68 CL175 Project Vicarious
- Thread starter Big R
- Start date
Big R
Heaven is so far away.
Re: 68 CL175 Project Vicarious - first riding video
Don't get too excited yet - I was still surging so I tried 160's..... still surging. So I knew it was a fuel delivery issue. Ended up being a clogged filter. And I'm at work right now so I can't try anything else til tomorrow morning.
Don't get too excited yet - I was still surging so I tried 160's..... still surging. So I knew it was a fuel delivery issue. Ended up being a clogged filter. And I'm at work right now so I can't try anything else til tomorrow morning.
Big R
Heaven is so far away.
Re: 68 CL175 Project Vicarious - first riding video
Flickable is right - that's what I think of when I see a golf-ball size rock in the middle of the road.
Tuning this thing is driving me nuts!! I have 160 mains in right now (Mikunis) and it's still lean at the uppermost rpm's. I've put on a fresh fuel filter, tried opening the gas cap at WOT, checking all the gas flow to the carbs. I can't imagine getting bigger mains for this thing. I've got it down to a last few options:
1) since my 200 tank has a single outlet petcock, I can put the original tank back on which is a dual outlet
2) upgrade my coil to a Dyna coil
3) get an electronic ignition
4) sacrifice the entire bike to the Honda gods in a massive fire
Right now #4 is at the bottom of the list......
Flickable is right - that's what I think of when I see a golf-ball size rock in the middle of the road.
Tuning this thing is driving me nuts!! I have 160 mains in right now (Mikunis) and it's still lean at the uppermost rpm's. I've put on a fresh fuel filter, tried opening the gas cap at WOT, checking all the gas flow to the carbs. I can't imagine getting bigger mains for this thing. I've got it down to a last few options:
1) since my 200 tank has a single outlet petcock, I can put the original tank back on which is a dual outlet
2) upgrade my coil to a Dyna coil
3) get an electronic ignition
4) sacrifice the entire bike to the Honda gods in a massive fire
Right now #4 is at the bottom of the list......
Re: 68 CL175 Project Vicarious - tuning woes.......
Well, these things did come stock with 180 mains. I keep going back to "CB200 remix" 135 mains, he ended up running stock exhaust though. Have you messed with the air mix screws to richen things up?
Well, these things did come stock with 180 mains. I keep going back to "CB200 remix" 135 mains, he ended up running stock exhaust though. Have you messed with the air mix screws to richen things up?
Re: 68 CL175 Project Vicarious - tuning woes.......
Rich, I tried reading through all 55 pages and I'm sure I missed something, but that jetting sounds a long way out. Are they still the stock carbs or did you fit Mikunis? Stock jets are a different numbering system and it's almost impossible to compare Keihin jet numbers to Mikuni rounds or Hex jets.
What carbs
What size and style and make of main jets
What needle number and clip position
What slide
What slow jet and air screw position
What float needle jets are in there (size)?
We have build several fast sloper motors from 160cc to 240cc with carbs ranging from stock to 26mm keihin and 26mm Mikuni. may be able to point you in the right direction.
One simple test you can do is to remove the fuel pipe from the carbs, and put it into a measuring jug. Measure how much fuel flows out in say 1 minute. If it's not much try for a longer time and let's be sure there's enough flow to the carbs first. If the flow to the carbs is adequate, we can move on to the carbs and test to see that there's enough flow into the bowls.
You can lightly port the feed ports to allow more fuel to get to the float valve if necessary.
Or email me
Rich, I tried reading through all 55 pages and I'm sure I missed something, but that jetting sounds a long way out. Are they still the stock carbs or did you fit Mikunis? Stock jets are a different numbering system and it's almost impossible to compare Keihin jet numbers to Mikuni rounds or Hex jets.
What carbs
What size and style and make of main jets
What needle number and clip position
What slide
What slow jet and air screw position
What float needle jets are in there (size)?
We have build several fast sloper motors from 160cc to 240cc with carbs ranging from stock to 26mm keihin and 26mm Mikuni. may be able to point you in the right direction.
One simple test you can do is to remove the fuel pipe from the carbs, and put it into a measuring jug. Measure how much fuel flows out in say 1 minute. If it's not much try for a longer time and let's be sure there's enough flow to the carbs first. If the flow to the carbs is adequate, we can move on to the carbs and test to see that there's enough flow into the bowls.
You can lightly port the feed ports to allow more fuel to get to the float valve if necessary.
Or email me
Re: 68 CL175 Project Vicarious - tuning woes.......
Teazer, Rich and I are both running Mikuni VM20's. Once I get my electrical sorted I'll be doing the same tuning. another CB200 project here with the same mikunis ended up with good running conditions with 17 pilots and 135 mains with pod filters and stock exhaust. that is sort of what we are using as a baseline.
On your fuel flow test what are you looking for for flow?
Teazer, Rich and I are both running Mikuni VM20's. Once I get my electrical sorted I'll be doing the same tuning. another CB200 project here with the same mikunis ended up with good running conditions with 17 pilots and 135 mains with pod filters and stock exhaust. that is sort of what we are using as a baseline.
On your fuel flow test what are you looking for for flow?
Big R
Heaven is so far away.
Re: 68 CL175 Project Vicarious - tuning woes.......
Sorry Teazer, I work midnight and sleep all day.
But ya, Diesel's right - VM20's. Everything's stock (needle, slide, etc) except for the pilot and the main jet. Oh, and the clip is in the 2nd notch from the bottom on the needle. I do appreciate any help you can offer though.
What should the flow rate be? Would that be on Mikuni's website somewhere?
Sorry Teazer, I work midnight and sleep all day.
But ya, Diesel's right - VM20's. Everything's stock (needle, slide, etc) except for the pilot and the main jet. Oh, and the clip is in the 2nd notch from the bottom on the needle. I do appreciate any help you can offer though.
What should the flow rate be? Would that be on Mikuni's website somewhere?
Re: 68 CL175 Project Vicarious - tuning woes.......
Good Question. let's say the motor makes 25Hp and runs with BSFC of say 0.6 pounds of fuel per hour per HP. so that's 3 pounds of fuel per hour or roughly 100cc per minute.
If the motor burn less efficiently than that it would need more fuel. So we want to see at least say 200cc/minute to have a reasonable margin of safety.
Those carbs don't have a lot of parts available for them. they caome, according to my notes, with #239 series O-6 nozzle. The O-6 is probably OK but may make it a little rich in the middle which is a safe way to go. the air jet is fixed and is a tiny 0.5mm, so Mr mikuni doesn't think teh fuel slope needs to be trimmed at the top end.
The Needle is middle of teh road 4J13 which is right in the middle of the 5 optional 4 series needles. Good safe place to start swapping brass.
Our 240cc motor uses 26mm Mic's and runs 130 mains in the same large hex 4/042 series, so with a smaller motor and smaller carbs and lower state of tune, I'd start in the 130-150 range. We need a #40 slow jet!!.
I'd start off by getting the slow jets right. Air screw should be in the 1 -2 turns range. If it's further out go down a jet size and if it's less than 1 turn go up on that jet. When the idle seems right, try to ride off with just small throttle opening and test to see if slightly more (or less) air screw improves that. It should pull cleanly off idle.
Next get the main jet right and that requires either a dyno with gas analysis or a long slight hill to ride up, flat out. Do a plug chop at the top and see what color the plugs are. They should be WHITE on the tips with some color way down inside the body. You are looking for 2mm or so of color band on the insulator down where it meets the body. Check teh side strap and center tip for signs of overheating or of deposits. the tips of both electrodes should be burned clean but not showing signs of distress.
Forget all the BS about brown plugs at part throttle - it's all meaningless. Plugs are not hot enough to read properly unless the motor is WFO and working hard.
You will need a flashlight and magnifying glass or spark plug reader - that's a flashlight with a lupe on the end. You don't need a super expensive tool. Your Maglight and a cheap small magnifying glass are OK.
When you are sure the very top end is OK, then it;s time to look at part throttle. Revs are less of an issue than how wide the throttle is open. mark the throttle at 1/4, 1/2 and 3/4 and ride along and see how it performs at each setting. If it's fine at the bottom and get lean and gutless at 3/4, raise the needles a notch.
It's easy to convince yourself that the main jet is right when you accelerate at say 1/2 throttle up to moderate revs, but in truth the M/J is not the limiting factor under those conditions.
BTW, get the ignition timing right first and use a clean new pair of plugs.
So to recap, with open pipes and pods I'd start with 25 pilot jets and 150 mains and see where it takes you.
Good Question. let's say the motor makes 25Hp and runs with BSFC of say 0.6 pounds of fuel per hour per HP. so that's 3 pounds of fuel per hour or roughly 100cc per minute.
If the motor burn less efficiently than that it would need more fuel. So we want to see at least say 200cc/minute to have a reasonable margin of safety.
Those carbs don't have a lot of parts available for them. they caome, according to my notes, with #239 series O-6 nozzle. The O-6 is probably OK but may make it a little rich in the middle which is a safe way to go. the air jet is fixed and is a tiny 0.5mm, so Mr mikuni doesn't think teh fuel slope needs to be trimmed at the top end.
The Needle is middle of teh road 4J13 which is right in the middle of the 5 optional 4 series needles. Good safe place to start swapping brass.
Our 240cc motor uses 26mm Mic's and runs 130 mains in the same large hex 4/042 series, so with a smaller motor and smaller carbs and lower state of tune, I'd start in the 130-150 range. We need a #40 slow jet!!.
I'd start off by getting the slow jets right. Air screw should be in the 1 -2 turns range. If it's further out go down a jet size and if it's less than 1 turn go up on that jet. When the idle seems right, try to ride off with just small throttle opening and test to see if slightly more (or less) air screw improves that. It should pull cleanly off idle.
Next get the main jet right and that requires either a dyno with gas analysis or a long slight hill to ride up, flat out. Do a plug chop at the top and see what color the plugs are. They should be WHITE on the tips with some color way down inside the body. You are looking for 2mm or so of color band on the insulator down where it meets the body. Check teh side strap and center tip for signs of overheating or of deposits. the tips of both electrodes should be burned clean but not showing signs of distress.
Forget all the BS about brown plugs at part throttle - it's all meaningless. Plugs are not hot enough to read properly unless the motor is WFO and working hard.
You will need a flashlight and magnifying glass or spark plug reader - that's a flashlight with a lupe on the end. You don't need a super expensive tool. Your Maglight and a cheap small magnifying glass are OK.
When you are sure the very top end is OK, then it;s time to look at part throttle. Revs are less of an issue than how wide the throttle is open. mark the throttle at 1/4, 1/2 and 3/4 and ride along and see how it performs at each setting. If it's fine at the bottom and get lean and gutless at 3/4, raise the needles a notch.
It's easy to convince yourself that the main jet is right when you accelerate at say 1/2 throttle up to moderate revs, but in truth the M/J is not the limiting factor under those conditions.
BTW, get the ignition timing right first and use a clean new pair of plugs.
So to recap, with open pipes and pods I'd start with 25 pilot jets and 150 mains and see where it takes you.
Big R
Heaven is so far away.
Re: 68 CL175 Project Vicarious - tuning woes.......
Whoa..... That's some great info Teazer! Any chance you will be in PA soon and wanna tune for me?
I do have 17's in for the slow jets but have the original 22.5's (or whatever was stock?) so I'll drop them back in. I've tried going both ways with the mixture screws and nothing really helped the top end. The timing has been set, valves adjusted recently, and the advance is working properly so I'm not really looking at them.
I still have plans to swap out the coil and get an electronic ignition - think that could help? Thanks again man!
Whoa..... That's some great info Teazer! Any chance you will be in PA soon and wanna tune for me?
I do have 17's in for the slow jets but have the original 22.5's (or whatever was stock?) so I'll drop them back in. I've tried going both ways with the mixture screws and nothing really helped the top end. The timing has been set, valves adjusted recently, and the advance is working properly so I'm not really looking at them.
I still have plans to swap out the coil and get an electronic ignition - think that could help? Thanks again man!
Re: 68 CL175 Project Vicarious - tuning woes.......
Adjusting the mixture screw has most effect at idle and just off idle and has little effect at the top end, but we need to get that into the ball park first.
If you were over near Chi Town, I'd be happy to help out. I have tuned for a couple of AHRMA champions as well as on my own bikes for a long time. one thing you learn is that every bike is slightly different, even when you think they are identical. You just need a methodical approach aand to eliminate other issues.
Electronic ignition wouldn't hurt but points are less likely to be an issue. Coils do breakdown and cause misfires, points bounce etc, so a good coil is always a good place to start, but if it's OK then changing it will have no effect.
You could also get a cheap spark tester from Autozone or PepBoys and clip it on one plug and fire the bike up. rev and see if the spark stays fat and blue all the way up as it revs. it's a pretty crude test but may reveal something. of course if one plug is fouling, the coil will struggle because it's double ended. So get a box of cheap D8 plugs and remember that a CB200 is 3/4 inch reach and Slopers etc are 1/2" reach on the plugs. Don't put long plugs into an early motor...
Adjusting the mixture screw has most effect at idle and just off idle and has little effect at the top end, but we need to get that into the ball park first.
If you were over near Chi Town, I'd be happy to help out. I have tuned for a couple of AHRMA champions as well as on my own bikes for a long time. one thing you learn is that every bike is slightly different, even when you think they are identical. You just need a methodical approach aand to eliminate other issues.
Electronic ignition wouldn't hurt but points are less likely to be an issue. Coils do breakdown and cause misfires, points bounce etc, so a good coil is always a good place to start, but if it's OK then changing it will have no effect.
You could also get a cheap spark tester from Autozone or PepBoys and clip it on one plug and fire the bike up. rev and see if the spark stays fat and blue all the way up as it revs. it's a pretty crude test but may reveal something. of course if one plug is fouling, the coil will struggle because it's double ended. So get a box of cheap D8 plugs and remember that a CB200 is 3/4 inch reach and Slopers etc are 1/2" reach on the plugs. Don't put long plugs into an early motor...
Big R
Heaven is so far away.
Re: 68 CL175 Project Vicarious - tuning woes.......
What a great way to ruin a motor....
I'll try and get a spark tester soon - might help out a couple of us locally as well. I replaced the coil with the cheap one from JCWhitney almost immediately after getting the bike. While the cheap one is better than the original, I fear it may not be up to the task anymore.
Thanks again for the info Teazer. Any good references online to these small cc bikes? Aside from Bateman and GroupW?
What a great way to ruin a motor....
I'll try and get a spark tester soon - might help out a couple of us locally as well. I replaced the coil with the cheap one from JCWhitney almost immediately after getting the bike. While the cheap one is better than the original, I fear it may not be up to the task anymore.
Thanks again for the info Teazer. Any good references online to these small cc bikes? Aside from Bateman and GroupW?
Big R
Heaven is so far away.
Re: 68 CL175 Project Vicarious - tuning woes.......
Got her movin again! Here's what I did:
put the 68 tank back on since it has dual outlets on the petcock
tried 150's (too big), put 140's in
cleaned the bowls out
checked the timing again
checked the valves again
cleaned and checked gap on the plugs
mixture screws 2 turns out (still rich at idle w/ 22.5 pilots)
When I was changing the tanks, I noticed the fuel filter was clogged pretty good. Then flogged it through the back roads this morning. It ran like a top the whole time, but it was fairly cool this morning so I want to take her for a decent ride midday tomorrow to see how well the jets are after it heats up outside. Might even try some 145's to see if that helps (better a little rich than lean, right?)
Got her movin again! Here's what I did:
put the 68 tank back on since it has dual outlets on the petcock
tried 150's (too big), put 140's in
cleaned the bowls out
checked the timing again
checked the valves again
cleaned and checked gap on the plugs
mixture screws 2 turns out (still rich at idle w/ 22.5 pilots)
When I was changing the tanks, I noticed the fuel filter was clogged pretty good. Then flogged it through the back roads this morning. It ran like a top the whole time, but it was fairly cool this morning so I want to take her for a decent ride midday tomorrow to see how well the jets are after it heats up outside. Might even try some 145's to see if that helps (better a little rich than lean, right?)
Big R
Heaven is so far away.
Re: 68 CL175 Project Vicarious - tuning woes.......
The 200 tank is going back on. I just wanted to use the 68 tank so I KNOW it was getting a good flow.
I thought about the single outlet on the 200 tank not sending enough gas but it didn't make sense - much bigger bikes came stock with single outlet petcocks.
The 200 tank is going back on. I just wanted to use the 68 tank so I KNOW it was getting a good flow.
I thought about the single outlet on the 200 tank not sending enough gas but it didn't make sense - much bigger bikes came stock with single outlet petcocks.
Big R
Heaven is so far away.
Re: 68 CL175 Project Vicarious - tuning woes.......
Just a small update:
I think I'm gonna need a new one of these
It's amazing what a little vibration can do to plastic! ;D
Also called Les Baker the other day and ordered a Dyna coil. When it comes in I'm sending out a points plate so I'll have an electronic ignition soon after. Going to order up some new turn signals, jets, brake + clutch levers, etc, etc.
Just a small update:
I think I'm gonna need a new one of these
It's amazing what a little vibration can do to plastic! ;D
Also called Les Baker the other day and ordered a Dyna coil. When it comes in I'm sending out a points plate so I'll have an electronic ignition soon after. Going to order up some new turn signals, jets, brake + clutch levers, etc, etc.
