Miss when cold runs well when hot?

[Gijoerambo]

Ok,
So I have a 1989 full power bike with 20k kms.
It starts right up no issues, but runs very rough, pooping etc
And the left rear cylinder is def not firing as the exhaust header is cold.

After I take off and run for maybe 5 mins, the bike comes good and runs great, pulls like a train, isles and runs smooth.

I have tried the shot gun and it did improve the running however the next time I took it out it’s running like crap again.

I’m starting to worry it’s maybe ignition? Or even compression? As it seems to change with engine heat..?


Any thoughts would be great.

 

[Killjoy]

Cops.

 

[digin150]

Sounds like the carbs need to be cleaned jet blocks probably pluged

 

[Gijoerambo]

Thanks guys.
Not keen on taking bike away from standard with cops.

Would the pilot jet being blocked effect it only when cold?? Because it runs great when hot.

I’m going to do a compression test, could it be that the rings are sealing better when hot? Or is that a silly idea..

Failing that I’ll have a look in to my ignition wiring, as I know not a single thing has been even touched since 1989!!! The bike has always been serviced with oil etc but I doubt the carbs and or ignition have been overhauled ever.

Oh I’ve put in brand new plugs, no change.

 

[VE/MAX]

I'm new here, I hope this question isn't it too out of line with the thread. Is there any sort of fuel additive that would help clean the carbs and the jets? Could one try that before disassembling the bike to take the carbs out and clean them?
I took my Honda completely down but it was a piece of .... wouldn't start at all without the choke. Now it starts every time first try without the choke.
I've seen and learned how to do the shotgun method but I will probably wait till winter before completely disassembling the my vmax

 

[marsmax85]

You could run seafoam thru a couple tankfulls 1oz per gallon

 

[VE/MAX]

You could run seafoam thru a couple tankfulls 1oz per gallon

Thanks!

 

[digin150]

I have had good luck with lucas injector cleaner bought my 85 new had alot of experience with carb cleaning it only has 10000 miles on it.had to take them apart every few years.Lucas every so often havent had to mess with them works for me

 

[Gijoerambo]

Did your have the same symptoms as mine? Very rough when cold but runs fine when hot?

 

[sdt354]

Ok,
So I have a 1989 full power bike with 20k kms.
It starts right up no issues, but runs very rough, pooping etc
And the left rear cylinder is def not firing as the exhaust header is cold.

After I take off and run for maybe 5 mins, the bike comes good and runs great, pulls like a train, isles and runs smooth.

I have tried the shot gun and it did improve the running however the next time I took it out it’s running like crap again.

I’m starting to worry it’s maybe ignition? Or even compression? As it seems to change with engine heat..?


Any thoughts would be great.

I think you're looking for an issue that isn't there. A properly tuned Vmax needs fuel enrichment when cold. If it runs well after it's up to temp. I'd just ride it.
'

 

[D-Max2012]

Steve, I was thinking the same thing.. Gijoerambo posted that his runs like crap when cold. I was wondering if he's on choke while the bike warms up like the rest of us. He did not mention this. If WE tried to ride before the bike warms up a little, we all would be complaining about the same thing.. Just a thought..

Note for VE/MAX,, Welcome to the forum.. You might want to open a new thread with the same pictures and description of your issues. You may find it difficult to get help on your particular issue, when most are replying to the original poster of this topic.. It's called "hijacking" a topic, and may not get you the answers you were looking for.. Just an FYI.. take care..

 

[digin150]

If you have a cold cyclinder you have a problem. I would run some injector cleaner through it, maybe it would clear it up if it runs good warm might be able to clear it up. They do pop and stumble a little when their cold if you dont run a little choke.Good luck.

 

[VE/MAX]

Steve, I was thinking the same thing.. Gijoerambo posted that his runs like crap when cold. I was wondering if he's on choke while the bike warms up like the rest of us. He did not mention this. If WE tried to ride before the bike warms up a little, we all would be complaining about the same thing.. Just a thought..

Note for VE/MAX,, Welcome to the forum.. You might want to open a new thread with the same pictures and description of your issues. You may find it difficult to get help on your particular issue, when most are replying to the original poster of this topic.. It's called "hijacking" a topic, and may not get you the answers you were looking for.. Just an FYI.. take care..

Hey thanks for the welcome and you're right I do need to introduce myself.
My Vmax actually does not have this issue. I was posing the question to start the discussion of fuel additive/cleaner. It looks like some other members suggest it's a good idea to start there. My intent was not to hijack the thread, I only wondered if there was a simpler solution one could try first.

This forum seems a little slow, I thought pictures of my Honda carburetor cleaning job would interest some and be relatively on point. I didn't mean to step on any toes.

 

[Gijoerambo]

I understand that however I have three v maxes previously and many bikes.
This is a clear issue, popping, missing, one cylinder not firing.....
I am running choke as normal.

I’ll look to try the shot gun again and see if that makes any difference.
Then I’ll check my coils etc.
I know the carbs ya e not been touched in circa 8years!
Thanks

 

[marsmax85]

wouldn't hurt to check the sync ..

 

[D-Max2012]

Sorry for the long wind, but if this helps anyone, its worth the aching fingers, typing this up.

I was beating my head against the wall trying to iron out a bad stumble I was having with my used 91. I literally tried every thing you can think of.
Changed cracked boots, v-boost boots, needles, plugs, spark wires, synced, broke down carbs about over 10 times to clean out, 5 of those times, using an ultra-sonic cleaner. Cleaned R/R terminals and contact points.

I spent months trying to figure this thing out.
I kept noticing my fuel was kind of brownish and had foreign matter (FM) in the bowls.

Broke down the carbs again and kept noticing a growth like substance on the gaskets inside the carbs. I would clean everything out, and within 2 weeks time, it was back again.

Doing some research, I found that the ethanol that's in most fuels these days, draws in water from the atmosphere. When it separates from the fuel (Phase Separation), it settles on the steel surface, creates rust, and collects at the bottom of the tank.

So, I finally decided to kill it as the source. Removed my tank, cleaned, etched and coated the inside. While waiting a full week for the coating to cure, I removed all fuel lines, carbs, and fuel pump, to give everything a good cleaning before the tank was placed back in.

At this point I still had that stumble but I read someplace that there's FM that you may never get out until you run some Seafoam in your tank.

I put 1/2 bottle after each fill-up. I did this 3 times. About midway thru the 3rd fill up, I noticed the bike started pulling strong thru all throttle positions, and it's been that way now for 5 years and counting.

 

[VE/MAX]

Awesome great to hear

 

[rogvmax]

I have a problem with the spark wire on my left side back cylinder. Put Your finger on top of the spark plugg cap and at the same time nearly touching the top cover. You can feel It. Thats how i found out. Or use a screwdriver. And You can se the spark jumping on to the cover. Maybe You have a realy bad spar wire.

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