74jimbo's engine build thread

[HansLanda]

On 9/10/2017 at 1:30 AM, 74jimbo said:

I am going to be rebuilding my own engine,

 

On 9/10/2017 at 1:30 AM, 74jimbo said:

I will be doing the rebuild myself

 

[74jimbo]

assembling parts is a lot different than machining heads requiring tens of thousands of dollars worth of special equipment......

[ohiodrz400sm]

assembling parts is a lot different than machining heads requiring tens of thousands of dollars worth of special equipment......

I don't know if you need a valve job but the prices I listed were out the door prices. Send them the head, they send it back ready to bolt-on. Cut seat, valves, springs, seal, everything. Unless the head is warped you don't need it milled. If you have a pane of glass or granite countertops, you can measure the out-of-flatness yourself with a .002" feeler gauge. If the gauge slides under it's out of spec.

In the age of 4 stroke motocross bikes there are numerous shops and prices are competitive. Nobody is going to charge you $1500 simply because you can buy a new head assembly for less than half of that.

 

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[74jimbo]

Not a new, oem assembly. Anyways, couldn't find meyers racing. Looked at fast heads. They look the best. The other seemed more quad oriented. So, unless fh site is just weird, I was seeing $600 for their suzuki, and if I didn't need parts.... Wasn't trying to spend $2k on a motor build..... live and learn I guess..... for $2k though, I could probably pick up a running bike pretty easily, one that would handle my commute a little easier....

[ohiodrz400sm]

Not a new, oem assembly.

A brand new head is $612 from Motosport.

Since most of the knowledge of the head is based off the LT-Z400 racing effort there is nothing wrong with using a "quad shop". The aftermarket certainly didn't make all those cams and oversized valve options with the DRZ400S in mind. The quad is 99% of the reason for such a large aftermarket for this bike

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[74jimbo]

myers seems to have a facebook page, do they have an actual website?

I am looking into those 3, it's just more expensive of a build now..... ugh......

I really like my drz, I am just afraid it's trying to polish a turd (not that the drz is a turd) just hard to come up with the $, when I have really only had the bike since may. It's been down longer than it has been up...

[HansLanda]

What about getting a good condition used head...?

[74jimbo]

Just now, HansLanda said:

What about getting a good condition used head...?

my head is used, and should be in fine condition... the valves all checked within spec before I tore it down, and other than begin a little dirty, cam timing and all of that was spot on....

everyone here is saying my new motor is going to blow up if I don't replace my head..

I could jsut piece together all used engine parts believed to be in good condition, for way cheaper, but then, what exactly does that mean? I mean some chop shop and ebay could be all like it's good condition, got it off a bike with 3k miles on.... but who knows what those 3k miles consisted of?

[ohiodrz400sm]

How many miles are you at?


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[74jimbo]

I am around 18k. My motor was worked on at some point possibly, almost all the bolts are allen cap heads

 

 

[0macman0]

Not a new, oem assembly. Anyways, couldn't find meyers racing. Looked at fast heads. They look the best. The other seemed more quad oriented. So, unless fh site is just weird, I was seeing $600 for their suzuki, and if I didn't need parts.... Wasn't trying to spend $2k on a motor build..... live and learn I guess..... for $2k though, I could probably pick up a running bike pretty easily, one that would handle my commute a little easier....

Have you checked with engine dynamics? They fixed my WR250F head and are in the Bay Area.

[timbanditos]

74Jimbo, I would say you are not going to get your bang for your buck if you big bore and stroke that motor and only let it drink from the stock carb, at a minimum I would go FCR 39, but ideally FCR 41. I had a BB 434cc with the FCR 39 and that was a totally different bike than stock, but I did the FCR 39 before the big bore and it was a very noticeable difference. I have to admit, the FCR carb is a pricey upgrade but well worth it. 

[74jimbo]

never heard of engine dynamics, but will look into them. I do like they are in the bay area, but as you know, that menas they will just charge 3x everyone else, because hte bay area is expensive....

 

tim, eventually, I will upgrade the carb, but right now, it isn't going to happen.... already pinching pennies to get this back and running, and larger jets will be just fine for now

[74jimbo]

ok need to get some tools, looking to get a flywheel holder, a case splitter, and a clutch hub holder... any recommendations?

looking to order these tools, not build my own

still looking into a proper chain tool, I think I have seen the motion pro pcb? or pbr? mentioned here

[samacart]

2 hours ago, 74jimbo said:

ok need to get some tools, looking to get a flywheel holder, a case splitter, and a clutch hub holder... any recommendations?

looking to order these tools, not build my own

still looking into a proper chain tool, I think I have seen the motion pro pcb? or pbr? mentioned here

Look at Rockymountainatvmc.com.  Their Tusk products are inexpensive and seem to be a good quality. I can at least vouch for the Tusk chain breaker and the press tool. I haven't gotten anything Tusk that I haven't been impressed with especially for the price. 

[ontheroad68]

Following, as I am considering a 462 build myself. My question: if you go +4 on the crank what do you do to + that and keep the CR correct? Meaning, do you ad a 4mm spacer at the base of the cylinder? or do they make "stroker pistons" with the pin in a different location?

 

Also, if you're going to split the case, ad those ACT gears, you won't regret it.

[Atolduso]

On 2017-09-15 at 5:46 AM, 74jimbo said:

never heard of engine dynamics, but will look into them. I do like they are in the bay area, but as you know, that menas they will just charge 3x everyone else, because hte bay area is expensive....

 

tim, eventually, I will upgrade the carb, but right now, it isn't going to happen.... already pinching pennies to get this back and running, and larger jets will be just fine for now

I used to think this too but I learned from here big bores and strokers often need smaller jets because there is more vacuum, just fyi. 

Edited September 19, 2017 by Atolduso

[74jimbo]

40 minutes ago, Atolduso said:

I used to think this too but I learned from here big bores and strokers often need smaller jets because there is more vacuum, just fyi. 

then the mikuni will be just fine ? it's already smaller.. I will get a different carb eventually, jsut wont have it to start with, sure, it wont e ideal, but it wont hurt it either....

 

looks like it motion pro, tusk, and pit posse are decent tools

[74jimbo]

so..... how is this stuff?

 

https://www.amazon.com/Crank-Splitter-Separator-Puller-Installer/dp/B00PNWAW26/ref=pd_lutyp_simh_1_2?_encoding=UTF8&pd_rd_i=B00PNWAW26&pd_rd_r=CEB58VKBRZN9XF03K2KY&pd_rd_w=1PrhZ&pd_rd_wg=cT4DM&psc=1&refRID=CEB58VKBRZN9XF03K2KY

 

https://www.amazon.com/Tusk-L35-471-Clutch-Holding-Tool/dp/B0039LEZFS/ref=pd_bxgy_263_img_2?_encoding=UTF8&pd_rd_i=B0039LEZFS&pd_rd_r=JHWS1Z8519G5DGYZ63PQ&pd_rd_w=pl9Tq&pd_rd_wg=k2oXA&psc=1&refRID=JHWS1Z8519G5DGYZ63PQ&dpID=31d%2BrNj5EfL&preST=_SY300_QL70_&dpSrc=detail

[ontheroad68]

I think you will also need a generator rotor puller