advice, my new and first SM, 07, modded, head gasket blew after 2 weeks, advice please....thanks!

[dual sport seattle]

Hello TT people's, how's it going.  This is my first thread, I have been a lurker for a year +.   I have had a reliable dr350 for the past year.  I decided I really wanted a drz400SM, so I picked up a local bike, pretty fair deal I guess.  Seemed ok.  A little rough, but was assured it is heck of reliable etc.  After riding it a little for a couple weeks, apparently the head gasket has failed.

  I put the axle sliders on, mirrors, blinkers.

  I am getting myself psyched to try this myself.  I wanted advice on what I may want to do.

    This is what I was told by previous owner.  2007 drz400sm he bought with 12.5k, then he and his dad did mods.....    hot rods big bore 434, 39fcr carb, full yoshimura exhaust, vapor speedo, external timing chain tensioner?  maybe wheels, not sure.  Then he put about 2800 miles on bike after all that over 7 years, then sold it to me.  It has stock cams.  He said it was super reliable.   So at least I got a couple weeks to ride, 100 miles maybe, what a blast.  There was a tiny bit of oil spray coming from front of head gasket, some smoking on start up around pipe header that went away in a minute.

    diagnose:   I asked him when oil was changed, 1500 ago full synthetic, year and a half maybe.  I changed oil with MOBIL 1 full synthetic, the oil in there looked like right color for miles, no water at all.  Few more rides.  Then, a couple days ago on starting, engine made a pop from left side, then another, then started.  I checked oil, and there was the white past around top.  Water was low.  I added anti freeze.  I hoped white paste  was just from some short rides, I started it up and warmed it up today, and there was way more white on dipstick etc, and you could see some antifreeze tiny drops coming from head gasket on left side.  Also tiny drops of oil. 

  Do you guys think changing the head gasket could fix this?   I am on good terms with the seller.  He said he did the head gasket once, not sure why.  It lasted at least the 1500 miles from last oil change far as I can figure.  Is it possible I need to have the head machined?  And,  would you guys recommend putting in stage 2 hotcams to match up other mods?  I would have to learn to do shimes and valve adjustment minumum?   I haven't torn apart a moto engine or done heads or valve adjustments.  I have worked on a lot of cars various stuff, brakes, struts, starter, basic stuff like that.  I have a lot of tools and my garage is clean now with lights to work on this.  Thanks in advance for any advice or encouragement.  

[1hp]

you may want to get a factory service manual. after looking through it, you should know if you want to try it.

[Atolduso]

It's not a hard job if you've worked on cars. It can all be done in the frame. A couple hours at most. Check the surfaces, and make sure the bike isn't overheating. Obviously you are going to want to find out why its blowing gaskets so easily. 

[dual sport seattle]

Ok, the seller has offered to help, so I am going to start taking it apart tomorrow, following the thread I found from Eddie? explaining step by step with pics.

    Thanks for replies guys!    So I think I will get the head resurfaced at a machine shop while I'm doing this.

  What do you think about adding the stage 2 hotcams for this bike?  I guess I would need to buy a shim kit and adjust valves with new cams?  Anything else?

[roleyrev]

27 minutes ago, dual sport seattle said:

Ok, the seller has offered to help, so I am going to start taking it apart tomorrow, following the thread I found from Eddie? explaining step by step with pics.

    Thanks for replies guys!    So I think I will get the head resurfaced at a machine shop while I'm doing this.

  What do you think about adding the stage 2 hotcams for this bike?  I guess I would need to buy a shim kit and adjust valves with new cams?  Anything else?

Yes, Yes and yes - Stage 2 hotcams work a treat (particularly well with what has already been done), you have the perfect opportunity to install them.  My experience is they drop straight in.  I found that my valve clearances had not moved at all with the install so I would pop them in then do a clearance check before ordering up a shim kit.   If there are required changes you may be able to purchase just the shims you need through you local Suzuki service agent - it would save having to buy a whole kit. Best of luck with head gasket. 

[Barry Ries]

  If this is the second time it blew a head gasket I would have the head and barrel checked for flatness and have them machined to make them flat.  I'm suspecting a slight warp that seals pretty good but not as good as it should.  Of course sometimes people will get lucky and a new head gasket will seal and stay sealed.

[dual sport seattle]

1 hour ago, roleyrev said:

Yes, Yes and yes - Stage 2 hotcams work a treat (particularly well with what has already been done), you have the perfect opportunity to install them.  My experience is they drop straight in.  I found that my valve clearances had not moved at all with the install so I would pop them in then do a clearance check before ordering up a shim kit.   If there are required changes you may be able to purchase just the shims you need through you local Suzuki service agent - it would save having to buy a whole kit. Best of luck with head gasket. 

Thanks.  Seems there are many ebay hotcam listings for intake cam, good deal.  Exhaust cam is more money.  I read somewhere on TT that some people do intake only, somewhat because the exhaust cam makes it start harder?    I kind of like that the bike is hotrodded somewhat, is the performance of intake AND exhaust much better than intake cam only? 

[dual sport seattle]

29 minutes ago, Barry Ries said:

  If this is the second time it blew a head gasket I would have the head and barrel checked for flatness and have them machined to make them flat.  I'm suspecting a slight warp that seals pretty good but not as good as it should.  Of course sometimes people will get lucky and a new head gasket will seal and stay sealed.

Is the barrel also known as cylinder?   My other friend was saying I might want to check the cylinder for flatness.  It can be removed from bottom of engine and taken to machine shop at same time as head?  I would have to figure that out, dealing with piston etc. I think?  Ya, my first time doing this stuff. Thanks.

[roleyrev]

1 hour ago, dual sport seattle said:

Thanks.  Seems there are many ebay hotcam listings for intake cam, good deal.  Exhaust cam is more money.  I read somewhere on TT that some people do intake only, somewhat because the exhaust cam makes it start harder?    I kind of like that the bike is hotrodded somewhat, is the performance of intake AND exhaust much better than intake cam only? 

Worth doing both in my opinion.  The hard starting, to which you refer, may be in reference to the older hotcams that didn't have the auto decompressor on them.  The new version with the decompressor is no harder to turn over than the stock cams.  @ohiodrz400sm May be able to chime in on exactly what effect only the intake cam will have as he has tried most combinations. In my experience the bike goes way better from 4500 rpm to about 8000rpm compared to standard with both cams fitted (and their appears to be no real downside) . One of the best modifications after an FCR 39 (which you have) and a good exhaust (which you also have)

[ohiodrz400sm]

Hot Rods makes a stroker kit, not a big bore, which do you have?

Many of the 94mm big bore head gaskets need the rivets removed as they interfere with the mating surfaces. Also, it is highly recommended to increase the torque on the head bolts to 43 ft/lbs vs the manuals 34.

What kind of power do you want dictates which cams you go with. Stock cams are tuned for emissions, they are of no benefit to any part of the powerband. Despite their marketing Hotcams are more of low to mid-range cams. As engine displacement increases cams respond at lower rpm. If you want really strong low to mid-range than Hotcams are a fine choice. If you want even more mid-range with a bit more top Web 536/536 might be better. If you want a very linear powerband that pulls evenly from low to top Web 536/540 works well. If you want it to run like a 2 stroke than Web 540/540 or 540/539 is the way to go. Your Yoshimura bexhaust system is choking top end power anyway so you would probably be better off with 1 of the low to mid-range cam choices

[76xtdrvr]

Check your base gasket thickness also. It's possible the P.O. removed one of two of the gasket sections, plus the center metal section, to gain more compression. This, coupled with other factors mentioned, may have contributed to the blown head gasket.

[dual sport seattle]

3 hours ago, ohiodrz400sm said:

Hot Rods makes a stroker kit, not a big bore, which do you have?

Many of the 94mm big bore head gaskets need the rivets removed as they interfere with the mating surfaces. Also, it is highly recommended to increase the torque on the head bolts to 43 ft/lbs vs the manuals 34.

What kind of power do you want dictates which cams you go with. Stock cams are tuned for emissions, they are of no benefit to any part of the powerband. Despite their marketing Hotcams are more of low to mid-range cams. As engine displacement increases cams respond at lower rpm. If you want really strong low to mid-range than Hotcams are a fine choice. If you want even more mid-range with a bit more top Web 536/536 might be better. If you want a very linear powerband that pulls evenly from low to top Web 536/540 works well. If you want it to run like a 2 stroke than Web 540/540 or 540/539 is the way to go. Your Yoshimura bexhaust system is choking top end power anyway so you would probably be better off with 1 of the low to mid-range cam choices

His memory on this question was "I think it was hotrods"?    I don't know.  There seems to be a lot of 434 kits,  athena, wiseco, wonder if i would see a stamp when i remove head.       stage 2 hotcams is sort of mellow then, the appeal is the lower cost and they might drop in without a lot of other work, since I don't know much about working on these,......yet    Right now it has great low end torque ok mid, i guess i don't really rev it out seems to kind of fall off, power band is mostly low end and good mid

[dual sport seattle]

I have removed the seat , gas tank, radiators, now attempting to figure how to get header off.  There was some thick oil in top of left radiator, and right radiator the anti freeze was slightly discolored a little with brown.  Mostly antifreeze was green, not all oil mixed yet.

[Barry Ries]

13 hours ago, dual sport seattle said:

Is the barrel also known as cylinder?   My other friend was saying I might want to check the cylinder for flatness.  It can be removed from bottom of engine and taken to machine shop at same time as head?  I would have to figure that out, dealing with piston etc. I think?  Ya, my first time doing this stuff. Thanks.

  Yes back in the old days we sometimes called cylinders barrels.

[dual sport seattle]

https://www.amazon.com/PRO-CAKEN-Gasket-DR-Z400-DRZ400/dp/B07JGXSR77/ref=sr_1_fkmr1_1?keywords=drz400+94mm+head+gasket&qid=1553795404&s=gateway&sr=8-1-fkmr1

12$ us,  with couple other gaskets, 94mm    too good to be true?  what if i treat it with copper spray stuff?

 I just ordered this gasket because of super fast shipping, and really low price.  Hmm, now I wonder if this is just too risky on if it will work ok.

 

 I have been working on this for some time now,  removed lots in order, managed to get exhaust header off, now working on removing fcr 39 carb, almost getting to actually taking engine apart. 

 

  I have been using this TT thread for reference, good stuff.   I have been taken lots of pics with digital camera.   I guess this beats trying to do this bending over a car fender, under a hood, right?

 

 

 

Edited March 28, 2019 by dual sport seattle

[Atolduso]

Terrible offbrand, get Cometic gaskets. 

Do you want to be doing this again soon?! It's not much more money for the kit. 

Edited March 28, 2019 by Atolduso

[BluePill]

1 hour ago, Barry Ries said:

  Yes back in the old days we sometimes called cylinders barrels.

Harley guys always liked to refer to them as "Jugs".

 

No real surprise there.

[dual sport seattle]

39 minutes ago, Atolduso said:

Terrible offbrand, get Cometic gaskets. 

Do you want to be doing this again soon?! It's not much more money for the kit. 

Thank you!  I just ordered a cometic 94mm 434 big bore gasket. 

[hinksy]

1 hour ago, dual sport seattle said:

https://www.amazon.com/PRO-CAKEN-Gasket-DR-Z400-DRZ400/dp/B07JGXSR77/ref=sr_1_fkmr1_1?keywords=drz400+94mm+head+gasket&qid=1553795404&s=gateway&sr=8-1-fkmr1

12$ us,  with couple other gaskets, 94mm    too good to be true?  what if i treat it with copper spray stuff?

 I just ordered this gasket because of super fast shipping, and really low price.  Hmm, now I wonder if this is just too risky on if it will work ok.

 

 I have been working on this for some time now,  removed lots in order, managed to get exhaust header off, now working on removing fcr 39 carb, almost getting to actually taking engine apart. 

 

  I have been using this TT thread for reference, good stuff.   I have been taken lots of pics with digital camera.   I guess this beats trying to do this bending over a car fender, under a hood, right?

 

 

 

Yes , copper coat the head gasket and torque the head to 43 ftlbs , the manual has a misprint . This could be the main reason why it blew the gasket , but do check the level of the mating surfaces , just in case . There were some examples of poor castings on here a few years back , so you never know . The way you boost the compression in these motors , is through  the base gasket . It is a 3 part gasket , all 3 give you a lower compression and you can run low octane fuel . Use either the top or bottom pieces of the gasket ( the paper ) and it will raise the compression and you will most likely have to use high octane fuel . By itself alone , changing compression doesnt do much horsepower wise , but with the big bore / hotcams / FCRMX 39mm it will add to the package and give you up to 48-50 horse power at the rear wheel on a good tune . I fitted the hotcams into my SM and it was just a straight fit which needed no shim adjustment . Doesnt mean that yours will be to , so be safe and check once you put them in , greg

[dual sport seattle]

Does it matter if I buy the stage 2 hotcams, intake and exhaust separately, from 2 different sellers?  Or do I need to buy the pair together in same package?