RZ 250 51l. I recently bought a new crank and was thinking of a Niche banshee cylinder
upgrade. My searches of this sight did not come up with much (probably my computer) and was wondering if many people had tried them and any thoughts in general on banshee Athena upgrades. I have had a look at Jon Wallis wonderful 2smoked sight and was wondering what would be involved using the 250 expansion chambers-Jon mentions their is some work involved. I do love the the power valve system and was wondering if anyone does after market 350 cylinders that retain the power valve system. My YPVS controller is playing up as well so I thought the money spent on a Zeeltronic controller rebore etc may be better spent on a Banshee set up. Any thoughts or opinions would be greatly appreciated.

This is the kit I was considering

www.ebay.com.au/itm/Cylinder-Head-Piston-Gasket-Top-End-Kit-for-Yamaha-Banshee-350-1987-2006/333640479332



Thank you!      

[Deleted]

Hi Todd

Jon’s site is a really good place to start, he’s a member on here and will probably be along shortly to offer his advice

Looking briefly at the eBay ad, I afraid to say it, if they are genuine then that’s about a 1/4 of the price they should be

I’d look very carefully before jumping in

Banshee’s don’t have power valves, you can however bolt 350 barrels to 250 casings, obviously your need to change the carbies, not so obvious will be the exhausts and the oil pump and it’s drive mechanism

The 250 exhaust will not work real well with a 350 set up. Pretty much everything else is the same except for the front and rear ? sprocket

If you are getting a Zeel then you don’t need to worry about the cdi pv controller or stator as you can get a zeel with both cdi and pv built in

Whereabouts are you located, I’m in WA there are a quite a few of us that waste an hour or five chatting on here

We are a friendly bunch and do do a bit of p1ss take when we get to know each other

I’m hoping to do a 51L in the hopefully not too distant future so I’ll be keen on listening to your tail

ATB for now

[JonW]

Hi Todd.

Hmm, I would not go with the aftermarket (chinese I would say) standard banshee cyls you mention. That will make less power than the 250 you have now.

You say you have the 51L cyls. Ive written a lot about them on here and on my site. They are a wonderful 250 cylinder and much better than the 29L / 1XG which came before / after. The extra boysen port is the key. back to back on normal roads the 51L gives up very little to the 350 in real world riding etc.

On my site there is a 250-350 conversion page as well as a big bore primer. both of those are worth reading I think.

Doing an Athena or other quality big bore will net you good power and reliability but it all depends on your budget. If you must go faster than your 51L 250 then it will cost you quite a bit, reusing your current carbs/pipes/CDI is not the way to real power as those parts will hold back the potential of the cylinders you do buy.

You say I mention the 250 pipes need work? can you point me at where i said that as Im not sure what you mean. You should not use any 250 pipe with a big bore banshee cylinder, its not going to make the power you want or rev out - it might be torquey tho, who knows? Dave might hazard a guess perhaps? but lets just say its a no if you want a big power RZ.

[midlifecrisisrd]

I fitted 250 51l pipes on a 350 ypvs

Great midrange but as Jonw says it loses power at the top

Steve

[toddo]

Thank you all!

I thought the price seemed too good. I will most likely stick with the 51l cylinders after all, especially after what Jon has stated. Apologies Jon I must have mistaken your exhaust advice for something else I was reading. I am not too interested in speed I just thought the 350 cylinders would give better low down toque which seems extremely poor on my bike however I have heard that is the case -I may be use to the torque of my  DT400? I recently attempted building a power valve controller using an Arduino however I think I will invest in a Zeeltronic. I have had a couple of oil pump failures on a Kawasaki and was wondering if  anyone runs premix and what ratio? Or does everyone have faith in the RZ oil pump? I am in Googong just outside Canberra which is quite hilly. Prior to the rebuild I just about killed the clutch doing a hill start - I thought the 350 conversion might help this  sort of thing. I would love to examine a 29l port arrangement to see how they differ from the 51l. I am guessing Jon is referring to the port in the middle above the center piston bridge? I am currently trying to fix crash damage to the fairing and will hopefully start rebuilding the motor after Christmas.


Todd

[JonW]

I think you'll find a lot of 2Ts lack low end torque, Ive never ridden a DT400 tho.

Send your pump to Arrow. He is a god of pumps... and a lovely bloke as well. I trust our pumps, especially after his work. End of. no need for premix.

This is some 51L info: www.2smoked.com/Yamaha_251LC_1982_RD251LC_Home.html you can clearly see the extra port on the side.

Have a bit of a read of my site while its still up (Ive not paid the hosting bill so it should be taken down at some point, im amazed its been left up so long really) as you will find lots of good info about these bikes in Aus and the 51L engine etc.

[toddo]

Thanks Jon!! I will check him out

I have not got to that section of your site yet and assumed the 29l had that port!
I have taken screen shots of your site and I really hope it does not go down as it is a wealth of knowledge and a most interesting read. The DT400 seems to have port timing suited to low down torque and not much of a power band I am guessing similar to a two stroke trials bike. My RZ seemed exceptionally ordinary down low but I am thinking it could be attributed to a number of things.


Todd 

[Tobyjugs]

Welcome to the forum.

I use a few different size engines and they are all different animals but one of my favorite's is a standard 250 4L1 engine. Its smooth and revs up nicely. Great for short back lane scratching and dancing on the gear box.

[arrow]

Welcome to the forum.

[JonW]

There ya go, Arrow himself has joined the conversation. (side note to Gary, Merry Xmas mate!)

No, the 29L is just like the 350 only smaller. You mentioned before that your PV controller was stuffed. Maybe your PVS are not turning, that would account for lack of low down torque.

Have a good read around my site, here and also Xavier's rd350lc.net site. There isnt that much info about the Aussie (and JDM) 51L engined bikes and these will cover it pretty much as well as give you more info about mods and mechanical issues than you ever wanted. Some Merry Christmas reading from us all, should get you through a family xmas no problem lol

Put some pics up of your bike and also start a build thread in the builds section, we'll help you along the way. Weve done that for plenty of other people (even those non tech savvy) as well as we love to see a bike being saved and used.

[arrow]

A merry Christmas to you Jon, and everyone else.

[toddo]

Thanks and Merry Christmas!

I will get some photos together.