Posts
12455
Joined
11/16/2011
Location
Menifee, CA, USA
Son's friend has a YZ 250 with a pinched, stuck throttle housing.... Somehow. New ODI lock-on grips, I've triple-checked that it has the right cam, no binding or hangups in the cable, perfect position on the bars... Still runs like WFO when started. I've swapped my own Renthal grip into the system and no change. When I remove the throttle grip and let the cable hang free, it idles fine. WTAF???
Check to make sure the cam isn't installed backwards/flipped in the housing.
I once had this exact issue happen to me.
Yeah, cam is fine.
Also, the cable and sheath are nice and loose in the routing:
"runs like WFO when started"
Does it have an air leak?
Didn't have an air leak last time he rode. The cable feels too short. Even when adjusted as loose as it can go, there's clearly tension on it. I'm going to try a new cable on it.
The Shop
Free shipping: VITALMX
Luxon 4-Post Bar Mounts
$189.95 - $239.95
DeCal Works Huge Plastic Inventory of UFO and Polisport kits.
Sounds like it actually is not the right cam. Line up the new and previous cams side by side and compare the location of the cable hole, etc. Obviously something is weird with the cam if it's holding tension on the cable.
I know you said it's not the cam but....Try flipping the cam. If it's orientated the wrong way it will cause the throttle housing to bind once the housing bolts are tightened.
I'm on my 2nd cam, both identical, labeled as cam "C," which is the right one according to ODI, and both look to have the same profile as my Renthal one. 🤷😑
There's only one way for that cam to go. It's oriented so that the cable ramps up through the split to the seat for the cable end.
Yep. I'm just suggesting to have a another look at it with fresh eyes.
Sounds like a problem with the cable not seating properly in the housing, I'd look at the inline adjuster. Especially with the cable being used/stretched, too loose and it pops out of the housing, puts weird angle/tension on the cable.
ON a related issue, anyone know what the correct bolt size is to replace the screws on the housing? I can't believe that they still use the same system.
Check that the cable adjuster under the rubber boot isn't threaded out of the throttle housing.
Check that the cable sheath isn't pulled out of the adjuster and hooked on the side.
Check that the cable sheath isn't pulled out of the carburetor slide cap.
It is less likely, but possible that he has popped the cable out of the little groove in the carburetor slide.
I have seen lots of people do that while working on their carb because they don't line up the little rail in the plastic spring-seat with the groove.
I have the throttle off of one of my bikes and I'm showing about 66mm of braided cable between the threaded adjuster and the crimped end.
M6-1.0mm x 25mm for both housing bolts. They are flanged 8mm hex heads.
The Yamaha pulley systems have a nice light pull that rivals aftermarket throttles and they still feel good after 100 hours.
The KTM and other OE carburetor throttles feel terrible at 20 hours.
Why would they change the throttle design?
I just installed ODI cam C on my YZ250 couple weeks ago. No issues.
Thanks for the info....I was really just referring to the screws. For my entire riding life I have nearly stripped the heads on those suckers at the first turn.
Post a reply to: YZ250 Throttle assembly help