need help with my top rebuilt

cresstt · 04-08-2008, 04:05 AM

My street bike has an OHC 200cc Zongshen engine. I've used it for 2 years.
Recently I pull off the head and the sleeve off the crankcase and discovered that the timing chain is rubbing against the wall.
What could cause the timing chain to rub against the wall ? the black platic tensioners are okay and there is no sign of extensive wear. The funny thing is that it's the side of the chain that's rubbing against the wall ..not the part of the chain that comes into contact with the tensioner.

also I pulled the stud and accidently mixed them. There are 4 engine studs and 3 are the same size. 1 is slightly smaller. My question is, does the smaller diameter stud goes to the hole where the oil travels from the crankcase to the top (or vice versa)?

I'm trying to back everything back together and having some trouble with the chain. The timing marks are all okay, but I'm having trouble with the cogs on the crankshaft, There are two cogs. where do I hook the chain to ? the inner or the outer cog ? If you look at the blown up parts list in roketa's website, then you know what I'm talking about. Refer to the picture below. Notice that there's two cogs on the right of the crankshaft just below of the dowel.

click to supersize

any idea? thanks

red2003 · 04-08-2008, 07:55 AM

I don't think any of us have had one of these engines apart. Not needed to. Someone with knowledge of the Honda xr200r motor should know as they are a very similar design. You could always call up your local Honda dealer and tell him you have a 1983 Honda XR200R. Same motor pretty much.

fatboy250 · 04-08-2008, 08:46 AM

About how many miles does this engine have on it? I have over 13k on mine and I haven't experienced this ((yet))

It sounds like the chain tensioners could be adjusted to provide more tension or they have maxed out and it's time for a new chain.

cresstt · 04-08-2008, 09:15 PM

Quote:

Originally Posted by fatboy250

About how many miles does this engine have on it? I have over 13k on mine and I haven't experienced this ((yet))

It sounds like the chain tensioners could be adjusted to provide more tension or they have maxed out and it's time for a new chain.

I've put around 20k miles on mine. You are probably right. The engine was previously removed to fix a weakening weld joint. On this bike you cant remove the engine as a whole without first removing the head and the sleeve. So I'd guess that the mechanic that was working on the bike did not set the tensioner properly. I'll definitely be looking at that area.

Red2003,
As for the honda bike similarity, I've browsed part fiche for Xr's and crf's with similar displacement on www.powersportpro.com. None of the bike has the twin cogs setup on the crankshaft. The only reference picture I can find on the web was the Roketa's parts pic. I will remove the rotor and the flywheel later, and see if I can figure out which cog the timing chain should sit on.

katoranger · 04-10-2008, 10:24 AM

20K is probably the highest mileage I have seen.

Sounds like the chain is stretched.

Allen

04-08-2008, 04:05 AM	#1
cresstt Join Date: Jul 2006 Location: KL, Malaysia Posts: 33	need help with my top rebuilt My street bike has an OHC 200cc Zongshen engine. I've used it for 2 years. Recently I pull off the head and the sleeve off the crankcase and discovered that the timing chain is rubbing against the wall. What could cause the timing chain to rub against the wall ? the black platic tensioners are okay and there is no sign of extensive wear. The funny thing is that it's the side of the chain that's rubbing against the wall ..not the part of the chain that comes into contact with the tensioner. also I pulled the stud and accidently mixed them. There are 4 engine studs and 3 are the same size. 1 is slightly smaller. My question is, does the smaller diameter stud goes to the hole where the oil travels from the crankcase to the top (or vice versa)? I'm trying to back everything back together and having some trouble with the chain. The timing marks are all okay, but I'm having trouble with the cogs on the crankshaft, There are two cogs. where do I hook the chain to ? the inner or the outer cog ? If you look at the blown up parts list in roketa's website, then you know what I'm talking about. Refer to the picture below. Notice that there's two cogs on the right of the crankshaft just below of the dowel. click to supersize any idea? thanks
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04-08-2008, 07:55 AM	#2
red2003 Join Date: Jan 2007 Location: Northern Vermont, USA Posts: 1,244	I don't think any of us have had one of these engines apart. Not needed to. Someone with knowledge of the Honda xr200r motor should know as they are a very similar design. You could always call up your local Honda dealer and tell him you have a 1983 Honda XR200R. Same motor pretty much. __________________ First Chinabike: 2006 Roketa RSX200E Current Chinabikes: 2023 Titan DLX & 2022 Lifan KP Mini w/ 210cc BRT kit, 22 RWHP!
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04-08-2008, 08:46 AM	#3
fatboy250 Join Date: Sep 2006 Location: COLUMBIA, SC Posts: 973	About how many miles does this engine have on it? I have over 13k on mine and I haven't experienced this ((yet)) It sounds like the chain tensioners could be adjusted to provide more tension or they have maxed out and it's time for a new chain. __________________ 2008 Jonway MC-70-150 2007 Roketa DB-07B (RSM-200E) 2006 Roketa DB-07A (RSX-200E) 1995 Kawasaki Concours (ZG1000)
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04-10-2008, 10:24 AM	#5
katoranger Join Date: May 2007 Location: Altamont, Kansas Posts: 15,103	20K is probably the highest mileage I have seen. Sounds like the chain is stretched. Allen __________________ You meet the nicest people on a Honda Clone.
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