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Project bike

Herb400t

Well-known Member
Joined
Jun 30, 2021
Total Posts
91
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0
Location
North Salem, NY, US
CM400T.Final.jpg
after 6+ years, she's done!

Many mistakes made along the way. MUCH money wasted. A LOT of swearing and cursing and even some crying... but I'm pretty pleased with final results. Highlight for me is hand-made fiberglass seat. Took me awhile but I think it came out looking pretty fine.

Yes, I did that dumb thing; pulling out airbox and going with little pod filters which really screws with the CV carbs. I think that someone has posted some specs for rejetting that might help mitigate issue, but I can't find. If anyone can point me in right direction...

also, quite awhile back, a guy at a motorcycle shop was trying to convince me to go with racing carbs--which seemed like a possibility.... until I saw price! Now that she's running and I'm experiencing that "lag" at upper rpms, I might reconsider. Anyone have a suggestion on carbs that would fit bill, that would be greatly appreciated
 
Original carbs and airbox will make tuning a lot easier. "Pods" cause more problems than they solve. That's for race bikes. You'll find that subtle changes in humidity/temperature/pressure will make it run different from day to day. Even changes in elevation.
 
Herb400t said:
after 6+ years, she's done!
Click to expand...

Glad you got it to the finish line, and though it isn't my style I like the work you've done. The little touches make the look, from the paint scheme and quality of the job to the little filler panel below the nicely-done seat. That frame design is not one easily worked with for modifications but you've made it look really nice with your efforts.
 
You'll want larger air filters, the small ones start restricting air flow under high load/rpm conditions.
Memory says a 90/130 or 140 combination will get close plus 1-2 needle shims.
You probably want to change the slow jet to a 40 from 38, might need to go to a 42.
https://www.jetsrus.com/a_jet_kit_street/honda_450_CM450_1982.html
Be sure your float level is correct at 15.5mm
One thing to remember is that these particular carbs are a cumulative addition type meaning each circuit adds to the previous.
 
Thanks for thoughts and the feedback. It was a struggle. But i got a lot of great info/advice from you and others on this forum!
 
Jim, Thanks for info. I think I can sort out jets BUT 90/130 filters? I'm not sure what those numbers mean? must be measurements of some sort but not ID or OD.
 
Jim, Thanks for clarification.

also, thanks for all the help you provided me over the (way too) many years as I worked on this bike!. Invaluable.

one quick question; do you think those little stacks I have on carbs are of any benefit? Or maybe it would be better to just attached filters directly to crabs?
 
Herb400t said:
do you think those little stacks I have on carbs are of any benefit? Or maybe it would be better to just attached filters directly to crabs?
Click to expand...

I'm not much of a crab guy, but I do think the extensions help with the use of pods on those CV carbs.
 
Herb400t said:
Jim, Thanks for clarification.

also, thanks for all the help you provided me over the (way too) many years as I worked on this bike!. Invaluable.

one quick question; do you think those little stacks I have on carbs are of any benefit? Or maybe it would be better to just attached filters directly to crabs?
Click to expand...
You absolutely need the extension tubes. They should match the length of the original air box boots and if you can flare the intake side like a velocity stack. The tubes smooth the airflow into the carbs which is critical to their function. One thing that is also critical is the openings on the face of the carbs cannot be restricted at all.
201_4534 (1).jpg
 
Ok. I made the intake tubes to just about the length of original boots. But not sure how pod filter would fit over the flared end of tube? kinda a moot point since I don't have capability to make flare anyhow
 
LongDistanceRider said:
You'll want larger air filters, the small ones start restricting air flow under high load/rpm conditions.
Memory says a 90/130 or 140 combination will get close plus 1-2 needle shims.
You probably want to change the slow jet to a 40 from 38, might need to go to a 42.
https://www.jetsrus.com/a_jet_kit_street/honda_450_CM450_1982.html
Be sure your float level is correct at 15.5mm
One thing to remember is that these particular carbs are a cumulative addition type meaning each circuit adds to the previous.
Click to expand...

Jim, NEW questions. But specifically about carbs so maybe I should move this text chain to the "Carburetor" portion of forum?
 
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