Another 81 question

[brent j]

From different sources I've seen the rake angle on the 81 490 MX bikes listed as 27.5 or 28.5 degrees.
Can anyone confirm if either is correct?

Thanks

Brent

[mick25]

I read in a write up on the TT500 c thats its 30.5 deg    ... I have a 84 xr500 and they reckon its 25.5 no way
more like 27,28 the specs say that the CR500 84 has a deg 28.5, I did a post on a way i work out the steering deg angle.. the builders way   I would say that the 490 bikes would have to be around 27.5 28.5 I owe you a email to havent forgot BJ

[norm17]

1981 490 manual gives fork rake as 27.5 degrees- Manual actually shows 'rake' as 62 degrees and 30 seconds from vertical which is the opposite to what we deem conventional but still 27.5 degrees.
Norm

[firko]

I always thought that it was 27.5 deg but can't remember where I got the info. It's a pretty steep angle for a motocrosser, no wonder they turn so well.

[brent j]

Thanks guys for the replies. I had one test in a magazine that said 28.5 but I was told 27.5 by a forum member nearly 8 years ago. He took the info from his manual so it was right but over time I started to doubt my memory of the conversation.

Mick, I work out my steering head angle as follows. I put a stand under the centre of the bike and get it as close to the balance point as possible. I use a stand with just a bar rather than a plate so it will rock freely. Using bits of wood or whatever I get the bike to nearly balance with weight on both wheels but with the suspension fully extended.
I have an adjustable spirit level I use to measure the angle on the fork tubes (only works with triple clamps with parallel offset).
This may not be the “right” way to do things but it is consistent. If I make a change to the ride height (front or rear) I reset the packing to get the same as above.
If the suspension is working right I figure the bike should stay level when it sits on it’s own wheels and when I sit on it.

Yes I am cheating and copying Maico geometry for my Yamaha 500’s, I’ve been doing it for years.

Thanks again

Brent

[paul]

brett why dont you wack a 500 engine in a 81 maico frame (shit did i just say that )

[maicostu]

Paul,
Thats enough of that crap

Maico Stu

[GMC]

Wasn't there a couple of different frames for 81?
With different backbones.
Maybe they had different steering head angles which might be why you have heard of 2 different specs.

[paul]

Paul,
Thats enough of that crap

Maico Stu

i had 2 bex and a lay down  i feel better now  what was i thinking

[brent j]

brett why dont you wack a 500 engine in a 81 maico frame (shit did i just say that )

You did say that Paul, and we all have proof!

I've seen it done (Someone on this site has one I think)

You don't happen to have a spare frame by chance do you?

Seriously, I'll keep playing with mine rather than cut up a good bike. It's surprising how easily, with a bit of mixing and matching parts, I've been able to copy most of the chassis dimensions. My bike sits a bit lower than an 81 but as I get older I don't mind that so much

If I cut up a Maico chassis I don't know that I'd end up with something that would be much better than what I've got as fitting an XT/TT motor to a Maico would spoil the total balance of the bike and I think that is the real Maico secret.

I'm also learning a lot about chassis dynamics and that is as much fun as riding the thing.

Brent

[cloggy]

 From what I've read and my own bodged SP400 in a maico enduro frame a yaico isn't nearly as straight forward as a Yusky

[brent j]

Over time I’ve thought of putting an XT/TT engine in all sorts of frames. In a Husky frame would be an HL but at the risk of incurring the wrath of every Husky owner alive I don’t think they turn very well. Then there’s the need to make an oil tank and line everything up again.
With any frame there is the need to fit an oil tank or dry sump the motor. Modifying an XT/TT frame is not that difficult and every thing lines up from the start. Yes they are heavy in standard trim but I removed all the extra bracing and brackets and the pile of metal I removed weighed about 2kg!
In 9 years of use I have never had a frame failure. I will weigh my spare “trimmed” frame and post the result in the relevant post.

When I first built the bike I had the same geometry as an HL (from what info I could find) and it did a great impersonation of a plough when you tried to turn it. I was forever finding something to bounce the bike off to get it to turn. A couple of HL and Husky owners have said the same thing.
Changing the offset in the triple clamps was the first big positive change I made and copying the geometry figures for an 81 Maico and was another big improvement.

I’ve often wondered how an HL would handle with different triple clamp offset. Most HL’s are built with SUZUKI or YAMAHA forks. Both have a total offset of 60mm but a different combination of offsets in the clamps and fork legs. I believe it is “Hotrod Husky” who make Husky triple clamps with 5mm less offset than standard. Use Yamaha triples and Suzuki fork legs and you get the same effect, food for thought maybe?

I’ve never ridden an 81 Maico but what I have read of how they handle suggests my XT is similar. It will never handle the same as the Maico as the total weight is different and the different amount and delivery of power will have a different effect.
What I do have is an XT500 that is very safe and stable and it will turn when you want it to. It will happily run around a berm or change lines half way round a corner.

This bike has also taught me a lot about chassis dynamics and the effect of different parts and changes. Every thing on the bike must work together and it’s amazing how changing just one thing can upset everything else.

Cheers

Brent

[mick25]

Hey BJ ,Your way of working out the deg angle is close to the way i do it ,I use the sprit level way and a sliding bevel.
and leveling bike out
Its just hard to work out the spot on %100 level on the bike or frame to match the angle ,
I think no one would really know what the frame angles were put at in the jigs (level spot) when the frames were made
when they done there deg angle spec on frames,
so its hard 30 years later to find out what your frame is %100 deg angle is....I give my self 1 deg play   
I have had a ride on the mighty maico 490 only round the block must say it did turn nice and heaps of GRUNT