Big wheel problems [Archive]

hoosierlogger

01-15-2013, 11:02 AM

Well I was enjoying my BW200 that I have had for 2 weeks yesterday. When it started making a hammering noise from the top end. If you let off of the throttle and pull in the clutch it dies like you flipped the kill switch, but will power through it while running rough. It always starts right back up and would run fine for a few more minutes till it done it again. I have eliminated any shorts in the wiring. I am leaning towards a sticky valve, broken valve spring, or slightly bent valve since it will come out of it. I assume the hammering is the rocker hitting the valve. I tried some seafoam and marvel mystery oil to clean and free the valve. Nothing worked. Looks like i am going to have to tear the top end off to take a look.

Vealmonkey

01-15-2013, 11:22 AM

Did you run a compression check? Pull the plug and inspect that? Check your valve chain tension? Check oil? Check timing? Start simple first. Maybe the decomp?

hoosierlogger

01-15-2013, 11:26 AM

I adjusted the cam chain and timing per the ytm200 manual. Ialso unhooked the decompression cable, no difference. Fresh oil and filter. It just about has to be in the head. Cant see a compression test telling anything since it will run fine till it acts up then once it dies, runs great again. That is what makes me think sticky valve taking too long to close.

ezmoney1979

01-15-2013, 11:40 AM

Might be time for a 225 swap!

MIK6

01-15-2013, 11:46 AM

ezmoney1979

01-15-2013, 11:55 AM

hoosierlogger

01-15-2013, 12:27 PM

Did you leave the fuel on? Could it be fluid locked?
I have had this problem on my T3s, my P3 and just fought it w my GFs trailblazer250. The blazer would run then build up pressure and either just die or it would backfire than die. I cleaned carb, new plug ect befor i found gas in the base.

MIK6/ MikeNo, the fuel was shut off before storage. It did it before I did the oil change. I thought it was starved of oil to the top end. I loosened the screw on the head and plenty of oil came out. I am afraid I am going to have to go inside.

MIK6

01-15-2013, 01:44 PM

That's more of a two stroke issue with the crankcase filling with fuel.
I agree its a 2stroke issue, but prairie700 (which i also have lol) are known to do it as well. Just something i always keep in the back of my head when something wont start.. lol
MIK6/ Mike

Doink

01-17-2013, 10:58 PM

The noise is definitely worth investigating, but it is very possible (probable, even) that your CDI is shot. Start searching for an affordable one now. I have read, heard and experienced the very same problem you are describing. A new CDI won't be cheap, so eliminate everything else before you put money down.

hoosierlogger

01-18-2013, 06:07 AM

Are the CDI's the same as the ones from a ytm200?

Doink

01-18-2013, 11:56 PM

No compatible unit has been found for the BW200 CDI so far. If you try a ytm200 and it works, let me know. I'll be VERY interested.

El Camexican

01-20-2013, 02:53 AM

I'd open the carb and look for a piece of junk that could be causing it to lean out before you pull the top off it. You might get lucky.

hoosierlogger

01-20-2013, 07:21 AM

I'd open the carb and look for a piece of junk that could be causing it to lean out before you pull the top off it. You might get lucky.

I cleaned the carb the day I brought it home. It had been sitting for a while in the guys barn.

When it dies, it is like some one flips the kill switch. There is no stumbling like it is running out of gas. And the funny part is it will start right back up 2 seconds after it dies.

El Camexican

01-20-2013, 11:34 AM

I cleaned the carb the day I brought it home. It had been sitting for a while in the guys barn.

When it dies, it is like some one flips the kill switch. There is no stumbling like it is running out of gas. And the funny part is it will start right back up 2 seconds after it dies.

I had a very similar issue on another bike. In the end the problem was a piece of steel-wool leftover from a cleaning that was wound up like a spring in the main jet causing it to curl up and close when under load causing the bike to stall and then allowing it to start and idle a few seconds later. I am speculating that your “knock” which I understand to be intermittent, could be caused by detonation brought on by an extremely lean condition which is occurring just prior to the engine stalling. That said I haven’t heard and felt what is happening, so I may be 180 degrees off, but the combination of symptoms you are describing seem to rule out a valve train/piston failure.

You may be right, it might be in the head, but you may just have a plugged, or loose jet, a sticking float or a clip off the needle. If it’s not the carb you’ve lost 15 minutes of your life, but if you open that head for no reason you have lost a lot more.

hoosierlogger

01-20-2013, 04:48 PM

After a thorough session of beating on it and paying close attention to what it is doing, It only seems to be happening in the mid range. It will sit and idle forever. It runs WOT no problem as long as you have the room to do it. It only seems to happen in the mid range. Ill go through it again as soon as I get the time.

captainweezy

01-22-2013, 01:09 PM

So you wont be riding it up the backbone any time soon? :D

hoosierlogger

01-22-2013, 07:48 PM

So you wont be riding it up the backbone any time soon? :D
Not till I figure out why it is doing this. If Jensen can ride a 70 up it, a big wheel shouldn't have any problems.

kiser

01-23-2013, 10:18 PM

Good luck on the BW problem. Hope it isnt to serious. I think a BW would have a decent chance on the backbone! They are like a 2 wheeled goat! LOL!

hoosierlogger

01-24-2013, 06:20 AM

Thanks for the support guys. There is another one for sale local to me. It sounds like it needs a top end re build, but the plastics all look good. I might try to pick it up for #300 or so. just to try a different CDI before I tear the top end off. I could always part it out and make my money back then some.

Doink

01-24-2013, 02:02 PM

If you've got WOT and idle, then that CDI is probably OK. I would go through the carb again. Before you do, take out the spark plug when it stalls and see what it looks like. It will you give you an idea of the condition of the combustion chamber when it shuts off.

hoosierlogger

05-27-2013, 08:34 AM

Ok Here is a little update. I got it out of the shed a couple of weeks ago. I rode it for about a half an hour, shut it off. When I went to start it to put it away, it wouldnt start. I pushed it in the garage and took the top end off of it. When I had the head apart nothing looked out of place. Valves had a good sealing ring all the way around and they were both straight with no signs of hanging up in the guides.

I put it all together and tried to start it, no spark. Ordered a CDI off of ebay. Got it, swapped it, still no spark. So today I am going to investigate the kill switch, wiring, coil, and stator. The connections on the CDI looked a little dirty, so Ill clean them up too.

I friggin hate electrical.

hoosierlogger

05-27-2013, 11:19 AM

Well gang the stator is supposed to show 415 ohms +/- 10%. Mine shows 0. Looks like a good place to start.

my1423

05-27-2013, 09:31 PM

Chasing an electrical bug myself.
Found bad connections on my cdi.
Good cleaning and all back to normal.
The cdi prices are silly!

Do you have an electric start or just kick?

Can you post a pic of the stator?
What is the flywheel diameter in millimeters?
Debating about opening mine up and swapping the cdi primer for one on a honda.
They can be had for 20$ then a pit bike/ honda cdi will work for mine.
Ordered one to test with but still waiting for delivery.
If the stator is too far different to swap in I was planning on adding resistors to bring the output of the stock down to tolerance for the pit cdi.
Kinda hesitant to open the case up if it is not needed.

For your stator. No common ground.
Check from black to brown and black to red need ohmed.