little help please!

[bear]

Ok heres the problem. I replaced the rings on my dazon 150r & the thing was running awesome, and then of course, something went amiss! I went to start it one day and it would turn over and almost catch, but not do so! I took the top end off to find that the cam chain tensioner had slipped down beside the chain causing it to catch and jerk. I fixed the problem, put the piston back tdc, and put everything back together as should be. I still cant get the thing to fire! it just almost hits, then nothing any suggestions?

[xlint89]

What's your compression?

Have you checked the valve adjustment?

Made sure the cam is in time with the piston?

Good spark?

Can you smell fuel?

Ignition switch grounded?

[bear]

I checked to make sure cam was in sync with piston, checked valve adjustment, got good spark, fuel supply, & switch is ground. I can't officially check comp. due to took gage back (was a loaner), but definitly feels the same and has a good chuff to engine when it does try to kick over, this one has me kinda stumped! I just know its gonna be something simple and be one of those doh! moments when I discover what it is!!!

[xlint89]

Cam chain tensioner "unlocked"?

[bear]

I thought that too, especially after putting it together the 2nd time, but its unlocked

[xlint89]

Is your flywheel actually lining up with the piston at TDC? What i mean is the flywheel timing matching the cam timing? (possible sheared woodruff)

[bear]

I'll check it out n let you know, actually have a day off 2marrow!

[bear]

I got a chance to check "everything" over again today and yes it all lines up as it should. I have done all I know to do, even took my other one apart to see if I missed something and I can't figure it out!!! I'm just going to bite the bullet and take it to the shop, as much as I hate this idea, I'm flat stumped!

[SLESTAK75]

Did you actually look at the plug to make sure its not shorted, this could show good spark with traditional tests but no spark in the chamber.

[xlint89]

Did you happen to get a compression reading?

Why did the cam chain pop out of the tensioner? Did your chain have alot of slack when installing the cam?

[bear]

#1 Ok slestak changed out the plug & no go #2 xman i think when i was putting the tensioner back in the block it pushed the plastic guide to the side of the chain & then after a little rotation of the cam chain it grabbed it and pulled it down beside the chain itself! once I took the topend back apart I discovered the tensioner beside the chain. I need to stress that the buggy was running great for about 2 days before this happened & then when I went to start it on the 3rd day I could tell something wasnt right & thats when I discovered the tensioner problem and corrected it, could the cam chain have slipped a little when this happened and if so what damage could it cause? I have put the piston back tdc and realigned the cam & chain, checked tolerances on valves made sure I have spark & fuel, I just dont know! I'm going to take it all apart again 2marrow & put it back together again just to make sure again!!!

[xlint89]

How much slack is on the chain when you installed the cam? Compression?

[SLESTAK75]

If the chain was slack enough it could have jumped a few teeth and put the piston in contact with a valve bending it ever so slightly. Really need to check compression. Double check that the cam isn't 180 degrees out. That's all I've got. Have you made sure that the Klingons haven't put some sort of power dampening field around your buggy?

[bear]

I'll have more answers later today guys, when I get my honeydo's done -n- get to tear into it again! more later.

[bear]

Ok guys took it all apart (again) today and checked it over. It seems as if slestak was right my intake valve has made contact with the piston and has ever so slight a bend to it, also see the contact point on the valve head! there also seems to be some extra slack in the cam chain as x-man was asking about! sssoooo what now do I just need new valves or will it also need the new cam chain as well?

[xlint89]

New valve shouldn't be an issue as long as the valve guide or seat isn't damaged.

A new cam chain may be in order. According to the manual, you need to remove the crank to replace. Many guys have installed the chains by cutting the side plate, tieing it to the old chain, pulling it through, and resecuring the side plate.

[SLESTAK75]

Tear down your valves and make sure the valve seats aren't damaged where the bent valve came in contact. My need to lap new valves to the seats. Also better check that piston over really well for damage that could come back to bite at around 7000 rpm's one day. Sorry to hear of your damage. Don't know if you have replaced springs or not but this could have been caused by floating valves as well. If you are going to do it why not look into something like this.
http://www.ebay.com/itm/180705617664...84.m1423.l2649

[SLESTAK75]

Also should have a good look at the tensioner for damage.