Loss of one cylinder
TrapperAH1G:
Today, a friend and I worked on the bike. Cutting to the chase, we determined it wasn't getting fuel at idle but was at higher rpm. So, removed the intake manifold tubes on 2 and 4, removed bowl on #2 and then took out the jets. Main jet was clear, idle jet (38S) was totally blocked. Took almost half an hour using carb cleaner, very small wire and air to clear. Put it all back together and it does better at idle but isn't totally cured.
I'm running B12 thru it, letting it sit for a few hours, repeating. Thinking with the jet closed I may have varnish/build up farther back. Time will tell, but at least I can now tell a difference when I pull the plug wire at idle.
Oh, I now know someone in the past has changed the idle jets from 35S. Mains are still 100's.
Joe333x:
Quote from: TrapperAH1G on June 11, 2025, 06:14:42 PM
Today, a friend and I worked on the bike. Cutting to the chase, we determined it wasn't getting fuel at idle but was at higher rpm. So, removed the intake manifold tubes on 2 and 4, removed bowl on #2 and then took out the jets. Main jet was clear, idle jet (38S) was totally blocked. Took almost half an hour using carb cleaner, very small wire and air to clear. Put it all back together and it does better at idle but isn't totally cured.
I'm running B12 thru it, letting it sit for a few hours, repeating. Thinking with the jet closed I may have varnish/build up farther back. Time will tell, but at least I can now tell a difference when I pull the plug wire at idle.
Oh, I now know someone in the past has changed the idle jets from 35S. Mains are still 100's.
B12 is good stuff, hopefully clears up the issue for you. Also having a colortune is a great tool to see the combustion in the chamber so you know if you have space and makes tuning a breeze. They seem to be out of stock but maybe you can order one if you call.
https://www.freedomracing.com/g4171-colortune-for-12mm-spark-plug.html?___store=default&srsltid=AfmBOopKZjEluVCg6aoNt6g396L-PXqjqAyHkBkQy_1ujJ2C0Rcqh3NZ-zs&gQT=2
TrapperAH1G:
Update: NO real improvement. Been using B12, even used Lucas cleaner & Seafoam. There is no change to idle when I remove the plub wire, BUT, get it to 2000 rpm and there's a noticeable change in sound and a drop in rpm when the wire is removed. Truly seems just the lower rpm's are involved. So, if the slow jet is clear, any opinions on what would be the cause?
Thanks.
Pluggy:
Old Honda coils can create "on-again, off-again" problems. It is possible cylinder #2 side of the coil can fail and #1 is OK. I removed the coils on a 4 cylinder Honda to find both plastic cases had cracked. The eBay replacements have worked fine.
Before you dump more solvent (and money) into the gas tank, consider a replacement set like this:
https://www.ebay.com/itm/145786137878?chn=ps&norover=1&mkevt=1&mkrid=711-166974-028196-7&mkcid=2&mkscid=101&itemid=145786137878&targetid=2274951440814&device=c&mktype=pla&googleloc=9010069&poi=&campaignid=22079117232&mkgroupid=170385470061&rlsatarget=pla-2274951440814&abcId=10150408&merchantid=5089702184&geoid=9010069&gad_source=1&gad_campaignid=22079117232&gbraid=0AAAAAD_QDh949p7p18B2teoViFhVl_ya4&gclid=Cj0KCQjw953DBhCyARIsANhIZoYOj7xGFyf8UTnXMJV-TIz2Kj0rEP9aC9bIe91J9CWMPm_e5vFlZzAaAlS4EALw_wcB
It is not particularly expensive.
If you prefer, try exchanging the 1-2 coil and wires with the 3-4 set and see if the problem moves with it. Thats a lot of work.
TrapperAH1G:
Have a spare parts bike, 2000 Standard. I'll take a coil from it and swap, just to see. Thinking I may have to rebuild this carb, so will do all at that time. Went to Red Eye site and didn't see any kits for this, and didn't see where I could order final drive O rings either. Left a message.
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