15 replies to this topic

[wilsonwash8]

The Wiseco page shows pistons for the XR 200 in 65.5mm with over bores at 66, 66.5, and 67mm. What's the standard bore of the TLR 200? I've located a local who can resleeve my TLR to standard, but am curious about the Wiseco.

[Brian R]

Yep, stock bore is 65.5 stroke is 57.
Compession ratio is 9:1 and the XR is 10:1 though.
I'm not sure but check out an early ATC 200. Before
the electric start they started with a pull rope and had
fairly low compression. Somewhere around 8.5: 1 if
I remember right.

[wilsonwash8]

hEY bRIAN,

pLAYING "WHAT IF": iF THE BOOST IN COMPRESSION WAS NOT ADVISABLE FOR THE TLR APPLICATION, WHAT WOULD HAPPEN WITH MAYBE AND ADDITIONAL HEAD GASET OR EVEN A BASE GASKET? WOULD THAT BE ENOUGH TO LOWER THE COMPRESSION? sHOULDN'T AFFECT THE CAM CHAIN TOO MUCH. wHAT OTHER PROBLEMS WOULD i ENCOUNTER? TIMING? UNSURE AS ALWAYS! I'LL LOOK INTO THE ATC, THOUGH.

[Brian R]

Use this handy compression ratio calculator
http://www.csgnetwor...m/compcalc.html
I wouldn't be afraid of the XR piston with a thicker
base gasket.
I have a small laser and I make my own gaskets.
It allows me to use thicker gasket material and it's
cheaper than Honda.

Banging an the calculator some it looks like
.031" thicker than stock gasket would lower
compression from 10:1 to 9:1

[wilsonwash8]

I did some research and hit paydirt, or so it seems: I found this comparison and further along in the article it mentions that both the TLR and XR use a flat dome piston. I think I'm going to take a gambe and get one in one over size.

CB100N
XL125S
XL185S
XR185A$
XR200
TLR200R
CRF230F#

Bore
50.5
56.5
63
63
65.5
65.5
65.5

Stroke
49.6
49.5
57.8
57.8
57.8
57.8
66.2

Capacity
99.35
124.11
180.18
180.18
194.76
194.76
223.06

Wrist Pin, mm
15
15
15
15
15
15
15

CR
9
9.4
9.2
10
10
9
9

Power,

bhp/rpm

9.7

9500
14.3

8000
18

9000
19

9000
11.8

6500


Torque,

lb-ft

7.09

8000
10.34

6500
11.49

7500
11.5l

7500
11.6

4000


Carb Diameter
22
22
22
24
26
22
28

[wilsonwash8]

I went ahead and ordered the Wiseco. Should arrive in a day or two. I have a stock piston laying about, so I'll give it a look see right away and let y'all know if it's a match. Worse case is I have a 30 day trial to send it back if it's a no-go. Best case is I lose the smoking and piston slap and know that there are pistons available!

[muddytires]

I just got a wiseco piston for my tlr200 about a month ago. I had it bored to the next size up (66mm).
I was also unsure it would work as the new piston has a slightly raised head but the valve cut outs were big.
This past weekend i got to ride it for the first time. At first the motor was making a knocking noise under load ( going up a steep hill). Found out that i had to use a higher octane gas(97) , which solved the problem.
the bike sputtered at mid to high rpms, so i put a small washer under the needle as someone suggested ( there is no needle groove adjustment on my carb); that solved the mid rpms. Now i just need to get a larger main jet for the carb to solve the high rpm range.

So the Wiseco piston works good you just have to adjust the stock carb to run better with the higher compression. I tried to measure the compression but had trouble calculating the wiseco piston head volume, so i dont know for sure what it ended up being.

[Brian R]

Wilson,
what county are you in?

[wilsonwash8]

I'm right up I 65 from you in Bloomington, Ind. and I've been know to pester Bob Ginder thru B&J for parts and at the AHRMA trials for help!

I have also been trying to find an adjustable needle for the bike. Someone suggested an older SL/XL 125 needle would work. How does the washer work? I'm assuming that it just works as a spacer to raise it? I have a freind who is is a machinst. I wonder if the needle could be modified to accept a clip.

[Brian R]

Let me do some measuring and I'll send you a thicker base gasket to
help on the compression.
Send me an e mail

Brian (at sign) metalmarkers.org

[mcman56]

What would be the disadvantage of increased compression?

The SL/XL 125 adjustable needle does work well in the Reflex. Larger main jets are available from Honda and are the same as an XR100. A slightly bigger pilot jet will eliminate the cough and die syndrome but is not readily available. Drilling with a #78 drill (0.016") will produce a jet close to a #40 (.40 mm = 0.0157"). Stock is #38 (.38 mm = .015)

[Brian R]

Less "tickover"
Off idle it would have more of a tendency to stall.
Add that along with the famous 4 stroke off idle
cough and BAM, that's a 5!

[muddytires]

I installed the small washer under the needle clip to raise it a mm or two, and just used the retainer as normal. I am still in the process of tuning it in as i need a bigger main as it sputters at high rpms. At idle and mid rpms it runs perfect, and i can blip the throttle with no hesitation. I noticed that in the Parts unlimited online Catalogue the have many different size jets for the KJ series carbs. $2.50 a piece.

[Brian R]

New base gasket is on it's way.
Looks like it's about .025" thicker than stock before it's squished.
It should lower it by about a half point at least.

[wilsonwash8]

Thanks! What do I owe you? Glad to send some $$ right away, or I have a few spares from various bikes - RL 250, TY 250... anything you need?