xr 250 hotstart problems

[brettkrupa]

xr 250 decompression problems

I was wondering if anyone has any experience with the hotstart (decompression) system on a '84 Honda 250xr? Something is totally messed with it and I do not understand how it works. There is a small black lever for it under the clutch, the cable from that goes to the top end on a swivel mount (which may or may not be doing something inside the engine?) then from there another cable attaches and runs down to where the kick-start is and attaches to another swivel on the case. Anyone have any knowledge on how all this stuff works and why the hotstart would be stuck on?
Thanks, Brett
(sorry if this is a dumb question, i am new to the whole dirtbiking scene)

 

[Tom68]

Cable to topend is decompressor, hot starts are are bleeds which you hold in when kicking a hot or flooded motor. If either decompressor cable is holding a valve open its adjusted incorrectly. The cable from the kickstarter works automatically I use the hand control to get the motor just past TDC so Ican get a full kick, the bottom cable I back off so it doesn't work.

 

[Ol'89r]

Like Tom said, the decompressor unit from the kickstarter to the head works automatically. If the lever on the head is moving back and forth when you first start to kick the kickstarter, it should be ok. It should move back at first and then snap forward as you kick the kickstarter. If it doesn't, make sure the cable is adjusted correctly and the lever or cable isn't binding. The little tab on the decompression lever on the head can break off sometimes inside the head. When this happens the decompression lever stops working. It's easy to replace but make sure you remove the little broken piece from the top of the engine.

The first thing I would do is check the valve clearance to make sure you don't have a tight valve. Should have at least .002" clearance on the intake and .003" on the exhaust. Check your manual for the exact figures and proceedure for how to adjust your valves. If you don't have a manual, now may be a good time to buy one.

 

[brettkrupa]

I used to have a manual until I lent it out and never got it back, I have ordered a new manual but it will be a couple weeks until it gets here (live in small town so there are none locally)
I'm thinking that it sounds like that tab on the inside might have broken off as I removed all the cables from it and turned it back and forth by hand but it does not do anything. I also kicked the engine over a couple times and the cable that comes from near the kick-start was indeed moving back and forth.
Am I going to need to pull the whole engine and take the top end off to fix this? Because I was thinking that I could get started on that while I wait if that is going to be the necessary. As well, is it true that the decompression just works with a plug that opens and allows air through and that you can just take that plug out and screw in a normal spark plug to temporarily disable it?
Thanks a ton!, Brett

 

[Ol'89r]

You only need to remove the top cover, (rocker cover) on the engine. One of the bolts that holds the rocker cover on also holds the decompression lever in the head. Once the cover is removed, the decompression lever will slip out.

There is no plug. The decompression lever pushes down on the rocker arm and holds the exhaust valve open a little bit. That is how it works.

 

[brettkrupa]

Okay thanks, I will take the top cover off and inspect the decompression lever and see what the problem is and if anything has been sheared off now that I know how it works. Thanks again!