Engine Warmup

[leo3wheel]

It had been two months since I started my RSV, so I did so today. Temperature was in the 30's F. Took three hits of the starter, fully choked, and RSV started up. After a minute or two, was able to take choke off. Let RSV run about 25 minutes, and engine sounded smooth and was responsive. Noticed cylinders 2 & 4 were hot to the touch, but cylinders 1 & 3 were just warm. I've noticed this on other occasions, but just asking for thoughts about this discrepancy. Is it normal for two front cylinders to warm up before two rear cylinders? Engine seems to be running well. It was nice to hear her run. Going to be a long winter. Thanks!

[Marcarl]

Feeling the pipes is an indicator, but it is not what might be called scientific. If you think you have an issue then the pipes need to be measured with an infrared thermometer right at the manifold for each one. That would give a true reading and something to work with. Just feeling them will give you enough info to get a thermometer. And yes, they should all be close.

[leo3wheel]

Thanks for the tips Carl!

[Condor]

If memory services me correctly the coolant flow is directed to the rear V cylinders first and then thru the front V and into the radiator. Why? Because the rears run the hottest when moving. When the bike is just sitting there idling the coolant is sorta pre-heated by the rears before it passes thru the fronts. Since the motor is not generating a lot of heat the fronts will run hotter... In theory..., but in practice who the hell knows for sure???

[CaseyJ955]

 

I do a spit sizzle test and while less scientific it quickly lets me know if they are all hitting approximately the same. One day I'll stop being cheap and buy a quality IR thermometer, sadly to get one regarded as accurate you have to part with a couple bones. A cheaper one might not be as accurate but it will show you consistency between pots, or lack thereof. These V4s run pretty well even if they are missing a cyl.

 

A couple quick things that come to mind would be to check your carb synch. When was it last done? When were plugs last changed out, I assume your using the NGKs. Check condition of the HT leads, especially where they join the coils and can get that green muck buildup. I noticed this on mine before getting the carbs synched and dialed in.

[Condor]

 

I do a spit sizzle test and while less scientific it quickly lets me know if they are all hitting approximately the same. One day I'll stop being cheap and buy a quality IR thermometer, sadly to get one regarded as accurate you have to part with a couple bones. A cheaper one might not be as accurate but it will show you consistency between pots, or lack thereof. These V4s run pretty well even if they are missing a cyl.

 

It's not so much the accuracy but the repeat-ability that's important. This is the one I use and it didn't break the bank....

 

https://www.harborfreight.com/infrared-thermometer-93984.html

[leo3wheel]

Condor, Like that Infrared Laser Thermometer! Thanks! FYI, my initial checks were done by placing my hands on the cooling fins. Not very scientific... Should have touched the actual pipes. Like the explanation of why the back cylinders are running cooler after initial startup. Have noticed this at other times, and often wondered if all cylinders were performing equally. Spark plugs were changed not so long ago, maybe 10K miles ago. Should check my carb sync in the spring. Will pay closer attention to the pipes when I start it again at the end of January. See I have another puddle of antifreeze under #1 cylinder. Must be the drain plug again. Thanks for all your ideas!

[Flyinfool]

Don't check the pies with your fingers after it has been running for more that about 15-30 seconds. It will be really hard to clean the burnt on skin off of the pipes while your hands are all bandaged up.

[leo3wheel]

Thanks for the heads-up Jeff!

[Yammer Dan]

That's one of my favorite Harbor Freight items. Gotta be careful what ya grab there but this one is great although I've found it to be off a little at times it will give you a good general idea what is going on. In my opinion ( which has been wrong ONCE) they should run fairly close when you take temp readings as close to head (stay on the pipe) as you can. And as a afterthought Don't Leave These Animals sitting WITHOUT CLEANER OR STABILIZER!! Sea-Foam is Great stuff for this if you are not a old retired codger on a small fixed income. Instead of Sea-Foam I use a mix I came up with a few years ago. The thing is use something to keep this Crap they call gas now from ruining the carbs.

[leo3wheel]

Been conditioning fuel for years. There is no real indication that there is anything wrong with my RSV, except for recent #1 cylinder antifreeze leak. Supposed to be in the 50's tomorrow, so I'll fix the antifreeze leak. Will examine the temperature issue more closely next time I start RSV, and that's usually once a month.

[etcswjoe]

If memory services me correctly the coolant flow is directed to the rear V cylinders first and then thru the front V and into the radiator. Why? Because the rears run the hottest when moving. When the bike is just sitting there idling the coolant is sorta pre-heated by the rears before it passes thru the fronts. Since the motor is not generating a lot of heat the fronts will run hotter... In theory..., but in practice who the hell knows for sure???

 

 

Sounds reasonable to me, need to take the bike out for a spin, since you do not have normal airflow like you would when you ride it can be deceptive.

[leo3wheel]

Temps were in the 50's today, so took a look at my RSV. Tightened down the cooling fins for all cylinders. Checked that radiator is full and topped off coolant reservoir. Warmed up RSV for about a minute and verified that exhaust pipes were getting hot at heads. They were! Looks like there is nothing to worry about. Bet it could make another cross country trip this summer, but not sure my body has recovered. Thanks for your feedback! It was very comforting!