Roadie Engine Compression Question? SVS?

[129drifter]

I bought a non running 2006 Midnight 1700 about a year and a half ago and been working on it a little bit at a time to get it up to where it needs to be. I have no idea how many total miles are on it. The speedo unit was hosed up and I bought a good used speedometer with about 20k miles -- that replacement item works great. The fuel pump was removed and that whole system was hands on setup to be pumpless by SkwearPeg. (he lives close by) Pretty sure that part is OK because he remotely helped hundreds of people on this message board do that in the past. We used Mikuni jets and stuff from a Barons kit to do that.

I thought I had a blown head gasket on the rear cylinder because the rear plugs get crudded up / black after every thousand miles (or less). Attached are the cylinder compression readings this morning after being cranked from cold start and then warmed up about 60 seconds before the test. Decompression solenoid was disconnected and the throttle opened up. I am at about zero ft elevation / sea level here in the Florida panhandle. Both were really equal and about 142 - 143 psi. .

The guy I bought it from had over six qts of oil in the crankcase that I drained out when I trailered it home. No telling how long he had ran it like that.

I removed the AIS and Barons block off plates were installed about a year ago.

My next thought is to do Curts SVS cure procedure step by step but I am wondering if the engine compression is ok to keep going forward?

Your thoughts?

Thanks

[Lug Nut]

Same on both cylinders and I think 14w is fine...but don't remember the spec. Spray entire can of seafoam deep creep into exhaust ports (half can each) and let set overnight. Then button it up and run it (with Seafoam gas treatment in tank...2 oz per gal)....run it hard lots of full throttle....I would put some seafoam in oil also...ride it 30-40 miles and then come back and drain the oil (it will be nasty)

[Tcontrol]

I didnt think the 2006 motors are very prone to svs… before i went to all the trouble of the treatment for svs, have you done an exhaust/tissue test?

Maybe remove the rocker cover and just taking a look at the valve train/lifter situation… the other test would involve the coil/spark energy…. (Loose primary coil blade connection on +12v side or ECU side)

simple checks may lead you down a different diagnostic path…

[rrps18admnrsc]

All the Roadstar carbureted engines are prone to SVS if they're stock and have been run with high octane fuel.
Yamaha developed "Ring Free" specifically for correcting SVS from the wrong fuel in the Roadstar engines.

It can be an issue with stock EFI engines as well, but less likely since the ECU will compensate for the wrong fuel - to a point.
Modded engines with higher compression need high octane fuel.
The Roadstar isn't one of them unless you're at altitude or have other issues creating pinging or knocking.

Intake leaks can also cause pinging, knocking under load and overheating.
Attempting to fix knocking under load with higher octane fuel isn't fixing the real problem, but it can make the noise go away for a while.

[129drifter]

I didnt think the 2006 motors are very prone to svs… before i went to all the trouble of the treatment for svs, have you done an exhaust/tissue test?

Maybe remove the rocker cover and just taking a look at the valve train/lifter situation… the other test would involve the coil/spark energy…. (Loose primary coil blade connection on +12v side or ECU side)

simple checks may lead you down a different diagnostic path…

I did the exhaust test a couple of months ago and it appeared to be intermittently sucking the thin paper back inward for the rear cylinder.

Had a whole set of (known to be good) 1700cc ignition coils that I exchanged with the ones that came on this bike and it did not make any difference over a period of a couple thousand miles.

Evidently I do not do anything in a hurry. Some people would have done all this in the first week of ownership. Been piddling with this bike a little at a time since June of 2021.

[davej]

is the only issue that the rear plugs carbon up after 1000 miles but in general the bike runs good? You say the jetting is correct but didn't say what jets were used. I know Gordon was pretty precise with his work but jetting info would help us as far as what jets were used and what groove the clip is in.

Was it 1 of Gordons bikes?
Also was the float messed with when the pump was removed?

[129drifter]

This was not one of his bikes. I bought it down near Orlando and brought it home on a trailer without being able to hear it run.

Bike now starts easy and idles fine -- runs good other than the rear plugs getting alot more black and sooty than the ones on the front. I can definately tell when that happens after installing four new NGK DPR7EA-9 plugs each time because it starts running rougher. (vibration also)

I just rode it all over the NC /TN mountains a couple weeks ago so it does fine other than this symptom that repeats itself with an accumulation of miles put on the engine.

When I first got the bike, the intake manifold was bad and a section of it came apart when we removed it in Gordons garage. I bought a new OEM Yamaha one and he did the figure 8 surfacing of the mating edges and soldered the nipple closed before we installed it together with new OEM O rings. That was last summer and several thousand miles ago.

The carb was setup as follows -- 172.5 main and 40 pilot. Clip in 4th groove. 2.5 on the PMS screw. He checked the float height at his work bench using a clear tube but I am not sure if the float itself was actually altered or not.

Bike has a K&N filter with additional medium sized holes drilled in the black plastic housing. Stock exhaust pipes because I like quiet.

[Lug Nut]

This was not one of his bikes. I bought it down near Orlando and brought it home on a trailer without being able to hear it run.

Bike now starts easy and idles fine -- runs good other than the rear plugs getting alot more black and sooty than the ones on the front. I can definately tell when that happens after installing four new NGK DPR7EA-9 plugs because it starts running rougher. (vibration also)

I just rode it all over the NC /TN mountains a couple weeks ago so it does fine other than this symptom that repeats itself with time.

When I first got the bike, the intake manifold was bad and a section of it came apart when we removed it in his garage. I bought a new OEM Yamaha one and he did the figure 8 surfacing of the mating edges and soldered the nipple closed before we installed it together with new OEM O rings.

The carb was setup as follows -- 172.5 main and 40 pilot. Clip in 4th groove. 2.5 on the PMS screw. He checked the float height at his work bench using a clear tube but I am not sure if the float itself was actually altered or not.

Has a K&N filter with additional medium sized holes drilled in the black plastic housing. Stock exhaust pipes because I like quiet.

Not sure... but maybe step down to a 170 main since you air box is drilled but not running a true open element assembly and stock pipes.

[129drifter]

I looked at the airbox tonight and there are five holes that I had drilled in the black plastic appearing to be at least 1 inch each so it is opened up pretty good for the K&N. I will try changing the main to a 170 when I remove the pipes and spray the Seafoam brand Deep Creep everywhere inside the exhaust openings. Should be sometime in the next couple of weeks.

This is my second Road Star. The first was a 1600 Silverado with a Cobra 2 into 1 setup that a friend now owns. I would install a more free flowing exhaust on this 1700 but I am old and crotchety and decided I like to hear the wind instead of loud noise while riding

I will report back after trying these things but it might take a month or so after I get it back together --- install a new round of NGK plugs -- and then accumulate another 1000 miles to know if that resolves the problem.

[davej]

stepping down on the main jet might do it. But if that don't do it you could step down 1/2 step on the needle by removing the silver washer to see if that helps without causing any other issues. it seems the richness is during cruising speeds and that is mostly from the needle.

[brianmac]

Does bike smell of gas at rest?

[129drifter]

No smell of raw fuel stopped at a red light or after shutdown in a parking lot. The gas cap was vented when we did the pumpless setup over a year ago so when it is about 100 degrees here in the Florida summers one can get an occasional whiff of gas smell. My previous Roadie 1600 did that also.

[davej]

There for a while members were setting float levels a little high when going pumpless. It was found later that setting high wasn't needed when using the grizzly valve. If he set it to that high standard that could also add to the richness.

[brianmac]

thats what i was thinking the 6 qt of gas was part gas? from flooding carb,. has he replaced the needle and seat ? it can still run well with hi float setting

[129drifter]

You are correct brianmac that the six quarts I drained out of the crankcase when I first brought it home reeked of raw fuel. That is when the previous owner had the stock carb setup and the fuel pump installed. I am sure the standard needle and seat he was using leaked fuel into the oil.

Shortly after bringing it home on a trailer, I changed the oil and filter using 4 qts of Mobil One Vtwin 20W50 when SkwearPeg helped me do the pumpless setup at the same time. The oil and filter has been changed again in the last couple of months with no fuel aroma in the oil now that the correct pumpless setup has been working for more than a year now.

We installed the 2C6-14190-30-00 grizzly valve in the process of eliminating the fuel pump.

Ive got a separate bone stock unmolested Road Star carburetor sitting in a box. Before I take the pipes off and do the SVS cure procedure -- should I try taking the float out of the stocker and install it in the pumpless carb setup that has the Grizzly valve to restore the float height to stock if it had been moved?

[Tcontrol]

You appear fixated on svs or carb at this point…

i would at least perform the easiest compression check test before i treat for svs…

use a jumper cable from positive battery to the starter with a compression gauge installed in the cylinder… you do not have to worry about the decompression solenoid interferance at all… heck.. you do not even need to turn the key on… just turn the starter over with the jumper cable to battery connection to pump up the cylinder….. it aint rocket science…

you would be surprised what a simple test procedure can tell you before you delve into more complicated tests…

[Brad_G]

That's a good tip for how to do the test without the decompression solenoid coming into play. I'll have to remember that (although I hope I never need to do a compression test on my RS).

[davej]

he already did a compression test

[Tcontrol]

Missed that post… those compression readings are pretty normal … and well within reasonable tolerance…
svs treatment seems a bit ill advised just due to those readings… of course heating everything up might change things but i sincerely doubt his issue has anything to do with sticky valves…

Spark plug carbonization is most likely due to incorrect mixture or excess oil burning since compression is generally equal between cylinders…

what i find most curious is that the plugs are getting fouled pretty quickly on the rear cylinder only… a rich mixture in a common manifold should also show fouling on the front plugs as well with that low of an elapsed mileage…. Has the rocker cover vent tube become blocked and pressurized the rear cylinder top end?… are all the hoses connected correctly…?

regardless of swapping out coils… have the resistors been checked for corrosion?.. have the spark plug caps/ high voltage lead connections been refreshed… ?

maybe a carb guru can explain why the rear plugs are so much more prone to fouling than the front plugs with the current jetting… i am not convinced of that…. There is something more to this than just jetting…

[davej]

What I have found in the past for this exact issue was an air leak in the front intake runner and improper carb settings. The jetting appears correct if in fact he is using a Barons needle but wrong if using a Dynojet or Speedstar needle. Unless you purchased the Barons kit yourself don't just assume you have a barons needle. Measurements on the needle will be the only way to Identify the needle. The idea of installing a float from an untouched stock carb as he asked might be a good idea as a mis-adjusted float can cause a rich condition with proper jetting.

[Shores]

Stupid question because I'm not a carb guru, but if the bike was jetted rich to begin with and you had a very slight air leak on the front cylinder, would that produce what he is finding?

[Brad_G]

I too wondered about an air leak skewing things. Always like to hear from the carb gurus as I learn new things from them.

[davej]

Yes that is correct. see my comment above. I wrote it before I seen this post.

[129drifter]

The idea of too rich of a mixture is probably a good one. All four spark plugs are black each time when removed at about 1000 miles from new. I am on set number 5 or so in the last several thousand miles. The back two plugs are really black and contaminated compared to the front.. Last night I remembered that on a recent five day Smoky Mountain ride round trip from a buds house in Birmingham AL -- one of the guys following me the whole time voluntarily mentioned my bike had an exhaust odor that would indicate that.

When I first got this bike I did the time honored Clinic mod of routing the rocker cover vent tube up the frame backbone and attaching it to an automotive PVC type filter that is zip strip attached to the ignition key unit.

The plastic coasting enricher cover on the carb was replaced over a year ago with one of the metal items being sold by a few people on the various Road Star sites.

When the stock fuel pump setup was eliminated, my bud Gordon and I installed a new OEM intake manifold as described in an earlier post because my bike would not stay running without a clothespin holding the enricher / choke cable open on the way over to his house. That was well over a year ago and several thousands of miles are on the bike since then. As stated above the nipple was soldered closed and I have a rubber vacuum hose cap on top of that for good measure. I sprayed starting fluid around the edges of the intake a couple of times since then (including recently) with the engine completely warmed up and running at idle and there was no difference in RPM level

These responses are very good and I appreciate it.

This site rocks and shows how we can all learn from each other!

[Lug Nut]

Maybe you're enricher cable knob is not seating fully in the closed position and therefore altering your mixture when running.

[Shores]

Why buy new plugs each time? Can't you just clean them off and hit them with a propane torch to burn everything off? Seems like I've heard about doing that.

[davej]

yes you can do that. I spray them with starting fluid or carb clean then put the torch to them until they are clean and dry.

[Tcontrol]

With the additional information presented regarding front plugs also indicating a rich mixture…. It becomes quite obviously a carb issue regarding a mixture….
special attention regarding the primary metering screw, the accelerator pump assembly, the main slide/diaphragm assembly and enricher attachment/ o-ring seals… is strongly advised…. You may also check that metal enricher cover and confirm it hasnt warped due to internal spring tension…

typically a leak at the float bowl needle shows itself by flooding the engine… it is easiest to check and adjust float level with the carb off of the bike using a clear tube and a level workbench… a little tang bend will be a big float level adjustment… i personally set the bowl level slightly on the low side with a pumpless bike and suggest you keep a minimum 1/4 tank of fuel to keep from fuel starving the carb at higher rpms.. ( float bowl sucks out gas faster than you can refill it using gravity at low tank levels… a minor inconvenience )
the carb gurus will advise recommended jetting with stock pipes since the pipes are still reducing your airflow through the motor… different pipes would require different jetting as airflow restrictions through the motor are reduced…