m3hl
Member
Mine is a 2016 race bike and it just blew. 2300 miles. I am running a PCV, Spal fan and a 1.6 bar rad cap. Never over heated.
Blown gaskets. Is there anything that can be done to prevent it?
Mine is a 2016 race bike and it just blew. 2300 miles. I am running a PCV, Spal fan and a 1.6 bar rad cap. Never over heated.
Mkinzer126
New Member
I wonder if the 2016’s have / had the revised cylinder / piston parts (new part numbers) that have superseded the original part numbers in the KTM Online parts manual?
Mkinzer126
New Member
Maybe I should ask if anyone with a racing RC 390 (especially a 2015) HASN’T had a head gasket failure...
Russian roulette has better odds.
Mkinzer126
New Member
Is this why everyone that races them is moving to an R3? I really would love to race the 390, but I don’t want a timebomb underneath me. I also realize that most people only take time to tell a bad story rather than praise. SO I always treat the internet as “a source” not “the source” of truth.
Just the fix it before it blows up or wait to see if it does, but you will still need to prepare for it.
Mkinzer126
New Member
Bike I’m getting is a 2015 with a manufacturing date of 02/15 with 6 sprint races on it. Has 1400 miles total with most of those being street miles. . Stock engine. Miiv exhaust and Bazazz FI, BMC filter with MNNTHBX airbox cover.
Tom
New Member
Sorry to revive a zombie thread here. But it seems like even the '17 models are blowing head gaskets (which scares me as I just bought one).
Has anyone measured their head bolts after a blown head gasket? I'm curious to see if there is some stretching compared to the factory new units. I'm really surprised that one of the vendors here hasn't found a high carbon steel replacement yet!
Has anyone measured their head bolts after a blown head gasket? I'm curious to see if there is some stretching compared to the factory new units. I'm really surprised that one of the vendors here hasn't found a high carbon steel replacement yet!
We looked into ARP head studs and it did not pass the cost benefit analysis in the slightest. We use a dial indicated torque wrench and with that you can see when a bolt won't hold torque values. We usually throw away about 1/3rd of the OEM bolts because of this.
Tom
New Member
That's a shame. You would think a set of ARP 2000 studs would out weigh the cost/benefit ratio of getting stuck somewhere and having to tow/trailer your bike.
Quoted from ARP 50 kits would put the price well into the $400 dollar range. Maybe it passes yours but it certainly didn't make any sense to me
Knock on wood, two full race seasons only had one minor issue of the stator bolts coming loose. Run the 1.6 bar rad cap and original fan. Never had an overheat issue once. Was apart first year purchased with less than 200 km on it for another issue. But, its coming apart shortly for preventative maintenance/upgrage cooling system
Well, I think I may join this club. I have a '15 with about 900 miles on it. I have raced it one weekend and had a relaxed practice day yesterday. Never once in practice did I hit the rev limiter (just to try and avoid this issue). When preparing for my first race today, I looked in the sightglass and it looks like an emulsion. I checked the water overflow and it's nearly empty (it had been perfectly full and consistent). No ridability issues during practice, so it was fortunate I saw the issue in the sightglass. In fact, it starts and idles just fine.
I put the 1.6 bar cap, SPAL fan, PCV, and run water wetter before racing. It has never gave me any indication of being hot. The outside was only 70 deg as well.
I'll put some pressure on the cylinder when I get home and try to make sure the head gasket is actually bad and not the water pump. Are your gasket failures letting water into the oil? It's possible the water leaked in overnight as well since I had no reason to suspect anything yesterday.
Are you guys having to replace all the bearings / cylinder / etc from water in the oil or does a quick easy head gasket change usually fix it?
When getting the head decked, do you need to put a slotted cam sprocket on to compensate for the now longer chain?
Any other reliability upgrades for racing while I'm this far in the engine?
Any recommendations of who to send the heads or engine to who really knows this platform?
Thanks in advance!
I put the 1.6 bar cap, SPAL fan, PCV, and run water wetter before racing. It has never gave me any indication of being hot. The outside was only 70 deg as well.
I'll put some pressure on the cylinder when I get home and try to make sure the head gasket is actually bad and not the water pump. Are your gasket failures letting water into the oil? It's possible the water leaked in overnight as well since I had no reason to suspect anything yesterday.
Are you guys having to replace all the bearings / cylinder / etc from water in the oil or does a quick easy head gasket change usually fix it?
When getting the head decked, do you need to put a slotted cam sprocket on to compensate for the now longer chain?
Any other reliability upgrades for racing while I'm this far in the engine?
Any recommendations of who to send the heads or engine to who really knows this platform?
Thanks in advance!
I have this question also, not just about the base gasket but also the head gasket. I've almost always used a copper spray on head gaskets. What about on the 390?
Also, it appears that at least the stock head gasket has a new part number. Could that mean KTM has maybe made a significant improvement? Put another way, has anyone here installed the new gasket and then had a subsequent failure?
Another concern that I'm sure someone can address: Thinner gaskets change the valve timing as noted in the Motorcyclist article. But I've seen no mention of how to actually correct this. On my Ducati I use a special tool to hold the camshafts at perfect TDC position, and the camshaft sprockets can then be loosened and rotated so that the crankshaft can also be put at perfect TDC. Then the sprocket screws are tightened and the cams are perfectly matched to the crankshaft position. But I don't see any obvious provision for this on the 390.
Moreover, the service manual is pathetically devoid of any information about cam timing. It just assumes that the timing chain is perfect the sprockets are perfect, and the gasket thicknesses and head milling all are perfect. This leaves me feeling very uneasy.
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Bumping this thread because I have to think that someone has dealt with my questions and probably has some valuable knowledge to share.
Please see my previous post. Thanks very much!
Please see my previous post. Thanks very much!
Fangfactor
Member
I blew a head gasket between the exhaust valves into the coolant jacket on my 2015.
I used the updated ktm gasket and also used the copper spray to coat it.
My head h
ad a slight hollow in the spot it blew of about .001 inch
I used a thick piece of glass with 600 grit emery paper taped to the glass and lapped the head in a figure 8 pattern using kerosene as a cutting lubricant until the hollow was gone.
The bike has done about 3000km of race track thrashing since then and has ran faultlessly
Thanks, Fangfactor, for the helpful info about your experience. This is very useful. I'm still wondering about valve timing, though.
Thinner gaskets or milled heads/decks change the valve timing as noted in the Motorcyclist article. But I've seen no mention of how to actually correct this. On my Ducati I use a special tool to hold the camshafts at perfect TDC position, and the camshaft sprockets can then be loosened and rotated so that the crankshaft can also be put at perfect TDC. Then, after the belts are tensioned, the sprocket screws are tightened and the cams are perfectly matched to the crankshaft position. But I don't see any obvious provision for this on the 390.
Has anyone here worked through that issue? Or do you just let there be some imperfection and try not to worry about it? (That's hard for me to do)
Has anyone here worked through that issue? Or do you just let there be some imperfection and try not to worry about it? (That's hard for me to do)
Seth
Member
Above is true knowledge. 600 grit on a figure 8 seems just perfect
Below maybe someone else could chime in.
Thinner gaskets or milled heads/decks change the valve timing as noted in the Motorcyclist article. But I've seen no mention of how to actually correct this. On my Ducati I use a special tool to hold the camshafts at perfect TDC position, and the camshaft sprockets can then be loosened and rotated so that the crankshaft can also be put at perfect TDC. Then, after the belts are tensioned, the sprocket screws are tightened and the cams are perfectly matched to the crankshaft position. But I don't see any obvious provision for this on the 390.
Has anyone here worked through that issue? Or do you just let there be some imperfection and try not to worry about it? (That's hard for me to do)
Fangfactor
Member
Regarding the difference I noticed in the head gaskets,
The original one installed that blew had a rubberised coating on both sides and that is what actually blew out.
The upgraded gasket didnt have the rubberised coating but has like an anodised finish.
The original one installed that blew had a rubberised coating on both sides and that is what actually blew out.
The upgraded gasket didnt have the rubberised coating but has like an anodised finish.
In addition to my still-open question about valve timing adjustment, I'd like to understand more about the seemingly prevalent inferior head bolts. Specifically, is there a procedure that a home mechanic can use to evaluate these bolts to identify any that should be discarded?
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