MKII Pampera engine questions

[Grinch]

Yea, I know the limitations of the Pamp and it's intended use so I have no issue in that respect. Power is fine (not that I want to lose any), brake and suspension limitations are fine for now and it may get a fair bit of use on-road so that's great too. Lowering a 200 has been done several times but our terrain out here is too tight and the need for ground clearance too great for a bike that ends up with about 8" of ground clearance. The additional problem is the 58" wheel base is huge given some of the ridiculously tight trails we have to negotiate so the Pamp at 53" and over 10" ground clearance is ideal. IN addition, in order to race Enduros or participate in Turkey Runs a bike must have 18/21 wheels so a mini is out of the question. Parts upgrades are not much of an issue so we'll work that way.

A little background- My wife was a pro MTB racer and amazing endurance athlete so, in turn, she is an AMAZING rider but if you have ever seen an adult try to learn to play hockey or tennis without exposure as a child, it is awkward at best. The same goes for Sandy in that she never learned that intuitive skill of kicking a bike, a skill that we all take for granted. At 49 and with only four years under her belt I'm not sending her to dirt bike camp to learn to start a high-compression bike.

As far as my ability to facilitate such a change, it's a bit of an assumption on your part that it is beyond someone's capabilities. I'm quite sure I could handle it in an afternoon, and as a matter of fact it's what some people refer to as a 'hobby', things we do to relax. Some people collect stamps or cave wooden ducks, I hack up perfectly good motorcycles. I offer;

THIS, a 250 4 stroke in an aluminum mini-

THIS, a TTR125 motor in a YZ 85 chassis-

and a KTM105 motor in an aluminum mini-

 

[GMP]

OK Grinch you got me, I stand corrected! Nothing bad intended. Very nice work. I did say "likely" and "most" though and you have to admit there are a lot less skilled guys on these forums than BSers. This site seems to have a lot of sharp people though.

Now, if you use that Pampera frame and running gear, and your wife adapts and starts going fast, she will destroy it. It has happened. Somewhere there was a pic of a Pamp ridden by a fast girl that had the frame snapped in half. Since your a good fabricator, I would consider beefing up the frame and upgrading some of the components. I can't imagine your trails being tighter than south NJ where half of our races are and Mike Lafferty grew up. Big obstacles are another matter and I can see the ground clearance issue of a lowered bike.

For the stock motor, just try the gaskets and/or mod the head. Maybe even try adjusting the kickstarter one spline back if it will fit to start the stroke more downward and less backward.

Hey, ever thought of putting a Yamaha 250F motor in a GasGas EC frame?

 

[Grinch]

Hey, ever thought of putting a Yamaha 250F motor in a GasGas EC frame?

Actually, yes. It's not as difficult as it looks, actually but the airbox is usually what comes out as the biggest PIA. Working with steel frames is actually pretty easy, it's the aluminum ones that are difficult. The YZF motor was one of the considerations for this bike.

I'm sure by the time I get done this thing will not be very stock but the MSO allows me to register it for street use and overall the geometry is quite good. As I said, components can be upgraded and frames can be gusseted

 

[GMP]

The good MSO makes things a little more clear now. Sounds good.

Have you ever done any evaluation of different motors and mounting positions for your conversions for best CG, etc? Just curious if you did and what you may have discovered.

Oh, welcome to the site and keep us posted on the project, and others. Enjoyed the pics.

 

[Brian VT]

...the geometry is quite good.

+2. I took it for a quick spin. It feels like a great bike for NE woods. Especially for riders like me that end up on the ground often.
I can stand that bike back up with one hand.
I think my XR650R was easier to kick over than that bike, though.
I was also suprised at what little power that 320 has compared to my 300 (I realize it's a trials motor but...).
Grinch, did you check to see if there's an EPA screen in the headpipe ?

 

[Grinch]

I'm very much of a newb when it comes to GG but the big deal is the swingarm pivot and whether or not it is an integral part of the motor case. I did a CRF250 into a frame-only for a guy and had to rework the width of the case to fit... kind of scary, I must admit. Otherwise I've had to reroute downtubes for 2T expansion chambers, etc, it's not really a big deal. I also have to look at which side the carb comes out on and compare it the piggy back reservoir on the rear shock, the YZ project I was able to just rotate the shock 180 degrees and all was good.

Otherwise I haven't seen many problems with front mounting plates, etc. I think I've just been lucky so far too.

 

[Grinch]

+2. I took it for a quick spin. It feels like a great bike for NE woods. Especially for riders like me that end up on the ground often.
I can stand that bike back up with one hand.
I think my XR650R was easier to kick over than that bike, though.
I was also suprised at what little power that 320 has compared to my 300 (I realize it's a trials motor but...).
Grinch, did you check to see if there's an EPA screen in the headpipe ?

Yea, took it down to the frame, no screen but the exhaust sytem as a whole must weigh 20+ pounds. Everything is so clean and neat under the plastic, they really did a nice job on these things. Cooling fan, battery placement, it's a great starting point.

 

[GMP]

Technical trails at low speeds, yes. When things get faster the stock bike breaks. That model is like a heavier trials bike with a seat, the newer ones are more like an EC with respect to geometery, but weigh around 200 lbs. Everything is light duty and is highly stressed at the pace we can ride. I've also bent linkage bolts and many things loosen quickly.

Also I forgot to mention the airbox, totally inadequate for a woods bike. One of my projects in the Q is to adapt an EC or KX85 airbox, but my wife doesn't ride much anymore. I'd sell it if it was worth more.

 

[Grinch]

Ultimately what I want to do is sort this bike out, learn from the geometry then use the frame as a jig to rework an EC or a KTM to be a shorter wheelbased, lowered bike without working the suspension to an inch of it's life. When I have the jig I will offer the frame as a stand-alone item so that you can swap an entire bike over to it for about the same price as having your suspension done.

How's that for a vision statement... and if someone steals my idea I'd be happy to buy a frame from them

 

[widebear]

Why would anybody want a chassis designe with geometry that has all the medium speed stability characteristics of a two legged bar stool? Why for that matter try and re- invent the wheel. Grinch you may be a capable fabricator but if there is'nt a off the floor bike that meets a riders needs maybee they should consider changing leisure activities. Was'nt there once a company called Cannondale who were going to show the rest of the motorcyle world how its done.

 

[Grinch]

It's a good thing guys like the Wright Bros, Thomas Edison and Bill Gates didn't think like you. If a product is not available, QUIT!!! Those comments are laughable...

 

[widebear]

It's a good thing guys like the Wright Bros, Thomas Edison and Bill Gates didn't think like you. If a product is not available, QUIT!!! Those comments are laughable...

Heres how I think. I think I'm a pretty damned good rider but one who's not quite, never was, never will be, good enough to extract even all of the performance offered from a fifteen year old mx bike. I do however realize that the problem is not the bike but the rider, in this case me. So I work harder at training, understanding the pyhsics and dynamics of whats happening when I'm riding. I have no delusions about a new bike making me a better rider, I'll never be David Knight and I'm just happy to be able to ride period. Your spirit and curiosty is commendable but you cant, as the saying goes, make a silk purse out of a sows ear.

 

[Grinch]

So my wife's a sows ear? You're making an ass of yourself, please stop. I never asked your opinion in regards to whether you thought I should build a custom bike for my wife but rather how to make the bike easier to kick. Because you probably think full-faced helmets and nylon riding pants won't make you a better rider has no impact on my life. Step into the 20th century.... Oh wait, make that the 21st.

 

[widebear]

GRINCH YOU NEED TO GET A GRIP.I'm not calling your wife anything.I was trying to make a point about about pampera's and modifieying bikes in general and trying to turn it them into something they were never designed for.You should go back to the begining of this thread and read it very slowly and carefully from start to end. Your reaction is way out of context.

 

[GMP]

Lets start to lighten the tone here. I think you guys are getting a little hot and misreading each other slightly.

I don't think its neccassarily about the riding for Grinch, I'd say the wrenching may be the real passion. We don't have to agree what he wants to do is the only solution, but hell more power to him for trying something different if he has the talent.

 

[Grinch]

Thanks Glenn,
I have no reason to be mean-spirited but I do find the advice to just quit if the proper equipment is not readily available to be quite funny. Someone riding a 15 year old bike because a new one is not going to make them faster is certainly open to some advice-giving themselves... glass houses, as they say?

As I said earlier, I simply wanted a solution to a bike which kicked over like a 650 Honda and not for riding, marriage or training advice. I got some good technical advice and for that I'm appreciative. However, if someone would like to tell my wife she needs to quit is welcome to.. and good luck, LOL.

 

[blitz11]

I'll chime in here, too. (I have a few minutes while I'll eat lunch).

1. I never understood why people criticize others who do things that make them happy. I never understood why people care if someone rides a harley or someone rides a bmw or someone rides a honda. Who cares if someone trailers their bike to Sturgis or if they ride it? No one is hurt if someone rides or trailers. If it makes them happy and it doesn't affect your life, why care?

2. Having said that, maybe Widebear meant that he didn't understand why Grinch was doing what he was doing. I don't think that he meant to condemn him (but reading his post, it did seem a bit harsh). I would hope that Widebear may not fully understand Grinch' motivation.

3. I am impressed with Grinch' ambition, and what he is doing does fill a particular need. My 12 year old daughter has recently found some speed, and is going to need a better bike next year. She presently rides a TTR125, and she's outgrown it. (She's gonna' be tall as she is already wearing men's size 11 shoes!) Right now, she's probably a bit too small (short legs, long torso) for a KTM 200 (and I'll say KTM as GG doesn't offer a 200 now), but between the TTR and that KTM, there isn't a bike which really "works" for her. Having something in between would be perfect for her for the next couple of years. The 125 is too small, and the 200 a bit big. My realistic option is to shorten the suspension, and have new springs made for the 200. (I don't have the fab skills Grinch has).

(TTR and CRF 230s would suck for my kids. Too heavy. Too dull. Yecchh.)

The niche Grinch is filling would fit my daughter to a T. The problem is that for kids growing up, the kids outgrow that niche pretty quickly. If i am a major manufacturer, because kids pass through that stage quickly, I wouldn't expect parents to drop a ton of dough on a transition bike. Thus, they won't make much $$. Kids grow up fast between 12 and 14.

If Grinch builds/sold a stop-gap frame/suspension system which was smaller than the KTM 200 and offered 80% of the KTM's handling/performance, it fills a market gap. When my daughter can really ride the stop-gap bike, and she has physically outgrown it, then we move on. If he can sell that frame for less than fixing suspension, people would be on it.

Better yet, Grinch offers a frame kit using the KTM suspension & wheels, I buy the KTM, do the transfer, then transfer back to the KTM when she's ready. It's a great idea, I think. (Again, sorry for the KTM reference, but at this point, it's my best option.)

I really learn a great deal on this site, and it is good to see different opinions. As i get older, i appreciate innovation and design trade-offs more and more. "Optimal" is only optimal with respect to a particular criterion. Change that criterion only slightly, and the "optimal" solution can change a great deal. What is optimal to Grinch my be severely less than optimal to Widebear as their criteria are very different.

Thanks.

blitz

 

[Grinch]

Better yet, Grinch offers a frame kit using the KTM suspension & wheels, I buy the KTM, do the transfer, then transfer back to the KTM when she's ready. It's a great idea, I think. (Again, sorry for the KTM reference, but at this point, it's my best option.)
blitz

Now you get it !! This is exactly my point, to make a frame that only needs to last a year or two then gets handed down or sold. By having to go to such a great extent (cost, work, time) to make a bike fit properly, many simply 'settle' for something that does nothing correctly. People spend $1000 on suspension and still have a 58" wheelbase so why not just build a frame to hang the ENTIRE KTM parts list on? BRILLIANT !! ahem, sorry.