2006 YFZ project timing issue welded crank nut and carb dilemma

[RaptorChaser]

Just got my hands on a rough '06 YFZ. It's got a bit of a shady history and supposedly has a big bore kit, Hot Cams, and other mods. It starts up but just won't rev past idle. My mechanic noticed the exhaust cam timing is off by two teeth, so we'll fix that. But here's the weird part: the crank nut is welded on. Has anyone ever seen that before? Why would someone do that?

I also took a look at the Keihin carb, and it's in pretty rough shape. I'm torn between spending $300 on a dealer rebuild, finding a used one to fix up myself, or trying one of those $65 Amazon knockoffs that my mechanic says aren't too bad.

I'm new to YFZs (I've only had Hondas and Polaris), so any tips or experiences you can share would be really helpful.

 

[Dylan1]

Welding the crank nut's rare, it is probably to keep it from loosening or theft and for the carb, I'd avoid cheap knockoffs

 

[like it like it]

Just got my hands on a rough '06 YFZ. It's got a bit of a shady history and supposedly has a big bore kit, Hot Cams, and other mods. It starts up but just won't rev past idle. My mechanic noticed the exhaust cam timing is off by two teeth, so we'll fix that. But here's the weird part: the crank nut is welded on. Has anyone ever seen that before? Why would someone do that?

I also took a look at the Keihin carb, and it's in pretty rough shape. I'm torn between spending $300 on a dealer rebuild, finding a used one to fix up myself, or trying one of those $65 Amazon knockoffs that my mechanic says aren't too bad.

I'm new to YFZs (I've only had Hondas and Polaris), so any tips or experiences you can share would be really helpful.

To add to @Dylan1 here, probably stripped it and just sent it with the welder. As for the carb, if you're already deep in a sketchy build, might as well try the Amazon one first and upgrade later if it sucks.

 

[Veronica.sims002]

I wouldn't dump $300 at the dealer unless you're going for showroom perfect. If you're confident with a wrench, grab a used OEM and rebuild it yourself, its way better than gambling on the $65 eBay specials

 

[Jah.got.me]

Welded crank nut isn't normal but I've seen it done to keep it from loosening, usually a sketchy fix and I kinda agree with @Veronica.sims002

 

[Frosties]

Just got my hands on a rough '06 YFZ. It's got a bit of a shady history and supposedly has a big bore kit, Hot Cams, and other mods. It starts up but just won't rev past idle. My mechanic noticed the exhaust cam timing is off by two teeth, so we'll fix that. But here's the weird part: the crank nut is welded on. Has anyone ever seen that before? Why would someone do that?

I also took a look at the Keihin carb, and it's in pretty rough shape. I'm torn between spending $300 on a dealer rebuild, finding a used one to fix up myself, or trying one of those $65 Amazon knockoffs that my mechanic says aren't too bad.

I'm new to YFZs (I've only had Hondas and Polaris), so any tips or experiences you can share would be really helpful.

Wow, that's quite the project! Do you think the welded crank nut might have been done as a quick fix for a stripped or damaged thread, or have you seen it done for performance reasons on other YFZs?