The cheater MX85 argument. I might be changing my mind.

[Drew]

Most people probably know where I stand on this issue but out of interest how many people would actually build one?

How many people even have access to a motor? It's a big class for current bikes, but the old stuff is mostly junk by now.

[F5 Dave]

Ok so I did a Tardme search using Dirtbikes, key word 85, and upper price of 2k.

20 listings of pukka mx85s



From that you would get lots of useful chassis parts along with complete engine, electrics, carb, pipe, radiator package.

I've seen mx frame used with shortened forks and 17" wheels laced on.



I searched FXR, I found one Bucket, and a Harley.

Just saying.

[speedpro]

I'd be really tempted

[F5 Dave]

Well one day I might be able to return. Just seeing this post makes me think, even though I would no longer be pointy end this might be a good way. If we don't run out of skinny slick tyres. Or tracks.

[speights_bud]

I provided the prototype engine and then on sold it very quickly 6 months after I got it back.

To someone who wanted it hoarded for the day these rules are changed.

I originally found it with a seized piston in a shed for nothing. They are out there.

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[jasonu]

I'd be really tempted

I'd do it.
I'd also remit for CRF150R motors at the same time.

[cotswold]

Most people probably know where I stand on this issue but out of interest how many people would actually build one?

It may solve some of our noise issues.

[TZ350]

.
Team ESE are not much interest in MX85's as we are heavily invested in our H2O GP100's and RG 50's and make quite good engines out of them.

But we can see MX80's and 85's are nice light reliable engines that are ready to go. And considering everything that is easily available over the net for the European scooter market and with the availability of reasonable two stroke MX engines locally then maybe its time for anything 85cc or less to be totally open.

Everything has its advantages and disadvantages but we can see that being able to use all the commonly/easily available 2T bits without having to do too much could be a positive thing.

And to keep rule things simple, maybe for two strokes 85cc or less, make them totally open, more than 85cc as per current rules.

People might even start replacing their expensively blown up 4T 150's with off the shelf 2T MX 80's and 85 engines.

Nothing wrong with re-purposing a good FXR or other 150 Bucket chassis that needs a new motor with something cheaper, more reliable and easily available.

[speights_bud]

So who here is going to put forward the proposed 85cc open rule?

Talking here is great but it doesn't mean anything unless someone picks up the flag and runs with it.

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[Drew]

So who here is going to put forward the proposed 85cc open rule?

Talking here is great but it doesn't mean anything unless someone picks up the flag and runs with it.

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Any MNZ member motivated to do so.

[F5 Dave]

Don't look at me. I'm not currently racing so I should have no say in the matter.

[speights_bud]

Don't look at me. I'm not currently racing so I should have no say in the matter.

Neither was I when I put forward the last proposal. But it started the conversation.

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[TZ350]

So to summaries the MX85 proposal as there are about 50 versions in this thread
F4
MX engines, limited to 85cc no other restrictions
100cc 2t no other restrictions max overbore 110cc if new rule change allowed
125cc 2t carb restriction 130cc max over size (considered dangerous in Australia)
150cc 4t no other restrictions 158.6cc max oversize

Looks good to me in this form , plenty of choices, cream always rises to the top

I like the idea of no restrictions on any normally aspirated 2T engines of 85cc or less. It could simplify a lot of things.

If someone wants to work that into the current rules and unless someone else wants to run with it I am happy to put any proposed rule changes in front of the Auckland Motorcycle Club for them to submit if they like the idea.

[speedpro]

Lose the capacity + overbore wording. Simply state the maximum size and don't mention boring as a capacity increase might be due to an increased stroke. Keep it simple.

There may be a few 4T engines that suddenly become eligible as they start bigger than 150cc so don't comply with current rules, though there is an argument that they might not be eligible anyway due to the word competition somewhere in the promotional literature.

This constantly changing the rules and increasing capacity has to end somewhere. F3 anyone?

[F5 Dave]

I think this thread was purely as topic line, it will go nowhere if everything else is brought in to the discussion. Maybe it won't or shouldn't.