Gorr 144 vs. Blaster swap?

Been thinking about getting a second bike to take friends riding. Thinking '02 YZ125 chassis, for the same reasons I went '02 on my 250: first year of an improved chassis and last year for green sticker. All the plastics interchange, so it saves on parts inventory. I have three friends I already know about who would go, ranging from 5'3"/110 lb (rides a Buell streetbike) to 5'9"/127 lb (has ridden every kind of bike everywhere) to 6'3"/155 lb (has done some street and off-road riding) to 6'1"/200 lb (drives an automatic Accord), so I'll probably end up with a little bit of a spring collection and setup notebook. Typical riding terrain is probably just ordinary Mojave trails and desert. Nothing too challenging.

I like that at least one of the lowering links available also reduces the wheel rate, so installing that for shorter riders would also automatically help with the suspension stiffness for their lower weight. However, I'm a little concerned about the increased rake from lower rear suspension hurting the handling. You can slide the forks up in the tubes a little bit, but not enough to keep the angles the same when the rear is down 1.6 in. or so. Anyone have experience? I'll be reading some more on lowering links, I guess.

I got sucked into a bunch of different threads talking about swapping in Blaster engines (smooth, rideable power band, light weight, no radiators, etc.). I think most of the challenges are reasonably easily solved, but there's the unknown of the pipe. Blaster pipe doesn't work on a bike frame. WR200 pipe would fit the motor, but wants to go right through the frame and shock reservoir on a modern chassis, so it would take serious mods. Could easily become a science project sucking up significant amounts of time and money. (I built a spreadsheet to analyze the weird quad gearing, and decided it's not a negative.)

On the other hand, just getting an Eric Gorr 144 ported for low-to-mid range power would probably cost less in the first place, be a heck of a lot easier to build and take less time. When I eventually went to sell it, it would actually have some resale value. I'm an experienced vehicle builder and all that, but Gorr's name is worth a lot more in the used bike market than mine.

What I typically see from beginning riders on easy terrain is issues using the clutch, revs, shifting, etc. A 125 is great for teaching that, if someone is committed to learning, but could be frustrating for someone not naturally inclined or experienced who just wants to try something new. Does the extra displacement and low-mid porting of the 144 tame the 125 and make it more noob- and trail-friendly?

Neither Moose nor BPD radiator guards are listed for the 125. I've installed the '05+ Moose guards on my '02 (posted the details on TT a few weeks ago). Would just have to fabricate something for the 125, I guess.

Generalizations driving my thoughts in this direction: I'm not really interested in anything with a rear drum brake - this is a personal preference based mostly on emotions that I'm not about to debate with anyone. An XR250R would be a good choice based on maintenance requirements and power characteristics, but is probably too heavy for the 100-ish pound riders. The 125 can be set up for the full range of riders. I definitely don't want the maintenance of a modern four-stroke race bike.

Edited by FRECNDY

You already have the answer, go with the 144 kit for all the reasons you mention. You can drop the forks in the triple clamps, but the lower you go the twitchier it will be at higher speeds. My buddy had Suzuki with 144 kit and his wife rode it in the woods. She was not an experienced rider and she did quite well.

Go with Gorr. In the process of getting my 295 done. Super nice guy to deal with and he is as smart as anything when it comes to engines. It will probally give you more power than a blaster engine too.

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