'72 CL175 engine trouble?
- Thread starter echo
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Started my leak test this evening on the valves, look like the right hand cylinder drained about 5 mm already after just a few minutes. It appears to be coming from the intake valve. I checked to make sure the source of the leak was not the spark plug hole. Hmmm that was the cylinder with the higher compression. Next I will post some better photos of the bores.
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If the gas in the head didn't just pour out of the ports, it suggests that the real leak is past the piston rings.
The bores don't look bad. If you have the budget, I'd suggest new pistons and a rebore and if cash is really tight, glaze bust the bores and fit new rings and then do the head and button it back up. Pistons are not expensive but boring costs money. Someone here had a cheap recommendation not too long ago.
The bores don't look bad. If you have the budget, I'd suggest new pistons and a rebore and if cash is really tight, glaze bust the bores and fit new rings and then do the head and button it back up. Pistons are not expensive but boring costs money. Someone here had a cheap recommendation not too long ago.
I'm having trouble finding air filters for the CL175K6. Anyone know of any source offering them? If not I will attempt to rebuild the old ones with new paper. I saw a few threads on this subject but can anyone refer me to where I can buy the bulk filter paper and what product is good? Thanks and Happy Holidays.
I did my valves this evening and I think it went well. The seats came nice and clean. I made sure to clean off all the grinding compound off (I don't need any liquid sandpaper eating up the valve guides or cylinders). It's not as easy as it looks to use the lapping tool. Kept having re stick the suction cup. And it would seem as you spin it you have to press hard enough to cause abrasion but too hard and the valve does not move. Anyways it was a learning experience as always. Next I was gonna wash the head out real good with soap and warm water - immediately dry and oil the steel valve guides, journals, etc. then reassemble the head and repeat the leak test. But first I was going to try to get some new valve stem seals. The only rubber parts that came out with the valves were on the exhaust side. Do the intake valves not have seals?
Honda changed the seal design a few times. IIRC, CB160 had no seals. CL175 sloper had an O ring design on the exhausts. 175 uprights had a real seal but only on the exhausts and CB200 had proper seals on intake and exhaust.
So called upright motors are still inclined a little - 8 degrees I think, so oil tends to collect at the front of the motor. In general, intakes need seals because they are subject to low pressure that tends to pull oil down the valve stem. Exhausts by comparison are under higher pressure, so there's less tendency to suck oil. CB200 guides will work in a 175 head, but that's a lot more work than necessary if the guides are OK.
So called upright motors are still inclined a little - 8 degrees I think, so oil tends to collect at the front of the motor. In general, intakes need seals because they are subject to low pressure that tends to pull oil down the valve stem. Exhausts by comparison are under higher pressure, so there's less tendency to suck oil. CB200 guides will work in a 175 head, but that's a lot more work than necessary if the guides are OK.
Ok I found the exploded diagram for the valves in the shop manual. Looks like only the exhaust valves are supposed to have seals. I have ordered 2 seals but cannot find the o-ring cushion that sits underneath it (#8 in diagram). Wonder if I can get away without it? The old ones are no good.
One other thing that's bothering me is the o ring, #11. Looks like they are supposed to fit around the bottom of the exhaust valve guide at the base? I did not find these on either exhaust valve guide when I disassembled my head. Nor do I see how to install the new ones and what keeps them in place. Any ideas?
One other thing that's bothering me is the o ring, #11. Looks like they are supposed to fit around the bottom of the exhaust valve guide at the base? I did not find these on either exhaust valve guide when I disassembled my head. Nor do I see how to install the new ones and what keeps them in place. Any ideas?
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themotoworks
Been Around the Block
try mcmaster.com, you can find any o ring of any material there, and usually quite inexpensive
Thanks to themotoworks for your suggestion. I've ordered from mcmaster for stuff before. After reading carefully on some other posts, the 2nd stem seal o ring "cushion" should not be needed with the ones I have ordered. I found #11 seals mentioned on partsfish and have some on the way, but still I don't see where they go in. There's a very detailed cl175 thread on Hondatwins forum and he does not show them in his photos of disassembled valve components. So I'm wondering if it's something that came out on early models.
New piston kits are on the way for 0.5 mm overbore. The overboring will be done at Combustion cycles in Durham NC. I was debating on having them hone the cylinders or to do it myself with a flex hone and drill. It's another skill I would like to put under the belt, but I don't want to screw up everything with a bad hone job.
Lastly, I decided to rebuild the air filters. I cut out the old filter material as much as I could with a razor knife and burned out the remaining filter and glue after soaking in kerosene. It comes out real nice with a putty knife when it's hot. That was kind of fun actually. A Fram auto filter was located with the same size pleats and cut up for new filter paper. Finally glued it in with gorilla glue (it expands to fill all the little gaps). Not a bad result for $15.
New piston kits are on the way for 0.5 mm overbore. The overboring will be done at Combustion cycles in Durham NC. I was debating on having them hone the cylinders or to do it myself with a flex hone and drill. It's another skill I would like to put under the belt, but I don't want to screw up everything with a bad hone job.
Lastly, I decided to rebuild the air filters. I cut out the old filter material as much as I could with a razor knife and burned out the remaining filter and glue after soaking in kerosene. It comes out real nice with a putty knife when it's hot. That was kind of fun actually. A Fram auto filter was located with the same size pleats and cut up for new filter paper. Finally glued it in with gorilla glue (it expands to fill all the little gaps). Not a bad result for $15.
