Top end rebuild, what would you do, big bore, hi comp or stock?

The head, piston and cam chain in one of my DRZ E models is toast so I am trying to decide which direction to go with the rebuild. It was dropped a few months back and cut off in a large mudhole and sucked water back into engine, oil was changed numberous times, but apparently it did some damage anyway even though it seemed to run fine for a few weeks afterward. Oh well, regardless it is broken down now and needs fixing so the question is how.

 

The cylinder isn't messed up, a decent honing and it shoud clean right up, but regardless it needs a new piston and rings so I have been considering just getting a big bore 434 bolt on kit.

 

Anyone had any issues with the full bolt on and go big bore kits? Any particular makers people have had problems from?

 

I also thought of just putting a stock piston or maybe just one size up after cleaing the cylinder and maybe installing some hot cams and having the head ported and polished.

 

Anyone have anything to say about HotCams? Stage 1 or 2? I mainly ride woods and some MX so I'm thinking stage 1, don't need the power on the top end as much as low end.

 

Final thought is to do a big bore with Hot Cams and porting and polishing, but don't know if I want to put that much into it honestly.

 

What does the crowd think, what would you do or what have you done that has worked well?

 

I'm more interested in reliability than a little extra performance, if I just wanted pure power I could just get a 450 race bike, but I like the reliability and ease of maintenance of the DRZ or at least I did anyway.

Edited by dirtdude723

The head, piston and cam chain in one of my DRZ E models is toast so I am trying to decide which direction to go with the rebuild. It was dropped a few months back and cut off in a large mudhole and sucked water back into engine, oil was changed numberous times, but apparently it did some damage anyway even though it seemed to run fine for a few weeks afterward. Oh well, regardless it is broken down now and needs fixing so the question is how.

 

The cylinder isn't messed up, a decent honing and it shoud clean right up, but regardless it needs a new piston and rings so I have been considering just getting a big bore 434 bolt on kit.

 

Anyone had any issues with the full bolt on and go big bore kits? Any particular makers people have had problems from?

 

I also thought of just putting a stock piston or maybe just one size up after cleaing the cylinder and maybe installing some hot cams and having the head ported and polished.

 

Anyone have anything to say about HotCams? Stage 1 or 2? I mainly ride woods and some MX so I'm thinking stage 1, don't need the power on the top end as much as low end.

 

Final thought is to do a big bore with Hot Cams and porting and polishing, but don't know if I want to put that much into it honestly.

 

What does the crowd think, what would you do or what have you done that has worked well?

 

I'm more interested in reliability than a little extra performance, if I just wanted pure power I could just get a 450 race bike, but I like the reliability and ease of maintenance of the DRZ or at least I did anyway.

Don't know as much as the guru's here, but I got the Cylinder Works kit and have to say it was really worth it. 150ron got Hot Cams and he's very happy, but in your case, I'd definitely go for the Stg1 v/s the Stg2.

 

Have no idea about porting and polishing, and/or the cost and whether it's worth it or not, but I ride dirt too, and the big bore was WORTH IT!

 

The reliability factor won't change, but the enjoyment will..........good luck!!

If you have the earlier E model the standard A and B stamped cams are around stage 2 HC anyway, the E exhaust is actually more aggressive, you may benefit in just putting in a stage 2 inlet cam which has a longer duration and slightly more lift than the A inlet cam, go for a CW 434 kit and be done with it, according to the hoards of threads in TT, reliability is not an issue but the benefits are well worth it.

I know you dont intend on using the old cylinder....but honing it isnt a good idea. It has a special coating. if you hone it off the cylinder wont last long at all.

 

and i say go for the high comp BB setup W/ hotcams and a rejet to suit. :thumbsup:

Edited by seemus

 It was dropped a few months back and cut off in a large mudhole and sucked water back into engine, 

This here could suggest that your bottom end's days are numbered also.

Depending on how many miles, seeing you're in the States and it is an E, it would be getting on in age and miles. 

If you plan on keeping it, then I would suggest replacing the crank, either standard or stroker.

There is also the ACT kit for the gearbox, all comes down to if you plan on keeping it, and how much you want to spend.

Or you could patch it up and sell it.

Hotrods and cylinder works are tried and true , on the other hand namura isnt , greg

+1

I know you dont intend on using the old cylinder....but honing it isnt a good idea. It has a special coating. if you hone it off the cylinder wont last long at all.

 

and i say go for the high comp BB setup W/ hotcams and a rejet to suit. :thumbsup:

 Nikasil is incredibility hard, all honing does is deglaze the cylinder. If you managed to break through the coating the cylinder is well past time for replacement.

I have a good stock cylinder and piston but it needs rings, will let it go at a good price. PM me if interested. I would ball hone th ecylinder before install.

Thanks for all the info and replies. I was thinking I had read and heard the CW bb kit works well on the DRZ, but wanted to get the public opinion from a group that should know.

 

Both my E models are actually 2000-2001 editions so they have the early model cams, wasn't aware they are more aggressive from the box but makes sense seeing as how my E models have always seemed a little more pepy than other DRZ I have been around, granted the FCR 39 on the early models helps too.

 

My main concern with a bb kit was more heat, but that doesn't seem to be an issue or at least not enough of one for people to say not to go 434 so that seems like the direction I will go.

 

As for porting and polishing I may get the owner/head mechanic at the shop I work at to do a little work on the head, may as well while I have it off, never hurts to have things flowing better.

 

Also have given the bottom end a good bit of attention to look for play in bearings and such, but all seems decent enough, as best as one can tell without cracking the cases so I'm going to put the bb kit on, button it up and ride it til it needs attention again, hopefully it will be as long as the last.

 

Thanks again for all the input. I will let you know how it turns out, may even put up a few pics

If you have the earlier E model the standard A and B stamped cams are around stage 2 HC anyway, the E exhaust is actually more aggressive, you may benefit in just putting in a stage 2 inlet cam which has a longer duration and slightly more lift than the A inlet cam, go for a CW 434 kit and be done with it, according to the hoards of threads in TT, reliability is not an issue but the benefits are well worth it.

e model cam is more similar to the stage 1 HC.. not stg 2..

stg 1 low to mid power

stg 2 mid to high power..

Proper E model cams, Exhaust B cam, 9.3mm lift 243 dur @ 1mm, Inlet A cam 8.9mm lift, 227 dur @ 1mm, current available stage 2 hotcams 9.05mm lift, 238 dur @ 1mm on both sides, available stage 1 HCs down to 8.7mm lift less duration exhaust, 9.13 lift inlet 230 duration inlet, I have 2 B exhaust cams on both sides which is close to the older model stage 2 HC which aren't available, 9.5mm lift 244 duration both sides, hence why I suggested stage 2 on Inlet only, the E ex cam is a good one as long as its stamped B, proper E inlet cam is stamped A, if his is a proper earlier FCR equipped E the the cams are good ones anyway, just look on the Hotcams website for specs, by standard bore S is fantastic on dirt and road with big cams. 

The head, piston and cam chain in one of my DRZ E models is toast so I am trying to decide which direction to go with the rebuild. It was dropped a few months back and cut off in a large mudhole and sucked water back into engine, oil was changed numberous times, but apparently it did some damage anyway even though it seemed to run fine for a few weeks afterward. Oh well, regardless it is broken down now and needs fixing so the question is how.

 

The cylinder isn't messed up, a decent honing and it shoud clean right up, but regardless it needs a new piston and rings so I have been considering just getting a big bore 434 bolt on kit.

 

Anyone had any issues with the full bolt on and go big bore kits? Any particular makers people have had problems from?

 

I also thought of just putting a stock piston or maybe just one size up after cleaing the cylinder and maybe installing some hot cams and having the head ported and polished.

 

Anyone have anything to say about HotCams? Stage 1 or 2? I mainly ride woods and some MX so I'm thinking stage 1, don't need the power on the top end as much as low end.

 

Final thought is to do a big bore with Hot Cams and porting and polishing, but don't know if I want to put that much into it honestly.

 

What does the crowd think, what would you do or what have you done that has worked well?

 

I'm more interested in reliability than a little extra performance, if I just wanted pure power I could just get a 450 race bike, but I like the reliability and ease of maintenance of the DRZ or at least I did anyway.

 

Go for the Cylinder Works Big Bore kit,... current hotcams are no advantage over "real" E cams

 

head flowing will be more benefit if you go BB, replace your valves and timing chain if required

Edited by Craigo 485sm

Go for the Cylinder Works Big Bore kit,... current hotcams are no advantage over "real" E cams

 

head flowing will be more benefit if you go BB, replace your valves and timing chain if required

Speaking of guru's......what he just said......... :lol: :lol:

e model cam is more similar to the stage 1 HC.. not stg 2..

stg 1 low to mid power

stg 2 mid to high power..

I looked and I do have the A/B cams which makes sense given my bikes are year one and two of production and E models so I'm not going to mess with cams

Proper E model cams, Exhaust B cam, 9.3mm lift 243 dur @ 1mm, Inlet A cam 8.9mm lift, 227 dur @ 1mm, current available stage 2 hotcams 9.05mm lift, 238 dur @ 1mm on both sides, available stage 1 HCs down to 8.7mm lift less duration exhaust, 9.13 lift inlet 230 duration inlet, I have 2 B exhaust cams on both sides which is close to the older model stage 2 HC which aren't available, 9.5mm lift 244 duration both sides, hence why I suggested stage 2 on Inlet only, the E ex cam is a good one as long as its stamped B, proper E inlet cam is stamped A, if his is a proper earlier FCR equipped E the the cams are good ones anyway, just look on the Hotcams website for specs, by standard bore S is fantastic on dirt and road with big cams. 

I have two sets of cams, both A/B so I'm going to just keep the stock E cams and bolt on a big bore kit and call it a day

 

BTW one E model does dirt duty and the other is in supermoto form most of the time unless a friend needs a bike for dirt or I'm going to do some dual sporting

 

just looking for the most return with the least amount cost and maintenance, seems the bolt on big bore kit is the way to do just that

 

I already sourced a head off eBay for $240 shipped with all internals, nice that they used the same engine in a few different bikes, makes parts easier to find and cheaper too

I have two sets of cams, both A/B so I'm going to just keep the stock E cams and bolt on a big bore kit and call it a day

 

BTW one E model does dirt duty and the other is in supermoto form most of the time unless a friend needs a bike for dirt or I'm going to do some dual sporting

 

just looking for the most return with the least amount cost and maintenance, seems the bolt on big bore kit is the way to do just that

 

I already sourced a head off eBay for $240 shipped with all internals, nice that they used the same engine in a few different bikes, makes parts easier to find and cheaper too

Excellent, the big bore will certainly aid the function of the setup you have, there is one on youtube with 47 at the RW with e cams, best of luck

Thanks for all the info and replies. I was thinking I had read and heard the CW bb kit works well on the DRZ, but wanted to get the public opinion from a group that should know.

 

Both my E models are actually 2000-2001 editions so they have the early model cams, wasn't aware they are more aggressive from the box but makes sense seeing as how my E models have always seemed a little more pepy than other DRZ I have been around, granted the FCR 39 on the early models helps too.

 

My main concern with a bb kit was more heat, but that doesn't seem to be an issue or at least not enough of one for people to say not to go 434 so that seems like the direction I will go.

 

As for porting and polishing I may get the owner/head mechanic at the shop I work at to do a little work on the head, may as well while I have it off, never hurts to have things flowing better.

 

Also have given the bottom end a good bit of attention to look for play in bearings and such, but all seems decent enough, as best as one can tell without cracking the cases so I'm going to put the bb kit on, button it up and ride it til it needs attention again, hopefully it will be as long as the last.

 

Thanks again for all the input. I will let you know how it turns out, may even put up a few pics

 

 

The main concern with the big bore is sealing not overheating . You must copper coat the head gasket and use 43 ftlb of torque on the head bolts , and bob`s your uncle  :thumbsup:

and bob`s your uncle  :thumbsup:

 

Before any foreigners ask....."Bob's your Uncle" .....is Aussie slang :aussy: meaning ...."She"ll be right mate"..... :thumbsup:

Do you think we should explain , she`ll be right ?

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