185s compression

[Bo0YaA]

Ok I need some advise,

I have purchased 2 185s trikes and have been going through them thinking I would make 1 good machine out of the 2 and sell the other. Tonight I was riding the one I have decided to keep around and its real strong other then a real bad slapping noise comming from the head. The guy I bought it from said it was probably the timing chain. It doesnt smoke at all and idles great. Now heres the issue, I tested the compression and all three times I did so I got a reading of 60lbs so I thought I would check the other motor just to see how it compares and it had 75 on two of the three tests and 90 on another. The problem is, the motor that has the higher compression runs like crap lol. Im sure that its just simple stuff to fix it but to keep the higher compression bike would mean a complete swap of everything from one bike to the other
So I guess my question is, first what is the compression supposed to be on an 83 185s and is 15lbs difference in reading a dramatic difference.

Thanks again for the help

[bigreddaddy]

Did you test compression with the throttle help open all the way? If not test them again because those results seem very low. I would guess around 150psi or somewhere in that area is where they should be.

[Bo0YaA]

No I didnt open the throttle, ill test agian in the morning.

[3 weelin geezer]

Mine is a whole lot higher than that. 140 psi at least. How did you test it? The book says to give it a few whirls I believe. My guage reads the peak compression only it seems. I don't remember if I held the throttle open or not though. It might not have had the carb attached at the moment either. My compression ratio is around 10:1 though. I had to replace the piston and hone the jug to make it stop smoking like a 1800's locomotive. Still, 60 is really low. how does your plug look? All fouled up?

Whats wrong with the 'other' motor that you don't want to swap parts into? If it makes a slapping sound and you think its the chain, try adjusting the tensioner.

The book says for a 185S it should read 8.0:1 and for a 200 it should be 7.8:1. That means that you should be getting somewhere in the neighborhood of 120 psi. +/- 10 psi I think. Whats the condition of the engines? Are they well kept and just worn out or are the abused and worn out? ( take a look at the oil filter) Pics would be nice.

[Bo0YaA]

Ok I checked them both again today, this time I pulled three times with wot and each was 150 psi so I guess its sixes which motor I keep. I ordered a manual today and Ill try to tighten the chain once i know 100% how to do it.

Also, the one that runs like crap doesnt have an air filter on at all could this be the reason why?

[3 weelin geezer]

Maybe. Mine had a dryred shop rag for a filter when I bought it and it smoked like an old 1800's coal powered train.

They didn't even put any filter oil in it. Thats why I had to get a bigger piston. I had to hone the jug real bad. Some people think that removing that filter is a good thing that it gives it more power but it doesn't. Thats why there are different jets. To get the right amount of fuel for the available air. Besides, that filter was engineered not only to keep the dirt out but to keep a certain level of vacuum in there. Tighteneing the chain is easy. All you do is loosen the tenisoner when its running and it automaticly adjusts. Then, you just lock it down and stick the rubber cap back on.

[Bo0YaA]

Really?? just take the rubber cap off while the thing is running and loosen it up? and I guess if it is the chain thats making all the noise it will quit. Then just tighten and its done right?

[3 weelin geezer]

Cam chain tension--adjustment

31 With the engine idling, remove the rubber cap and loosen the cam chain tension adjusting bolt (dont loosen the smaller 6 mm bolt)

32 When the adjuster is loosened, the tensioner will automatically tension the chain properly.

33 Retighten the adjuster and install the rubber cap.

[Bo0YaA]

Worked like a charm slapping noise is gone!! Thanks geezer